Albizia amara Roxb. Mediated Gold Nanoparticles and Evaluation of Their Antioxidant, Antibacterial and Cytotoxic Properties

The bio-reduction of chloroauric acid (HAuCl4) into well dispersed gold nanoparticles (GNPs) was achieved using the Albizia amara Roxb. plant extract. The formation of GNPs was confirmed by a change of color from yellowish green to purple with a characteristic peak at 543 nm. Further, the characterization of the synthesized GNPs showed their crystalline nature, functional groups, size and dispersed shapes, purity and Bragg's reflections of face centered cubic structure. The zeta potential analysis revealed that A. amara GNPs did not aggregate and were quite stable which is in agreement with the constancy found during the dynamic light scattering measurements. During the DPPH assay, the GNPs and leaf aqueous extract showed the scavenging activity of 74 and 65 %, respectively and their in vitro IC50 inhibitory values (A mu g ml(-1)) were; 47.77 (HeLa) and 72.28 (Vero). The Gram positive, Staphylococcus aureus (MTCC 96) was found to be more sensitive to GNPs (16 mm) than the leaf aqueous extract (12 mm). In view of the recorded free radical, cytotoxic and antibacterial effects, the GNPs of A. amara could be a potential source for further research towards therapeutic development.