Discovery, structural determination and anticancer activities of lactucin-like guaianolides

We reported that the extract of Mulgedium tatarica DC. exhibits anticancer activity. With the help of a tumor cell killing bioassay, the sesquiterpene lactones lactucopicrin (1), 11,13 beta-dihydrolactucopicrin (2), lactucin (3) and 11,13 beta-dihydrolactucin (4) were isolated and identified from this medicinal herb. SAR studies indicate that the ester group at position 8 and the exocyclic methylene group at position 11 play a major role in anticancer activities of lactucin-like guaianolides, a kind of sesquiterpene lactone.