Green synthesis of silver nanoparticles using tinospora cordifolia extract and evaluation of its antimicrobial activity

Abstract

Background: With the threat of the growing number of bacteria resistant to different antibiotics, the re-emergence of previously deadly infections and the emergence of new infections, there is an urgent need for novel therapeutic agent. Silver in the nano form, which is being used increasingly as bactericides, may extend its bactericidal application to emerging and re-emerging multidrug-resistant pathogens, the main cause of nosocomial diseases worldwide. newline newlineAim: The aim of the present study was to determine the bactericidal efficacy of green synthesized silver nanoparticles with its membrane destroying property using emerging and re-emerging pathogenic bacteria. newline newlineMaterials and Methods: In the present study, bactericidal assessment of silver nanoparticles with different antibiotics was determined against emerging Bacillus megaterium MTCC 7192 and re-emerging Escherichia coli MTCC 443, Pseudomonas aeruginosa MTCC 741, and Staphylococcus aureus MTCC 3160 pathogenic bacteria by agar well diffusion method. Interaction of silver nanoparticles towards bacterial membrane was carried to understand the probable bactericidal actions of silver nanoparticles, which was further confirmed by respiratory chain dehydrogenases, Zeta potential, Scanning Electron Microscopy (SEM) and Gas Chromatography- Mass Spectrometry (GC-MS). newline newlineResults and Discussion: In this work, we observed genuine bactericidal property of silver nanoparticles as compare to broad spectrum antibiotics against emerging and re-emerging mode. The binding affinity of silver nanoparticles towards bacterial membrane induced loss of catalytic activity for respiratory chain dehydrogenases. After being exposed to nanoparticles, the membrane becomes scattered from their original ordered arrangement based on SEM observation. Moreover, our results also suggested that alternation of zeta potential enhanced membrane permeability, and beyond a critical point, it leads to cell death. The leakages of intracellular constituents were confirmed by GC MS.