57 results on '"Chaudhari AK"'
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2. Capture and immobilisation of iodine utilising polymer-based ZIF-8 nanocomposite membranes
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Mahdi, EM, Chaudhari, AK, and Tan, JC
- Abstract
Polymer nanocomposites made up of nanoporous metal–organic frameworks (MOFs) are fast becoming a staple of next generation hybrid composites, and are currently being intensely developed for gas capture and separation. This work reports the first attempt to capture and retain iodine (I2) using polymer-MOF (ZIF-8) nanocomposites. Membranes of ZIF-8-based nanocomposites (comprising either a glassy Matrimid or a rubbery polyurethane (PU) matrix) were preparedviaa colloidal-mixing approach and their viability for I2 capture and retention effects was determined through absorption experiments, nanoindentation mechanical measurements, and thermogravimetric (TGA) analysis. The absorption experiments demonstrated that I2capture and retention is possible in all of the nanocomposite membranes, although the PU/ZIF-8 30 wt% nanocomposite exhibited higher affinity for I2absorption (>32 wt%). It is reasoned that the molecular affinity and attraction between I2, (2-methylimidazolate organic ligands of) ZIF-8 nanoparticles, and polymer matrices (Matrimid and PU) will catalyse the formation of weak secondary bonds, resulting in the‘capture’ and‘retention’ of I2within molecular segments of the polymers and inside the pores of ZIF-8. The enhancement of the Young's modulus (E) of the PU/ZIF-8 30 wt% nanocomposite (Eincreased by ∼6%) is postulated to be due to I2rigidification, while TGA analysis proved that I2retention within both free volume of the polymer and ZIF-8 sodalite cages remained intact up till the points of structural degradation, at ∼200°C for the PU-based nanocomposites, and at∼300°C for the Matrimid-based nanocomposites. We propose that the affinity of the organic ligands in ZIF-8 and the formation of free volume in the nanocomposites from the presence of ZIF-8 attracted I2, and the formation of secondary bonds between these constituents (H-bonds) strengthened not only the nanocomposite, but also kept I2from being released despite the larger pore size and gate-opening dynamics of ZIF-8. It was therefore concluded that a combination of nanoparticles of porous MOFs and a rubbery polymer is promising for further development to enable I2 capture and retention applications.
- Published
- 2016
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3. Efficacy of Pogostemon cablin essential oil loaded chitosan nanoemulsion as novel coating agent for inhibition of potato sprouting and maintenance of storage quality.
- Author
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Das S and Chaudhari AK
- Subjects
- Food Preservation methods, Chitosan chemistry, Chitosan pharmacology, Solanum tuberosum chemistry, Emulsions chemistry, Oils, Volatile chemistry, Oils, Volatile pharmacology, Food Storage, Plant Tubers chemistry, Pogostemon chemistry
- Abstract
Application of synthetic compounds to inhibit potato sprouting is a major challenge in the storage conditions. The replacement of synthetic compounds by essential oils for inhibition of potato sprouting is of current research hotspot. This is the first time investigation on encapsulation of Pogostemon cablin essential oil into chitosan nanoemulsion (Ne-PCEO) and its application as coating agent for anti-sprouting activity of potato tubers. The Ne-PCEO was characterized through SEM, DLS, FTIR, and XRD assay along with controlled delivery of PCEO. The Ne-PCEO coating inhibited in-vivo potato sprouting and regulated gibberellins (GA
3 ) and aminocyclopropane-1-carboxylate (ACC) content along with impediment of respiration rate over 90 days of storage at 25 ± 2 °C (RH ∼ 70 %). The Ne-PCEO coating also prevented the weight loss, starch degradation, and increased the reducing sugar content of tubers without affecting the sensory qualities (p < 0.05), which strongly recommends its potential application as novel anti-sprouting coating agent for maintenance of potato storage quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2025
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4. An Unusual Case of Esophageal Perforation Following C5-C7 Anterior Cervical Corpectomy and Fusion Managed Surgically With Esophageal Repair and Long-Segment Cervical Fusion.
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Pisal T, Gurnani S, and Chaudhari AK
- Abstract
Anterior cervical corpectomy and fusion (ACCF) is frequently the surgical management for myelopathy, radiculopathy, and cervical spine trauma. Although esophageal perforation is an uncommon complication, it remains a serious concern. This report details the case of a 50-year-old female who underwent a C6 corpectomy with C5-C7 ACCF due to degenerative pathology and subsequently developed an esophageal perforation that required revision surgery and surgical repair of the perforated esophagus. A comprehensive review for surgically managing esophageal perforation following cervical spine surgery is essential for intensivists to improve postoperative airway management strategies., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Pisal et al.)
- Published
- 2024
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5. Non-pharmacological Methods of Deep Vein Thrombosis Prophylaxis in Orthopaedic Wards.
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Phalak MO, Chaudhari AK, and Gurnani S
- Abstract
Deep vein thrombosis (DVT) is a dreaded post-operative complication for surgeons and warrants prophylactic measures. The risk of DVT is significantly higher in almost any and all major surgery. The common prophylactic measures are pharmacological methods like subcutaneous low-molecular-weight heparin and oral anticoagulants. In some cases, these are contraindicated due to the risk of post-operative bleeding and wound soakage. In the editorial, we discuss the non-pharmacological methods of DVT prophylaxis in the form of basic physiotherapy. In our orthopaedic wards, we initiate basic physiotherapy like static hamstring, quadriceps exercises and ankle pumps. These exercises work by preventing the pooling of blood in the lower limbs, thereby hypothesized to prevent DVT. We have been implementing this method in all patients; hence, it has a universal application. It is cost-effective and does not have any adverse reactions. However, its use has some limitations, such as in patients with lower limb ankle fractures, polytrauma patients who are intubated, spinal cord injury patients with power loss and patients with neurological injury, although this cohort is a smaller fraction of the patients undergoing orthopaedic surgical intervention. In our experience, this method is an excellent non-pharmacological method of DVT prophylaxis which is easy to implement, is universally applicable, does not require any major special instrumentation or infrastructure and is cost-effective for the patient as well as the hospital., Competing Interests: Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Phalak et al.)
- Published
- 2024
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6. Dr. John H. Charnley: An Architect and Pioneer of the Modern Era of Hip Replacement Surgery.
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Phalak MO, Chaudhari AK, Chaudhari T, and Birajdar A
- Abstract
Dr. John H. Charnley (1924-1982) revolutionized orthopedic surgery with his groundbreaking innovations in hip replacement with exceptional skill and a holistic thought process, which has had an impact to this day in the world of arthroplasty. His innovations have improved the lives of numerous patients who had painful and discomforting arthritis and have been instrumental in providing painless mobile joints to these patients. This article reviews Charnley's contributions to the development of low-friction arthroplasty using ultra-high-molecular-weight polyethylene and the use of acrylic bone cement for improved implant fixation. These advancements dealt with the critical issues of friction, wear, and implant stability, significantly enhancing patient outcomes and implant longevity. Charnley's work led to the global standardization of hip replacement procedures, influencing orthopedic practices globally and setting benchmarks for modern implant designs. His principles continue to inform ongoing research and advancements in hip replacement technology. This review also discusses the challenges and criticisms faced by Charnley's innovations, reflecting on their evolution and impact on contemporary orthopedic surgery. A surgeon blessed with a noble heart who would help his patients who were in trouble by going out of the way and was determined for a better tomorrow, self-driven by his compassion and ambition for treating his patients. Charnley's legacy remains pivotal in shaping the field and improving the quality of life for patients undergoing hip replacement surgery., Competing Interests: Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Phalak et al.)
- Published
- 2024
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7. A Rare Case of a Bilateral Olecranon Fracture in a Young Adult With a Two-Year Follow-Up.
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Nair A, Phalak MO, and Chaudhari AK
- Abstract
Olecranon fractures are common in orthopedic wards and can be traumatic or pathological in origin. There are very few cases of bilateral olecranon fractures without any associated injuries to the long bones in the literature. We present a unique case of a young 21-year-old male who has an isolated bilateral olecranon fracture following a road traffic accident. The patient had a closed fracture of the ulna on both sides without any associated injuries or neurovascular compromise. Since the patient was young and had good muscle strength preoperatively, we planned fixation of both sides. The patient underwent open reduction and internal fixation with tension band wiring on the right side, which was his dominant side. The left side was operated on by open reduction and internal fixation with an anatomical plate. The patient was started on elbow range of motion on the right side from the second
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- 2024
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8. Bipolar Hemiarthroplasty With a Calcar Stem for the Management of a Failed Proximal Femoral Nail Anti-rotation Asia (PFNA2) in a Case of Geriatric Unstable Intertrochanteric Femur Fracture.
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Phalak MO, Chaudhari T, and Chaudhari AK
- Abstract
Intertrochanteric (IT) femur fractures in the elderly population comprise a major part of geriatric trauma and fractures. There are various modalities of surgical management, ranging from intramedullary fixation and extramedullary fixation to even replacing the hip joint. Apart from the surgeon's choice, other factors, such as geriatric age, bone quality and osteoporosis, medical comorbidities, life expectancy, pre-operative ambulatory status, muscle strength, type and pattern of fracture, and mental health of the patient, play vital roles in determining the ideal modality of management and the long-term outcome. The present case is a 75-year-old lady who had an IT fracture due to a domestic fall, managed surgically with a proximal femoral nail anti-rotation Asia (PFNA2) for an unstable fracture. She presented with blade back-out on the 11th day postoperatively. The patient was investigated thoroughly, and infection was ruled out. She was managed by the removal of the nail, followed by a cemented calcar-replacing bipolar hemiarthroplasty for an unstable comminuted IT fracture. The patient was ambulatory with a walker by the seventh postoperative day and without a walker by the sixth week, and she was self-sufficient in her activities of daily living. Every geriatric IT fracture must be evaluated thoroughly for contributing factors, such as osteoporosis and fracture pattern, to predict outcomes, and a tailor-made strategy of surgical management and stepwise physiotherapy must be provided to the patient for the best results., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Phalak et al.)
- Published
- 2024
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9. Cemented Bipolar Hemiarthroplasty as a Treatment Modality for Pathological Fracture in the Proximal Femur Metastasis Without the Recurrence of Primary Breast Cancer: A Case Report.
