An extract from ginger (root of Zingiber officinale) reduced the minimum inhibitory concentrations (MICs) of aminoglycosides in vancomycin-resistant enterococci (VRE). The effective compound was isolated and identified as -gingerol. In the presence of -gingerol at 1/10 concentration of its own MIC, the MIC of arbekacin was lowered by 1/32 to 1/16. -Gingerol also reduced the MICs of other aminoglycosides, and of bacitracin and polymixin B, but not of other antimicrobial agents tested. Because -gingerol reduced the MICs of several aminoglycosides both in strains possessing or lacking aminoglycoside-modification enzymes, it seems that the effect of -gingerol is not related to these enzymes, which mainly confer bacterial resistance against aminoglycosides. It seemed that a detergent-like effect of -gingerol potentiated the antimicrobial activity of the aminoglycosides. In fact, some detergents such as sodium dodecyl sulfate (SDS) and Triton X-100 reduced the MICs of aminoglycosides, bacitracin and polymixin B in VRE. Since the intrinsic resistance to aminoglycosides in enterococci is due to low level of entry of the drugs into the cells, increase in the membrane permeability caused by -gingerol will enhance the influx of aminoglycosides into enterococcal cells.
- Vancomycin-resistant enterococci (VRE)
ASJC Scopus subject areas
- Pharmaceutical Science