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Incorporation of betel leaf extract (BE) into chitosan and chitosan/vanillin (CH/Vn) blend films was carried out in order to improve the mechanical, thermal and antimicrobial properties of chitosan films. The influence of morphology, crystallinity and glass transition temperature (T g) on the mechanical properties of chitosan/betel leaf extract (CH/BE) and chitosan/vanillin/betel leaf extract (CH/Vn/BE) films was analyzed. The smooth homogeneous morphology, decreased crystallinity and shift of T g to a higher value resulted in improved mechanical properties. Scanning electron microscopy, atomic force microscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and Fourier transform infrared studies indicated that inclusion of BE into CH/Vn led to enhanced physicochemical properties. The results of antimicrobial activity, oxygen gas permeability and contact angle measurements confirmed the significantly improved activity and hydrophilic nature of the blend films compared with those of pure chitosan. The authors confirmed that the plant-extract-doped polymer material can be a novel antimicrobial agent for food-packaging application. Addition of BE at a higher weight percentage is a major limitation that has a major influence on the properties of the blend films.

With the intent to discover new antituberculosis (TB) compounds, coumarinthymidine analogs were synthesized using second-order nucleophilic substitution reactions of bromomethyl coumarin with thymidine. The newly synthesized coumarin-thymidine conjugates (1a-l) were characterized using IR, NMR, GC-MS, and CHN elemental analysis. The novel conjugates were found to exhibit potent anti-TB activity against the Mycobacterium tuberculosis H 37 Rv strain, with minimum inhibitory concentrations (MIC) of the active compounds ranging between 0.012 and 0.482 µM. Compound 1k was established as the most active candidate with a MIC of 0.012 µM. The toxicity study on HEK cells confirmed the nontoxic nature of compounds 1e, 1h, 1i, 1j, and 1k. Also, the most active compounds (1k, 1j, and 1e) were stable in the pH range from 2.5 to 10, indicating compatibility with the biophysical environment. Based on the pK a studies, compounds 1k, 1j, and 1e are capable of crossing lipid-membrane barriers and acting on target cells. Molecular docking studies on the M. tuberculosis β-oxidation trifunctional enzyme (PDB ID: 7O4V) were conducted to investigate the mechanisms of anti-TB activity. All compounds showed excellent hydrogen binding interactions and exceptional docking scores against M. tuberculosis, which was in accordance with the results.Compounds 1a-l possessed excellent affinity to proteins, with binding energies ranging from −7.4 to −8.7 kcal/mol.

Herein, an efficient and convenient method for the synthesis of 4-(substitutedphenyl)-1,2-dihydro-2-oxo-6-(2-oxo-2H-benzo[g]chromen-3-yl)pyridine-3-carbonitrile derivatives have been reported using ammonium acetate as catalyst. The structures of synthesized compounds were confirmed using FT-IR, 1H, 13C-NMR and LC-MS spectroscopic techniques. The synthesized compounds have been evaluated for antibacterial activity against bacterial strains by agar diffusion method at different concentrations. Further, all the targeted compounds were screened for anti-oxidant and anti-cancer studies by DPPH and MTT assay methods at different concentrations. Compound 4b displayed good antioxidant and anticancer (against MCF-7 cell line) activity. Further, the binding capability for the synthesized compounds (4a–j) was analyzed by molecular docking studies using human peroxiredoxin 5 (PDB ID: 1HD2) and P38 MAP kinase (PDB ID: 1OUK) protein. Further, the physicochemical properties were analysed from ADME studies respectively.

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