Use of checkerboard assay to determine the synergy between essential oils extracted from leaves of Aegle marmelos (L.) Correa and nystatin against Candida albicans.

Background: Candida albicans is one of the most common pathogenic yeasts, responsible for causing candidiasis. The use of conventional antifungal agents for the treatment of Candida is reported to be less effective and hence alternative therapies for the treatment are needed. Essential oils of medicinal plants may serve as a strong candidate for natural products in modern therapies.

Aim: The aim of this study was to determine the synergistic potential of essential oils extracted from leaves of Aegle marmelos (L.) Correa and a potent antifungal agent, nystatin, against three clinical isolates of C. albicans using checkerboard assay.

Materials and methods: The antifungal activity of the essential oils of A. marmelos was screened against test cultures by disc diffusion technique. Antibiograms of the test organisms were developed. To determine the minimum fungicidal concentration of the essential oil and nystatin, the broth microdilution method was employed, and a checkerboard assay was used to investigate the synergistic potential of the essential oil and nystatin against the clinical isolates under study. The data were expressed as mean ± standard deviation.

Results: The Σ fractional inhibitory concentration values were calculated as 0.12, 0.37, and 0.28 for three different strains of C. albicans used, respectively, which was <0.5, therefore, the synergy was demonstrated between essential oils and nystatin against the test cultures.

Conclusions: Combinatorial therapy of the essential oils extracted from the leaves of A. marmelos and nystatin may be considered a line of treatment for candidal infections.