ABSTRACT: A new flavanol derivative, (2R,3R)-3-acetoxy-7-hydroxy-3',4'-methylenedioxyflavan (1), was co-isolated from the rhizomes of Zephyranthes ajax Hort. with the following seven known compounds: 7-hydroxyflavan (2), 7,4'-dihydroxyflavan (3), 7,4'-dihydroxy-8-methylflavan (4), 7,3'-dihydroxy-4'-methoxyflavan (5), 5,4'-dihydroxy-7-methoxy-6-methylflavan (6), 7-hydroxy-3',4'-methylenedioxyflavanone (7) and haemanthamine (8). Their structures were elucidated by combining 1D-/2D-NMR, CD, UV and HRESIMS data, and comparisons with reported data in literature were made. Among these known compounds, 2, 3, 4, 6 and 7 were isolated from the genus Zephyranthes for the first time. In addition, the cytotoxicity assay indicated that compound 8 has potent cytotoxic activity against human hepatocellular carcino
