In vitro activity of propyl gallate-azole drug combination against fluconazole- and itraconazole-resistant Candida albicans strains

Aims: The influence of an antioxidant, propyl gallate (PG), on the In vitro antifungal activity of itraconazole and fluconazole, was investigated to d etermine whether PG could increase the antifungal activity and reduce strai n resistance. Methods and Results: Susceptibility tests were performed against azole-resi stant isolates of Candida albicans by the microbroth dilution method in the presence of PG at 400 mug ml(-1). PG-triazole combination brought about a marked reduction of inhibitory azole concentration. In particular, the MIC9 0 for itraconazole and fluconazole dropped from 1 mug ml(-1) to 0.125 mug m l(-1) and from >64 mug ml(-1)-8 mug ml(-1), respectively. Conclusions: It is likely that more than one mechanism is involved in the a bove synergistic interaction, including effects of PG on ATP synthesis, thu s reducing the ABC transporters activity, or an effect on the target of azo le, i.e. the P-450 cytochrome. Significance and Impact of the Study: The PG-triazole combination may have a role in future topical antifungal strategies but other studies are warran ted.