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Natural products from plants have the potential to exert antioxidant, anti-tyrosinase, antibacterial, and cytotoxic activities and have been widely used as ingredients in cosmetics, medicines, or supplementary food. Several types of secondary metabolites from the Citrus genus have been reported to exhibit interesting biological activity. Due to this lack of studies and biological activity of compounds from related species, it was considered important to investigate Citrus grandis Linn. (Tubtim Siam Pomelo) to be studied. The objective of this research was to isolate and elucidate the structures of chemical constituents and to evaluate their biological activity from the peels of C. grandis Linn. A coumarin (1) and 3 flavonoids (2 - 4) were isolated from the peels of C. grandis Linn. The structures of these compounds were elucidated by analyses of spectroscopic data as well as comparison of their spectroscopic data with the previously published data. Compounds 1 - 4 have been evaluated for antioxidant, anti-tyrosinase, antibacterial and cytotoxic activities. Compound 2 showed the highest inhibition in DPPH and tyrosinase with IC50 values of 0.219 ± 0.011 and 0.033 ± 0.002 mg/mL, respectively. Interestingly, compound 1 - 4 were the first time being isolated from Tubtim Siam Pomelo. [ABSTRACT FROM AUTHOR]

Acylphloroglucinols are well-known Eucalyptus secondary metabolites which exhibit a variety of structures and bioactivities. The investigation of a crude acetone extract of Eucalyptus camaldulensis leaves led to the isolation of two new acylphloroglucinols, eucalypcamals O and P (1 and 2) together with seven phloroglucinols (3–9), and a benzene derivative (10). Their chemical structures were elucidated by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and mass spectroscopy. The absolute configurations of compounds 1 and 2 were established by comparison of experimental and calculated electronic circular dichroism (ECD) data. In the putative biosynthetic pathway, eucalypcamals O and P should be derived from hetero-Diels-Alder reaction between grandinol and trans-isoeugenol. [ABSTRACT FROM AUTHOR]

Aims Quercus infectoria (Qi), a traditional herbal plant with a broad spectrum of activities on multidrug-resistant bacteria, has been developed for hand sanitizer applications. Methods and Results Antimicrobial activity was evaluated using agar-well diffusion and broth microdilution method. Bactericidal activity was determined following the European Standard 1276 antibacterial suspension test. Neutralization assay was performed to assess antirespiratory syncytial virus. Safety, stability, and skin permeation of Qi hand gel was investigated. Qi hand sanitizer gel inhibited microorganisms ranging from 99.9% to 99.999% against Enterococcus faecalis, Staphylococcus aureus , methicillin-resistant Staph. aureus, Staph. epidermidis, Staph. pseudintermedius, Staph. saprophyticus, Streptococcus pyogenes, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa , and Candida albicans. A significant reduction in main human dermatophytes including Microsporum canis, M. gypseum , and Talaromyces marneffei of ∼50% was observed (P  < .05). Qi hand sanitizer gel inactivated >99% viral particles entering human laryngeal epidermoid carcinoma cells in a dose-dependent manner. Scanning electron micrographs further illustrated that Qi hand sanitizer gel disrupted microbial cell membrane after 1-min contact time resulting in cell death. Qi hand sanitizer gel delivered emollient compounds through simulated human skin layers and showed no cytotoxicity on fibroblast cells. Moreover, Qi hand sanitizer gel demonstrated stability under extreme conditions. Conclusions Qi hand sanitizer gel was able to inhibit various microorganisms including bacteria, dermatophytes, and virus. [ABSTRACT FROM AUTHOR]

Annually, a great number of bananas are produced, and those that do not satisfy commercialization criteria are discarded, resulting in a considerable amount of agricultural waste. This work aimed at valorizing rejected unripe Musa sapientum fruit by microwave-assisted extraction using glycerol-ethanol mixtures for development of cosmeceuticals. The fruit extract exhibited potent radical scavenging activity towards 2,2-diphenylpicrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays in a concentration-dependent manner. Ferric reducing power was 199.13 μM FeSO4/mg extract. Total phenolic content was 39 mg gallic acid equivalent/100 g extract and total flavonoid content was 26 mg quercetin equivalent/100 g extract. Vitamin C and E contents of the extract were 10.47 and 4.77 mg/100 g, respectively. The extract demonstrated strong antibacterial activity against a wide range of pathogenic bacteria. The extract significantly reduced nitric oxide production in murine macrophage RAW 264.7 cells (p < 0.05). Biocompatibility assessment of the extract with L929 murine fibroblast cells demonstrated no toxic effects. In the next series of experiments, a commercial prototype was developed. M. sapientum-loaded serum significantly inhibited DPPH scavenging activity with a value of 50.62% when compared with commercially available product (p < 0.05). Our prototype significantly suppressed tyrosinase activity compared with both serum base and commercially available products (p < 0.05). This finding implies that M. sapientum fruit extract has a high potential to be used as an alternative natural depigmenting agent. [ABSTRACT FROM AUTHOR]