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Chaudhari T, Phalak MO, and Chaudhari AK
- Abstract
Metastatic lesions in the proximal femur are well-known in the literature and are important since they can progress to pathological fractures and impair the patient's mobility. We present the case of a middle-aged female with a history of breast carcinoma 20 years ago, who experienced diffuse chronic hip pain for the past two months. Radiographs, MRI, and PET scans revealed a metastatic lesion in her proximal femur. After consulting with an oncologist, it was determined that adjuvant chemoradiotherapy was unnecessary. The treatment strategy was dependent on the preoperative general health condition, the life expectancy, amount of metastasis, bone quality, pathological fractures and factors affecting the union and capacity to ambulate the patient postoperatively. The patient underwent a cemented bipolar hemiarthroplasty to excise all metastatic tissue and provide a painless, functional, and mobile joint. Bipolar hemiarthroplasties articulate at two levels, and this dual-bearing design is believed to reduce acetabular wear. The bipolar hemiarthroplasty also eliminated the risk of complications associated with the acetabular component, which would necessitate early revision surgery. Modular bipolar hemiarthroplasty is a good modality of replacement associated with fewer complications and improves quality of life., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Chaudhari et al.)
- Published
- 2024
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10. Chitosan nanoemulsion incorporated with Carum carvi essential oil as ecofriendly alternative for mitigation of aflatoxin B 1 contamination in stored herbal raw materials.
- Author
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Das S, Maurya A, Singh VK, Chaudhari AK, Singh BK, Dwivedy AK, and Dubey NK
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- Animals, Mice, Food Contamination prevention & control, Antioxidants pharmacology, Antioxidants chemistry, Aflatoxin B1, Chitosan chemistry, Oils, Volatile pharmacology, Oils, Volatile chemistry, Emulsions chemistry, Carum chemistry, Aspergillus flavus drug effects, Antifungal Agents pharmacology, Antifungal Agents chemistry
- Abstract
The present investigation entails the first report on entrapment of Carum carvi essential oil (CCEO) into chitosan polymer matrix for protection of stored herbal raw materials against fungal inhabitation and aflatoxin B
1 (AFB1 ) production. Physico-chemical characterization of nanoencapsulated CCEO was performed through Fourier transform infrared spectroscopy, dynamic light scattering, X-ray diffractometry, and scanning electron microscopy. The nanoencapsulated CCEO displayed improved antifungal and AFB1 suppressing potentiality along with controlled delivery over unencapsulated CCEO. The encapsulated CCEO nanoemulsion obstructed the ergosterol production and escalated the efflux of cellular ions, thereby suggesting plasma membrane as prime target of antifungal action in Aspergillus flavus cells. The impairment in methyglyoxal production and modeling based carvone interaction with Afl-R protein validated the antiaflatoxigenic mechanism of action. In addition, CCEO displayed augmentation in antioxidant potentiality after encapsulation into chitosan nanomatrix. Moreover, the in-situ study demonstrated the effective protection of Withania somnifera root samples (model herbal raw material) against fungal infestation and AFB1 contamination along with prevention of lipid peroxidation. The acceptable organoleptic qualities of W. somnifera root samples and favorable safety profile in mice (animal model) strengthen the application of nanoencapsulated CCEO emulsion as nano-fungitoxicant for preservation of herbal raw materials against fungi and AFB1 mediated biodeterioration., Competing Interests: Declaration of competing interest The authors declare no conflicts of financial and competing interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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11. Encapsulation of Apium graveolens essential oil into chitosan nanobiopolymer for protection of stored rice against Fusarium verticill i oides and fumonisins contamination.
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Das S and Chaudhari AK
- Abstract
The present investigation entails the encapsulation of Apium graveolens essential oil into chitosan nanobiopolymer (AGEO-Ne) and assessment of its efficacy against Fusarium verticill i oides contamination and fumonisins biosynthesis in stored rice ( Oryza sativa L.) samples. The AGEO was encapsulated through ionic gelation process and characterized by scanning electron microscopy (SEM), Dynamic light scattering (DLS), X-ray diffractometry (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses. The AGEO exhibited bi-phasic delivery pattern from chitosan matrix. The AGEO caused complete inhibition of F. verticill i oides growth at 1.2 μL/mL, while fumonisin B
1 (FB1 ) and B2 (FB2 ) biosynthesis at 1.2 and 1.0 μL/mL, respectively. On the other hand, nanoencapsulated AGEO (AGEO-Ne) exhibited improved efficacy, caused complete inhibition of fungal growth at 0.8 μL/mL, and FB1 and FB2 production at 0.8 and 0.6 μL/mL, respectively. AGEO-Ne caused 100 % inhibition of ergosterol synthesis at 0.8 μL/mL and exhibited greater efflux of Ca2+ , Mg2+ , K+ ions (18.99, 21.63, and 25.38 mg/L) as well as 260 and 280 nm absorbing materials from exposed fungal cells. The in silico interaction of granyl acetate and linalyl acetate with FUM 21 protein validated the molecular mechanism for inhibition of FB1 and FB2 biosynthesis. Further, improvement in antioxidant activity of AGEO-Ne was observed after encapsulation with IC50 values of 12.08 and 6.40 μL/mL against DPPH and ABTS radicals, respectively. During in situ investigation, AGEO caused 82.09 and 86.32 % protection of rice against F. verticill i oides contamination in inoculated and uninoculated rice samples, respectively, while AGEO-Ne exhibited 100 % protection of fumigated rice samples against F. verticill i oides proliferation as well as FB1 and FB2 contamination. The AGEO-Ne also caused better retardation of lipid peroxidation (41.35 and 37.52 μM/g FW malondialdehyde in inoculated and uninoculated treatment) and acceptable organoleptic properties in rice samples, which strengthen its application as plant based novel preservative in food and agricultural industries., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)- Published
- 2024
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12. Encapsulation of carvone in chitosan nanoemulsion as edible film for preservation of slice breads against Aspergillus flavus contamination and aflatoxin B 1 production.
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Das S, Chaudhari AK, Singh VK, Dwivedy AK, and Dubey NK
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- Aspergillus flavus, Aflatoxin B1 analysis, Bread, Antifungal Agents pharmacology, Chitosan pharmacology, Edible Films, Oils, Volatile pharmacology
- Abstract
Aspergillus flavus is a common fungus causing bread spoilage by aflatoxin B
1 (AFB1 ) production. Essential oil components are considered as effective antifungal agent; however, volatility and oxidative-instability limited their practical applications. The aim of this study was to fabricate novel chitosan nanoemulsion film incorporating carvone (carvone-Ne) for protection of bread slices against A. flavus and AFB1 contamination in storage conditions. The nanoemulsion was characterized by SEM, DLS, XRD, and FTIR analyses accompanying with sustained delivery of carvone. The carvone-Ne displayed better inhibition of A. flavus (0.5 µL/mL) and AFB1 production (0.4 µL/mL) over unencapsulated carvone along with promising antioxidant activity (p < 0.05). Destruction of ergosterol, mitochondrial-membrane-potential, ions leakage, deformities in methylglyoxal biosynthesis, and in-silico interaction of carvone with Afl-R protein emphasized the antifungal and antiaflatoxigenic mechanisms of action. Further, in-situ preservation potentiality of Carvone-Ne in bread slices with improved gas compositions, and acceptable sensory qualities strengthen its application as innovative packaging material for food preservation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)- Published
- 2024
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13. Application of chitosan and other biopolymers based edible coatings containing essential oils as green and innovative strategy for preservation of perishable food products: A review.
- Author
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Chaudhari AK, Das S, Dwivedi A, and Dubey NK
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- Food Preservatives pharmacology, Food Preservatives chemistry, Food Preservation, Food Packaging, Biopolymers pharmacology, Oils, Volatile pharmacology, Oils, Volatile chemistry, Edible Films, Chitosan pharmacology, Chitosan chemistry
- Abstract
Deterioration of perishable foods due to fungal contamination and lipid peroxidation are the most threatened concern to food industry. Different chemical preservatives have been used to overcome these constrains; however their repetitive use has been cautioned owing to their negative impact after consumption. Therefore, attention has been paid to essential oils (EOs) because of their natural origin and proven antifungal and antioxidant activities. Many EO-based formulations have been in use but their industrial-scale application is still limited, possibly due to its poor solubility, vulnerability towards oxidation, and aroma effect on treated foods. In this sense, active food packaging using biopolymers could be considered as promising approach. The biopolymers can enhance the stability and effectiveness of EOs through controlled release, thus minimizes the deterioration of foods caused by fungal pathogens and oxidation without compromising their sensory properties. This review gives a concise appraisal on latest advances in active food packaging, particularly developed from natural polymers (chitosan, cellulose, cyclodextrins etc.), characteristics of biopolymers, and current status of EOs. Then, different packaging and their effectiveness against fungal pathogens, lipid-oxidation, and sensory properties with recent previous works has been discussed. Finally, effort was made to highlights their safety and commercialization aspects towards market solutions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)
- Published
- 2023
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14. Chitosan based encapsulation of Valeriana officinalis essential oil as edible coating for inhibition of fungi and aflatoxin B 1 contamination, nutritional quality improvement, and shelf life extension of Citrus sinensis fruits.
- Author
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Das S, Chaudhari AK, Singh VK, Dwivedy AK, and Dubey NK
- Subjects
- Aflatoxin B1 metabolism, Fruit chemistry, Quality Improvement, Fungi metabolism, Aspergillus flavus, Antifungal Agents pharmacology, Oils, Volatile chemistry, Chitosan chemistry, Citrus sinensis metabolism, Valerian metabolism, Citrus metabolism, Edible Films
- Abstract
In this study, a novel chitosan nanoemulsion coating embedded with Valeriana officinalis essential oil (Ne-VOEO) was synthesized in order to improve the postharvest quality of Citrus sinensis fruits against infesting fungi, and aflatoxin B
1 (AFB1 ) mediated nutritional deterioration. The developed nanoemulsion was characterized through SEM, FTIR, XRD, and DLS analyses. The nanoemulsion showed controlled delivery of VOEO responsible for effective inhibition of Aspergillus flavus, A. niger, A. versicolor, Penicillium italicum, and Fusarium oxysporum growth at 6.5, 5.0, 4.0, 5.5, and 3.5 μL/mL, respectively and AFB1 production at 5.0 μL/mL. The biochemical and molecular mechanism of aflatoxigenic A. flavus inhibition, and AFB1 diminution was associated with impairment in ergosterol biosynthesis, methylglyoxal production, and stereo-spatial binding of valerianol in the cavity of Ver-1 protein. During in vivo investigation, Ne-VOEO coating potentially restrained the weight loss, and respiratory rate of C. sinensis fruits with delayed degradation of soluble solids, titrable acidity, pH, and phenolic contents along with maintenance of SOD, CAT, APX activities (p < 0.05) and sensory attributes under specific storage conditions. Based on overall findings, Ne-VOEO nanoemulsion could be recommended as green, and smart antifungal coating agent in prolonging the shelf-life of stored fruits with enhanced AFB1 mitigation., Competing Interests: Declaration of competing interest The authors declare no conflict of interest. The design of the experiment through manuscript writing and the decision to publish the results has no role with financial assistance., (Copyright © 2023 Elsevier B.V. All rights reserved.)- Published
- 2023
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15. Green facile synthesis of cajuput (Melaleuca cajuputi Powell.) essential oil loaded chitosan film and evaluation of its effectiveness on shelf-life extension of white button mushroom.
