In vitro effect of Melaleuca alternifolia and Eucalyptus globulus essential oils on mycelia formation by oral Candida albicans strains

Abstract

Several mechanisms can inhibit mycelium formation which is an essential step forCandida albicans virulence. In this study, two essential oils of Melaleuca alternifoliaand Eucalyptus globulus were tested for their ability to inhibit the mycelium formed on Lee medium by oral C. albicans. Lee medium was added with different concentrations of M. alternifolia essential oil ranging from 0.156 to 10 mg/ml and from 0.039 to 10 mg/ml for E. globulus. The results obtained showed that 5/17 of C.albicans strains were strongly mycelium producers, nine strains were moderately mycelium producers and three isolates were unable to form hyphae after 2 h of incubation in the same medium. M. alternifolia essential oil has an antimycelial activity against C. albicans isolates than E. globulus essential oil. In fact, only 1/2 minimum inhibitory concentration (MIC) (0.312 mg/ml) of M. alternifolia was able to inhibit total mycelium in C. albicans isolate while 2 MIC (0.312 mg/ml) of the second essential oil was necessary to inhibit germ tube formation in the same strain. Key words: Candida albicans, Melaleuca alternifolia, Eucalyptus globulus, mycelium, lee medium.