Studies On Antifungal Activity Of Extracts From Traditional Chinese Medicines

Objective: The studies dealt with in vitro antifungal activity against seven pathogenic superficial fungi by means of aqueous and ethanol extracts from six kinds of traditional Chinese medicines (TCMs). The experiments were evaluated on the basis of the following outcome Variables : minimal inhibitory concentration(MIC), minimal fungicidal concentration(MFC) and the results of scanning electron micrograph (SEM). In order to screen the efficacy of antifungal extracts and influence of different strains and pathways.Methods : The aqueous and ethanol extracts from 6 TCMs were obtained , including Rhizoma Coptidis, cortex Phellodendri, Cortex pseudolaricis tincture, Dictamnus dasycarpus Turcz., Fructus cnidii, Kochia scoparia Schrad.. The test organisms were Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum gypseum, Microsporum canis, Epidermophyton floccosum, Candida albicans, Malassezia furfur. The 16 strains were inoculated to obtain young, actively growing cultures. The resulting suspensions were adjusted to a concentration of 1×106～6×106 CFU /ml using blood cell counting plate. The aqueous and ethanol extracts were dissolved in sterile distilled water or dehydrated alcohol, and ten twofold serial dilutions were made. The solutions mixed with SDA slants and SDA slants containing 4% olive oil , and then inoculated the prepared suspensions. C. albicans slants were incubated at 37℃for 24～48 hours,M. furfur. slants were incubated at 37℃for 3～4 days,and dermatophytes slants were incubated at 26℃for 7 days. The MICs were defined as the lowest drug concentrations that inhibited visible growth of the fungi. The MFCs for C. albicans and dermatophytes were determined by subculturingfrom each slant with no visible growth onto liquid SDA mediums. C. albicans mediums were incubated at 37℃for 3 days and dermatophytes mediums were incubated at 26℃for 7 days. Every M. furfur. slant with no visible growth was subcultured onto SDA slants containing 4% olive oil, and then incubated at 37℃for 7 days. The MFC was defined as the lowest concentration which yielded a negative subculture. Trichophyton rubrum morphology with SEM was observed after infused with 2.5mg/ml aqueous extract from Rhizoma Coptidis and 0.3125mg/ml ethanol extract from Fructus cnidii.Results:1. The MIC range of aqueous extracts from Rhizoma Coptidis, cortex Phellodendri, Cortex pseudolaricis tincture, Dictamnus dasycarpus Turcz., Fructus cnidii, Kochia scoparia Schrad. and ethanol extracts from above 6 TCMs against 10 dermatophyte strains are 0.3125~2.5mg/ml, 0.625~1.25mg/ml, 1.25~≥5.0mg/ml, >5.0mg/ml,≥5.0mg/ml,>5.0mg/ml, 0.156~1.25mg/ml, 0.156~1.25mg/ml,0.156~2.5mg/ml, 0.039~0.156mg/ml, 0.0195~0.156mg/ml, 0.625~2.5mg/ml; against 3C. albicans strains are 0.625~1.25mg/ml,≥5.0mg/ml, 2.5~5.0mg/ml, > 5.0mg/ml, > 5.0mg/ml, >5.0mg/ml,1.25mg/ml, 0.625~1.25mg/ml, 0.3125~0.625mg/ml,≥2.5mg/ml,≥2.5mg/ml,≥2.5mg/ml; against 3 M. furfur. strains are 0.625~1.25 mg/ml,>5.0mg/ml,>5.0mg/ml,>5.0mg/ml,>5.0mg/ml,>5.0mg/ml,1.25mg/ml , > 2.5mg/ml , > 2.5mg/ml , > 2.5mg/ml ,≥2.5mg/ml , >2.5mg/ml.2. The MFC range of aqueous and ethanol extracts from above 6 TCMs against 10 dermatophyte strains are 2.5~≥5.0mg/ml, > 5.0mg/ml,>5.0mg/ml,>5.0mg/ml,>5.0mg/ml,>5.0mg/ml,1.25~≥2.5 mg/ml,>2.5mg/ml,>2.5mg/ml,>2.5mg/ml,0.078~0.3125 mg/ml,>2.5mg/ml;against 3C. albicans strains are >5.0mg/ml,>5.0mg/ml,5.0mg/ml,>5.0mg/ml , > 5.0mg/ml , > 5.0mg/ml , > 2.5mg/ml , > 2.5mg/ml ,0.625~2.5mg/ml,>2.5mg/ml,>2.5mg/ml,>2.5mg/ml;The MFC range of aqueous extracts from above 6 TCMs against 3 M. furfur. strains are>5.0mg/ml all,and the MFC range of ethanol extracts from above 6 TCMs against 3 M. furfur. strains are>2.5mg/ml all.3. The results of SEM exhibited that the serial variation ofTrichophyton rubrum morphology was closely related to the infusion time by 2.5mg/ml aqueous extract from Rhizoma Coptidis and 0.3125mg/ml ethanol extract from Fructus cnidii.Conclusions:1. The results showed that the 6 aqueous extracts and 6 ethanol extracts demonstrated different antifungal activity against different superficial fungi.2. The aqueous extracts from Rhizoma Coptidis and the enthanol extracts from Rhizoma Coptidis, Fructus cnidii against dermatophytes dexhibited fungicidal activity. The aqueous and ethanol extracts from Cortex pseudolaricis tincture against C. albicans exhibited fungicidal activity.