Two new sesquiterpene lactones from Ixeris chinensis

Abstract

Phytochemical investigation of Ixeris chinensis NAKAI (Asteraceae) has resulted in the isolation of a new guaianolide-type sesquiterpene lactone, ixerochinolide (1) as well as the related glucoside, ixerochinoside (2). In addition, the known guaianolides, 8βhydroxy-3-oxo-guaia-4(15),10(14),11(13) -trien-1α,5α,6β,7αH-12,6-olide (8β)- hydroxydehydrozaluzanin), 8β,15-dihydroxy-2-oxo-guaia-1(10),3,11(13)-trien- 5α,6β,7αH-12,6-olide (lactucin), 3β8α,10α- trihydroxy-guaia-4(15),11(13)-dien-1α,5α,6β,7αH-12, 6-olide (10α-hydroxy-10,14-dihydro-desacylcynaropicrin) and 3β-D-glucopyranosyloxy-8β-(p-hydroxyphenylacetyloxy)-guaia-4(15), 10(14),11(13)-trien-1α,5α,6β,7αH-12,6-olide (8-epicrepioside) were identified. The structures were determined on the basis of spectral analyses, especially 1- and 2D NMR. Compound 1 exhibited significant cytotoxicity against human PC-3 tumor cells. © 2005 Pharmaceutical Society of Japan.