The Inhibitory Effect of Essential Oils on Rhizopus stolonifer, Trichophyton mentagrophytes, and Microsporum gypseum.

Abstract

Rhizopus stolonifer is an opportunistic fungus that causes respiratory infections, sinusitis, and otomycosis. Trichophyton mentagrophytes and Microsporum gypseum cause athlete's foot, ringworm, and nail infections. Previous research has shown that some essential oils inhibit fungal growth. We investigated the effects of 0.5% and 1% concentrations of Rosmarinus officinalis, Cinnamomum verum, Citrus paradisi, and Capsicum annuum extracts on the growth of R. stolonifer and T. mentagrophytes. The combined effects also were determined at 0.5% concentration for these fungal species and for M. gypseum. Fungal species were grown in flasks, along with growth media, for 7, 14, and 21 days, with each species of essential oil or combination of oils and mass determined and compared to its control. Rosmarinus officinalis, Cinnamomum verum, and Citrus paradisi had overall significant inhibitory effects (P ≤.05) on R. stolonifer and T. mentagrophytes. C. annuum significantly (P ≤.05) inhibited the growth of T. mentagrophytes and enhanced that of R. stolonifer. The combination of essential oils resulted in inhibition of growth (P ≤.05) at similar percentages as R. officinalis, C. verum, and C. paradisi only. Essential oils such as Rosmarinus officinalis, Cinnamomum verum, and Citrus paradisi may be useful for treating opportunistic and dermatophytic fungal diseases.