Antiproliferiative Activity of Biogenic Silver Nanoparticles Synthesized from Leonotis nepetifolia (L) on Human Cancer Cell lines

Abstract

Currently, nanobiotechnology is the growing science in the field of medicine employing silver nanoparticles to deliver drugs to target cancer cells and proved to be potential anticancer agents. In this study, silver nanoparticles were synthesized using leaf extract of Leonotis nepetifolia (L). Gas chromatography-mass spectrometry data showed a total of 13 phytochemical constituents identified from ethanolic leaf extract of Leonotis nepetifolia (L). The effect of physicochemical factors such as the reaction time, temperature, concentration of Silver nitrate, concentration of leaf extract and pH in the synthesis of silver nanoparticles. For biosynthesis, the optimal conditions were 1 mM silver nitrate, 0.1 ml of leaf extract at 80° for 90 min. Ultra violet-visible spectroscopy, field emission scanning electron microscopy; high-resolution transmission electron microscopy and various techniques characterized the synthesized AgNPs. The silver nanoparticles obtained had absorbance maxima at 398 nm, were spherical in shape, had an average particle size of 11.32 nm, polydispersity index 0.44, the zeta potential of -23.75.69 mv and were crystalline. A cytotoxicity study was conducted on two human cancer cell lines, pancreatic and ovarian, using sulforhodamine B assay. We had compared the cytotoxicity of biogenic silver nanoparticles with that of synthetic silver nanoparticles. Treatment of pancreatic and ovarian with different concentrations of silver nanoparticles inhibited the cell viability with half maximal inhibitory concentration values of 25.4 µg/ml and 23.9 µg/ml. In contrast, silver nanoparticles inhibited cell viability with half maximal inhibitory concentration values of 48.2 µg/ ml and 42 μg/ml, which were statistically significant (p<0.001), when compared with that of doxorubicin and Camptothecin. Leonotis nepetifolia mediated silver nanoparticles effectively reduced the proliferation of pancreatic and ovarian cancer cell lines than that of synthetic nanoparticles.