Iridoide aus Verbascum sinuatum

Abstract

From the underareal part of Verbascum sinuatum harpagoside [1] and a new diacyl-iridoid-diglycoside [2] has been isolated. The structure of the new compound is elucidated on the basis of (1)H-NMR, (13)C-NMR, mass spectral data and chemical degradation as 6-O-(2'',3''-Di-O-acyl)-alpha-L-rhamnopyranosylcatalpol.

Gmelinosides A−L, Twelve Acylated Iridoid Glycosides from Gmelina arborea

“…These known compounds were identified by direct comparison with authentic samples and by spectroscopic analysis (UV, IR, 1 H and 13 C NMR, and FABMS) as 6-O-R-L-rhamnopyranosylcatalpol (1), 12 6-O-(3′′-O-trans-feruloyl)-R-L-rhamnopyranosylcatalpol (14), 15 6-O-(2′′-O-acetyl-3′′, 4′′-O-di-trans-cinnamoyl)-R-L-rhamnopyranosylcatalpol (15), 8 verbascoside, 35 and martynoside, 36 respectively. All 13 C NMR multiplicities of gmelinosides A-L (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) were confirmed by DEPT measurements, and signal connectivities were determined by HMBC and HMQC. The new iridoid constituents (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) of G. arborea contained the same iridoid enol-ether system of 6-O-R-L-rhamnopyranosylcatalpol, and were esterified with cinnamoyl or benzoyl derivatives attached to different hydroxyl groups on the sugars or the aglycon moieties.…”

“…A combination of polyamide and Si gel column chromatography followed by further purification using reversed-phase chromatography and Sephadex LH 20 column chromatography led to the isolation of several new acylated gmelinosides glycosides A-L (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) in addition to several known iridoid and phenylpropanoid glycosides. These known compounds were identified by direct comparison with authentic samples and by spectroscopic analysis (UV, IR, 1 H and 13 C NMR, and FABMS) as 6-O-R-L-rhamnopyranosylcatalpol (1), 12 6-O-(3′′-O-trans-feruloyl)-R-L-rhamnopyranosylcatalpol (14), 15 6-O-(2′′-O-acetyl-3′′, 4′′-O-di-trans-cinnamoyl)-R-L-rhamnopyranosylcatalpol (15), 8 verbascoside, 35 and martynoside, 36 respectively.…”

“…1 The isolation of monoacyl, diacyl, and triacyl derivatives of 6-O-R-L-rhamnopyranosylcatalpol has been reported from several plant families including the Buddlejaceae, Scrophulariaceae, and Verbenaceae. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The genus Gmelina belongs to the subfamily Viticoideae, of the Verbenaceae and is a subcosmopolitan genus centered in the warm temperate regions of the Mediterranean and South Asia. The important commercial timber species, Gmelina arborea Roxb., is found in many ornamental gardens in Egypt.…”

“…Our present research on the leaves of G.arborea has resulted in the isolation of several new monoacylated, diacylated, and triacylated iridoid glycosides. We wish to report herein the isolation and structure elucidation of 12 new acylated iridoid glycosides (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) isolated from the leaves of G. arborea, in addition to three known iridoid glycosides (1,14,15) and two known phenylpropanoid glycosides.…”

Mass spectrometry of iridoids

“…Such differences can be used to determine the location of the acyl residue in similar iridoids. An example is provided by the new iridoid isolated from Verbuscum species with a partial structure 42 (43). The position of the p-methoxycinnamoyl group (C-2" or C-3") has not been established.…”