Percentage Inhibition of Diameter Growth of eugenol against Candida albicans

Introduction: Candida albicans is the predominant species of oral candidiasis. Eugenol (4-allyl-2-methoxyphenol) extract from cloves is known to exhibit antifungal activity towards several microorganisms, but very little information is known about its antifungal action against C. albicans. Objective: This study aims to determine the susceptibility of C. albicans against eugenol extract and to obtain the Percentage Inhibition of Diameter Growth exhibited by eugenol. Methods: The disc diffusion test using Kirby-Bauer method was used to determine the antifungal activity of eugenol extract at various concentrations (1%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.05% and 0.0025% v/v). The MIC and the MFC analysis have been carried out using microbroth dilution method. Results were recorded and PIDG values against Amphotericin B were calculated. Results: It was found that the MIC and MFC of eugenol extract towards C. albicans were 0.94% and 0.002%, respectively. Except for 1% v/v of eugenol extract, all other concentrations exhibit low antifungal effects which were indicated by the negative values of PIDGs towards C. albicans. These results showed the sub-MIC concentrations of eugenol has low antifungal influence which were reflected by the growth inhibition zones compared to Amphotericin B. In contrast, the PIDG value of 1% v/v eugenol was found to outstrips Amphotericin B by 19.05%; suggesting that C. albicans is more susceptibility to 1% v/v of eugenol compared to 20µg/mL Amphotericin B. Conclusion: Eugenol extract has exhibited good antifungal activity towards C. albicans, thus could significantly contribute to the development of an alternative antifungal agent of a natural product.