Chemical composition, antioxidant activity and antibacterial mechanism of action from Marsilea minuta leaf hexane: methanol extract

Abstract

Background In the present study, hexane: methanol (50:50) leaf extract of Marisela minuta has been evaluated for its chemical composition, antioxidant effect and the antimicrobial mechanism of action against food borne pathogenic bacteria.

Results The phytochemical evaluation of extract by GC/MS revealed the major abundance of benzoic acid-4-ethoxyethyl ester (43.39%) and farnesol acetate (18.42%). The extract exhibited potential antioxidant and free radical scavenging properties with promising antibacterial activities against the test pathogens withPseudomonas aeruginosa being the most susceptible with maximum inhibition zone (17mm) and IC50 value of 125µg, respectively. The significant (p < 0.05) increase in intracellular super oxide dismutase (SOD), protein leakage, extracellular alkaline phosphatase and lactate dehydrogenase in treated test pathogens suggested an increase in oxidative stress reveling the mechanism of action of phytochemicals. Scanning electron microscopy analysis of treated pathogens also showed swollen and distorted cells. The bioactive molecules in the extract were efficiently docked with virulent enzymes and farnesol acetate showed best energy value of − 5.19 and − 4.27kcal/mol towards Topoisomerase IV and SHV-2 respectively. Benzoic acid-4-ethoxyethyl ester showed best binding against TEM-72 with low binding energy value of − 4.35kcal/mol.

Conclusion Due to its antioxidant and antibacterial properties, the leaf extract of M. minuta may act as promising natural additives to prevent food spoilage bacteria.