Potential anticancer agents. XIV. Isolation of spruceanol and montanin from Cunuria spruceana (Euphorbiaceae).

Montanin (1) and spruceanol (2), two quite different diterpenes, were found to be responsible for the cytotoxic and antitumor activity of the root and root bark of Cunuria spruceana (Euphorbiaceae). The structure of spruceanol (2) was deduced from spectral interpretation and chemical correlation with 12-methoxycleistanth-8,11,13-trien-3-one (4).