Antimicrobial activities of biosynthesized silver nano particles from leaves extract of some medicinal plants

Abstract

The antimicrobial activity of biosynthesized silver nanoparticles (AgNPs) from the leaves of four medicinal plants, Carica papaya (CP), Moringa oleifera (MO), Mangifera indica (MI) and Garcinia kola (GK) were assessed against selected gram positive and gram-negative bacteria. Method of synthesis of nanoparticles utilized was the eco-friendly Bio-based method using plant leaves extract as reducing and stabilizing agents. Two different ratios for each plant extract and silver nitrate (1:1 and 1:2) respectively were used. Particle characterization was carried out using visual inspection and UV-Vis spectrophotometry. Antimicrobial activity was assessed using agar diffusion method. Visual inspection revealed gradual color change from golden yellow to dark brown, confirming nanoparticles formation. The surface plasmon resonance peak was between 416 and 438 nm for the silver nanoparticles. The minimum inhibitory concentration ranged from 3.125 - 12.5µg/ml. In conclusion, all four biogenic silver nanoparticles have reasonable antimicrobial activity with ratio 1:2 being more potent.