Synergistic Antifungal Activities of Thymol Analogues with Propolis

Abstract

In this study, an attempt was made to elucidate the combined effect of thymol analogues with propolis on fungi that are involved in human diseases. Antifungal activity of thymol analogues was examined by the agar dilution method, using antibiotic medium-3-enriched with 0.2% dextrose. The activity of thymol analogues against Penicillium rastrickii appeared to be more marked than against Candida albicans and Saccharomyces cerevisiae. Various thymol analogues and propolis, when tested alone, did not exhibit significant inhibitory activity. However, in the presence of sub-inhibitory concentrations of propolis, the relative antifungal potency of the thymol analogues was greatly enhanced. Natural thymol was found to be superior to the synthetic thymol analogues. In particular, the MIC of thymol was considerably reduced (191-fold) against Candida albicans by combination with propolis. This study highlights the potential of the combination of either thymol or synthetic thymol analogues with propolis to inhibit fungi.