Anti-Candida effects of estragole in combination with ketoconazole or amphotericin B

The anti-Candida effects of estragole combined with amphotericin B or ketoconazole, commonly used antifungal drugs for treatment of candidasis, were evaluated in this study. The fractional inhibitory concentration (FIC) indices of both estragole combined with ketoconazole against C. albicans and C. utilis calculated from the checkerboard microtiter assay were 0.28 and 0.50 respectively, indicating significant synergism. These drug combinations exhibited additive effects against C. tropicalis, with FIC index of 0.75. Consistent for the most part with the results from the checkerboard titer tests, the time-kill curves of the tested samples also indicated significant synergism or additive effect between ketoconazole and estragole against the Candida species evaluated. In contrast, amphotericin B showed antagonism in combination with estragole in most experiments of this study. Thus, we have shown the synergistic combination effects between estragole and ketoconazole, which may be effective combinations for the treatment of Candida infections. Copyright (C) 2004 John Wiley Sons, Ltd.