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[摘要]：18 beta-Glycyrrhetinic acid (18 beta GA) is a major bioactive component of liquorice with known activity. In this study, we found that both 18 beta GA and its derivative glycyrrhetinic acid-30-piperazine (PGA), have potent antimycobacterial properties against the drug-susceptible and drug-resistant Mycobacterium bovis. More importantly, they exhibited synergistic effects with the first-line drugs isoniazid (INH), rifampicin (RIF) and streptomycin (SM) against clinical M. bovis isolates, including drug-resistant strains. In combination with a subinhibitory concentration of 18 beta GA, the minimum inhibitory concentrations (MICs) of the anti-tuberculosis agents decreased, ranging from 4- to 16-, 4- to 8- and 4- to 8-fold for INH (fractional inhibitory concentration index (FICI) 0.1250.375), RIF (FICI 0.1180.281) and SM (FICI 0.0940.275), respectively. In the presence of PGA, MICs for the first-line agents resulted in a 416-fold decrease for INH (FICI 0.0940.266, RIF (FICI 0.1140.313) and SM (FICI 0.0940.281). Additionally, the MICs of 18 beta GA or PGA alone showed significant decreases ranging from 8- to 16-, 8- to 64- and 8- to 128-fold in the presence of INH, RIF and SM, respectively. These findings indicate that 18 beta GA and its derivatives might serve as potential therapeutic compounds for future antimycobacterial drug development. Copyright (C) 2011 John Wiley & Sons, Ltd. |
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