Chemical composition, antioxidant and antifungal potential of Melaleuca alternifolia (tea tree) and Eucalyptus globulus essential oils against oralCandida species

Abstract

Eucalyptus globulus and Melaleuca alternifolia essential oils has been of interest to researchers because they are traditionally used for the treatment of fungal infections and especially candidiasis. The chemical composition of hydrodistilled essential oils were analyzed by gas chromatography-mass spectrometry (GC-MS), and their antifungal activity was tested against 32 Candida strains including 15 species. The antioxidant activities (DPPH, reducing power, and superoxide anion radical-scavenging activity) were also investigated. Tea tree essential oil was particularly rich on terpinen-4-ol (40.44%), gamma terpinene (19.54%) and 1,8-cineole (95.61%) and alpha-pinene (1.5%) for the E. globulus oil. E. globulus oil was more efficient and had the best antifungal effect on oral Candida albicans and Candida glabratastrains comparing to the results obtained with Amphotericin B. Even at low concentrations, these oils drastically impair the maximum yield and growth rate of both C. albicans and C. glabrata on YPD medium. The Tea Tree essential oil displayed the highest DPPH scavenging ability with the lowest IC50 value (IC50, 12.5 µg/ml), the greater reducing power and bleaching of β-carotene (EC50, 24 µgml-1 and IC50, 42 µgml-1, respectively) as compared to E. globulusoil and BHT. These findings support the interest of E. globulus and M. alternifolia essential oilsas an efficient oral hygiene tool (anti-Candida spp.) and as a source of antioxidant compounds. Key words: Candida, Melaleuca alternifolia, Eucalyptus globulus, gas chromatography-mass spectrometry, antioxidant, antifungal activities.