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The objectives of the present study are to synthesize a series of chitosan oligosaccharide-O-Terpenol (COS-O-Ter) derivatives and their implication to evaluate in vitro antibacterial activity. Herein, a general strategy is described for preparing COS-O-Ter derivatives, including substitution and deprotection reactions. The structures of COS-O-Ter derivatives were characterized by FT-IR, 1 H NMR, XRD, TGA, and elemental analysis. COS-O-Ter derivatives revealed the excellent solubility and in vitro antibacterial activity. Moreover, their antibacterial activities were more sensitive to Staphylococcus aureus (S. aureus) than Escherichia coli (E. coli) indicating the effective potential application of COS-O-Ter derivatives as natural antibacterial agents. The aforementioned study opens a pave to expand the application scope of COS and its derivatives in the food and pharmaceutical industries., (Copyright © 2021. Published by Elsevier Ltd.)

Objective: To determine the effective narrow spectrum antibiotics for treatment of UTI in children in order to control the rapidly increasing antibiotic resistance to broad spectrum antibiotics. Study Design: Prospective Clinical study. Setting: Department of Pediatric, Akbar Niazi Teaching Hospital, Bhara Kahu-Pakistan. Period: January 2021 to December 2021. Material & Methods: 361 children with clinical suspicion of UTI were enrolled in the study.. Antimicrobial sensitivity test was applied on Samples on which bacterial growth was identified using Clinical Laboratory Standards Institute (CLSI) guidelines. The data was analyzed using SPSS version 25. Results: Total 361 patients were enrolled in the study according to inclusion criteria, out of which, 30 (8.3%) were infants (<1 years old), 178 (49.3%) were aged 1 to 5 years and 153 (42.4%) were aged from 5 to 12 years of age. Out of 361 patients, 125 (34.6%) patients were males and 236 (65.4%) were females. Out of 124 patients, whose urine culture was positive, most common pathogen was E. coli that was observed in 92 (25.5%) cases, followed by Klebsialla in 9 (2.5%) and enterococcus in 9 (2.5%) patients, Pseudomonas in 5 (1.4%), Proteus in 4 (1.1%), Mirabilis in 4 (1.1%), Acinobacter in 2 (0.6%), and enterobacter in 2 (0.6%) cases. Spectrum of sensitivity of 17 drugs was studied. The most sensitive drug was Imipenem, (29.9%), followed by Nitrofurantoin, Fosfomycin (25.8%), Amikacin (24.1%), Piperacilin / Tazobactam (22.7%). Conclusion: Thus E. coli was the most common pathogen and the most sensitive drug was Imipenem, followed by Nitrofurantoin, Fosfomycin, Amikacin, and Piperacilin / Tazobactam. [ABSTRACT FROM AUTHOR]

Summary: Inventions into chitosan oligosaccharide (COS) derivatives over recent decades have hugely broadened their application in food safety. Herein, monomethyl fumaric acid (MFA) was grafted on the OH position of COS to synthesise new COS‐O‐MFA derivatives and evaluated their in vitro antibacterial properties. The degrees of substitution (DS) of the derivatives yielded almost 15% with the range of 0.093 to 0.260. The in vitro antibacterial properties of the new COS‐O‐MFA1‐3 derivatives against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were significantly enhanced concerning COS. Based on the finding, the introduction of MFA and increasing DS have a great impact on the enhancement of antibacterial properties of the COS‐O‐MFA1‐3 derivatives. This work proves that COS‐O‐MFA1‐3 derivatives can be potential novel antibacterial agents and also open up a new avenue to improve their antibacterial attributes. [ABSTRACT FROM AUTHOR]

Curcumin (Cur) is a natural pigment with excellent biological activity. The poor stability and insolubility of Cur in water severely limit its application. Therefore, to overcome these dilemmas which are big hindrances in their application, a novel derivative (COCS-Cur) was prepared by the esterification reaction of carboxylated chitosan (COCS) and Cur. The structure and properties of conjugate were determined through a series of characterizations. The derivatives had excellent solubility as well as stability. In addition, antioxidant and photodynamic antibacterial experiments proved that COCS-Cur had the excellent free radical scavenging ability and photodynamic antibacterial activity. The derivatives presented a better antibacterial effect on Staphylococcus aureus (S. aureus) than Escherichia coli (E. coli). Noteworthy, the COCS-Cur derivatives showed no obvious toxicity which makes them a stronger contender and potential antimicrobial agent or functional nutrient for application in the food industry. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of new antimicrobial agents is important to combat infections caused by pathogenic bacteria. Herein, Hydroxypropyl chitosan (HPCS), a hydrophilic modified product of chitosan (CS), was employed as a carrier of the photosensitizer chlorin e6 (Ce6) through an amide bond to obtain the products (HPCS-Ce6 conjugates) with a degree of substitution (DS) ranging from 2.95% to 5.25%. The UV–vis absorption spectra and 1H NMR spectra confirmed the successful synthesis of the products. The products have a better and more stable reactive oxygen species (ROS) generation capacity and higher bacterial affinity than Ce6. At a very low dose (1.8 μg/mL), the highest DS product (HPCS-Ce6-3) can effectively kill Staphylococcus aureus (S. aureus) under 660 nm irradiation. In addition, the HPCS-Ce6 conjugates showed high biocompatibility in the CCK-8 test. The HPCS-Ce6 conjugates could be a photodynamic antibacterial agent with good water solubility, high biocompatibility, and antibacterial activity. • Hydroxypropyl chitosan (HPCS) and chlorin e6 (HPCS-Ce6) conjugates were synthesized through amide reaction. • The HPCS-Ce6 conjugates were characterized by the spectroscopic method. • The HPCS-Ce6 conjugates showed an enhanced photodynamic antibacterial effect on S. aureus than E. coli relative to Ce6 and HPCS. • The HPCS-Ce6 conjugates showed DS-dependent reactive oxygen generation ability and antibacterial ability. [ABSTRACT FROM AUTHOR]

