Phytochemical Screening and In Vitro Antimicrobial Activity of Desmodium triflorum Against Escherichia coli, Enterococcus faecalis, and Klebsiella pneumoniae

Abstract

Emergence of multidrug resistant microorganisms become a major threat to treat gastroenteric diseases. Phytomedicines, derived from diverse medicinal plants in Sri Lanka, offer potent antimicrobial agents against microorganisms, making them a valuable alternative to antibiotics in treating gastroenteric diseases. This study aims to control gastroenteric diseases causing microorganisms by Desmodium triflorum plant extracts. Crude plant extracts were obtained with maceration; using Hexane, Dichloromethane (DCM), Ethyl acetate, Acetone and Methanol solvents separately. Antimicrobial activity of plant extracts was investigated by Kirby-Bauer disk-diffusion method against Klebsiella pneumoniae, Escherichia coli, and Enterococcus faecalis. Zone Of Inhibition (ZOI) was measured and calculated mean ZOI were interpreted based on CLSI zone dimeter breakpoints. All extracts from D. triflorum showed significant difference (P≤0.05) in antimicrobial activity against tested microorganisms. DCM extracts of D. triflorum, showed remarkable in vitro antimicrobial activity by suppressing E. faecalis with the highest mean of ZOI (9.333± 0.577 mm). Minimum inhibitory concentrations (MIC) of DCM extract from D. triflorum were determined by microbroth dilution method. D. triflorum showed MIC of 10.5 mg/mL for K. pneumoniae, 21 mg/mL for E. coli, and 21 mg/mL for E. faecalis. Preliminary phytochemical analysis revealed the presence of terpenoids in hexane extract, alkaloids, terpenoids, saponins in DCM extract, alkaloids, saponins in ethyl acetate extract, alkaloids, saponins in acetone extract, and phenols, tannins, alkaloids, saponins, terpenoids, flavonoids in methanol extract obtained from D. triflorum. DCM extract of D. triflorum was subjected to GC–MS analysis to identify the likely compounds responsible for the antimicrobial properties. Ten compounds in D. triflorum were identified as potential contributors to its antimicrobial activity. The highest percentage of total observed as n[1]Hexadecanoic acid which is 3.927%. Present study concludes DCM is the most effective solvent for solubilizing antimicrobial compounds. The highest inhibitory action of D. triflorum was demonstrated against E. faecalis. Isolated active compounds from D. triflorum will be a potential source for the synthesis of novel drugs to control the pathogenicity of E. faecalis by addressing multidrug resistance in gastroenteric microorganisms.

Keywords: Desmodium triflorum, Multidrug resistant, Antimicrobial activity, DCM extract, GC-MS analysis