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, 8b b-hydroxy-3-oxo-guaia-4(15),10(14),11(13)-trien-1a a,5a a,6b b,7a aH-12,6-olide (8b b-hydroxydehydrozaluzanin), 8b b,15-dihydroxy-2-oxo-guaia-1(10),3,11(13)-trien-5a a,6b b,7a aH-12,6-olide (lactucin), 3b b,8a a,10a a-trihydroxy-guaia-4(15),11(13)-dien-1a a,5a a,6b b,7a aH-12,6-olide (10a a-hydroxy-10,14-dihydro-desacylcynaropicrin) and 3b b-D-glucopyranosyloxy-8b b-(p-hydroxyphenylacetyloxy)-guaia-4(15),10(14),11(13)-trien1a a,5a a,6b b,7a aH-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.

Bioactive Guaianolides from Siyekucai (Ixeris chinensis)

“…Compound 7 has also been prepared as an intermediate in the synthesis of plagiochiline N from santonin 23b. Compound 8 was identical with ixerochinoside that was isolated from I. chinensis 12b. Compound 9 was identical with 8-deoxylactucin 24a…”

“…Studies on some other species of this genus revealed the presence of sesquiterpene lactones such as guaianolides, eudesmanolides, germacranolides, and their glycosides. − Because of our interest in the biological activity of sesquiterpene lactones related to the medicinal effects of I. chinensis , we previously isolated three guaianolides ( 1 − 3 ) from this plant . Lee et al and Khalil et al also reported glycosides of guaianolides from this plant . The diverse biological activity reported for guaianolides − prompted us to undertake a further investigation of the guaianolides in this plant.…”

“…In this paper, we report the isolation of two additional new natural guaianolides, which we have named chinensiolides D ( 5 ) and E ( 6 ), and the first isolation of a known compound, (11 S )-10α-hydroxy-3-oxoguaia-4-eno-12,6α-lactone ( 4 ), from natural sources. Also isolated were three known compounds, (11 S )-10α-hydroxy-3-oxo-4β H -guaiano-12,6α-lactone ( 7 ), ixerochinoside ( 8 ),12b and 8-deoxylactucin ( 9 ) . We also report their potential as immunomodulators because of their influence on induction of ICAM-1 (intercellular adhesion molecule-1) and on the basis of the reported antiinflammatory activity of this plant and their cytotoxic activity against A 549 lung carcinoma, WI-38 lung fibroblast, VA-13 lung malignant tumor, and HepG2 human liver tumor cells.…”