Phytochemical studies and evaluation of silver nanoparticles synthesized from <i>Solanum elaeagnifolium</i> leaves extract for antioxidant and antibacterial activities

Abstract

Solanum elaeagnifolium is a medicinal plant in the Solanaceae family and the leaves extract have traditionally been used to treat several diseases, including skin infections, respiratory problems, and digestive disorders. The purpose of the study was to formulate silver nanoparticles (AgNPs) from the leaves extract of Solanum elaeagnifolium using the green synthesis method and to evaluate the formulated nanoparticles using scanning electron microscope (SEM) and X-ray diffraction (XRD). The powdered leaves were analyzed for macroscopic, microscopic, and physicochemical characteristics before being extracted using a Soxhlet apparatus. The antioxidant effect was analyzed using 2,2-diphenyl-1-picryl hydrazyl (DPPH). The disk diffusion method was used for assessing the antibacterial activity. Microscopic examinations confirmed the existence of stellate trichomes. Phytochemical screening, confirmed the presence of flavonoids, alkaloids, tannins, saponins, triterpenoids, steroids, and cardiac glycosides. SEM revealed a porous, spherical and crystalline structure with particle sizes of 70-95 nm. The DPPH assay revealed IC₅₀ values of 3.40, 2.30 and 1.40 mg/mL for the methanolic extract, silver nanoparticles and ascorbic acid respectively. The results of the antioxidant studies revealed that the formulated silver nanoparticles had higher antioxidant activity than the leaves extract at all concentrations. The leaves extract and silver nanoparticles demonstrated significant antibacterial activity against all the bacteria used in the study with zones of inhibition ranging from 2.9-4.8 mm and 5.7-9.2 mm respectively. The formulated silver nanoparticles demonstrated significant antibacterial and antioxidant effects as a result of the presence of some secondary metabolites such as phenols, saponins, flavonoids and tannins in the leaves extract.