Zwei stark bittere glucoside aus swertia japonica makino: Amarogentin und amaroswerin

Studies on the Constituents of Swertia japonica MAKINO I. On the Structures of New Secoiridoid Diglycosides

“…The composition was determined by GLC analysis to be Dfructose and D-glucose as their TMSi derivatives. GLC condition: column, 3% SE-52 on Chromosorb W (AW) 2 mm i.d.ϫ1.5 m; column temp., 160°C; carrier gas, N 2 (Table 3), 13 C-NMR (Table 3) and HMBC data.…”

“…The constituents of this crude drug have previously been investigated and were shown to contain secoiridoid glycosides, [1][2][3][4][5] xanthones, [6][7][8][9] flavonoids, 10) biphenyl glycosides, 11) triterpenoids 7,12) and 2,8-dioxabicyclo[3.3.1] nonanes. 13) In this paper, we describe the isolation and structural elucidation of eight new secoiridoid diglycosides, 6Ј-Oa-L-arabinopyranosylswertiamarin (8), 14) chironiside (9), 15) swertiapunimarin (10), 16) 6Ј-O-b-D-glucopyranosylgentiopicroside (11) 17) and 5Љ-O-b-D-glucopyranosylamarogentin (13), 18) respectively, by comparison of their spectroscopic data with those previously described in the literature.…”

Unexpected Biosynthetic Precursors of Amarogentin − A Retrobiosynthetic13C NMR Study

“…On the basis of homocorrelation (COSY) and heterocorrelation (HMQC, HMBC) spectra, the assignments of 11 13 C signals (specifically carbon atoms 1, 4, 1Ј, 2Ј, 3Ј, 2ЈЈ, 4ЈЈ, 3ЈЈ, 5ЈЈ, 2ЈЈЈ and 4ЈЈЈ) required revision. 1 H and 13 C chemical shift values, together with 1 H 13 C and 13 C 13 C coupling constants, are summarized in Table 1. Supporting evidence for the novel assignments were obtained by INADEQUATE spectroscopy of a multiply 13 C-labeled amarogentin sample (from the incorporation experiment with fully 13 C-labeled glucose), affording carbon connectivities for 15 pairs of directly adjacent carbon atoms ( Figure 3, Table 1).…”

“…[1,2] The compound is used in alcoholic beverages (e.g. ''Enzian Schnaps'' in German) and, because of its extremely bitter taste, it has been proposed as an additive for soft drinks in place of quinine.…”

“…The biphenylcarboxylic acid moiety is biosynthesized by a polyketide-type pathway, with three units of acetyl-CoA and one unit of 3-hydroxybenzoyl-CoA, this being formed from an early shikimate pathway intermediate and not via cinnamic or benzoic acid. (1) pyrophosphate (2, DMAPP) and isopentenyl pyrophosphate (3, IPP) ( Figure 2). Incorporation experiments with [ 14 C]acetate were interpreted in terms of DMAPP/IPP formation via mevalonate.…”