Evaluation of Antifungal Activity and Mechanism of Action of Citral against Candida albicans.

Maria Clerya Alvino Leite,Felipe Queiroga Sarmento Guerra,Janiere Pereira De Sousa,Edeltrudes De Oliveira Lima,André Parente De Brito Bezerra

doi:10.1155/2014/378280

Abstract

Candida albicans is a yeast that commensally inhabits the human body and can cause opportunistic or pathogenic infections. Objective. To investigate the antifungal activity of citral against C. albicans. Methodology. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) were determined by the broth microdilution techniques. We also investigated possible citral action on cell walls (0.8 M sorbitol), cell membranes (citral to ergosterol binding), the time-kill curve, and biological activity on the yeast's morphology. Results. The MIC and MFC of citral were, respectively, 64 µg/mL and 256 µg/mL. Involvement with the cell wall and ergosterol binding were excluded as possible mechanisms of action. In the morphological interference assay, it was observed that the product inhibited pseudohyphae and chlamydoconidia formation. The MIC and the MFC of citral required only 4 hours of exposure to effectively kill 99.9% of the inoculum. Conclusion. Citral showed in vitro antifungal potential against strains of C. albicans. Citral's mechanism of action does not involve the cell wall or ergosterol, and further study is needed to completely describe its effects before being used in the future as a component of new antifungals.

Highlights

The prevalence of Candida albicans infections is increasing at an alarming rate, and this is especially true for immunocompromised individuals, such as AIDS patients, transplant patients, and neonates [1, 2]
The aim of this study was to determine the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) and to investigate the action mechanism of citral against C. albicans in its growth kinetics, micromorphology, cell wall formation, and ergosterol interactions
The MFC against these microorganisms almost entirely coincided with the MIC (64 μg/mL), except that for the LM-11 strain it was 256 μg/mL

Summary

Introduction

The prevalence of Candida albicans infections is increasing at an alarming rate, and this is especially true for immunocompromised individuals, such as AIDS patients, transplant patients, and neonates [1, 2]. C. albicans is an opportunist pathogen that lives commensally within the human body; it is the leading cause of human fungal infections. C. albicans infection usually develops as a consequence of host immune response alterations [3]. The increased incidence of Candida infections can be attributed to a variety of factors, either exogenous or (especially) endogenous. Over 100 species of Candida are known; C. albicans is the main representative. Among the Candida species, it is C. albicans that is involved in bloodstream infections for 44% of Latin American and 62% of European cases [4]

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Conclusion