- Author
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Chaudhari AK, Das S, Singh BK, and Kishore Dubey N
- Subjects
- Food Preservation methods, Antioxidants pharmacology, Life Expectancy, Oils, Volatile pharmacology, Oils, Volatile chemistry, Chitosan chemistry, Melaleuca, Agaricus chemistry
- Abstract
This study reports first time investigation on efficacy of cajuput essential oil loaded chitosan nanoparticle (CjEO-CSNP) on shelf-life of white button mushroom (Agaricus bisporus) stored at 4±1 °C for 7-days. CjEO-CSNP was characterized through scanning electron microscopy, X-ray diffraction, and dynamic light scattering. The nanoparticles exhibited spherical shapes with average particle size 43.17-97.03 nm. The nanoencapsulation efficiency and loading capacity were ranged between 45.86 and 92.26% and 0.69-8.87%, respectively. The release study confirmed that CjEO-CSNP showed biphasic release patterns at different pH. Positive results were unveiled when the effect of CjEO-CSNP on shelf-life of mushroom was validated by analyzing the visual appearance and firmness. Further, CjEO-CSNP prevented weight loss and respiration rate, and improved the antioxidant activity of mushrooms. CjEO-CSNP also exhibited high safety profile (LD
50 = > 1200 mg/Kg body weight) without altering the sensory quality of coated mushrooms. Overall, CjEO-CSNP might be used as promising candidate to lengthen the shelf-life of button mushroom., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)- Published
- 2023
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16. High speed homogenization assisted encapsulation of synergistic essential oils formulation: Characterization, in vitro release study, safety profile, and efficacy towards mitigation of aflatoxin B 1 induced deterioration in rice samples.
- Author
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Das S, Chaudhari AK, Singh VK, Singh BK, and Dubey NK
- Subjects
- Animals, Antifungal Agents pharmacology, Antioxidants pharmacology, Ergosterol pharmacology, Fatty Acids metabolism, Pyruvaldehyde pharmacology, Aflatoxin B1 chemistry, Aflatoxin B1 toxicity, Chitosan pharmacology, Oils, Volatile chemical synthesis, Oils, Volatile chemistry, Oryza microbiology, Oryza toxicity, Food Contamination prevention & control, Fungi, Food Storage methods
- Abstract
Application of essential oils to mitigate aflatoxin B
1 (AFB1 ) contamination in food is a current research hotspot; however, their direct incorporation may cause toxic effects, and changes in food organoleptic properties. This work aimed to synthesize novel synergistic formulation of Pinus roxburghii, Juniperus communis, and Cupressus sempervirens essential oils by mixture design assay (PJC) and encapsulation of PJC formulation into chitosan nanocomposite (Nm-PJC) with an aim to protect stored rice (Oryza sativa L., prime staple food) against fungi and AFB1 mediated loss of valuable minerals, macronutrients, and fatty acids. Nm-PJC was characterized through DLS, SEM, FTIR, and XRD analyses, along with controlled delivery from chitosan nanobiopolymer. Encapsulation of synergistic formulation into chitosan-nanomatrix improved antifungal (4.0 μL/mL), antiaflatoxigenic (3.5 μL/mL), and antioxidant activities (P < 0.05). Impairment in ergosterol and methylglyoxal biosynthesis along with in-silico-homology-modeling of major components with Ver-1 and Omt-A proteins advocated chemico-molecular interaction responsible for fungal growth inhibition and AFB1 secretion. In addition, in-situ efficacy against lipid-peroxidation, fatty acid biodeterioration, and preservation of minerals, macronutrients without affecting organoleptic attributes in rice and high mammalian safety profile (9874.23 μL/kg) suggested practical application of synergistic nanoformulation as innovative smart, and green candidate to mitigate AFB1 contamination, and shelf-life extension of stored food products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)- Published
- 2022
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17. Preparation and characterization of a novel nanoemulsion consisting of chitosan and Cinnamomum tamala essential oil and its effect on shelf-life lengthening of stored millets.
- Author
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Singh BK, Chaudhari AK, Das S, Tiwari S, and Dubey NK
- Subjects
- Aflatoxin B1 metabolism, Antifungal Agents chemistry, Antifungal Agents pharmacology, Delayed-Action Preparations, Edible Grain, Ergosterol, Food Preservatives chemistry, Food Preservatives pharmacology, Free Radicals, Millets metabolism, Pyruvaldehyde, Chitosan chemistry, Chitosan pharmacology, Cinnamomum metabolism, Oils, Volatile chemistry, Oils, Volatile pharmacology
- Abstract
This study aimed to improve the stability of Cinnamomum tamala essential oil (CTEO) via encapsulating into chitosan nanoemulsion (CsNe) through an ionic-gelation technique and explore its food preservative efficacy against aflatoxigenic strain of Aspergillus flavus (AFLHPSi-1, isolated from stored millet), aflatoxin B
1 (AFB1 ) contamination, and lipid peroxidation, causing qualitative deterioration of stored millets. The CTEO was characterized through gas chromatography-mass spectrometry (GC-MS) analysis that confirmed the presence of linalool as a major component occupying approximately 82.64% of the total oil. The synthesized nanoparticles were characterized through scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) analysis. The encapsulation efficiency (EE) and loading capacity (LC) of CTEO-CsNe were found to be 97.71% and 3.33%, respectively. In vitro release study showed a biphasic release pattern: with an initial burst release followed by a controlled release of CTEO. During investigation of efficacy, the CTEO-CsNe caused complete inhibition of A. flavus growth, and AFB1 biosynthesis at 1.0 and 0.8 μL/mL, respectively. The CTEO-CsNe exhibited its antifungal mode of action by altering fungal plasma membrane integrity (ergosterol inhibition) and permeability (leakage of important cellular constituents), and antiaflatoxigenic mode of action by inhibiting cellular methylglyoxal biosynthesis. CTEO-CsNe showed high free radical scavenging capacity (IC50 = 5.08 and 2.56 μL/mL) against DPPH•+ and ABTS•+ radicals, respectively. In addition, CTEO-CsNe presented remarkable preservative efficacy, inhibiting AFB1 and lipid peroxidation in model food system (Setaria italica) without altering their organoleptic properties. Based on overall results, CTEO-CsNe can be recommended as a novel shelf-life enhancer of stored millet samples., Competing Interests: Declaration of Competing Interest The authors reports that they have no known conflicts of interest., (Copyright © 2022 Elsevier Inc. All rights reserved.)- Published
- 2022
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18. Mechanistic investigations on antifungal and antiaflatoxigenic activities of chemically characterised Carum carvi L. essential oil against fungal infestation and aflatoxin contamination of herbal raw materials.
- Author
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Maurya A, Kumar S, Singh BK, Chaudhari AK, Dwivedy AK, Prakash B, and Dubey NK
- Subjects
- Aflatoxin B1, Antifungal Agents pharmacology, Aspergillus flavus, Aflatoxins, Carum, Oils, Volatile pharmacology
- Abstract
This study aimed to investigate the efficiency of chemically characterised Carum carvi essential oil (CcEO) against aflatoxin B
1 (AFB1 ) producing strain of Aspergillus flavus (AF-LHP-WS-4) causing deterioration of herbal raw materials (HRM). GC-MS analysis of the EO revealed the presence of carvone (69.85%) as a dominant component. CcEO caused complete suppression of A . flavus growth and AFB1 secretion at 0.7 and 0.6 µL/mL, respectively. The investigation on antifungal mode of action showed that CcEO inhibited fungal growth via abrogating ergosterol biosynthesis and triggered efflux of vital cellular ions. The inhibition of AFB1 biosynthesis was attributed to the inhibition of cellular methylglyoxal (MG) biosynthesis. In addition, CcEO showed remarkable antioxidant activity (IC50 = 10.564 µL/mL) against DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals. Based on overall results, it can be concluded that the CcEO may be recommended as potential antifungal agent for protection of HRM from fungal infestation and AFB1 contamination.- Published
- 2022
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19. Chitosan encompassed Aniba rosaeodora essential oil as innovative green candidate for antifungal and antiaflatoxigenic activity in millets with emphasis on cellular and its mode of action.
- Author
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Singh BK, Chaudhari AK, Das S, Tiwari S, Maurya A, Singh VK, and Dubey NK
- Abstract
The present study demonstrates first time investigation on encapsulation of Aniba rosaeodora essential oil into chitosan nanoemulsion (AREO-CsNe) with the aim of improvement of its antifungal, and aflatoxin B
1 (AFB1 ) inhibitory performance in real food system. The GC-MS analysis of AREO revealed the presence of linalool (81.46%) as a major component. The successful encapsulation of EO into CsNe was confirmed through SEM, FTIR, and XRD analysis. The in-vitro release study showed the controlled release of AREO. AREO-CsNe caused complete inhibition of Aspergillus flavus (AFLHPSi-1) growth and AFB1 production at 0.8 and 0.6 μl/ml, respectively, which was far better than AREO (1.4 and 1.2 μl/ml, respectively). Impairment of ergosterol biosynthesis coupled with enhancement of cellular materials leakage confirmed plasma membrane as the possible antifungal target of both AREO and AREO-CsNe. Significant inhibition of methylglyoxal (AFB1 inducer) synthesis in AFLHPSi-1 cells by AREO and AREO-CsNe confirmed their novel antiaflatoxigenic mode of action. In-silico molecular docking studies revealed effective interaction of linalool with Ver-1 and Omt-A proteins, leading to inhibition of AFB1 biosynthesis. Further, AREO-CsNe showed enhanced antioxidant activity with IC50 values 3.792 and 1.706 μl/ml against DPPH• and ABTS•+ radicals, respectively. In addition, AREO-CsNe caused 100% protection of stored millets ( Setaria italica seeds) from AFB1 contamination and lipid peroxidation over a period of 1 year without compromising its sensory properties and exhibited high safety profile with LD50 value 9538.742 μl/kg body weight. Based on enhanced performance of AREO-CsNe over AREO, it can be recommended as a novel substitute of synthetic preservative for preservation of stored millets., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest, (Copyright © 2022 Singh, Chaudhari, Das, Tiwari, Maurya, Singh and Dubey.)- Published
- 2022
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20. Co-encapsulation of Pimpinella anisum and Coriandrum sativum essential oils based synergistic formulation through binary mixture: Physico-chemical characterization, appraisal of antifungal mechanism of action, and application as natural food preservative.
