Kaempferide, lead bioactive compound of Alpinia Officinarum hance rhizomes as potential antibacterial agent: Mechanisms of action and molecular targets.

The exploration of plant-based antimicrobials offers an optimistic approach to tackle the emergence and rapid spread of antibiotic-resistant bacteria. The antibacterial properties of Alpinia officinarum Hance have aroused growing interest during the past few decades given its high chemodiversity. This study aims to investigate antibacterial activity of the EtOAc extract from A. officinarum rhizomes, and the contribution of its major component, isolated and characterized using different spectroscopic techniques LC-MS/MS, FT-IR, and 1H/13C NMR 1D and 2D. Antibacterial activity was evaluated against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa strains, using microdilution method. Kaempferide was identified as a major antibacterial component in lesser galangal EtOAc extract, especially against the opportunistic P. aeruginosa, through potent bacteriostatic and bactericidal effects, with MIC = 0.024 mg/mL, and MBC = 0.39 mg/mL. Molecular docking revealed high binding affinity between kaempferide and several drug targets in P. aeruginosa. The disruption of the protective cell wall and inhibition of key molecular targets may represent potential mechanisms underlying its antipseudomonal activity. These encouraging findings highlight the diverse antibacterial potential of A. officinarum Hance rhizomes, providing valuable insights for the development of alternative antibacterials.