Comparative studies of sunlight mediated green synthesis of silver nanoparaticles from Azadirachta indica leaf extract and its antibacterial effect on Xanthomonas oryzae pv. oryzae

Abstract

Biogenic synthesis of silver nanoparticle (AgNPs) has attracted worldwide attention as it is cheap and non-toxic. Therefore, in present study sunlight mediated silver nanoparticle was synthesized from Azadirachta indica A. Juss (Neem) leaf extract. Various combinations i.e., reducing agent (5, 10, 15 and 20 ml leaf extract), substrate concentration (1 mM AgNO3) and sunlight durations (5, 10, 15 and 20 min) were assessed for their ability to synthesized stabilized AgNPs. Leaf extract provide both reducing and capping agent, while sunlight served as catalyst for the synthesis process. The green synthesized AgNPs were characterized using change in color due to Surface Plasmon Resonance further analyzed by UV–visible spectroscopy, dynamic light scattering for size, polydispersity index and zeta potential for stability studies and Fourier Transform Infrared Spectroscopy (FT-IR). The smallest size of synthesized AgNPs was 67.94 ± 0.72 nm synthesized using to 20 ml of reducing agent (leaf extract) and 5 min of sunlight exposure. Antibacterial activity of synthesized silver nanoparticle was examined against plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) and showed a good antimicrobial activity compared to 200 mg/l of streptocycline. Keywords: Sunlight, Azadirachta indica A. Juss (Neem), Green synthesis, Silver nanoparticles, Dynamic light scattering, FTIR, Xanthomonas oryzae pv. oryzae (Xoo)