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Das S, Singh VK, Chaudhari AK, Deepika, Dwivedy AK, and Dubey NK
- Subjects
- Animals, Antifungal Agents chemistry, Antifungal Agents pharmacology, Food Preservatives chemistry, Mammals, Chitosan chemistry, Chitosan pharmacology, Coriandrum chemistry, Oils, Volatile chemistry, Oils, Volatile pharmacology, Pimpinella
- Abstract
The present study aimed to co-encapsulate binary synergistic formulation of Pimpinella anisum and Coriandrum sativum (PC) essential oils (0.75:0.25) into chitosan nanoemulsion (Nm-PC) with effective inhibition against fungal proliferation, aflatoxin B
1 (AFB1 ) secretion, and lipid peroxidation in stored rice. Physico-chemical characterization of Nm-PC by SEM, FTIR, and XRD confirmed successful encompassment of PC inside the chitosan nanomatrix with efficient interaction by functional groups and reduction in crystallinity. Nm-PC showed superior antifungal, antiaflatoxigenic, and antioxidant activities over unencapsulated PC. Reduction in ergosterol biosynthesis and enhanced leakage of Ca2+ , K+ , Mg2+ ions and 260, 280 nm absorbing materials by Nm-PC fumigation confirmed irreversible damage of plasma membrane in toxigenic Aspergillus flavus cells. Significant diminution of methylglyoxal in A. flavus cells by Nm-PC fumigation illustrated biochemical mechanism for antiaflatoxigenic activity, suggesting future exploitation for development of aflatoxin resistant rice varieties through green transgenic technology. In silico findings indicated specific stereo-spatial interaction of anethole and linalool with Nor-1 protein, validating molecular mechanism for AFB1 inhibition. In addition, in situ investigation revealed effective protection of stored rice against fungal occurrence, AFB1 biosynthesis, and lipid peroxidation without affecting organoleptic attributes. Moreover, mammalian non-toxicity of chitosan entrapped PC synergistic nanoformulation could provide exciting potential for application as eco-smart safe nano-green food preservative., (Copyright © 2022 Elsevier Inc. All rights reserved.)- Published
- 2022
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21. Immune responses against different variants of SARS-CoV-2 including Omicron following 6 months of administration of heterologous prime-boost COVID-19 vaccine.
- Author
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Sapkal G, Kant R, Dwivedi G, Sahay RR, Yadav PD, Deshpande GR, Singh R, Nyayanit DA, Patil DY, Shete-Aich AM, Zaman K, Chaudhari AK, Gupta N, Panda S, Abraham P, and Bhargava B
- Subjects
- Humans, Immunity, Immunization, Secondary, SARS-CoV-2, COVID-19 prevention & control, COVID-19 Vaccines
- Published
- 2022
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22. Assessing the Levisticum officinale Koch. essential oil as a novel preservative for stored chia seeds (Salvia hispanica L.) with emphasis on probable mechanism of action.
- Author
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Deepika, Chaudhari AK, Das S, Singh VK, Prasad J, and Dubey NK
- Subjects
- Antifungal Agents pharmacology, Aspergillus flavus, Salvia hispanica, Levisticum, Oils, Volatile pharmacology
- Abstract
The present study was undertaken to explore the inhibitory effect of Levisticum officinale Koch. essential oil (L
off EO) on the growth and aflatoxin B1 secretion by Aspergillus flavus (AF-LHP-SH1, aflatoxigenic strain) causing deterioration of stored chia seeds (Salvia hispanica). The chemical profile analysis of Loff EO by GC-MS analysis revealed the presence of α-terpinyl acetate (26.03 %) as a major component followed by terpineol <1- > (24.03 %) and citronellal (24.03 %). Results on antifungal and antiaflatoxigenic activity indicated that Loff EO at 2.0 and 1.75 μL/mL caused complete inhibition of growth and aflatoxin B1 production, respectively. Antifungal toxicity of Loff EO was strongly correlated with the inhibition of ergosterol content, leakage of cellular ions, and disintegration of membrane permeability. Reduction in cellular methylglyoxal by Loff EO indicated a novel antiaflatoxigenic mechanism of action. The Loff EO showed moderate free radical quenching activity in DPPH assay (IC50 = 26.10 μL/mL) and exhibited remarkable inhibitory efficacy against lipid peroxidation of chia seeds. In addition, Loff EO presented strong in situ antiaflatoxigenic efficacy, and exhibited non-phytotoxic nature, acceptable sensory characteristics, and favorable safety profile (LD50 = 19786.59 μL/kg), which recommends its practical utilization as a novel and safe preservative to improve the shelf life of stored chia seeds from fungal infestation and aflatoxin B1 contamination., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)- Published
- 2021
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23. Fabrication, physico-chemical characterization, and bioactivity evaluation of chitosan-linalool composite nano-matrix as innovative controlled release delivery system for food preservation.
- Author
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Das S, Singh VK, Chaudhari AK, Dwivedy AK, and Dubey NK
- Subjects
- Aflatoxin B1 pharmacology, Antifungal Agents pharmacology, Antioxidants pharmacology, Colloids chemistry, Delayed-Action Preparations pharmacology, Drug Liberation, Fungi drug effects, Lipid Peroxidation drug effects, Malondialdehyde metabolism, Microbial Sensitivity Tests, Microscopy, Atomic Force, Mycelium drug effects, Nanocomposites ultrastructure, Oryza microbiology, Particle Size, Spectroscopy, Fourier Transform Infrared, Static Electricity, Thermogravimetry, X-Ray Diffraction, Acyclic Monoterpenes pharmacology, Biocompatible Materials chemistry, Chemical Phenomena, Chitosan chemistry, Food Preservation, Nanocomposites chemistry
- Abstract
The aim of the present study was to encapsulate linalool into chitosan nanocomposite (Nm-linalool) for developing novel controlled release delivery system in order to protect stored rice against fungal infestation, aflatoxin B
1 (AFB1 ) contamination, and lipid peroxidation. The chitosan-linalool nanocomposite showed spherical shapes, smooth surface with monomodal distribution as revealed by SEM and AFM investigation. FTIR and XRD represented peak shifting and changes in degree of crystallinity after incorporation of linalool into chitosan nanocomposite. Nanoencapsulation of linalool showed higher zeta potential and lowered polydispersity index. TGA analysis reflected the stability of Nm-linalool with reduced weight loss at varying temperatures. Biphasic pattern, with initial rapid release followed by sustained release illustrated controlled delivery of linalool from chitosan nanocomposite, a prerequisite for shelf-life enhancement of stored food products. Chitosan nanocomposite incorporating linalool displayed prominent antifungal and antiaflatoxigenic activity during in vitro as well as in situ investigation in rice with improved antioxidant potentiality. Further, Nm-linalool displayed considerable reduction of lipid peroxidation in rice without exerting any adverse impact on organoleptic attributes. In conclusion, the investigation strengthens the application of chitosan-linalool nanocomposite as an innovative controlled nano-delivery system for its practical application as novel environmentally friendly eco-smart preservative in food and agricultural industries., (Copyright © 2021 Elsevier B.V. All rights reserved.)- Published
- 2021
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24. Essential oils and their bioactive compounds as eco-friendly novel green pesticides for management of storage insect pests: prospects and retrospects.
- Author
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Chaudhari AK, Singh VK, Kedia A, Das S, and Dubey NK
- Subjects
- Animals, Insecta, Insect Repellents, Insecticides, Oils, Volatile pharmacology, Pesticides
- Abstract
The control of storage insect pests is largely based on synthetic pesticides. However, due to fast growing resistance in the targeted insects, negative impact on humans and non-target organisms as well as the environment, there is an urgent need to search some safer alternatives of these xenobiotics. Many essential oils (EOs) and their bioactive compounds have received particular attention for application as botanical pesticides, since they exhibited high insecticidal efficacy, diverse mode of action, and favourable safety profiles on mammalian system as well as to the non-target organisms. Data collected from scientific articles show that these EOs and their bioactive compounds exhibited insecticidal activity via fumigant, contact, repellent, antifeedant, ovicidal, oviposition deterrent and larvicidal activity, and by inhibiting/altering important neurotransmitters such as acetylcholine esterase (AChE) and octopamine or neurotransmitter inhibitor γ-amino butyric acid (GABA), as well as by altering the enzymatic [superoxide dismutase (SOD), catalase (CAT), peroxidases (POx), glutathione-S-transferase (GST) and glutathione reductase (GR)] and non-enzymatic [glutathione (GSH)] antioxidant defence systems. However, in spite of promising pesticidal efficacy against storage pests, the practical application of EOs and their bioactive compounds in real food systems remain rather limited because of their high volatility, poor water solubility and susceptibility towards degradation. Nanoencapsulation/nanoemulsion of EOs is currently considered as a promising tool that improved water solubility, enhanced bio-efficacy, stability and controlled release, thereby expanding their applicability.
- Published
- 2021
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25. Eugenol loaded chitosan nanoemulsion for food protection and inhibition of Aflatoxin B 1 synthesizing genes based on molecular docking.
