Antifungal activity of essential oil from Cinnamomum longepaniculatum leaves against three dermatophytes in vitro

The antifungal effects of essential oil from Cinnamomum longepaniculatum leaves were studied with special reference to minimal inhibitory concentration (MIC), minimal fungicidal concentration (MFC), time–kill studies and the mechanism of inhibition at ultrastructural level against Trichophyton mentagrophytes, Microsporum canis and Trichophyton gypseum. Its MICs against three important dermatophytes were 3.125, 3.125 and 3.125 ul/ml, while its MFCs against the same were 3.125, 3.125 and 3.125 ul/ml, respectively.  All strains exposed to 1×MIC showed a maximum decrease in fungal inoculum of less than 2log10 CFU/ml within 12 h, and all the strains exhibited no growth within 72 h. Transmission electron microscope (TEM) of three important dermatophytes exposed to MIC levels of essential oil showed irreversible damage to cell wall, cell membrane and cellular organelles. The results are compared and with the data in literature. In conclusion, essential oil has significant antifungal activity in vivo, weakening the virulence of three dermatophytes and killing fungi by destroying the cell membrane and organelles.   Key words: Essential oils, antifungal activity, time-kill curve, transmitted electron microscopy (TEM).