Antiproliferative activity of Artemisia asiatica extract and its constituents on human tumor cell lines

The extract of Artemisia asiatica herb with antiproliferative activity against four human tumor cell lines (A2780, A431, HeLa, and MCF7) was analyzed by the MTT assay, and bioassay-directed fractionation was carried out in order to identify the compounds responsible for the cytotoxic activity. Guaianolide (1-4), seco-guianolide (5), germacranolide (6) and eudesmanolide sesquiterpenes (7), monoterpenes (8, 9), including the new compound artemisia alcohol glucoside (8), and flavonoids (10-16) were isolated as a result of a multistep chromatographic procedure (CC, CPC, PLC, and gel filtration). The compounds were identified by means of UV, MS, and NMR spectroscopy, including (1)H-and (13)C-NMR, (1)H-(1)H COSY, NOESY, HSQC, and HMBC experiments. The isolated compounds 1-16 were evaluated for their tumor cell growth-inhibitory activities on a panel of four adherent cancer cell lines, and different types of secondary metabolites were found to be responsible for the cytotoxic effects of the extract. Especially cirsilineol (13), 3β-chloro-4α,10α-dihydroxy-1α,2α-epoxy-5α,7αH-guai-11(13)-en-12,6α-olide (3), and iso-seco-tanapartholide 3-O-methyl ester (5) exerted marked cytotoxic effects against the investigated cell lines, while jaceosidin (12), 6-methoxytricin (15), artecanin (2), and 5,7,4',5'-tetrahydroxy-6,3'-dimethoxyflavone (14) were moderately active. All the sesquiterpenes and monoterpenes are reported here for the first time from this species, and in the case of artecanin (2), 3α-chloro-4β,10α-dihydroxy-1β,2β-epoxy-5α,7αH-guai-11(13)-en-12,6α-olide (4), ridentin (6), and ridentin B (7), previously unreported NMR spectroscopic data were determined.