Synthesis of silver nanoparticles using plant extracts from Erythrina abyssinica aerial parts and assessment of their anti-bacterial and anti-oxidant activities

Abstract

In the present study, silver nanoparticles were synthesized using Erythrina abyssinica aerial parts as both reducing and capping agents. Three extracts were obtained from the plant using methanol, acetone and water. Successful biosynthesisof the silver nanoparticles was confirmed using Ultraviolet–Visible Spectrophotometry that recorded the Surface Plasmonic Resonance peak at around 420 nm. Phenyl, hydroxyl and carbonyl functional groups in Erythrina abyssinica were identified using Fourier Transform Infrared Spectrophotometry. Morphology of nanoparticles was studied using Scanning electron microscopy technique. The optimum conditions for nanoparticles synthesis were found to be; a pH of 13, 80 °C and 5 mM silver nitrate. The silver nanoparticles antioxidant and antimicrobial activities were comparable to ascorbic acid. A 73.4% scavenging activity at 400 μg/mL silver nanoparticle was obtained. At 100 μg/mL nanoparticle concentration, zones of inhibition for E. coli and Salmonella were found to be 17.8 ± 0.11 mm and 16.9 ± 0.10 mm, respectively.