Inhibitory effects of carvacrol on the expression of secreted aspartyl proteinases 1-3 in fluconazole-resistant Candida albicans isolates

Background and Objectives: Secreted Aspartyl Proteinase (SAP) is one of the main virulence factors in the pathogenesis of Candida. This enzyme is encoded by a family of at least ten genes. Among these genes, the role of SAP1-3 in mucosal infections is evident. This study aimed to investigate the expression of SAP1-3 genes of Candida albicans isolates after treatment with Echinophora platyloba extract, carvacrol and caspofungin drug. Materials and Methods: Vaginal samples of 68 women with suspected vaginitis were obtained and cultured. Canida albicans species were identified using phenotypic and genotyping methods. Spectrophotometry was used to investigate the presence of SAP protein in the vaginal samples, and SDS-PAGE was used to confirm its protein composition. Real-time PCR was performed to ascertain the effects of subinhibitory concentrations of Echinophora platyloba extract, carvacrol and caspofungin on the expression of SAP1-3 genes before and after treatment. Results: C. albicans was found as the abundant species (59.6%), and different amounts of SAP were present in all vaginal samples, which were higher than Candida krusei strain. The protein composition of SAP in C. albicans samples was estimated with the approximate molecular weight of 45 kDa. mRNA levels of total SAP in FLU-resistant isolates (P=0.01) were more than those of FLU-susceptible isolates (P=0.07). The findings indicated that carvacrol is effective in reduction of SAP1-3 expression with a particular effect against FLU-resistant isolates. Conclusion: Carvacrol contains an essential oil (carvacrol); therefore, it can be considered as an alternative effective antifungal compound.