The modified natural biopolymers, recognized as environmentally friendly flocculants, are gaining tremendous attention in the field of water treatment. In this study, a novel hybrid flocculant with antibacterial activity, cinnamic acid (CA) conjugated N-(2-hydroxy)-propyl-3-trimethylammonium chitosan chloride (HTCC) derivative (HTCC-CA), was prepared via quaternary ammonium and amide reactions. The characterization, flocculation, and antibacterial activities were carried out to access the structural properties and potential application. The results of UV–vis, FT-TR, and 1H NMR confirmed the successful synthesis of HTCC-CA1-3 derivatives. XRD and TGA revealed the lower crystallinity and thermal stability of HTCC-CA1-3 derivatives than chitosan (CS). Bacterial flocculation and antibacterial tests indicated the excellent flocculation effect of HTCC-CA1-3 derivatives and showed high antibacterial activity for Escherichia coli suspension. Moreover, the mechanism of action of the derivatives was investigated via zeta potential measurements and scanning electron microscope, which can be summed up as the effective interaction between charges. The results proved that HTCC-CA derivatives are promising agents for wastewater treatment. • A novel hybrid flocculant with antibacterial activity (HTCC-CA derivatives) was synthesized. • FT-IR, 1H NMR, and UV–vis revealed the successful preparation of HTCC-CA1-3 derivatives. • HTCC-CA derivatives can simultaneously have flocculation and antibacterial effects on E. coli suspension. • HTCC-CA derivatives provide a practical strategy for the design of new chitosan-based flocculant materials. [ABSTRACT FROM AUTHOR]

The novel chitosan oligosaccharide derivatives modified with cinnamyl onto the NH 2 position were synthesized through a one-step reaction and their in vitro antibacterial activities were ascertained. The structural characterization and properties of derivatives were verified by UV–vis, FT-IR, 1H, 13C NMR, TGA, XRD, and elemental analysis. The degrees of substitution (DS) of derivatives were from 0.255 to 0.366 with yields up to 82%. The in vitro antibacterial activities for the novel chitosan oligosaccharide derivatives against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were greatly improved compared to COS, sodium benzoate, and potassium sorbate. Moreover, their antibacterial activities were DS-dependent and more sensitive to S. aureus than E. coli. This study demonstrated that the new derivatives were expected to be a promising potential antimicrobial agent in the food industry. • Chitosan oligosaccharide derivatives modified with cinnamyl onto the NH 2 position were synthesized. • The structure of derivatives was identified by FT-IR, NMR, and elemental analysis. • The derivatives showed higher antibacterial activities than chitosan oligosaccharide. [ABSTRACT FROM AUTHOR]

To protect the food contents from the exterior environmental stimulus and microbial contamination, herein, a photodynamic and photothermal synergistic antibacterial film (PP/GC film), as food packaging material, was synthesized by a solution-casting method. In brief, the film utilized gelatin‒carboxymethyl cellulose (GC) as the matrix for accommodating PCN@PDA nanoparticles (PPNPs), a porphyrin metal‒organic framework (PCN‒224) coating with a polydopamine layer. Various characterizations were implemented to demonstrate the successful formation of PPNPs, which simultaneously exhibited the methyl orange photodegradation ability and the photothermal conversion capability under 660 nm irradiation. The incorporation of 5% wt PPNPs significantly improved the mechanical properties, water barrier properties and UV shielding performance of the films. Notably, the PP/GC films had efficient antibacterial activity within short periods of irradiation time. Moreover, the as‒prepared films significantly improved the storage safety of pork, which can be a good development prospect in the food industry. • A novel PCN@PDA-loaded Gel-CMC composite film was successfully fabricated. • PCN@PDA endowed the film photodynamic and photothermal performance. • The PP/GC film eradicated more than 99% of E. coli and S. aureus within 15 min. • The PP/GC film improved tensile strength, water resistance and UV barrier properties. • The PP/GC film exhibited a promising application in pork preservation. [ABSTRACT FROM AUTHOR]

• Chitosan oligosaccharide derivatives bearing geraniol moieties were synthesized. • The structure of derivatives was confirmed by FT-IR, NMR, and elemental analysis. • The derivatives showed higher antibacterial activity than chitosan oligosaccharide. A new chitosan oligosaccharide derivative (COS-N-Ger), based on geraniol (Ger) modificated onto the NH 2 position of chitosan oligosaccharide (COS) via a facile method, was prepared and employed to evaluate in vitro antibacterial activity. The structures of COS-N-Ger derivatives were confirmed by FT-IR, 1H, 13C NMR, and elemental analysis. The characterization results showed successful synthesis of derivatives and the degrees of substitution (DS) of COS-N-Ger1-3 were from 0.260 to 0.283 with the yields up to 78 %. The in vitro antibacterial activity evaluation results presented a significant inhibition effect of COS-N-Ger1-3 derivatives on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as compared to COS. Moreover, their antibacterial activities were dose-dependent and more sensitive to S. aureus than E. coli. The results provide reliable theoretical supports for exploring the application of COS derivatives in the food industry as new potential antibacterial agents. [ABSTRACT FROM AUTHOR]