Isolation of two new bioactive sesquiterpene lactone glycosides from the roots of Ixeris dentata

Two new sesquiterpene lactone glycosides, 3-O-β-d-glucopyranosyl-8-hydroxy-(1,5,6,7,11)-guaia-3,10(14)-dien-12,6-olide (1) and 3-O-β-d-glucopyranosyl-8-(4-hydroxyphenylacetyloxy)-(1.5.6,7)-guaia-3,10(14),11(13)-trien-12,6-olide (2), and 12 known sesquiterpene lactone derivatives (3-14) were isolated from the roots of Ixeris dentata. Their structures were determined by extensive spectroscopic methods including 1D and 2D NMR and MS spectra data. All compounds were tested for their ability to inhibit lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 microglial cell. 3-O-β-d-Glucopyranosyl-8-(4-hydroxyphenylacetyloxy)-(1.5.6,7)-guaia-3,10(14),11(13)-trien-12,6-olide (2) showed the most potent inhibitory activity at a concentration of 20 μM.