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The aim of the study was to characterize and compare films made of cellulose nanocrystals (CNC), nano-fibrils (CNF), and bacterial nanocellulose (BNC) in combination with chitosan and alginate in terms of applicability for potential food packaging applications. In total, 25 different formulations were made and evaluated, and seven biopolymer films with the best mechanical performance (tensile strength, strain)—alginate, alginate with 5% CNC, chitosan, chitosan with 3% CNC, BNC with and without glycerol, and CNF with glycerol—were selected and investigated regarding morphology (SEM), density, contact angle, surface energy, water absorption, and oxygen and water barrier properties. Studies revealed that polysaccharide-based films with added CNC are the most suitable for packaging purposes, and better dispersing of nanocellulose in chitosan than in alginate was observed. Results showed an increase in hydrophobicity (increase of contact angle and reduced moisture absorption) of chitosan and alginate films with the addition of CNC, and chitosan with 3% CNC had the highest contact angle, 108 ± 2, and 15% lower moisture absorption compared to pure chitosan. Overall, the ability of nanocellulose additives to preserve the structure and function of chitosan and alginate materials in a humid environment was convincingly demonstrated. Barrier properties were improved by combining the biopolymers, and water vapor transmission rate (WVTR) was reduced by 15–45% and oxygen permeability (OTR) up to 45% by adding nanocellulose compared to single biopolymer formulations. It was concluded that with a good oxygen barrier, a water barrier that is comparable to PLA, and good mechanical properties, biopolymer films would be a good alternative to conventional plastic packaging used for ready-to-eat foods with short storage time.

Nanoparticles based on chitosan modified with epigallocatechin gallate (EGCG) were synthetized by nanoprecipitation (EGCG-g-chitosan-P). Chitosan was modified by free-radical-induced grafting, which was verified by Fourier transform infrared (FTIR). Furthermore, the morphology, particle size, polydispersity index, and zeta potential of the nanoparticles were investigated. The grafting degree of EGCG, reactive oxygen species (ROS) production, antibacterial and antioxidant activities of EGCG-g-chitosan-P were evaluated and compared with those of pure EGCG and chitosan nanoparticles (Chitosan-P). FTIR results confirmed the modification of the chitosan with EGCG. The EGCG-g-chitosan-P showed spherical shapes and smoother surfaces than those of Chitosan-P. EGCG content of the grafted chitosan nanoparticles was 330 μg/g. Minimal inhibitory concentration (MIC) of EGCG-g-chitosan-P (15.6 μg/mL) was lower than Chitosan-P (31.2 μg/mL) and EGCG (500 μg/mL) against Pseudomonas fluorescens (p < 0.05). Additionally, EGCG-g-chitosan-P and Chitosan-P presented higher Staphylococcus aureus growth inhibition (100%) than EGCG at the lowest concentration tested. The nanoparticles produced an increase of ROS (p < 0.05) in both bacterial species assayed. Furthermore, EGCG-g-chitosan-P exhibited higher antioxidant activity than that of Chitosan-P (p < 0.05) in 2,2′-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and ferric-reducing antioxidant power assays. Based on the above results, EGCG-g-chitosan-P shows the potential for food packaging and biomedical applications.

A series of novel coumarin-3-carboxamide derivatives were designed and synthesized to evaluate their biological activities. The compounds showed little to no activity against gram-positive and gram-negative bacteria but specifically showed potential to inhibit the growth of cancer cells. In particular, among the tested compounds, 4-fluoro and 2,5-difluoro benzamide derivatives (14b and 14e, respectively) were found to be the most potent derivatives against HepG2 cancer cell lines (IC50 = 2.62–4.85 μM) and HeLa cancer cell lines (IC50 = 0.39–0.75 μM). The activities of these two compounds were comparable to that of the positive control doxorubicin; especially, 4-flurobenzamide derivative (14b) exhibited low cytotoxic activity against LLC-MK2 normal cell lines, with IC50 more than 100 μM. The molecular docking study of the synthesized compounds revealed the binding to the active site of the CK2 enzyme, indicating that the presence of the benzamide functionality is an important feature for anticancer activity.

Various dimeric derivatives of the glycopeptide antibiotic teicoplanin were prepared with the aim of increasing the activity of the parent compound against glycopeptide-resistant bacteria, primarily vancomycin-resistant enterococci. Starting from teicoplanin, four covalent dimers were prepared in two orientations, using an α,ω-bis-isothiocyanate linker. Formation of a dimeric cobalt coordination complex of an N-terminal L-histidyl derivative of teicoplanin pseudoaglycone has been detected and its antibacterial activity evaluated. The Co(III)-induced dimerization of the histidyl derivative was demonstrated by DOSY experiments. Both the covalent and the complex dimeric derivatives showed high activity against VanA teicoplanin-resistant enterococci, but their activity against other tested bacterial strains did not exceed that of the monomeric compounds.