COVID-19 patients have often required prolonged endotracheal intubation, increasing the risk of developing ventilator-associated pneumonia (VAP). A preventive strategy is proposed based on an endotracheal tube (ETT) modified by the in situ deposition of eucalyptus-mediated synthesized silver nanoparticles (AgNPs). The surfaces of the modified ETT were embedded with AgNPs of approximately 28 nm and presented a nanoscale roughness. Energy dispersive X-ray spectroscopy confirmed the presence of silver on and inside the coated ETT, which exhibited excellent antimicrobial activity against Gram-positive and Gram-negative bacteria, and fungi, including multidrug-resistant clinical isolates. Inhibition of planktonic growth and microbial adhesion ranged from 99 to 99.999% without cytotoxic effects on mammalian cells. Kinetic studies showed that microbial adhesion to the coated surface was inhibited within 2 h. Cell viability in biofilms supplemented with human tracheal mucus was reduced by up to 95%. In a porcine VAP model, the AgNPs-coated ETT prevented adhesion of Pseudomonas aeruginosa and completely inhibited bacterial invasion of lung tissue. The potential antimicrobial efficacy and safety of the coated ETT were established in a randomized control trial involving 47 veterinary patients. The microbial burden was significantly lower on the surface of the AgNPs-coated ETT than on the uncoated ETT (p < 0.05). Key points: • Endotracheal tube surfaces were modified by coating with green-synthesized AgNPs • P. aeruginosa burden of endotracheal tube and lung was reduced in a porcine model • Effective antimicrobial activity and safety was demonstrated in a clinical trial [ABSTRACT FROM AUTHOR]

Catheter-associated urinary tract infections (CAUTIs) are significant complications among catheterized patients, resulting in increased morbidity, mortality rates, and healthcare costs. Foley urinary catheters coated with synthesized silver nanoparticles (AgNPs) using Eucalyptus camaldulensis leaf extract were developed using a green chemistry principle. In situ-deposited AgNPs with particle size ranging between 20 and 120 nm on the catheter surface were illustrated by scanning electron microscopy. Atomic force microscopy revealed the changes in surface roughness after coating with nanoparticles. The coated catheter could significantly inhibit microbial adhesion and biofilm formation performed in pooled human urine-supplemented media to mimic a microenvironment during infections (p 0.05). AgNPs-coated catheter exhibited broad-spectrum antimicrobial activity against important pathogens, causing CAUTIs with no cytotoxic effects on HeLa cells. A reduction in microbial viability in biofilms was observed under confocal laser scanning microscopy. A catheter bridge model demonstrated complete prevention of Proteus mirabilis migration by the coated catheter. Significant inhibition of ascending motility of Escherichia coli and P. mirabilis along the AgNPs-coated catheter was demonstrated in an in vitro bladder model (p 0.05). The results suggested that the AgNPs-coated urinary catheter could be applied as an alternative strategy to minimize the risk of CAUTIs by preventing bacterial colonization and biofilm formation. [ABSTRACT FROM AUTHOR]

Certain foodborne diseases are associated with antibiotic resistance, a significant problem throughout the world. Silver nanoparticles (AgNPs) using industrial waste from Eucalyptus camaldulensis and sericin, a protein derived from Bombyx mori, were synthesised by a one‐step approach. Spherical‐shaped nanoparticles with the average size of 17.19 nm exhibited strong antioxidant activity. The minimum bactericidal concentrations against foodborne pathogens including Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, Klebsiella pneumoniae, Salmonella Typhimurium, Shigella sonnei, Vibrio cholerae and Vibrio parahaemolyticus were between 2.96 and 11.83 µg/mL. Killing against L. monocytogenes and E. coli O157:H7 was observed within 4 h. Treatment with AgNPs at 0.25 – 0.5 × MIC significantly reduced biofilm production in all isolates (P < 0.05). AgNPs significantly impeded adhesion to and invasion of human epithelial Caco‐2 cells by L. monocytogenes and E. coli O157:H7 (P < 0.05). Biocompatibility assessment of AgNPs with Caco‐2 and human red blood cells demonstrated no toxic effects. [ABSTRACT FROM AUTHOR]

