Neolignans and flavonol glycosides from the leaves of viburnum lutescens blume

Abstract

Four neolignans, (7S,8S)-dihydrodehydrodiconiferyl alcohol 9-O-β-D-glucopyranoside (1), (7S,8S)-dihydrodehydrodiconiferyl alcohol 9′-O-β-D-glucopyranoside (2), (7S,8R)-5-methoxydihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside (3), and (7S,8R)-5-methoxydihydrodehydrodiconiferyl alcohol 9′-O-β-D-glucopyranoside (4) and five flavonol glycosides, kaempferol-3-O-β-D-glucopyranoside (5), kaempferol 3-O-rutinoside (6), kaempferol 3-O-α-L-rhamnopyranosyl (1→6)-β-D-galactopyranoside (7), kaempferol 3-O-β-D-galactopyranoside (8), and quercetin 3-O-β-D-glucopyranoside (9) were isolated from the methanol extract of Viburnum lutescens Blume leaves. Their chemical structures were elucidated by 1D- and 2D-NMR spectra and comparison with those reported in the literature. Compounds 1, 2, and 4 were reported from Viburnum genus for the first time.

Phenolic compounds from knema pachycarpa leaves

“…The molecular formula of 5 was assigned as C 15 H 12 O 6 based on the pseudo-molecular ion peak m/z 465 [M+H] + in the ESI-MS spectrum. The coupling constant of anomer proton (J = 7.5 Hz) and 13 C NMR data suggested the sugar was β-glucose. HMBC spectrum showed the correlation of H-1 (δ H 5.25) to C-3 (δ C 134.2).…”

“…Sugar part was observed with two anomer protons at δ H 5.14 (1H, d, J = 7.5 Hz, H-1'') and δ H 4.54 (1H, d, J = 1.0 Hz, H-1'''), eleven protons in the range of 3.82-3.39 ppm and a methyl group at δ H 1.14 (3H, d, J = 6.5 Hz, H-6'''). The 13 2). The first sugar was assigned as βglucose while the second sugar was identified as α-rhamnose based on the coupling constants of anomer protons (J = 7.5 Hz and 1.0 Hz, respectively) and 13 C NMR data [13].…”

“…The 13 2). The first sugar was assigned as βglucose while the second sugar was identified as α-rhamnose based on the coupling constants of anomer protons (J = 7.5 Hz and 1.0 Hz, respectively) and 13 C NMR data [13]. Compound 6 was determined as kaempferol-3-rutinose or nicotiflorin (Figure 1) [13].…”

“…The 13 C-NMR spectrum showed six carbon aromatic signals ranging from 146.3 to 114.6 ppm. Combined MS and NMR analysis, the molecular formula of 7 was suggested as C 12 H 10 O 4 and signals in 1 H and 13 C NMR spectra were duplicated peaks. Compound 7 was identified as 3,3',4,4'-tetrahydroxybiphenyl (Figure 1).…”

“…The 1 H-NMR (500 MHz) and 13 C-NMR (125 MHz) spectra were recorded by a Bruker AM500 FT-NMR spectrometer using TMS as an internal standard. The electrospray ionization mass spectra (ESI-MS) were obtained on an Agilent 1260 single quadrupole LC/MS system.…”