Phytogreen synthesis of multifunctional nano selenium with antibacterial and antioxidant implications

Abstract

The exploitation of plant extracts for the synthesis of nano selenium having antibacterial and antioxidant activities is an exciting approach to counteract the prevalence of infections caused by antibiotic-resistant bacteria, which holds relevance for medical and food industries. In the present work, a green and facile method for the preparation of nano selenium (nSe) using the fruit extract of Indian gooseberry (Phyllanthus Emblica) has been reported. The optical and structural properties of the as-synthesized nSe were studied through various characterization techniques. Eventually, the antioxidant potential of nSe was investigated via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radical scavenging assays. Parallely, the antibacterial activity of nSe against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa was evaluated. The antioxidant assays indicated that even low dosage of nSe showed excellent activity with EC50 values of 0.21 μg ml-1 and 3.34 μg ml-1, respectively. Moreover, nSe exhibited significant inhibition in bacterial growth at low minimum inhibitory concentration (MIC) values against Escherichia coli (16 μg ml-1), Staphylococcus aureus (32 μg ml-1) and Pseudomonas aeruginosa (48 μg ml-1) compared to MIC values for standard drug ampicillin. Importantly, nSe did not induce any cytotoxic effects on normal human keratinocytes (HaCaT) at the tested concentrations; representing their biocompatible nature. The data obtained demonstrated the versatility of phytogreen nSe as a potent antioxidant and antibacterial agent to effectively prevent as well as treat multidrug-resistant bacterial infections.