Identification of antiviral phytochemicals from cranberry as potential inhibitors of SARS-CoV-2 main protease (Mpro).

Cranberry phytochemicals are known to possess antiviral activities. In the current study, we explored the therapeutic potential of cranberry against SARS-CoV-2 by targeting its main protease (Mpro) enzyme. Firstly, phytochemicals of cranberry origin were identified from three independent databases. Subsequently, virtual screening, using molecular docking and molecular dynamics simulation approaches, led to the identification of three lead phytochemicals namely, cyanidin 3-O-galactoside, ß-carotene and epicatechin. Furthermore, in vitro enzymatic assays revealed that cyanidin 3-O-galactoside had the highest inhibitory potential with IC50 of 9.98 µM compared to the other two phytochemicals. Cyanidin 3-O-galactoside belongs to the class of anthocyanins. Anthocyanins extracted from frozen cranberry also exhibited the highest inhibitory potential with IC50 of 23.58 µg/ml compared to the extracts of carotenoids and flavanols, the class for ß-carotene and epicatechin, respectively. Finally, we confirm the presence of the phytochemicals in the cranberry extracts using targeted LC-MS/MS analysis. Our results, therefore, indicate that the identified cranberry-derived bioactive compounds as well as cranberry could be used for therapeutic interventions against SARS-CoV-2.

Metallic Nanoparticle Integrated Ternary Polymer Blend of PVA/Starch/Glycerol: A Promising Antimicrobial Food Packaging Material.

Advances in food processing and food packaging play a major role in keeping food safe, increasing the shelf life, and maintaining the food supply chain. Good packaging materials that enable the safe travel of food are often non-degradable and tend to persist in the environment, thereby posing a hazard. One alternative is to synthesize biodegradable polymers with an antimicrobial property while maintaining their mechanical and thermal properties. In the present study, biodegradable composites of PVA-starch-glycerol (PSG) incorporated with CuO and ZnO nanoparticles (NPs) were prepared as PSG, PSG-Cu, PSG-Zn, and PSG-CuZn films. Scanning electron microscopy, energy dispersive x-ray analysis, and thermogravimetric analysis were performed to study and characterize these films. The water barrier properties of the films improved significantly as the hydrophobicity of the PSG-CuZn film increased by 32.9% while the water absorptivity and solubility decreased by 51.49% and 60% compared to the PSG film. The Young's modulus of the films incorporated with CuO and ZnO nanoparticles was lower than that reported for PVA, suggesting that the film possessed higher flexibility. The thermogravimetric analysis demonstrated high thermal stability for films. Biosynthesized CuO and ZnO nanoparticles exhibited antifungal activity against vegetable and fruit spoilage fungi, and hence the fabricated polymers incorporated with nanoparticles were anticipated to demonstrate an antifungal activity. The nanoparticle incorporated films exhibited fungicidal and bactericidal activity, suggesting their role in extending the shelf life of packaged food. The result of ICP-OES studies demonstrated the steady release of ions from the polymer films, however, EDX analysis demonstrated no leaching of CuO and ZnO nanoparticles from the films, thus ruling out the possibility of nanoparticles entering the packaged food. The strawberries wrapped with the fabricated films incorporated with nanoparticles demonstrated improved shelf life and retained the nutritional quality of the fruit. Among the four films, PSG-CuZn was the most promising for food wrapping since it exhibited better water-resistance, antimicrobial, thermal, and mechanical properties.