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.