Green Synthesis of Gold Nanoparticles using Leaves Extract of Bauhinia tomentosa Linn and invitro Anticancer Activity

Metal nanoparticles have several applications such as optics, biomedical sciences, drug delivery, catalysis and electronics. The present investigation deals with the green synthesis of gold nanoparticles (AuNP) using leaves extract of Bauhinia tomentosa Linn and its invitro anticancer activity. Qualitative phytochemical analysis of the leaves extract showed the presence of tannins, saponins, flavonoids, alkaloids, proteins, steroids and quinones. Aqueous extract (pH 7.4 inherent pH of the extract) was reacted with 1mM Chloroauric acid (HAuCl4.3H2O) and kept at room temperature. The immediate change in color from pale yellow to ruby red indicated the reduction of Au ions to Au. The synthesized AuNP’s were monitored using UV-Visible spectrophotometer. Gold Surface Plasmon Resonance (SPR) occurred at 563 nm and steadily increased in intensity with longer duration of incubation time without shift in wavelength. FTIR spectra revealed the presence of reducing groups in the extract responsible for AuNP synthesis. FESEM analysis showed the presence of polydispersed spherical AuNP’s. EDAX confirmed the presence of elemental gold. HR-TEM showed that the gold nanoparticles were near spherical with average diameter 31.32 nm. The XRD peaks at 38.04, 44.12, 64.52, 77.49 and 81.53 corresponding to [111], [200], [220], [311] and [222] showed that the AuNP’s were nanocrystalline with fcc crystal structure. The in-vitro anticancer activity confirmed by MTT assay on the cell lines of laryngeal HEp-2 carcinoma cells showed IC50 values of extract at 53.125 μg/mL and AuNP’s at 34.375 μg/mL.