BIOSYNTHESIS OF SILVER NANOPARTICLES USING EXTRACTS OF TWO SPECIES OF PORTULACA AND THEIR ANTIBACTERIAL ACTIVITY

Portulaca oleraceae commonly known as Purslane and Portulaca quadrifida commonly known as chicken weed are consumed in salads, pickles, and soup in Asia, Africa, and Mediterranean region. In the traditional systems of medicine in Asia and Africa, they have been attributed to several pharmacological properties. Phytochemical investigations point to the presence of various beneficial constituents including flavonoids, tannins, alkaloids, polysaccharides, vitamins, unsaturated fatty acids among others. In this study, ethanolic extracts of P. oleraceae and P. quadrifida were prepared using microwave-assisted extraction. These extracts were used separately to synthesize silver nanoparticles, and their characteristics were studied using SEM, TEM, and FTIR analysis. The antibacterial activity was tested on different gram-positive and gram-negative bacteria using agar diffusion technique and measuring the zone of inhibition. The analysis of biogenic nanoparticles indicated the presence of chemical bonds between the surface of nanoparticles and phytochemicals. The nanoparticles were found to be mostly spherical of diameters ranging from 140 nm to 1.1 µm present in clusters. All the nanoparticle samples exhibited antibacterial activity against the tested bacteria. The microwave assisted extracts obtained from both the species of Portulaca were thus used for the synthesis of biogenic nanoparticles with antibacterial activity. The obtained silver nanoparticles could further be used in medical or pharmacological applications requiring antibacterial agents after proper safety and efficacy tests are conducted.