Antibacterial and Motility-Modulating Activities of Red Ginger (Zingiber officinale Roscoe var. rubrum) Extract

Antimicrobial resistance is contributing significantly to the high mortality rate associated with infections caused by antibiotic-resistant bacteria. To address this issue, natural products such as red ginger (Zingiber officinale Roscoe var. rubrum), characterized by antimicrobial secondary metabolites, offer a promising source of effective antimicrobial agents. Therefore, this study aimed to investigate antibacterial and motility-modulating activities of red ginger extract to evaluate the potential as natural antimicrobial agent. The experiment was carried out by extracting red ginger rhizomes using 96% ethanol through maceration method. The extract was tested for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa ATCC 27853, and Salmonella typhimurium using the broth microdilution method, followed by the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Motility-modulating activity of extract was assessed by inoculating bacterial suspensions into media containing extract supplemented with low concentrations of agar. The diameters of swimming and swarming motility of the test bacteria were measured to determine the effect of extract. The results showed that red ginger extract, at a concentration of 10 mg/mL, did not have antibacterial activity against E. coli and P. aeruginosa ATCC 27853. The growth of S. typhimurium was inhibited, with both MIC and MBC values of 2.5 mg/mL, while swimming and swarming motility were enhanced in bacteria. This showed that red ginger extract possessed antibacterial activity against S. typhimurium with bactericidal effect. The extract was also capable of modulating the motility of all bacteria.