Biosynthesis of silver nanoparticles using the leaf and stem bark of Diospyros discolor Willd. (Ebenaceae)

The synthesis of nanoparticles using parts of plants is extremely attractive because it is environmentally friendly. This study examined the suitability of the leaf and stem bark extracts of the plant Diospyros discolor for the synthesis of silver nanoparticles. The reaction could be monitored by visual examination, because the formation of silver nanoparticles was accompanied by a color change of the solution. The characterization of silver nanoparticles was performed using UV-visible, particle size analyzer, and transmission electron microscopy analyses. We observed that the process of nucleation of the silver nanoparticles required several hours. The biosynthesis of silver nanoparticles using the stem bark extract was faster than that using the leaf extract. In addition, the volume ratio of the extracts and AgNO₃ solutions greatly affected the yield of silver nanoparticles. This effect was more significant in the case of the leaf extract. This biosynthesis successfully afforded spherical silver nanoparticles of about 30 nm in diameter, which were relatively stable on the basis of zeta potential measurements.