Eleutherine americana bulb known mainly as a flavouring agent has also beneficial role in food safety and preservation. The present study aims to evaluate the efficacy of Eleutherine americana bulb extract in controlling contamination of a major foodborne pathogen, Campylobacter jejuni in chicken meat. The treatment was divided into 3 sets (i) dipping chicken meat in the extract (ii) mixing the extract with chicken meat, and (iii) combination of the extract treatment with short-term freezing at − 20 °C. With dipping method, the addition of 8 mg mL−1 of the extract lowered C. jejuni ATCC 33560 counts in chicken meat to approximately 2 log on day 6. One log-fold decrease in the bacterial counts in chicken meat mixed with E. americana extract at 4 mg mL−1 was observed at day 7. Furthermore, the extract at 8 mg mL−1 caused reduction in the bacterial counts up to 2 log from day 4 till day 7 (P < 0.05). Combined treatment with the extract at 4 and 8 mg mL−1 and subsequent short-term freezing of chicken meat reduced survival of C. jejuni about 2 log from day 5 and day 3, respectively (P < 0.05). Sensory scores analysis demonstrated that addition of the extract did not adversely affect the properties of cooked chicken meat until day 5 (P < 0.05). The results suggest that E. americana extract could be a promising novel agent to control Campylobacter contamination in chicken meat. [ABSTRACT FROM AUTHOR]

Bionanotechnology has increasingly gained attention in biomedical fields as antifungal and antibiofilm agents. In this study, biosynthesized silver nanoparticles (bio‐AgNPs) using aqueous Eucalyptus camaldulensis leaf extract were successfully performed by a one‐step green approach. Spherical‐shaped nanoparticles, approximately 8.65 nm, exhibited noncytotoxicity to erythrocytes, HeLa, and HaCaT cells. The synthesized nanoparticles showed strong fungicidal activity ranging from 0.5 to 1 µg/ml. The nanoparticles affected Candida adhesion and invasion into host cells by reduced germ tube formation and hydrolytic enzyme secretion. Inhibitory effects of bio‐AgNPs on Candida biofilms were evaluated by the prevention of yeast‐to‐hyphal transition. A decrease in cell viability within mature biofilm demonstrated the ability of bio‐AgNPs to penetrate into the extracellular matrix and destroy yeast cell morphology, leading to cell death. Molecular biology study on biofilms confirmed downregulation in the expression of genes ALS3, HWP1, ECE1, EFG1, TEC1, ZAP1, encoding hyphal growth and biofilm development and PLB2, LIP9, SAP4, involved in hydrolytic enzymes. In addition to candida treatment, the bio‐AgNPs could be applied as an antioxidant to protect against oxidative stress‐related human diseases. The findings concluded that bio‐AgNPs could be used as an antifungal agent for candida treatment, as well as be incorporated in medical devices to prevent biofilm formation. [ABSTRACT FROM AUTHOR]

Pathogen resistance to conventional antibiotics has become a serious clinical and public health problem, making the development of an alternative mean a very urgent issue. Recently, biosynthesis of silver nanoparticles (AgNPs) was successfully accomplished in the presence of Eucalyptus citriodora leaf extract as a reducing agent. In this study, the antimicrobial mechanisms of AgNPs against important hospital‐acquired pathogens, including Gram‐positive, Gram‐negative bacteria, and fungi were further assessed. The results indicated that AgNPs could enhance a broad antimicrobial spectrum against drug‐resistant organisms, with a range of minimum inhibitory concentration from 0.02 to 0.36 μg/mL. Time‐kill assay showed that AgNPs produced bactericidal effects on the microorganisms. AgNPs could significantly reduce biofilm production in pathogens without affecting growth of the pathogens (p < 0.05). AgNPs inhibited cell viability and biofilm formation in a dose‐dependent manner. Cell membrane damage in microorganisms resulting from effects of AgNPs was observed. A significant increase in per cent uptake of crystal violet was observed in all isolates treated with AgNPs when compared with the control (p < 0.05). Upon treatment with AgNPs, the surface charge of the reference strains and clinical isolates of pathogens moved towards neutral. The alteration of surface potential after exposure to AgNPs could contribute to membrane disruption and cell viability. Scanning electron microscopy further confirmed morphological cell changes and disrupted the cell membrane. Increasing resistance to AgNPs was not induced by stepwise isolation of the bacteria after 45 passages on Luria‐Bertani agar supplemented with AgNPs. Furthermore, AgNPs was not toxic to red blood cells. [ABSTRACT FROM AUTHOR]