Eight known secondary metabolites were isolated from the methanolic extract of the whole plant of Astragalus lycius Boiss. They were identified as 5,5’dihydroxy-3’-methoxy-isoflavone-7-O? -D-glucoside (1), genistin (2), sissotrin (3), 5,4’-dimethoxy-isoflavone-7-O? -D-glucopyranoside (4), (7S,8R)-5methoxydehydrodiconiferyl alcohol-4-O? -D-glucopyranoside (5), 4-O-lariciresinol-glucoside (6), 2-phenylethyl? -D-glucopyranoside (7) and ? -sitosterol-3O-β-D-glucopyranoside (8) by spectroscopic methods including 1H- and 13C-NMR and HR-MS experiments, and by comparison with literature values. Compounds 1-7 are reported for the first time from Astragalus taxa. All of the compounds were tested for their cytotoxic activities against a number of cancer cell lines. Among them, only 6 exhibited significant activity against human colon carcinoma (HT-29) at 2.69 ?M concentration.
Keywords: Astragalus lycius, Isoflavone, Lignan, Cytotoxic activity, Cancer, Chemotaxanomy.