Antitumor agents XXIII: Helenalin, and antitumor principle from Anaphalis morrisonicola HAY

A chloroform extract of the whole plant of Anaphalis morrisonicola HAY, showed significant antitumor activity against Ehrlich ascites carcinoma, Walker 256 carcinosarcoma, and P-388 lymphocytic leukemia. Systematic fractionation of the extract led to isolation and characterization of helenalin, a pseudoguaianolide, as the major active principle.