- Author
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Das S, Singh VK, Dwivedy AK, Chaudhari AK, Deepika, and Dubey NK
- Subjects
- Aflatoxin B1 chemistry, Aflatoxin B1 metabolism, Aflatoxin B1 toxicity, Anti-Infective Agents metabolism, Aspergillus flavus growth & development, Aspergillus flavus metabolism, Binding Sites, Drug Compounding methods, Drug Liberation, Edible Grain, Emulsions, Ergosterol antagonists & inhibitors, Ergosterol metabolism, Eugenol metabolism, Food Preservation methods, Fungal Proteins chemistry, Fungal Proteins metabolism, Humans, Kinetics, Molecular Docking Simulation, Nanostructures ultrastructure, Nutrients analysis, Oryza drug effects, Oryza microbiology, Protein Binding, Protein Conformation, alpha-Helical, Protein Conformation, beta-Strand, Pyruvaldehyde antagonists & inhibitors, Pyruvaldehyde metabolism, Triglycerides analysis, Aflatoxin B1 antagonists & inhibitors, Anti-Infective Agents pharmacology, Aspergillus flavus drug effects, Chitosan chemistry, Eugenol pharmacology, Fungal Proteins antagonists & inhibitors, Nanostructures chemistry
- Abstract
The present investigation entails the fabrication and characterization of nanometric emulsion of eugenol (Nm-eugenol) encompassed into chitosan for assessing bio-efficacy in terms of in vitro antifungal actions, antiaflatoxigenic potential, and in situ preservative efficacy against Aspergillus flavus infestation and aflatoxin B
1 (AFB1 ) mediated loss of dietary minerals, lipid triglycerides and alterations in composition of important macronutrients in stored rice. Nm-eugenol characterized by SEM, XRD, and FTIR exhibited biphasic burst release of eugenol. Reduction in ergosterol and methylglyoxal (AFB1 -inducer) content after Nm-eugenol fumigation depicted biochemical mechanism of antifungal and antiaflatoxigenic activities. In silico 3D homology docking of eugenol with Ver-1 gene validated molecular mechanism of AFB1 inhibition. Further, significant protection of rice seeds from fungi, AFB1 contamination and preservation against loss of rice minerals, macronutrients and lipids during storage suggested deployment of chitosan as a biocompatible wall material for eugenol encapsulation and application as novel green preservative for food protection., (Copyright © 2020 Elsevier Ltd. All rights reserved.)- Published
- 2021
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26. Nanoencapsulation of essential oils and their bioactive constituents: A novel strategy to control mycotoxin contamination in food system.
- Author
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Chaudhari AK, Singh VK, Das S, and Dubey NK
- Subjects
- Food Preservatives chemistry, Humans, Mycotoxins toxicity, Oils, Volatile chemistry, Food Contamination prevention & control, Food Preservatives pharmacology, Mycotoxins chemistry, Nanoparticles chemistry, Oils, Volatile pharmacology
- Abstract
Spoilage of food by mycotoxigenic fungi poses a serious risk to food security throughout the world. In view of the negative effects of synthetic preservatives, essential oils (EOs) and their bioactive constituents are gaining momentum as suitable substitute to ensure food safety by controlling mycotoxins. However, despite their proven preservative potential against mycotoxins, the use of EOs/bioactive constituents in real food system is still restricted due to instability caused by abiotic factors and negative impact on organoleptic attributes after direct application. Nanoencapsulation in this regard could be a promising approach to address these problems, since the process can increase the stability of EOs/bioactive constituents, barricades their loss and considerably prevent their interaction with food matrices, thus preserving their original organoleptic qualities. The aim of this review is to provide wider and up-to-date overview on recent advances in nanoencapsulation of EOs/bioactive constituents with the objective to control mycotoxin contamination in food system. Further, the information on polymer characteristics, nanoencapsulation techniques, factors affecting the nanoencapsulation, applications of nanoencapsulated formulations, and characterization along with the study on their release kinetics and impacts on organoleptic attributes of food are discussed. Finally, the safety aspects of nanoencapsulated formulations for their safe utilization are also explored., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2021
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27. Assessment of nanoencapsulated Cananga odorata essential oil in chitosan nanopolymer as a green approach to boost the antifungal, antioxidant and in situ efficacy.
- Author
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Upadhyay N, Singh VK, Dwivedy AK, Chaudhari AK, and Dubey NK
- Subjects
- Aflatoxin B1 metabolism, Antifungal Agents pharmacology, Antioxidants pharmacology, Aspergillus flavus metabolism, Drug Evaluation, Preclinical, Emulsions, Food Preservatives pharmacology, Gas Chromatography-Mass Spectrometry, Germination drug effects, Green Chemistry Technology, Inhibitory Concentration 50, Lipid Peroxidation drug effects, Microscopy, Electron, Scanning, Oils, Volatile pharmacology, Plant Oils pharmacology, Seeds drug effects, Spectroscopy, Fourier Transform Infrared, X-Ray Diffraction, Antifungal Agents administration & dosage, Antioxidants administration & dosage, Arachis microbiology, Aspergillus flavus drug effects, Cananga chemistry, Food Preservatives administration & dosage, Nanocapsules administration & dosage, Oils, Volatile administration & dosage, Plant Oils administration & dosage
- Abstract
In this study, a comparative efficacy of Cananga odorata EO (CoEO) and its nanoencapsulated formulation into chitosan nanoemulsion (CoEO-CsNe) against a toxigenic strain of Aspergillus flavus (AF-M-K5) were investigated for the first time in order to determine its efficacy in preservation of stored food from fungal, aflatoxin B
1 (AFB1 ) contamination and lipid peroxidation. GC and GC-MS analysis of CoEO revealed the presence of linalool (24.56%) and benzyl acetate (22.43%) as the major components. CoEO was encapsulated into chitosan nanoemulsion (CsNe) through ionic-gelation technique and characterized by High Resolution-Scanning Electron Microscopy (HR-SEM), Fourier Transform Infrared spectroscopy (FTIR), and X-Ray Diffraction (XRD) analysis. The CoEO-CsNe during in vitro investigation against A. flavus completely inhibited the growth and AFB1 production at 1.0 μL/mL and 0.75 μL/mL, respectively. Additionally, CoEO-CsNe showed improved antioxidant activity against DPPH• and ABTS•+ with IC50 value 0.93 and 0.72 μL/mL, respectively. Further, CoEO-CsNe suppressed fungal growth, AFB1 secretion and lipid peroxidation in Arachis hypogea L. during in situ investigation without causing any adverse effect on seed germination. Overall results demonstrated that the CoEO-CsNe has potential of being utilized as a suitable plant based antifungal agent to improve the shelf-life of stored food against AFB1 and lipid peroxidation mediated biodeterioration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)- Published
- 2021
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28. Zingiber zerumbet L. essential oil-based chitosan nanoemulsion as an efficient green preservative against fungi and aflatoxin B 1 contamination.
- Author
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Deepika, Singh A, Chaudhari AK, Das S, and Dubey NK
- Subjects
- Aflatoxin B1 toxicity, Animals, Antifungal Agents chemistry, Chitosan pharmacology, Emulsions, Food Preservatives pharmacology, Fungi drug effects, Green Chemistry Technology, Lipid Peroxidation drug effects, Mice, Nanostructures chemistry, Oils, Volatile chemistry, Plant Oils chemistry, Aflatoxin B1 chemistry, Antifungal Agents pharmacology, Chitosan chemistry, Oils, Volatile pharmacology, Plant Oils pharmacology, Zingiberaceae chemistry
- Abstract
The present study envisages the potential application of chitosan-coated Zingiber zerumbet essential oil nanoemulsion (ZEO-CsNE) as green antimicrobial preservative against Aspergillus flavus, aflatoxin B
1 (AFB1 ), and lipid peroxidation of stored functional foods. GC-MS analysis of ZEO exhibited the abundance of cis-geraniol (15.53%) as the major component. ZEO-CsNE showed biphasic release profile during in vitro release study conducted for 10 days. The ZEO-CsNE inhibited the growth of A. flavus (strain AF-LHP-SH1) and AFB1 production at 1.0 and 0.8 µL/mL, respectively. Interestingly, considerable reduction in ergosterol biosynthesis followed by enhanced leakage of vital cellular contents and methylglyoxal inhibition represents novel antifungal and antiaflatoxigenic mechanism of action, respectively. Further, ZEO-CsNE inhibited lipid peroxidation and AFB1 production in postharvest Salvia hispanica seeds during in situ trial and presented favorable safety profile (median lethal dose [LD50 ] = 29,114 µL/kg) for male mice. Based on overall observations, ZEO-CsNE could be recommended as a green antimicrobial substitute of synthetic preservatives for in vitro and in situ protection of functional food samples. PRACTICAL APPLICATION: Food industries are facing enormous amount of burden coming from fungal and aflatoxin contamination that can cause severe adverse effects to humans. Essential oils (EOs) are well known for their food preservative efficacy; however, some limitations such as oxidative instability in open system may limit their application directly into food system. The encapsulation of the EOs into polymeric matrix could provide a barrier that will protect the EOs from degradation. This research could provide a basis for utilization of EO after encapsulation into chitosan nanoemulsion for industrial-scale application for preservation of stored functional foods from fungal and aflatoxin contamination., (© 2020 Institute of Food Technologists®.)- Published
- 2021
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29. Improvement of in vitro and in situ antifungal, AFB 1 inhibitory and antioxidant activity of Origanum majorana L. essential oil through nanoemulsion and recommending as novel food preservative.
