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The components of Basidiomyces have been examined for antitumor activity since 1957, when Ringler et al. published their report. Among the antitumor constituents, schizophyllan, lentinan and PS-K are outstanding examples. One of their characteristics is that they are not cytotoxic to tumor cells, but that they inhibit them through potentiation of the host immunity. Recently, cervinan A was isolated as an antitumor component from Pluteus cervinus by the author and associates. We also isolated lyophyllan A from Lyophyllum decastes. In the course of our screening program, we found that Lepiota procera contained an antitumor component. To produce the component, the fungal mycelia were grown in a nutrient solution. After the mycelia were extracted with hot water, the extract was purified by DEAE-Sephadex A-50 column chromatography and Sepharose-4 B gel filtration. Of these fractions, Fr. C₁ showed the highest inhibition ratio of 64.0% at a dose of 10 ㎎/㎏/day for 10 days. Fraction C contained 60% polysaccharide and 21% protein. The polysacchride moiety of Fr. C₁ consisted of glucose, fucose and mannose. The protein-polysaccharide increased plaque-forming cells and restored the suppressed delayed-type hypersensitivity in tumor-bearing mice. In addition, the antitumor activity of the polymer was reduced by carragenan, an antimacrophage drug, thereby indicating that macrophage played an important role in the antitumor activity.
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