Full Length Research Paper

Comparative studies of antimycotic potential of thyme and clove oil extracts with antifungal antibiotics on Candida albicans

Nzeako, B. C.* and Bushra Al. Lawati

Department of Microbiology and Immunology, Sultan Qaboos University, College of Medicine and Health Sciences, P.O. Box 35  Alkhoud, Muscat, 123, Sultanate of Oman.

*Corresponding author. E-mail: basil@squ.edu.om.  Tel: #968 24141131.

Accepted 14 April, 2008

This study was undertaken to compare the antifungal properties of clove (Syzygium aromaticus) and thyme (Thymus vulgaris) oils with the synthetic antifungal agents notably, amphotericin B, itraconazole, fluconazole and ketoconazole against Candida albicans in vitro. This is necessary if oil extracts can replace antifungal antibiotics as agents for the treatment of candidiasis. The minimal inhibitory concentrations (MICs) of the essential oils were determined by first solubilizing them with dimethyl sulphoxide (DMSO) followed by serial two-fold dilutions in Sabouraud’s broth using Candida albicans (ATCC 10231) control and other 10 isolates of C. albicans. The minimum inhibitory concentrations (MICs) of the oils, showing no visible fungal growth, varied from 1.0 x 10³ to 2.5 x 10³ µg/mL for clove and 4.6 x 10² to 9.3 x 10² µg/mL for thyme while their minimum antifungal end-points were 2.5 x 10³ and 1.9 x 10³µg/mL, respectively. Thyme oil was more antifungal than clove oil. The mean of the MIC’s of the antifungal agents notably amphotericin B, ketoconazole, fluconazole and itraconazole were 0.031, 0.015, 1.9, and 0.168 µg/mL, respectively, indicating that they are more antifungal than the oil extracts. The experiment indicates that, in vitro, the antifungal antibiotics are more antifungal than the essential oils. Perhaps, the mode of extraction of the oils may have contributed to the active agents being suboptimal in the extracts.

Key words: Candida spp., thyme, clove, antifungal antibiotics, essential oil.