Antitumor effect and structure-activity relationship of asterriquinone analogs.

Asterriquinone (ARQ), a metabolic product from Aspergillus terreus IFO 6123, showed an inhibitory effect on some transplantable animal tumors, Ehrlich carcinoma, ascites hepatoma AH13 and mouse P388 leukemia, but had little or no effect on Yoshida sarcoma, ascites hepatoma AH109A and mouse L1210 leukemia. ARQ also inhibited the growth of HeLa cells in monolayer culture. Although metabolic products from Aspergillus terreus var. africanus IFO 8835 were almost ineffective against Ehrlich carcinoma, some chemically modified ARQ-like compounds were found to have potent inhibitory activity against the growth of the carcinoma in mice. The presence of free hydroxyl groups in the benzoquinone moiety and the number and position of tert-, iso-pentenyl, or both pentyl groups seem to be important in relation to the antitumor activity.