A hot water extract of Flammulina velutipes Sing.(FEH-1) showed a markedly high antitumor effect against sarcoma 180 in ICR mice. FEH-1 (10mg/kg) was administered intraperitoneally for consecutive 21 days before and after the subcutaneous inoculation of sarcoma 180 (4.1X106 cells) to the mice. Animals were sacrificed on the 24th day after the inoculation of sarcoma 180 and tumor weight was determined. The highest tumor inhibition ratio was 98.5%, when FEH-1 was administered at the dose of 10mg/kg.
Cytotoxicity of FEH-1 was denied by the following two tests:(1) after mixed-culture of Vx2 tumor cells with FEH-1 for 7 days in vitro, number of Vx2 cells was counted by dye-exclusion technique, and (2) after contact of Vx2 cells with FEH-1 for 1 hour, the cell mixture was inoculated subcutaneously to the rabbits. It was suggested that antitumor effect of FEH-1 was host-mediated.