Phytochemicals and antibacterial activities of secondary metabolites from Malaysian Zingiber officinale roscoe rhizomes
摘要
Zingiber officinale (Ginger), belongs to the family of Zingiberaceae, is one of the most popular culinary spices and has been used for thousand years to treat variety of ailments. It is rich in phenolic compounds, which are largely attributed for its health benefits. However, in addition to the well-known gingerols and shogaols, there are many minor or trace metabolites in ginger remain unexplored. In this study, six compounds were isolated from the Malaysian Z. officinale rhizomes (Bentong ginger), which is widely cultivated in the highlands of Bentong District, Malaysia. The compounds were identified as 6-gingerol, 10-gingerol, 6-shogaol, 6-paradol, 2,4-di-tert-butylphenol, and farnesal. The structures of the compounds were identified by NMR, IR, UV and HRMS. Except for 6-gingerol and 6-shogaol, the other compounds were isolated from Bentong ginger for the first time. The antibacterial activities of the compounds against Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecium were investigated using the broth microdilution method with tetracycline HCl as a positive control. The acetone extract showed weak antibacterial activity (MIC = 625 µg/mL), and 10-gingerol demonstrated good antibacterial activity against A. baumannii and moderate activity against P. aeruginosa, with MIC values of 6.3 and 25 µM, respectively. This study suggests that the phenolic compounds in Bentong ginger have potential pharmacological application as anti-bacteriostatic agent. These findings open new avenues for future studies on the isolation of its minor components and their possible applications in drug discovery or functional food development.