Microwave Assisted One-Pot Green Synthesis of Silver Nanoparticles Using Leaf Extracts from Vigna Unguiculate: Evaluation of Antioxidant and Antimicrobial Activities

Abstract

Oxidative stress is caused by the increased levels of free radicals in the body which leads to various diseases. Antioxidants are known to reduce the risk of diseases caused by oxidative stress as they have the ability to donate electrons to these harmful free radicals. In addition to the natural antioxidants present in fruits and vegetables, synthetic antioxidants are also available. With the emergence of nanotechnology, the applications possessed by nanoparticles are limitless. One such application is in nanomedicine where nanoparticles are incorporated to study biological systems. The properties of the nanoparticles depend on the type of metal used and the method of synthesis. The use of plants for the production of silver nanoparticles (AgNPs) is key point of interest as it is rapid, eco-friendly, non-pathogenic and economical. Furthermore, this “Green synthesis” requires a single step for the biosynthesis of the nanoparticles as the silver ions are reduced and stabilized from the biomolecules present in the plant extract. In this study, cowpea leaf extracts were used for the on-pot green synthesis of silver nanoparticles to determine its antioxidant properties using phytochemical assays; Total flavonoid content (TFC), total phenolic content (TPC), total antioxidant activity (TAC), and free radical scavenging assays; Ferric reducing antioxidant properties (FRAP), ABTS and DPPH. The antibacterial activities were assessed by well diffusion method using gram positive (Staphylococus aureus) and gram negative (Escherichia coli) bacteria.