Application of MS and NMR to the structure elucidation of complex sugar moieties of natural products: exemplified by the steroidal saponin from Yucca filamentosa L.

Relevance of Fucose-Rich Extracellular Polysaccharides Produced by Rhizobium sullae Strains Nodulating Hedysarum coronarium L. Legumes

“…5). The determined chemical shifts were compared to those in the literature (24,(30)(31)(32)(33)(34)(35)(36) C (␦ ϭ 100.1 ppm) and 1 H (␦ ϭ 3.82, 3.88, and 3.70 ppm) corresponding respectively to the two H-6 and to H-3 or H-4 of the hexose. Attribution of the chemical shifts corresponding to the quaternary carbons (C and COOH) of the substituents was performed using the HMBC data.…”

New Epimeric Spirostanol and Furostanol-Type Steroidal Saponins fromCestrum laevigatumL.

“…The aglycones were characterized as gitogenin and neogitogenin after comparison with literature data. [10][11][12] The relative configuration of the hydroxyl and sugar portion at C-2 and C-3 was established by comparison with the 13 C NMR spectral data described to the gitogenin and its 2β,3α-dihydroxy isomer, through the characteristic chemical shifts relative to C-1 to C-5. The chemical shifts at d C 46.0 (C-1), 70.7 (C-2), 85.0 (C-3), 34.3 (C-4) and 44.9 (C-5) observed in 1/2 were in accordance with the 2α, 3β-orientation.…”

Chemical Constituents from the Roots of <i>Furcraea bedinghausii</i> Koch

“…: Yucca pringlei Greenm) belongs to the Agavaceae family which has more than 580 species widely distributed in tropic and subtropic dry climate regions [1,2]. The genus Furcraea has about 20 species, and is mainly cultivated as ornamental plants.…”

“…To the best of our knowledge, no phytochemical work is reported on Furcraea bedinghausii. However, phytochemical investigations on plants of the genera Furcraea and Yucca afforded steroidal saponins [1,3,4] and phenolic compounds [5,6]. In this paper, the chemical survey of secondary metabolites from the roots of Furcraea bedinghausii was achieved, leading to the isolation and structure elucidation of several compounds including an inseparable mixture of two new homoisoflavones.…”

“…The major compound 4a displayed in the 1 H NMR spectrum signals of three protons at δ 6.74 (dd, J = 8.5, 2.0, H-6'), 6.75 (brs, H-2') and 6.75 (d, J = 8.5, H-5'), characteristic of homoisoflavonoids having a 3',4'-dioxygenation of the B ring [18]. It also showed a two proton-singlet at δ 5.94 ppm suggesting a methylenedioxyl moiety [19].…”