In vitro antibacterial effect of the leaf extract of Murraya koenigii on cell membrane destruction against pathogenic bacteria and phenolic compounds identification

Introduction: Different parts of Murraya koenigii are traditionally used for treating various infections. Multidrug-resistant bacteria is considered one of the most significant threats to public health and urgent attention is needed to address this pressing problem. The aim of this study was to examine the antibacterial effect of the leaves and stems of the plant to identify and screen for phenolic compounds and to explore whether the potent plant extract had a destructive effect on the cell membrane. Materials and methods: Leaf and stem extracts extracts (hexane, chloroform, ethyl acetate and methanol) of the plant were screened using micro broth dilution methods. Nine strains of bacteria were used in this study. The identification of phenolic compounds was performed using UPLC, and the membrane destruction was observed using SEM. Results: The ethyl acetate extract of the leaves gave the lowest MIC value (15.63 μg/mL) against S. aureus, E. coli 0157:H7. V. alginolyticus, V. parahaemolyticus and Y. enterocolitica. Among the tested compounds, the least MIC value of 31.25 μg/ml was observed from myricetin and quercetin against Y. enterocolitica (ATCC 23715). The two major peaks matched with quercetin and myricetin aglycons at the retention time of 3.853 and 4.160 min and two myricetin and quercetin derivatives at the retention time of 4.162 and 4.406. The alteration of the cellular morphology of the bacteria which comprises alteration in their arrangement, rigidity and destruction of the membrane was observed after treatment with plant extract. Conclusions: The findings of this research establish the efficacy of ethyl acetate leaf extract of this plant in treating diseases associated with pathogenic bacteri