- Author
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Chaudhari AK, Singh VK, Das S, Deepika, Prasad J, Dwivedy AK, and Dubey NK
- Subjects
- Animals, Antifungal Agents chemistry, Antioxidants chemistry, Chitosan chemistry, Ergosterol, Food Preservatives chemistry, Food Preservatives pharmacology, Fungi drug effects, Lipid Peroxidation, Male, Mice, Nanostructures, Oils, Volatile chemistry, Oils, Volatile toxicity, Plant Oils chemistry, Plant Oils toxicity, Seeds microbiology, Toxicity Tests, Zea mays microbiology, Aflatoxin B1 antagonists & inhibitors, Antifungal Agents pharmacology, Antioxidants pharmacology, Oils, Volatile pharmacology, Origanum chemistry, Plant Oils pharmacology
- Abstract
Origanum majorana essential oil (OmEO) encapsulated into chitosan nanoemulsion is being reported as a novel preservative of stored food items against fungi, aflatoxin B
1 (AFB1 ) contamination and lipid peroxidation. The major component of OmEO identified through GC-MS was terpinen-4-ol (28.92%). HR-SEM, FTIR and XRD analyses confirmed successful encapsulation of OmEO into chitosan nanoemulsion (OmEO-CsNe). The results showed remarkable improvement in efficacy after nanoencapsulation, since OmEO-CsNe completely inhibited the growth and AFB1 production by Aspergillus flavus at 1.0 μL/mL, which was 2.5 and 1.5 μL/mL, respectively for OmEO. The inhibition of ergosterol followed by release of cellular ions and 260 and 280 nm absorbing materials demonstrated plasma membrane as possible antifungal target. Inhibition of methylglyoxal confirmed antiaflatoxigenic mode of action. OmEO-CsNe showed enhanced antioxidant activity (IC50 = 14.94 and 5.53 μL/mL for DPPH and ABTS, respectively) and caused in situ inhibition of lipid peroxidation and AFB1 production in maize (third most important staple crop after wheat and rice) without altering their sensory attributes and presented safety profile (LD50 = 11,889 μL/kg) when tested on mice. The findings indicate that the encapsulation considerably enhances the performance of OmEO, therefore can be recommended as a promising antifungal agent to extend the shelf-life of food items., (Copyright © 2020 Elsevier Ltd. All rights reserved.)- Published
- 2020
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30. Dye-Encapsulated Zeolitic Imidazolate Framework (ZIF-71) for Fluorochromic Sensing of Pressure, Temperature, and Volatile Solvents.
- Author
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Zhang Y, Gutiérrez M, Chaudhari AK, and Tan JC
- Abstract
Luminescent metal-organic frameworks (MOFs) offer a multifunctional platform for creating noninvasive sensors and tunable optoelectronics. However, fluorochromic materials that are photophysically resilient and show high sensitivity toward different physical and chemical stimuli are scarce. We report a facile host-guest nanoconfinement strategy to construct a fluorescent hybrid material with multiple sensing capabilities. We design and fabricate a new Guest@MOF material: comprising a zeolitic MOF (ZIF-71) as a nanoporous host for encapsulating rhodamine B (RhB dye) guest molecules, resulting in an RhB@ZIF-71 system with mechanochromic, thermochromic, and solvatochromic sensing response. The fluorochromic sensing properties stem from the nanoconfinement effect that ZIF-71 imposes on RhB monomers, yielding the H- or J-type aggregates with tunable photophysical and photochemical properties. For mechanochromism, the external pressure causes an emission red shift in a linear fashion, switching RhB guests from H-type to J-type aggregates through a shear deformation. For thermochromism, we demonstrate a linear scaling as a function of temperature due to the spatial restriction imposed on J-type aggregates incarcerated in ZIF-71 pores. Harnessing the solvatochromism of RhB@ZIF-71, we interrogated its photochemical response by employing three diverse groups of volatile organic compounds. The multimodal sensing response paved the way to smart applications like photonic pressure sensors, noninvasive thermometers, and ultrasensitive chemosensors.
- Published
- 2020
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31. Nanoencapsulated Monarda citriodora Cerv. ex Lag. essential oil as potential antifungal and antiaflatoxigenic agent against deterioration of stored functional foods.
- Author
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Deepika, Singh A, Chaudhari AK, Das S, and Dubey NK
- Abstract
In vitro antifungal activity of the essential oil from Monarda citriodora (MCEO) with possible mode of action was evaluated against A. flavus (AF-LHP-SH1) and 15 other storage molds for controlling postharvest deterioration of stored functional food samples. The chemical profiling of MCEO as done through GC-MS analysis revealed caryophyllene (19.15%) as the major component. The MCEO showed broad spectrum fungitoxicity and completely inhibited the growth of all tested molds and aflatoxin B
1 (AFB1 ) production by AF-LHP-SH1 at 1.40 and 1.20 µL/mL, respectively. Plasma membrane damage and methylglyoxal inhibition was confirmed as the possible antifungal and antiaflatoxigenic mode of action of MCEO. MCEO exhibited remarkable antioxidant activity with IC50 value 2.24 μL/mL as determined through DPPH assay and did not cause adverse effect on seed germination. In addition, the MCEO was encapsulated into chitosan nanoparticle, characterized (SEM, FTIR, XRD) and assessed for their potential against inhibition of growth and AFB1 production. MCEO after encapsulation exhibited enhanced efficacy inhibiting fungal growth and AFB1 production by AF-LHP-SH1 at 0.6 and 0.5 µL/mL, respectively. Encapsulated MCEO may be recommended as novel preservative to extend the shelf life of stored functional food samples., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© Association of Food Scientists & Technologists (India) 2020.)- Published
- 2020
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32. Assessment of preservative potential of Bunium persicum (Boiss) essential oil against fungal and aflatoxin contamination of stored masticatories and improvement in efficacy through encapsulation into chitosan nanomatrix.
- Author
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Singh A, Deepika, Chaudhari AK, Das S, Singh VK, Dwivedy AK, Shivalingam RK, and Dubey NK
- Subjects
- Animals, Antifungal Agents, Aspergillus flavus, Mice, Aflatoxins, Apiaceae, Chitosan, Oils, Volatile
- Abstract
The study reports the preservative efficacy of Bunium persicum (Boiss) essential oil (BPEO) against fungal and aflatoxin B
1 (AFB1 ) contamination of stored masticatories and boosting of its efficacy through encapsulation into chitosan. BPEO was chemically characterized through GC-MS analysis, which revealed γ-terpinene as the major compound. The BPEO at 1.2 μL/mL concentration completely inhibited the growth of toxigenic strain of Aspergillus flavus (AF-LHP-PE-4) along with 15 common food borne moulds and AFB1 secretion. The BPEO exerts its antifungal action on plasma membrane, as confirmed through ergosterol inhibition, alteration of membrane fluidity and enhancement of cellular ions and 260 and 280 nm absorbing material leakage. The antiaflatoxigenic mechanism of action of BPEO was confirmed through methylglyoxal reduction. Further, BPEO showed strong antioxidant activity (IC50 = 7.36 μL/mL) as measured by DPPH· assay. During in situ investigation, BPEO completely inhibited AFB1 production in model food (Phyllanthus emblica) system without altering the sensory properties and also exhibited high LD50 value (14,584.54 μL/kg) on mice. In addition, BPEO was encapsulated into chitosan, characterized and tested for their potential to inhibit growth and AFB1 production. The mean particle size, PDI and zeta potential of formed BPEO-loaded chitosan nanoparticle (CS-Np-BPEO) were performed to confirm successful encapsulation. The result revealed nanoencapsulated BPEO showed enhanced activity and completely inhibited the growth and AFB1 production by AF-LHP-PE-4 at 0.8 μL/mL. Based on findings, it could be concluded that the BPEO and its encapsulated formulation can be recommended as a potential plant-based preservative against fungal and aflatoxin contamination of stored masticatories.- Published
- 2020
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33. Chemically characterised Pimenta dioica (L.) Merr. essential oil as a novel plant based antimicrobial against fungal and aflatoxin B 1 contamination of stored maize and its possible mode of action.
- Author
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Chaudhari AK, Singh VK, Dwivedy AK, Das S, Upadhyay N, Singh A, Dkhar MS, Kayang H, Prakash B, and Dubey NK
- Subjects
- Acyclic Monoterpenes, Anti-Infective Agents pharmacology, Antifungal Agents isolation & purification, Antifungal Agents pharmacology, Cyclohexane Monoterpenes, Oils, Volatile chemistry, Oils, Volatile isolation & purification, Aflatoxin B1 antagonists & inhibitors, Anti-Infective Agents isolation & purification, Food Contamination prevention & control, Oils, Volatile pharmacology, Pimenta chemistry, Zea mays drug effects
- Abstract
The chemical characterisation of Pimenta dioica essential oil (PDEO) revealed the presence of 50 components, amongst which α-Terpineol (30.31%) was the major component followed by β-Linalool (6.75%) and γ-Terpinene (4.64%). The oil completely inhibited the growth of aflatoxin B
1 secreting strain Aspergillus flavus LHP-VS-8 and aflatoxin B1 production at 2.5 µL/mL and 1.5 µL/mL, respectively. The oil caused dose dependent reduction of methylglyoxal (an AFB1 inducer), enhanced leakage of Ca2+ , Mg2+ and K+ ions and significantly reduced ergosterol content of fungal plasma membrane. During in situ experiments, PDEO exhibited complete protection of fumigated maize cob slices from fungal infestation without affecting seed germination. The chemically characterised PDEO is recommended as a plant based preservative and shelf life enhancer of food commodities by preventing fungal growth, AFB1 production and lipid peroxidation. This is the first report on PDEO as inhibitor of AFB1 secretion and methylglyoxal biosynthesis.- Published
- 2020
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34. Fabrication, characterization and practical efficacy of Myristica fragrans essential oil nanoemulsion delivery system against postharvest biodeterioration.
- Author
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Das S, Singh VK, Dwivedy AK, Chaudhari AK, Upadhyay N, Singh A, Deepika, and Dubey NK
- Subjects
- Animals, Aspergillus flavus drug effects, Germination drug effects, Lethal Dose 50, Lipid Peroxidation drug effects, Male, Mice, Oils, Volatile chemistry, Oils, Volatile isolation & purification, Oryza drug effects, Oryza microbiology, Plant Extracts chemistry, Plant Extracts isolation & purification, Seeds drug effects, Seeds microbiology, Aflatoxins antagonists & inhibitors, Antifungal Agents pharmacology, Myristica chemistry, Oils, Volatile pharmacology, Plant Extracts pharmacology
- Abstract
The present study deals with encapsulation of Myristica fragrans essential oil (MFEO) into chitosan nano-matrix, their characterization and assessment of antimicrobial activity, aflatoxin inhibitory potential, safety profiling and in situ efficacy in stored rice as environment friendly effective preservative to control the postharvest losses of food commodities under storage. Surface morphology of MFEO-chitosan nanoemulsion as well as encapsulation of MFEO was confirmed through SEM, FTIR and XRD analysis. In vitro release characteristics with biphasic burst explained controlled volatilization from nanoencapsulated MFEO. Unencapsulated MFEO exhibited fungitoxicity against 15 food borne molds and inhibited aflatoxin B
1 secretion by toxigenic Aspergillus flavus LHP R14 strain. In contrast, nanoencapsulated MFEO showed better fungitoxicity and inhibitory effect on aflatoxin biosynthesis at lower doses. In situ efficacy of unencapsulated and nanoencapsulated MFEO on stored rice seeds exhibited effective protection against fungal infestation, aflatoxin B1 contamination, and lipid peroxidation. Both the unencapsulated and nanoencapsulated MFEO did not affect the germination of stored rice seeds confirming non-phytotoxic nature. In addition, negligible mammalian toxicity of unencapsulated MFEO (LD50 = 14,289.32 μL/kg body weight) and MFEO loaded chitosan nanoemulsion (LD50 = 9231.89 μL/kg body weight) as revealed through favorable safety profile recommend the industrial significance of nanoencapsulated MFEO as an effective green alternative to environmentally hazardous synthetic pesticides for protection of food commodities during storage., (Copyright © 2019 Elsevier Inc. All rights reserved.)- Published
- 2020
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35. Antimicrobial activity, antiaflatoxigenic potential and in situ efficacy of novel formulation comprising of Apium graveolens essential oil and its major component.
