Investigations on Synergistic and Antioxidant Actions of Medicinal Plant- Based Biosynthesis of Zinc Oxide Nanoparticles Against E.coli and K. pneumonia Bacteria.

INTRODUCTION: Bacterial resistance to multiple drugs is increasing at an alarming rate in the current era and nanotechnology is one of the effective and novel approaches to overcome drug resistance. METHODS: Zinc Oxide Nanoparticles (ZnO NPs) have stronger antibacterial activity and are regarded as bio-safe nanomaterial. The aim of the present study is to synthesize the ZnO NPs using Aloe vera leaves extract and to investigate the synergistic effects and antioxidant actions of biosynthesized ZnO NPs against gram-negative bacteria E.coli and K. pneumoniae. The synergistic effect of ß-lactam antibiotics (meropenem and ciprofloxacin) was tested along with ZnO NPs using Kirby's disc diffusion assay. The antioxidant activity was investigated by α, α-diphenyl-ß- picrylhydrazyl (DPPH) method. RESULTS: Results of the study revealed that the antibacterial activity of the selected antibiotics was much enhanced by ZnO NPs than the antibiotics alone. The resistant antibiotic (ciprofloxacin) became sensitive when combined with ZnO NPs. The antioxidant activity reveals that biosynthesized ZnO NPs possess significantly higher (p<0.05) antioxidant activity (77%). CONCLUSION: The findings reveal that biosynthesized ZnO NPs have a much more eco-friendly approach. It can act as a strong potentiator of ß-lactam antibiotics and put forward the possibility to use them effectively in targeted drug delivery, pharmaceuticals and biomedical fields.

A review on sources of heavy metals, their toxicity and removal technique using physico-chemical processes from wastewater.

The world is facing environmental pollution and is in an alarming situation due to industrialization and urbanization. Especially, industrial wastewater discharge is causing serious pollution in the environment (water, soil, and air) and has become a challenge for researchers and scientists. Wastewater contains heavy metals like Cu, Ni, Cr, Pb, and Ar and causes toxicity in living beings and the environment. In this review, the sources of heavy metals and their toxicological effects on the environment have been reviewed. Various remediation techniques such as reverse osmosis, chemical precipitation, and ultrafiltration are being used for the treatment of wastewater, but still are limited in their efficiencies, residues, cost, and versatility. In this study, the most promising wastewater treatment technique, the physic-chemical technique, has been reviewed along with its working mechanism and efficiency. Further, the pros and cons of this technique and sub-techniques have also been reviewed to provide a basic understanding to beginners and a pathway to experts in the selection of better techniques.