Phytochemical Analysis of Different Plant Organs of Bauhinia kockiana Korth. and Its Antibacterial Synergistic Interaction

The rise of antimicrobial resistance (AMR) necessitates novel natural therapeutics. Combining plant extracts offers a promising strategy to enhance antibacterial efficacy via synergistic, multi-target interactions. Bauhinia kockiana, a medicinal vine traditionally used for various treatments, exhibits promising antimicrobial properties, yet the synergistic potential of its multi-organ extracts remains unexplored. This study evaluated the phytochemical profiles and antibacterial activities of aqueous extracts against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. Liquid chromatography-mass spectrometry (LC-MS) and Fourier-transform infrared spectroscopy (FTIR) identified 10 organ-specific bioactive phytocompounds and characterized their functional groups. The flower extracts demonstrated the highest total phenolic and flavonoid contents, correlating with superior antibacterial activity. Disc diffusion assays revealed concentration-dependent effects, with flower extracts outperforming streptomycin against MRSA. Minimum inhibitory concentrations (MICs) ranged from 0.125 - 0.5% w/v, with flower extracts showing bactericidal effects against MRSA and P. aeruginosa. Checkerboard assays and well diffusion assays confirmed synergistic flower-stem interactions across multiple pathogens. This combination significantly inhibited S. aureus biofilm formation (> 50% at sub-MIC, complete at 2MIC) and induced morphological deformation. Time-kill kinetics confirmed concentration-dependent bactericidal effects, and mechanistic studies indicated membrane disruption as a primary mode of action, evidenced by enhanced cytoplasmic and protein leakage. These findings highlight the therapeutic potential of B. kockiana multi-organ extracts for combinatorial strategies to combat AMR sustainably.