- Author
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Das S, Singh VK, Dwivedy AK, Chaudhari AK, Upadhyay N, Singh A, Deepika, and Dubey NK
- Subjects
- Animals, Anti-Infective Agents toxicity, Chromatography, High Pressure Liquid, Male, Mice, Oils, Volatile toxicity, Aflatoxins antagonists & inhibitors, Anti-Infective Agents pharmacology, Apium chemistry, Oils, Volatile pharmacology
- Abstract
The present study reports the formulation of Apium graveolens essential oil (AGEO) with its major components linalyl acetate (LA) and geranyl acetate (GA) (1:1:1) as a novel green preservative for protection of postharvest food commodities from fungal infestations, aflatoxin B
1 (AFB1 ) secretion, free radical generation and lipid peroxidation. The essential oil based novel formulation displayed considerable inhibitory action against fourteen food borne molds responsible for deterioration of stored food commodities, in addition to the most toxigenic strain of Aspergillus flavus (AFLHPR14) isolated from fungal and aflatoxin contaminated rice seeds. The observed higher efficacy of designed formulation was due to the synergistic action of essential oil and its major components. Fungal plasma membrane was recorded as the possible target site of antifungal action of the formulation as revealed through reduction in membrane ergosterol content, increased intracellular propidium iodide (PI) fluorescence and enhanced leakage of cellular ions (sodium, potassium, calcium) and 260, 280 nm absorbing materials. Further, inhibition of methylglyoxal (an aflatoxin inducer) confirmed the aflatoxin inhibitory potential of novel formulation based on essential oil and its major components. High antioxidant potential as observed through DPPH and ABTS·+ radical scavenging assay, improved phenolic content, considerable inhibition of lipid peroxidation in stored rice seeds, in situ efficacy on AFB1 inhibition in food system under storage container system, acceptable sensorial characteristics and favorable safety profile during animal trials suggest the recommendation of the designed formulation for large scale application as green preservative by food and agriculture based industries against fungal and aflatoxin contamination of stored commodities., (Copyright © 2019 Elsevier Inc. All rights reserved.)- Published
- 2019
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36. Essential oils and their bioactive compounds as green preservatives against fungal and mycotoxin contamination of food commodities with special reference to their nanoencapsulation.
- Author
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Chaudhari AK, Dwivedy AK, Singh VK, Das S, Singh A, and Dubey NK
- Subjects
- Antifungal Agents chemistry, Food Microbiology, Food Preservation methods, Humans, Oils, Volatile pharmacology, Preservatives, Pharmaceutical, Prospective Studies, Antifungal Agents pharmacology, Food Contamination analysis, Fungi drug effects, Mycotoxins analysis, Oils, Volatile chemistry
- Abstract
Fungal and mycotoxin contamination of stored food items is of utmost concern throughout the world due to their hazardous effects on mammalian systems. Most of the synthetic chemicals used as preservatives have often been realised to be toxic to humans and also cause adverse environmental effects. In this respect, use of different plant products especially essential oils (EOs) and their bioactive compounds has been recognized as a green strategy and safer alternatives to grey synthetic chemicals in view of their long traditional use. The current nanoencapsulation technology has strengthened the prospective of EOs and their bioactive compounds in food preservation by enhancing their bioactivity and mitigating other problems regarding their large-scale application. Although, the antimicrobial potential of EOs and their bioactive compounds has been reviewed time to time by different food microbiologists, but very less is known about their mode of action. Based on these backgrounds, the present article provides an account on the antifungal and antimycotoxigenic mode of action of EOs as well as their bioactive compounds. In addition, the article also deals with the application of currently used nanoencapsulation approach to improve the stability and efficacy of EOs and their bioactive compounds against mycotoxigenic fungi causing deterioration of stored food items so as to recommend their large-scale application for safe preservation and enhancement of shelf life of food items during storage.
- Published
- 2019
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37. Encapsulation in chitosan-based nanomatrix as an efficient green technology to boost the antimicrobial, antioxidant and in situ efficacy of Coriandrum sativum essential oil.
- Author
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Das S, Singh VK, Dwivedy AK, Chaudhari AK, Upadhyay N, Singh P, Sharma S, and Dubey NK
- Subjects
- Aflatoxins chemistry, Aflatoxins pharmacology, Anti-Infective Agents chemistry, Anti-Infective Agents pharmacology, Antioxidants chemistry, Antioxidants pharmacology, Capsules, Food Industry, Green Chemistry Technology, Lipid Peroxidation drug effects, Structure-Activity Relationship, Chitosan chemistry, Coriandrum chemistry, Nanostructures chemistry, Oils, Volatile chemistry, Oils, Volatile pharmacology
- Abstract
The present investigation deals with first time report on encapsulation of Coriandrum sativum essential oil (CSEO) in chitosan nanomatrix as a green nanotechnology for enhancing its antimicrobial, aflatoxin inhibitory and antioxidant efficacy. Chitosan nano biopolymer entrapped CSEO as prepared through ionic gelation process showed broad spectrum fungitoxicity against molds infesting stored rice and also exhibited enhanced bioefficacy than unencapsulated CSEO. The CSEO entrapped in chitosan nanomatrix lead to decrement in important fungal membrane biomolecule i.e. ergosterol and leakage of UV-absorbing substances along with vital cellular ions. The CSEO encapsulation in selected biopolymer nanomatrix effectively checked methylglyoxal (the aflatoxin inducer) biosynthesis, confirming antiaflatoxigenic mode of action. The physico-chemical properties, considerable decrease in lipid peroxidation and improved in situ AFB
1 suppressive as well as antifungal potential of CSEO nanocapsules suggested the deployment of chitosan based nano biopolymer for encapsulation of essential oils as an ecofriendly technology for application in food industries in order to enhance the shelf life and control the fungal and aflatoxin contamination of stored rice., (Copyright © 2019 Elsevier B.V. All rights reserved.)- Published
- 2019
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38. Assessment of Melissa officinalis L. essential oil as an eco-friendly approach against biodeterioration of wheat flour caused by Tribolium castaneum Herbst.
- Author
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Upadhyay N, Singh VK, Dwivedy AK, Das S, Chaudhari AK, and Dubey NK
- Subjects
- Acyclic Monoterpenes, Animals, Food Storage, Gas Chromatography-Mass Spectrometry, Insect Repellents analysis, Insect Repellents toxicity, Lethal Dose 50, Male, Mice, Monoterpenes analysis, Oils, Volatile analysis, Oils, Volatile toxicity, Oxidative Stress drug effects, Polycyclic Sesquiterpenes, Reactive Oxygen Species metabolism, Sesquiterpenes analysis, Tribolium physiology, Triticum, Flour, Insect Repellents pharmacology, Melissa chemistry, Oils, Volatile pharmacology, Tribolium drug effects
- Abstract
The study reports efficacy of Melissa officinalis L. essential oil (MOEO) as a safe plant-based insecticide against Tribolium castaneum Herbst (TC) by induction of oxidative stress. MOEO nanoencapsulation in chitosan matrix was performed to enhance its bioefficacy. GC-MS analysis of MOEO depicted geranial (31.54%), neral (31.08%), and β-caryophyllene (12.42%) as the major components. MOEO showed excellent insecticidal potential in contact (100% mortality at 0.157 μL/cm
2 ) and fumigant bioassays (LC50 = 0.071 μL/mL air) and 100% repellency at concentration ≤ 0.028 μL/cm2 . Increased reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), and decreased ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) at the LC50 dose suggested significant oxidative stress on TC in MOEO treatment sets. The encapsulated MOEO exhibited enhanced activity as fumigant (LC50 = 0.048 μL/mL air) and showed significant antifeedant activity in situ (EC50 = 0.043 μL/mL). High LD50 value (13,956.87 μL/kg body weight of mice) confirmed favorable toxicological profile for non-target mammals. The findings depict potential of nanoencapsulated MOEO as an eco-friendly green pesticide against infestation of stored food by TC.- Published
- 2019
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39. Self-Assembled, Fluorine-Rich Porous Organic Polymers: A Class of Mechanically Stiff and Hydrophobic Materials.
- Author
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Mukherjee S, Zeng Z, Shirolkar MM, Samanta P, Chaudhari AK, Tan JC, and Ghosh SK
- Abstract
Fluorous organic building blocks were utilized to develop two self-assembled, hydrophobic, fluorinated porous organic polymers (FPOPs), namely, FPOP-100 and FPOP-101. Comprehensive mechanical analyses of these functionalised triazine network polymers marked the introduction of mechanical stiffness among all porous organic network materials; the recorded stiffnesses are analogous to those of their organic-inorganic hybrid polymer congeners, that is, metal-organic frameworks. Furthermore, this study introduces a new paradigm for the simultaneous installation of mechanical stiffness and high surface hydrophobicity into polymeric organic networks, with the potential for transfer among all porous solids. Control experiments with non-fluorinated congeners underlined the key role of fluorine, in particular, bis-trifluoromethyl functionalization in realizing the dual features of mechanical stiffness and superhydrophobicity., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2018
- Full Text
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40. Mechanochromic MOF nanoplates: spatial molecular isolation of light-emitting guests in a sodalite framework structure.
