Green synthesis, characterization and antimicrobial activity of nanosized Cuprous Oxide fabricated using aqueous extracts of Allium cepa and Raphanus sativus

Green synthesis of metal nanoparticles (MNPs) is attracting the attention of chemists as it is cost effective and environment benign technique.  Hence it is preferred to methods which use toxic reagents in the synthesis of MNPs. In. In this study, copper oxide nanoparticles (Cu2ONPs) were synthesized using Allium cepa (AC) and Raphanus sativus (RS) aqueous extracts.  The Cu2ONPs were investigated using UV–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). Peak positions (2θ values) in the XRD pattern of Cu2O NPs revealed (1 1 0), (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes of face-centered cubic (FCC) crystalline structure. The SEM images indicate spherical shape of Cu2ONPs having low particle size (12-30 nm). The present nanoparticles demonstrated substantial antimicrobial activity against harmful bacteria viz. S. aureus, and E. coli and also against C. albicans fungal species. The current study reveals efficacy of Allium cepa (Onion) and Raphanus sativus (Radish) aqueous extracts as reducing and capping agent for the green synthesis of Cu2O NPs. The copper nanoparticles derived from Raphanus sativus (RS) showed justifiably low grain size and comparable to recently studied copper nanoparticles prepared using plant extracts.