Biosynthesis and characterization of gold nanoparticles: Kinetics, in vitro and in vivo study

This study reports a facile, cost effective, nontoxic and eco-friendly method for the synthesis of gold nanoparticles. In this paper, leaf extract of Mentha piperita was successfully used to reduce chloroauric acid, leading to synthesis of gold nanoparticles (AuNPs). The synthesized nanoparticles were further characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy and field emission scanning electron microscopy. Kinetics studies like effect of volume of leaf extract, precursor, pH, temperature for the synthesis of AuNPs were studied spectrophotometrically. Synthesized AuNPs were found to possess hexagon structure where size of nanoparticles was ~78nm in diameter. These biologically synthesized AuNPs exhibited significant activity against cancerous cell lines MDA-MB-231 and A549 and was compared with the normal 3T3-L1 cell line. Anti-inflammatory and analgesic activities were studied on a Wistar rat model to gauge the impact of AuNPs for a probable role in these applications. AuNPs gave positive results for both these activities, although the potency was less as compared to the standard drugs. These results suggested that the leaves extract of Mentha piperita is a very good bioreductant for the synthesis of AuNPs and have potential for various biomedical and pharmaceutical applications.