Biosynthesis of Gold Nanoparticles using Leaf Extract of Desmodium gangeticum and their Antioxidant Activity

Chemical, physical, and biological methods have been developed to synthesis nanoparticles but chemical and physical methods are involved in the production of toxic byproducts which are hazardous moreover the methods are very expensive. To synthesis stable metal nanoparticles with controlled size and shape, there has been search for inexpensive, safe, and reliable and “green” approach. The present study reports an environmentally friendly, low cost, novel and rapid method for synthesis of silver nanoparticles. We have developed a green synthetic method for Gold nanoparticles using Desmodium gangeticum leaf extract which act as a reducing and capping agent. It was observed that use of Desmodium gangeticum leaf extract makes rapid and convenient method for synthesis of Gold nanoparticles and can reduce Gold ions in to Gold nanoparticles within few Minutes of reaction time. The prepared AuNPs showed surface Plasmon resonance centered at 525nm with average particle size of 16±4nm. The morphological studies of the biosynthesized nanoparticles are done using UV-vis, TEM, FESEM techniques. The nanoparticles formation takes place within short time as the reaction is completed few minutes. The EDAX and XRD confirm the crystallinity of the particles. This green-clean synthetic process is conducted in natural environmental conditions. Possible mechanism of the biosynthesis is studied by FTIR. The stability studies of the colloidal nanoparticles solution are done using Zeta potential analyzers which confirm that the solution is stable for many weeks. Study of bio-functionalized AuNP is done for in-vitro free radical scavenging activity using DPPH method. In free radical scavenging study, we observed that the AuNP mopped up the free radicals in dose dependent manner.