Silver nanoparticles from methanolic stem extract of Gymnema sylvestre and its characterisation studies

Abstract

In this approach silver nanoparticles (AgNPs) were synthesised from Gymnema sylvestre stem extract. Gymnema sylvestre herb exhibits wide range of therapeutic properties. Phytochemical studies of this plant extract revealed the presence of alkaloids, flavonoids, tannins and glycosides. These phytoconstituents were responsible for the reduction of silver ions to silver nanoparticles. The bioreduced silver nanoparticles were characterised by UV-visible spectroscopy, fourier transform infrared spectroscopy (FTIR), x-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM). The free radical scavenging activity of stem extract of Gymnema sylvestre was also evaluated using DPPH assay. The free radical scavenging capacity of plant extract as well as silver nanoparticles derived from same plant extracts was done. DPPH radical scavenging analysis of Gymnema sylvestre stem extract was found to be around 56.25% which was lower than the leaf extract of Gymnema sylvestre. DPPH radical scavenging ability of Gymnema sylvestre stem extract was found to be 56.25%. Antimicrobial activity of these silver nanoparticles was examined through disc diffusion method. Zone of inhibition formed against silver nanoparticles at different concentrations 30, 60, 100 μg/μl was studied. Zone formation was found to be higher in gram negative microorganism at concentration of 100 μg/μl. This study showed that the less used stem part of Gymnema sylvestre which has an extensive therapeutic value can be effectively used for green synthesis of silver nanoparticles.