Cytotoxicity of extracts from the mushroom Paxillus involutus.

The cytotoxicity of extracts of freshly collected Paxillus involutus against murine (L929 and RAW 264.7) and human (HeLa and EAhy926) derived cell lines was investigated. The water extract (15.6-1000 micrograms/ml) did not affect the viability of cells, while the butanol extract reduced cell viability by 30-45% at the highest concentration tested (1 mg/ml). The ethyl acetate extract was cytotoxic in a concentration-dependent manner, with IC50 values between 125 and 250 micrograms/ml. The cytotoxic principle appears to be heat and acid stable, as neither incubation at 37 degrees C for 4 hr nor overnight treatment at pH 0.5 altered the cytotoxicity of the ethyl acetate extract. This non-polar, acid- and thermo-stable cytotoxic principle may play a role in the haemolysis and other clinical manifestations that occur during poisoning by P. involutus.