- Author
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Chaudhari AK and Tan JC
- Abstract
Mechanochromic materials have a wide range of promising technological applications, such as photonics-based sensors and smart optoelectronics. The examples of mechanochromic metal-organic framework (MOF) materials, however, are still relatively uncommon in the literature. Herein, we present a previously undescribed Guest@MOF system, comprising "Perylene@ZIF-8" nanoplates, which will undergo a reversible 442 nm ⇌ 502 nm photoemission switching when subjected to a moderate level of mechanically-induced pressure at several tens of MPa. The nanoplates were constructed via high-concentration reaction (HCR) strategy at ambient conditions to yield a crystalline ZIF-8 framework hosting the luminous Perylene guests. The latter confined within the porous sodalite cages of ZIF-8. Remarkably, we show that in a solid-state condition, it is the spatial isolation and nano-partitioning of the luminescent guests that bestow the unique solution-like optical properties measured in the host-guest assembly. As such, we demonstrate that switchable red- or blue-shifts of the visible emission can be accomplished by mechanically modifying the nanoscale packing of the nanoplates (e.g. monoliths, pellets). Theoretical calculations suggest that the elasticity of the host's sodalite cage coupled with the intermolecular weak interactions of the confined guest are responsible for the unique mechanochromic luminescence behavior observed.
- Published
- 2018
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41. Probing Dielectric Properties of Metal-Organic Frameworks: MIL-53(Al) as a Model System for Theoretical Predictions and Experimental Measurements via Synchrotron Far- and Mid-Infrared Spectroscopy.
- Author
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Titov K, Zeng Z, Ryder MR, Chaudhari AK, Civalleri B, Kelley CS, Frogley MD, Cinque G, and Tan JC
- Abstract
Emerging nanoporous materials, such as metal-organic frameworks (MOFs), are promising low-k dielectrics central to next-generation electronics and high-speed communication. Hitherto, the dielectric characterization of MOFs is scarce, with very limited experimental data for guiding new materials design and synthesis. Herein we demonstrate the efficacy of high-resolution synchrotron infrared (IR) specular reflectance experiments to study the dynamic dielectric properties of a flexible MOF structure: bistable MIL-53(Al) that exhibits switching between a large pore (LP) and a narrow pore (NP) architecture. We show that the ratio of LP:NP content of a polycrystalline sample can be changed via increased mechanical stress applied for pelletizing the MIL-53(Al) powder. We quantify the frequency-dependent dielectric constants over ∼1 to 120 THz, identifying all dielectric transitions as a function of stress and phase mixtures, showing how porosity modifies MOF's dielectric properties.
- Published
- 2017
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42. Optochemically Responsive 2D Nanosheets of a 3D Metal-Organic Framework Material.
- Author
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Chaudhari AK, Kim HJ, Han I, and Tan JC
- Abstract
Outstanding functional tunability underpinning metal-organic framework (MOF) confers a versatile platform to contrive next-generation chemical sensors, optoelectronics, energy harvesters, and converters. A rare exemplar of a porous 2D nanosheet material constructed from an extended 3D MOF structure is reported. A rapid supramolecular self-assembly methodology at ambient conditions to synthesize readily exfoliatable MOF nanosheets, functionalized in situ by adopting the guest@MOF (host) strategy, is developed. Nanoscale confinement of light-emitting molecules (as functional guest) inside the MOF pores generates unusual combination of optical, electronic, and chemical properties, arising from the strong host-guest coupling effects. Highly promising photonics-based chemical sensing opened up by the new guest@MOF composite systems is shown. By harnessing host-guest optochemical interactions of functionalized MOF nanosheets, detection of an extensive range of volatile organic compounds and small molecules important for many practical applications has been accomplished., (© 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2017
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43. Photonic hybrid crystals constructed from in situ host-guest nanoconfinement of a light-emitting complex in metal-organic framework pores.
- Author
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Chaudhari AK, Ryder MR, and Tan JC
- Abstract
We report the concept underpinning the facile nanoconfinement of a bulky luminous guest molecule in the pores of a metal-organic framework (MOF) host, which yields a hybrid host ⊃ guest nanomaterial with tunable opto-electronic characteristics and enhanced photostability. Utilizing an in situ host-guest confinement strategy enabled by molecular self-assembly, we show that the highly emitting ZnQ [Zn-(bis-8-hydroxyquinoline)] guest complexes could be rapidly encapsulated within the sodalite nanocages of zeolitic imidazolate framework (ZIF-8) host crystals. The nature of optical and electronic transitions phenomena of the guest-encapsulated ZIF-8 ⊃ ZnQ has been elucidated by means of fluorescence and absorption spectroscopy measurements, and substantiated further via theoretical molecular orbital calculations revealing the plausible host-guest charge transfer mechanism involved. Evidence suggests that its photophysical properties are not only strongly determined by the host-guest co-operative bonding interactions within the environment of the confined MOF nanocage, but also can be engineered to manipulate its emission color chromaticity or to shield light-sensitive emitting guests against rapid photochemical degradation.
- Published
- 2016
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44. Bimodal Functionality in a Porous Covalent Triazine Framework by Rational Integration of an Electron-Rich and -Deficient Pore Surface.
- Author
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Karmakar A, Kumar A, Chaudhari AK, Samanta P, Desai AV, Krishna R, and Ghosh SK
- Abstract
A porous covalent triazine framework (CTF) consisting of both an electron-deficient central triazine core and electron-rich aromatic building blocks is reported. Taking advantage of the dual nature of the pore surface, bimodal functionality has been achieved. The electron deficiency in the central core has been utilized to address one of the pertinent problems in chemical industries, namely separation of benzene from its cyclic saturated congener, that is, cyclohexane. Also, by virtue of the electron-rich aromatic rings with Lewis basic sites, aqueous-phase chemical sensing of a nitroaromatic compound of highly explosive nature (2,4,6-trinitrophenol; TNP) has been achieved. The present compound supersedes the performance of previously reported COFs in both the aspects. Notably, this reports the first example of pore-surface engineering leading to bimodal functionality in CTFs., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2016
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45. Multifunctional Supramolecular Hybrid Materials Constructed from Hierarchical Self-Ordering of In Situ Generated Metal-Organic Framework (MOF) Nanoparticles.
- Author
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Chaudhari AK, Han I, and Tan JC
- Abstract
A synergistic approach is described to engineer supramolecular hybrid materials based on metal-organic frameworks, encompassing HKUST-1 nanoparticles formed in situ, coexisting with an electrically conducting gel fiber network. The following findings are made: i) multistimuli-responsive structural transformation via reversible sol-gel switching and ii) radical conversion of a soft hybrid gel into a mechanically malleable, viscoelastic matter., (© 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2015
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46. Supramolecular Materials: Multifunctional Supramolecular Hybrid Materials Constructed from Hierarchical Self-Ordering of In Situ Generated Metal-Organic Framework (MOF) Nanoparticles (Adv. Mater. 30/2015).
- Author
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Chaudhari AK, Han I, and Tan JC
- Abstract
The supramolecular engineering of a new family of hybrid gels coexisting with metal-organic framework (MOF) nano-particles created in situ is demonstrated by J. C. Tan and co-workers on page 4438. The rapid process of inorganic-organic self-assembly generates a hierarchical fiber network architecture, whose electrical conductivity and mechanical characteristics can be tuned to yield a range of bespoke soft matter with unconventional properties., (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2015
- Full Text
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47. Guest-responsive function of a dynamic metal-organic framework with a π Lewis acidic pore surface.
- Author
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Joarder B, Mukherjee S, Chaudhari AK, Desai AV, Manna B, and Ghosh SK
- Abstract
A 3D dynamic coordination framework with an electron-deficient pore surface has been synthesized by using Zn(II) (having a variable coordination number) and a predesigned flexible π-electron-deficient core-based ligand, exhibiting chemical separations based on pore surface functionalization (π Lewis acidic pore surfaces and open metal sites) and framework flexibility, giving rise to a unique smart guest-responsive material., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2014
- Full Text
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48. Framework-flexibility driven selective sorption of p-xylene over other isomers by a dynamic metal-organic framework.
- Author
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Mukherjee S, Joarder B, Manna B, Desai AV, Chaudhari AK, and Ghosh SK
- Abstract
Chemical separation has great importance in industrial applications. Separation of xylene isomers still prevails to be one of the most important challenges in chemical industry, due to the large amount of commercial use of p-xylene in the production of beverage bottles, fibers and films. A novel Zn(II)-based dynamic coordination framework based on flexible ether-linkage, exhibiting selective adsorption of p-Xylene over its congener C8-alkyl aromatic isomers at ambient conditions is reported. Notably, no dynamic structure based MOF compound is known in the literature which shows clear preference of p-xylene over other isomers. This type of framework-breathing and guest-induced reversible solid-state structural transformations with unique adsorption selectivity can be exploited purposefully to develop smart functional host materials capable of industrially important chemical separations.
- Published
- 2014
- Full Text
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49. Structural dynamism and controlled chemical blocking/unblocking of active coordination space of a soft porous crystal.
- Author
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Chaudhari AK, Nagarkar SS, Joarder B, Mukherjee S, and Ghosh SK
- Abstract
A three-dimensional biporous soft porous coordination polymer containing active coordination space, made of cadmium(II) and a tripodal carboxylate ligand bearing ether linkages, was synthesized and characterized. Guest-dependent dynamic activities in the active coordination space of the soft porous crystal have been explored. We have demonstrated controlled chemical blocking and unblocking of active pores of the dynamic framework along with guest-dependent contraction and expansion of the channels by single-crystal-to-single-crystal structural transformation studies. Detailed studies revealed up to 70% contraction of the void volume and almost a 100 times increase in gas sorption by controlled phases obtained by guest switching. These types of soft materials with porous scaffolds, also known as soft porous crystals, may have general implications in the preparation of intelligent host materials with zeolitic properties and enzyme-like specificity.
- Published
- 2013
- Full Text
- View/download PDF
50. Amino acid based dynamic metal-biomolecule frameworks.
- Author
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Joarder B, Chaudhari AK, Nagarkar SS, Manna B, and Ghosh SK
- Subjects
- Adsorption, Copper chemistry, Crystallization, Nanofibers chemistry, Polymers chemistry, Amino Acids chemistry, Organometallic Compounds chemistry
- Abstract
On the move: Two isostructural, homochiral Cu(II) coordination frameworks based on amino acids (D- and L-PGA) were synthesized. Dynamic behavior by solid-state structural transformation in single-crystal-to-single-crystal fashion was demonstrated. The extent of structural dynamism was shown by guest inclusion studies. Reversible sol-gel formation and anion-tuning morphology of the compounds is also discussed., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2013
- Full Text
- View/download PDF
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