Molecular diversity of bioactive compounds from horned melon peel: Solvent dynamics, antibacterial activity against multidrug-resistant Pseudomonas aeruginosa and in silico interactions with virulence factors

Abstract

This study examines chemical composition and the antibacterial properties of various hydro-ethanolic extracts of Cucumis metuliferus E. Mey peel against the multidrug-resistant pathogen Pseudomonas aeruginosa. Several parameters, including ethanol concentration, extraction time, and ultrasonic power, were used in the ultrasound-assisted extraction of C. metuliferus peel. UHPLC-QToF-MS analysis was used to explore the molecular diversity of bioactive compounds in the sample extracts (25 in total), identifying nine hydroxybenzoic acid derivatives and eleven other compounds. Furthermore, antibacterial activity of these extracts was determined. Four of the tested extracts exhibited promising antibacterial properties, with MIC value 0.25 mg/mL and MBC value 0.5 mg/mL. Molecular docking simulations were employed to identify bioactive compounds within the extracts that target some P. aeruginosa virulence factors, specifically elastase B and lipase A. The results revealed that several compounds, including decaffeoyl-acteoside, as well as derivatives of vanillic and hydroxybenzoic acids, exhibited strong binding affinities to both enzymes, suggesting their promising potential as inhibitors of P. aeruginosa virulence. Furthermore, decaffeoyl-acteoside exhibited high binding affinity for both enzymes, highlighting its potential as a dual-target therapeutic agent. The study effectively leverages solvent dynamics to maximize the extraction and bioactivity of C. metuliferus peel compounds. It provides a clear demonstration of how manipulating solvent conditions can influence molecular interactions, extraction yield, and the functional properties of bioactive compounds. The obtained results regarding promising antibacterial and virulence-inhibiting qualities support further research into C. metuliferus peel compounds as a natural alternative to traditional antimicrobial treatments.