Evaluation of the Antifungal Effect of Fluconazole Separately and with Coriander Essential Oil on Candida Species Isolated from the Mouth of HIV-Positive Individuals

Candida species are opportunistic yeasts that can cause opportunistic infections when the host becomes debilitated or immunocompromised. Coriander is a plant belonging to the Umbelliferae family and its leaves and seeds are widely used in traditional medicine. Coriander essential oil (E.O.) has shown antibacterial, antifungal, and antioxidant activities. This study aimed to evaluate the antifungal effect of fluconazole alone and with coriander E.O on 39 Candida species isolated from the mouth of Human Immunodeficiency Virus (HIV) positive individuals.

In this study, the broth microdilution tests according to the CLSI M27-S3 were applied to find the amount of Minimum inhibitory concentration (MIC) of fluconazole alone and together with coriander E.O (synergism) for each Candida isolate. For this purpose, the E.O. of Coriander seeds was extracted using a Clevenger apparatus by steam hydro-distillation, and then the synergism effect of E.O. and fluconazole on Candida isolates was investigated. Data were analyzed by SPSS-25 software. Mann-Whitney, and Tukey post hoc tests, and the one-way analysis of variance were used to analyze the results.

Susceptibility of fluconazole was determined as follows: 69.2% of the Candida isolates were sensitive, 17.9% were resistant and 12.9% were susceptible dose-dependent (SDD). The MIC mean was 27.3 μg/ml for fluconazole, 32.7 μg/ml for coriander E.O, and 9.39 μg/ml for the combined effect of fluconazole and Coriander E.O (synergistic effects).

The fact that Coriander E.O has an inhibitory effect on all Candida isolates used in this study, it can be considered a capable antifungal, especially in combination with fluconazole (synergistic effects), and the antifungal effect of Coriander E.O is proposed to investigate in treating candidiasis for future clinical trials.