Green synthesis of zinc nanoparticles using leaf extract of Clitoria ternatea and evaluation of its antimicrobial and anti-oxidant activity

Nanoparticles with antimicrobial activity are synthesized through the green route using various plant extracts. The study focused on the biosynthesis of zinc nanoparticles (ZnNPs) using Clitoria ternatea leaf extract. The synthesized nanoparticles were characterized through UV–visible spectroscopy, with absorbance peak of 430 nm, Dispersive Light Scattering analysis which showed a Zeta Potential of 10.4 mV, hydrodynamic diameter, and polydispersity index of 108.35 nm and 23.9 % respectively, Fourier Transformed Infrared Spectroscopy (FTIR) gave peaks for O-H stretching, C-H stretching, C-H bending, C O stretching, C C bending and zinc oxide. Scanning Electron Microscopy (SEM) revealed spherical to polymorphic nanoparticles of various sizes ranging from 38.67 nm to 134.7 nm. Further, the antimicrobial activities of ZnNPs against various pathogenic microbes were analyzed by disc diffusion assay with observed zones of inhibitions ranging from 8 mm to 22 mm. Cell viability assay was performed with THP-1 cells to evaluate the cytotoxicity of the synthesized nanoparticles. ZnNPs were found to be non-toxic upto 1 mg/ml. Further, ROS production was evaluated through nitroblue tetrazolium assay. A noticeable drop in ROS production was observed in cells pre-treated and post-treated with green synthesized Zn-NPs compared to LPS-treated control cells. These results concluded that plant extract-coated ZnNPs may be exploited to combat bacterial infections.