Flavonoid constituents from Eupatorium altissimum L. (Compositae).

An aqueous ethanol extract of Eupatorium altissimum L. (Compositae) showed confirmed activity in the P-388 lymphocytic leukemia assay in mice, and the chloroform solubles showed both cytotoxic activity in the 9KB carcinoma of the nasopharynx cell culture assay and antitumor activity in the P-388 lymphocytic leukemia assay. Two flavones, eupatorin and 5-hydroxy-3',4',6,7-tetramethoxyflavone, were isolated and identified. Both were devoid of cytotoxic and antitumor activity.