In vitro antifungal activity of Calocybe gambosa extracts against yeasts and filamentous fungi

Three strains of Calocybe gambosa (Fr.) Donk were investigated as possible sources of biologically active substances with antifungal activity. After submerged cultivation of C. gambosa mycelium, biologically active materials were isolated as ethyl acetate extracts from culture liquids. The in vitro activity of these C. gambosa extracts (Cg1, Cg2, Cg3) against yeasts and filamentous fungi was evaluated using the Clinical and Laboratory Standards Institute (CLSI) M27-A2 and M38-A2. The minimum inhibitory concentration (MIC) against most of the tested clinical fungal strains for Cg1 and Cg2 extracts ranges from 12.5 to 50 mu g/ml while Cg3 ranged from 1.56 to 12.5 mu g/ml. Candida albicans (DBVPG 4268) were the most sensitive fungal strain to C. gambosa extracts, with MIC ranges of 1.56 to 12.5 mu g/mL, while the strains of Aspergillus tubingensis showed the least sensitivity to the extracts. The high performance liquid chromatography (HPLC) fingerprint of the isolates shows four principal compounds produced by the cultured mycelium. Considering the potential use of natural antifungal compounds in medicine, we are currently working on a small-scale extraction, isolation and structural characterization of compounds produced from the C. gambosa.