Facile green biosynthesis of silver nanoparticles using Pisum sativum L. outer peel aqueous extract and its antidiabetic, cytotoxicity, antioxidant, and antibacterial activity

Background The synthesis of silver nanoparticles (AgNPs) using food waste materials and their biomedical applications have garnered considerable attention recently. Methods Here, we investigated the synthesis of AgNPs using an aqueous extract of outer peel of Pisum sativum under different lighting conditions using standard procedures and explored their antidiabetic, cytotoxicity, antioxidant, and antibacterial potential. Results Characterization of AgNPs was done by Ultra Violet (UV-VIS) spectroscopy that showed absorption maxima at 456 nm for the samples exposed to laboratory lighting and at 464 nm for the samples exposed to direct sunlight, by scanning electron microscopy and energy-dispersive X-ray analysis that showed the surface nature and their elemental composition with a strong peak at 3 keV that corresponded to Ag (61.85 wt%), by Fourier-transform infrared spectroscopy that predicted the functional groups involved, and by X-ray powder diffraction that showed the structural properties. The average diameter of the synthesized AgNPs was calculated to be in the range of 10-25 nm. AgNPs exhibited promising antidiabetic activity as determined by inhibition of α-glucosidase (95.29% inhibition at 10 µg/mL and IC50 value of 2.10 µg/mL) and cytotoxicity (IC50 value 4.0 µg/mL as calculated from the slope equation) against HepG2 cells. Furthermore, they also exhibited moderate antioxidant activity (50.17% reduction of 1,1-diphenyl-2-picrylhydrazyl at 100 µg/mL) and antibacterial activity against four human pathogenic bacteria (as indicated by 8.70-11.10 mm inhibition zones on agar plates). Conclusion In conclusion, the results confirm that food waste can be used in the synthesis of AgNPs and that the latter have the potential for applications in various fields including diabetic and cancer treatments as well as in biomedicine for the manufacture of antibacterial coatings in medical devices and instruments.