Prevention of Candida albicans biofilm by plant oils

The inhibitory effect of 30 plant oils was evaluated against biofilm forming Candida albicans strain (CA I) isolated from clinical samples, which was sensitive to 4 mu g/ml of fluconazole, used as a positive control. The standard strain (MTCC 227, CA II) used in this study was found to be highly resistant to fluconazole, 3,000 mu g/ml of which was required to inhibit the growth of this strain partially, and complete inhibition could not be achieved. Eighteen among the 30 plant oils tested were found to show anti-Candida activity by disc diffusion assay. Effective plant oils were assessed using XTT (2, 3-bis[2-Methoxy-4-nitro-5-sulphophenyl]-2H-tetrazolium5-carboxanilide) reduction assay for biofilm quantification. Four oils eucalyptus, peppermint, ginger grass and clove showed 80.87%, 74.16%, 40.46% and 28.57% biofilm reduction respectively. Minimum inhibitory concentration (MIC) values were calculated using agar dilution assay. Scanning electron microscopic (SEM) analysis further revealed reduction in C. albicans biofilm in response to effective oils. The substantial antifungal activity shown by these plant oils suggests their potential against infections caused by C. albicans.