Phytotherapeutic insights into Ageratum conyzoides for bovine mastitis: Antibacterial, anti-biofilm, and computational approaches.

Bovine mastitis adversely affects dairy production by lowering milk yield, increasing culling rates, and raising treatment costs, while antibiotic overuse exacerbates antimicrobial resistance. Ageratum conyzoides, a medicinal plant with antimicrobial properties, offers a potential plant-based alternative for mastitis management. This study evaluates the antibacterial and antibiofilm potential of A. conyzoides aqueous, ethanol and petroleum ether leaf extracts against S. aureus and E. coli from mastitic milk through in vitro assays, phytochemical profiling, and computational approaches. Antibacterial efficacy was determined using agar well diffusion, MIC, MBC assays, while antibiofilm potential was assessed via crystal violet assay. GC-MS identified bioactive compounds, and molecular docking examined interactions with S. aureus (type IIA topoisomerase, PBP4, enterotoxin B, SarA, BAP, DNA gyrase, TSST-1, and DHFR) and E. coli (DHPS, DNA gyrase, UPPS, AIDA-I, topoisomerase IV, and outer membrane protein A). The ethanolic extract exhibited the strongest antibacterial activity, with inhibition zones at 10-30 mg/mL, MIC values of 0.625 mg/mL for S. aureus and 1.25 mg/mL for E. coli, and biofilm inhibition of 90.13 % and 87.36 %, respectively, at 20 mg/mL. GC-MS detected 90 bioactive compounds, and docking identified five lead compounds with strong binding affinities and favorable ADME properties. Molecular dynamics simulations validated stable interactions with S. aureus PBP4 and DHFR and E. coli UPPS and AIDA-I. These findings suggest A. conyzoides as a promising natural alternative for mastitis treatment and AMR control. Further research should focus on bioactive compound isolation, in vivo validation, and large-scale extraction optimization for clinical application in dairy health.