Studies on antitumor substances produced by basidiomycetes.

The antitumor activity of the Basidiomycetes was first demonstrated by Lucas and his collaborators (4), who employed extracts of fruiting bodies of the mushroom Boletus edulis (Bull.) Fr. and other Holobasidiomycetes against Sarcoma 180 in the mouse. In a later paper (3) they described additional tests, made not only with extracts of fresh and frozen sporophores of several species of the genus Calvatia, but also with shake-flask cultures of sporophore-derived mycelia; C. bovista (Bull.) MacBride, C. cranijormis (Schw.) Fr., and C. cyathijormis (Bosc.) Morg. were found to produce tumor inhibitors. The successful in vitro culture of C. gigantea (Pers.) Lloyd and the production of tumor-inhibiting principles in fermentation cultures were also reported (3). The discovery of antitumor activity in fermentation cultures stimulated Lucas and his associates to seek a submerged fermentation process as a practical and reproducible source of large quantities of antitumor materials. Their study led to the isolation of a potent antitumor agent ("calvacin") from C. gigantea (Pers.) Lloyd (3). Roland et al. (5) purified a fraction derived from sporophores of this Basidiomycete and found it to possess antitumor activity against 14 of 24 various mouse, rat, and hamster tumors. More recently, Yoshida et al. (8) isolated from Lampteromyces japonica Singer an agent active against Ehrlich carcinoma of the mouse.