Green Synthesis of Gold Nanoparticles from Vitex negundo Leaf Extract to Inhibit Lipopolysaccharide-Induced Inflammation Through In Vitro and In Vivo

Abstract

Gold nanoparticles (AuNPs) have wide applications in the field of diagnosis and treatment of diseases which are attributed to their compatibility and high efficiency of drug delivery, because of their eco-friendly nature and easy handling. In the current study, we have used an extract of Vitex negundo, a traditional anti-inflammatory folk medicine in India and synthesized gold nanoparticles (VnAuNPs), to know the effects of anti-bacterial, antioxidant, and anti-inflammatory properties both in vivo and in vitro. V. negundo leaf extracts (VnLE) per se yielded high flavonoids, saponins, tannins, alkaloids, glycosides, phenols, terpenoids. The synthesized VnAuNPs in leaf extracts was confirmed by UV–vis spectra at 543 nm and further by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and through Dynamic light scattering (DLS). The FTIR showed the peaks at 3345, 1638, 692, 683, 662 cm−1 which are responsible for the reduction and capping of gold nanoparticles. The size and shape of the AuNPs were determined by SEM. DLS study analysed the particle size distribution of AuNPs. The VnAuNPs showed significant antibacterial activity on both gram positive and negative bacteria. VnAuNPs also showed strong antioxidant (DPPH, H2O2 scavenging, Nitric oxide scavenging power and reducing power) activities when compared to VnLE extract. The VnAuNPs exhibited strong anti-inflammatory activities (COX-2, lipoxygenase and xanthine oxidase inhibitory activity) in in vitro (HeLa cell model) and in vivo study of carrageenan induced paw edema model in Swiss albino mice (paw edema and acetic acid-induced writhing test). Results suggested that the synthesized VnAuNPs are potential candidates for treating inflammatory diseases and may find application in clinical studies.