Antibacterial activity and burn wound healing properties of biosynthesized silver nanoparticles using Mentha aquatica L. var.aquatica leaf extract

Abstract

Introduction: Mentha aquatica L. var. aquatica is a commonly used herb with medicinal prop-erties. Phytochemicals in the leaf extract act as reducing and stabilizing agents during the bio-synthesis of silver nanoparticles (SNPs). The bactericidal and wound healing properties of SNPs biosynthesized from M. aquatica L. var. aquatica leaf extract remain largely unexplored. This study therefore aimed to optimize SNP biosynthesis from M. aquatica L. var. aquatica leaf extract and investigate its antimicrobial properties against S. aureus (gram positive) and P. aeruginosa (gram negative) and potential applications in wound care. Methods: SNPs were synthesized using M. aquatica L. var. aquatica leaf extract; AgNO3 concen-tration, amount of initial leaf extract, and reaction time were analyzed to evaluate the efficiency of biosynthesis. SNPs were characterized through UV–Vis absorption, dynamic light scattering, scan-ning electron microscopy, and transmission electron microscopy. The functional groups of the leaf extract and SNPs were investigated using Fourier transform infrared spectros-copy (FTIR). Further analyses using the well diffusion method and burn wound contraction were performed to investi-gate the antibacterial activity and wound healing properties of SNPs in mice. Results: Optimum SNP synthesis was attained with 5 mM AgNO3, 40 mg/ml leaf extract, and a reaction time of 1 h. FTIR analysis confirmed the involvement of phytochemicals in SNP syn-thesis. SNPs had an average size of 67.05 nm with an irregular spherical shape. SNPs inhibited P. aeruginosa (ATCC 15442) and S. aureus (ATCC 6538); the bactericidal effects were greater on P. aeruginosa than S. aureus. SNP dressings accelerated the wound healing process without causing weight gain in mice.