Anti-oxidant and Anti-microbial Activities of Silver Nanoparticles of Essential Oil Extracts from Leaves of Zanthoxylum ovalifolium

Aim: The present study was aimed to synthesis and characterization of silver nanoparticles (AgNPs) using Zanthoxylum ovalifolium leaf essential oil extracts and to screen the anti-oxidant and antimicrobial potential of the same. Place and Duration of Study: The studies were carried out at Department of Botany, AVK College for Women, Hassan and Department of Biochemistry, Aurora’s Degree & PG College, Hyderabad from July 2017 to June 2018 Methodology: The essential oil from leaves of Zanthoxylum ovalifolium was obtained by hydrodistillation and analyzed by GC and GC-MS. Synthesis of silver nanoparticles of essential oil extract was carried out and characterized by using UV-VIS spectroscopy and transmission electron microscopy (TEM).  The total phenolic and flavonoid contents were estimated in all the extracts. Furthermore, all the extracts were evaluated for anti-microbial activity against two gram-positive and two gram-negative bacteria and four pathogenic fungi using agar disc diffusion technique. Subsequently the minimum inhibitory concentration (MIC) was also determined. Results: The major compounds identified were Limonene, isofenchol, Geijerene, isothujanol,  Borneol, dihydrocarveol, isobornyl acetate, pregeijerene, b-elemene, trans-caryophyllene and Germacrene D. The TEM analysis of nanoparticles synthesized showed a size of 8 to 14 nm with a  lmax of 450nm. All the extracts were evaluated for in vitro anti-oxidant activity where the AgNP of essential oil extract showed maximum activity of 89.61% and 84.92% respectively for both DPPH free radical scavenging and Hydrogen peroxide free radical scavenging assays at a concentration of 100µg/ml. Among all the bacteria tested, B. subtilis was most susceptible at 100µg/ml with zone of inhibition of 22.5mm. While among all the fungi tested, A. niger inhibited more effectively by the AgNP of essential oil extract at 100µg/ml with a zone of inhibition of 16.2mm. Conclusion: The results obtained were remarkable suggesting that AgNP of essential oil extract possess excellent anti-oxidant and anti-microbial activity and can be an alternative bio-friendly source for various pharmaceutical industries.