Influence of pH on the extraction of the bioactive substances of Fuligo septica (Myxomycetes)

The influence of solvent pH on the extraction of active substances from the aethalia of Fuligo septica (L.) Wigg. was verified. Methanol extracts were prepared at pH 2.0, 7.0 and 9.0, and shaken during 15 min at 100 rpm at room temperature; after filtration and readjustment to pH 7.0, they were allowed to dry. Antimicrobial activity was tested with solutions (10,000 mu g/ml) of the crude extracts; paper disc (6 mm empty set) were soaked with 30 mu l of the solution and placed on the surface of the medium sown with the microorganisms (Staphylococcus aureus Rosenbach W/UFPDA - 01, Bacillus subtilis Ehrenberg W/UFPDA - 16, Micrococcus luteus (Schroeter) Cohn UFPDA - 06 and Candida albicans (Robbin) Berkhout CMDA - 1007); halos of microbial growth inhibition of 8 mm empty set or more were considered positive: the extracts showed antibiotic activity (halos of 8-24 mm empty set) against all microorganisms tested. Cytotoxic activity was measured by the MTT method; using viable cells of strain HEp2, Cl-50 (concentration which inhibits cellular proliferation 50% in relation to the control) was calculated: no cytotoxicity was detected, It was evinced that solvent pH is very important for the extraction of the active substances of F. septica (L.) Wigg.