Molecular Characterization and Evaluation of Bioactive Compounds from Selected Medicinal Plant Extracts against Mastitis-Causing Pathogens among Dairy Cattle in Minna Niger State, Nigeria
Abstract
Mastitis is an important bacterial disease affecting dairy cattle and remains a challenge because of antimicrobial resistance and the limitations associated with conventional antibiotic treatment. This study isolated and identified mastitis-causing pathogens from cattle milk in Minna, Niger State, and subsequently characterized bioactive compounds in the most active plant extract using Gas Chromatography-Mass Spectrometry (GC-MS) and evaluated selected compounds through molecular docking. A total of 60 milk samples were collected from three locations, of which 15 tested positive for clinical mastitis. Five major bacterial groups were identified: Staphylococcus sp., Bacillus subtilis, Pseudomonas sp., Micrococcus luteus, and Neisseria sp. Staphylococcus sp. and B. subtilis were the most prevalent isolates, each accounting for 33.33%. Based on the antimicrobial activity observed in the study, Moringa oleifera was selected for GC-MS characterization. A total of 29 compounds were identified, with 9-octadecenoic acid, methyl ester (E) being the most abundant compound, accounting for 50.88% of the peak area. Other compounds included methyl stearate, hexadecanoic acid methyl ester, β-sitosterol, quercetin, kaempferol, rutin, chlorogenic acid, and ferulic acid. Molecular docking showed strong binding affinities for quercetin (−9.0 kcal/mol) against DNA gyrase (2XCT), kaempferol (−8.4 kcal/mol) against dihydrofolate reductase (3FYV), and rutin (−8.1 kcal/mol) against penicillin-binding protein 2a (5M18). Further docking of selected compounds demonstrated interactions between 1-methyl-4-phenyl-5-thioxo-1,2,4-triazolidin-3-one and DNA gyrase and between 1-tetradecyne and penicillin-binding protein 2a.These findings suggest that M. oleifera contains diverse bioactive compounds with potential activity against important bacterial targets and provides a basis for further experimental validation and development of plant-derived antimicrobial agents