Plant-mediated Green Synthesis of Mno2 Nanoparticles using Annona Muricata Flower Extract for Antibacterial and Antifungal Applications

Abstract

The current work deals with a green and sustainable approach for the biosynthesis of manganese dioxide (MnO2) nanoparticles by using Annona muricata flower extract as a reducing, capping and stabilizing agent. The phytoconstituents present in the flower extract reduce the Mn precursor solution to form MnO2 nanoparticles. MnO2 nanoparticles were synthesized by treating an aqueous solution of manganese precursor with various concentrations of A. muricata flower extract under optimized conditions, which resulted in a prominent colour change. The formed MnO2 nanoparticles were isolated and characterized by XRD, FT-IR, UV-Visible, FE-SEM and EDX analysis. UV-visible spectrophotometry confirmed the formation of MnO2 nanoparticles based on their characteristic absorption bands. The crystal structure and phase purity were analysed by X-ray diffraction. The surface morphology and nano structural features were examined by field emission-scanning electron microscopy. The characteristic elemental composition was analysed by energy-dispersive X-ray spectroscopy. Fourier-transform infrared (FT-IR) spectroscopy established the participation of phytochemical functional groups in reducing, stabilizing, and forming Mn-O bonds. The green-synthesized MnO2 nanoparticles demonstrated considerable antibacterial activity against the tested pathogenic bacteria and good antifungal activity against the tested pathogenic fungi. The comparison between the biologically synthesized and chemically synthesized MnO2 nanoparticles revealed the benefits of the green approach. In general, the present study offers a new protocol for MnO2 nanoparticle synthesis using Annona muricata flower extract that is easy to perform, economical, environmentally friendly, and promising in biomedical and antimicrobial applications.