Complete ¹H and ¹³C NMR assignments of sesquiterpene glucosides from Ixeris sonchifolia

Abstract

Four sesquiterpene glucosides were isolated from Ixeris sonchifolia Hance. The structure of a new compound (1) was assigned as 9beta-monohydroxy-2,12-dioxo-guaia-3,11(13)-dien-1alpha,5alpha,6beta,7alpha,9beta,10alphaH-12,6-olide-9-O-beta-D- glucopyranoside (ixerinoside). In addition, unambiguous and complete assignments of (1)H NMR chemical shifts for crepidiaside A (2), ixerin Z (3), and 11,13alpha-dihydroixerin Z (4) are presented. The assignments were achieved by two-dimensional NMR (gCOSY, gHSQC, gHMBC, NOESY) and one-dimensional nuclear Overhauser effect (NOE) experiments.

Isolation and Purification of Sesquiterpene Lactones from <i>Ixeris sonchifolia</i> (Bunge) Hance by High-Speed Counter- Current Chromatography and Semi-Preparative High Performance Liquid Chromatography

“…C-1'), 75.5 (C-2'), 78.4 (C-3'), 71.4 (C-4'), 78.0 (C-5'), 62.6 (C-6'). These data are in good agreement with those of 11,13α-dihydroixerin Z [18].…”

Systematic characterisation of secondary metabolites from Ixeris sonchifolia by the combined use of HPLC‐TOFMS and HPLC‐ITMS

“…Their chemical compositions were determined to be C 21 H 26 O 9 , C 21 H 28 O 9 and C 21 H 28 O 9 , respectively, based on the TOFMS data (Table 1). By comparing the 13 C‐NMR data (Table 3) with literature (Na et al ., 2007), compounds 12 and 16 were confirmed to be ixerin Z and 11 β ,13‐dihydroixerin Z, respectively. The 13 C‐NMR data of compound 13 were similar to those of compound 12 but there were still some differences: the C‐11 and C‐13 signals of compound 13 showed notable upfield shifts.…”

“…Ixerin Z, 11 β ,13‐dihydroixerin Z and 11 β ‐hydroxyleucodin‐11‐ O ‐ β ‐glucopyranoside were separated from I . sonchifolia and their structures elucidated by 13 C‐NMR and TOFMS and confirmed by comparison with literature data (Kisiel and Michalska, 2005; Na et al ., 2007). Purities of all these compounds were higher than 98%, as determined by peak area normalisation.…”

Cytotoxic constituents and a new hydroxycinnamic acid derivative from Leontodon saxatilis (Asteraceae, Cichorieae)

“…Separation of fraction B4 resulted in the isolation of six flavone glycosides, which were identified as luteolin 7- O -β- d -rutinoside (7), apigenin 4′- O -β- d -glucoside (8), apigenin 7- O -β- d -glucuronide (9), luteolin 7- O -β- d -glucoside (10), luteolin 7- O -β- d -glucuronide (11), and luteolin 4′- O -β- d -glucoside (12) after LC-MS analysis and comparison of NMR spectra to literature data, 20–22 as well as cichoric acid (13). 23 Fraction B3 yielded one sesquiterpenoid, namely crepidiaside A (4), 24 and five hydroxycinnamic acid derivatives, of which four were identified as chlorogenic acid (1), 5-feruloylquinic acid (3), 3,5-dicaffeoylquinic acid (6), and methyl 3,5-dicaffeoyl quinate (5). 25,26 NMR data of all isolated compounds are given in Tables S1–S5.…”

“…Separation of fraction B4 resulted in the isolation of six avone glycosides, which were identied as luteolin 7 [20][21][22] as well as cichoric acid (13). 23 Fraction B3 yielded one sesquiterpenoid, namely crepidiaside A (4), 24 and ve hydroxycinnamic acid derivatives, of which four were identied as chlorogenic acid (1), 5-feruloylquinic acid (3), 3,5-dicaffeoylquinic acid (6), and methyl 3,5-dicaffeoyl quinate (5). 25,26 NMR data of all isolated compounds are given in Tables S1-S5.…”