Mechanistic Approach of Functionalized Noble Metal Nanoparticles Synthesis From Cassia auriculata L.

Biological resources have gained importance in the synthesis and applications of the nanomaterials. Plants reduce the metal ions faster than fungi or bacteria. This paper aims to extend our previous work to find out the biological components involved in the bio-reduction and stabilization of noble metals by using aqueous (dry leaf) extract of Cassia auriculata L. The extracellular synthesized AuNPs and AgNPs were characterized by UV–Vis spectroscopy and transmission electron microscope. The phytochemical analysis revealed phenols, flavonoids, tannins, cardiac glycosides and saponins. Two associated proteins were found capping on nanoparticles. The study proposes thermostable, polar phytochemicals and polar proteins responsible for the reduction and stabilization of AuNPs and AgNPs in solution controlling partly the size and shape of NPs.