Carvacrol Improves antifungal activity of voriconazole against drug – resistant Candida species

Background and Aim : Terpenoid phenolsnare components of plant essential oils that exhibit potent antifungal activity against a wide range of pathogens, including Candida species. The purpose of this study was to determine the interaction activity of carvacrol in combination with voriconazole against Candida albicans (C. albicans), C. glabrata and C. krusei isolatesMethods : The minimum inhibitory and fungicidal concentrations (MICs and MFCs) of carvacrol and voriconazole were determined against various Candida species isolated from patients with candidiasis using the Clinical Laboratory Standards Institute (CLSI) M۲۷-A۲ broth microdilution method. The nature of the interaction was studied from fractional inhibitory concentration indices (FICIs) for carvacrol plus voriconazole combination calculated from checkerboard microdilution assayResults : Carvacrol presented an antifungal effect, with mean MICs of ۶۶.۸۷ mg/mL for C. albicans, ۷۵ mg/mL for C. glabrata and ۹۵ mg/mL for C. krusei isolates. The mean MICs of voriconazole against C. albicans, C. glabrata and C. krusei isolates were ۰.۰۸۷, ۱.۲۵ and ۰.۳۵ mg/mL, respectively. Carvacrol in combination with voriconazole exhibited the synergistic anti-Candida effects against all species of Candida tested. FICI values for carvacrol plus voriconazole combination ranged from ۰.۳۷۰ to ۰.۸۵۳ for C. albicans isolates, ۰.۴۱۲ to ۰.۶۲۵ for C. glabrata isolates, and ۰.۴۷۴ to ۰.۷۴۸ for C. krusei isolates. No antagonistic activity was seen in the strains tested.Conclusion : From these results we suggest that carvacrol has great potential as antifungal, and that voriconazole can be supplemented with carvacrol to inhibit clinical Candida isolates.

Keywords:

carvacrol , voriconazole , antifungal effect , Candida albicans