Biosynthesis and Antibacterial Activity of Metal Oxide Nanoparticles Using Brassica oleracea subsp. botrytis (L.) leaves, an Agricultural Waste

Abstract

Plant-extracted metabolites act as a reducing and stabilizing agent for the synthesis of metal nanoparticles. Brassica oleracea subsp. botrytis (L.) leaves are commonly discarded in huge quantities from vegetable markets, and it contribute to municipal solid waste. Hence, it was used for the synthesis of nanoparticles of oxides of metals, viz. copper, iron, lead and zinc. The synthesis of metal nanoparticles was indicated by absorption maxima peaks obtained from UV–Visible spectrophotometer. Metal nanoparticles were characterized by using AFM, FT-IR, FEG–SEM, FEG–TEM and SAED pattern. The average size of all metal oxide nanoparticles was found to be within 100 nm. The chemical composition of metal nanoparticles was determined by using SEM–EDAX. The SAED patterns revealed that the oxides of copper and zinc were polycrystalline, while that of iron and lead oxides were crystalline in nature. The synthesized ZnO nanoparticles were found to have antibacterial activity against E. coli and S. aureus as test organisms. Hence, it can find applications in cosmetics, wound dressings, textiles, etc. Thus, the present work can lead to sustainable approach by incorporating benign, solvent-free, eco-friendly and economical process of metal nanoparticle synthesis using Brassica oleracea leaves, an agricultural waste which can further give commercial significance to these leaves.