The combination effect of Korean red ginseng saponins with kanamycin and cefotaxime against methicillin-resistant Staphylococcus aureus

Korean red ginseng saponins (ginsenosides) have been reported as having various biological properties, but the combinational effects with commercial antibiotics and the mode of action of ginsenosides remain mostly unknown. In this study, saponins were isolated from Korean red ginseng, and the antibacterial effects of ginsenosides were investigated. Ginsenosides showed antibacterial activities toward pathogenic Gram-positive and Gram-negative bacteria. To elucidate the antibacterial mode of action of ginsenosides, we measured the release of the fluorescent marker calcein from negatively charged PC/PG (1 : 1, w/w) liposomes, which mimic bacterial membranes. The results suggest that ginsenosides may exert antibacterial activity by disrupting the cell membrane. To estimate the general combination effects of ginsenosides and commercial antibiotics, such as kanamycin and cefotaxime, on antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) strains that were clinically isolated from an infected patient, the fraction inhibitory concentration (FIC) indexes were determined by a checkerboard study. The FIC indexes showed synergistic or additive effects between the ginsenosides and antibiotics tested.