A New Neolignan Glycoside from the Leaves of Acer truncatum

Abstract

Abstract:A new neolignan glycoside, (7R,8R)-7,8-dihydro-9′-hydroxyl-3′-methoxyl-8-hydroxymethyl-7-(4-hydroxy-3-methoxyphenyl)-1′-benzofuranpropanol 9′-O-β-Dglucopyranoside (1) was isolated from the leaves of Acer truncatum along with (7), chlorogenic acid (8) and neochlorogenic acid (9). Their structures were elucidated on the basis of extensive spectroscopic data. The absolute configuration of compounds 1 was established by its CD spectrum. The antibacterial activities of compounds 1-7 were evaluated.

Three New Lignan Glycosides with IL-6 Inhibitory Activity from <i>Akebia quinata</i>

“…These results indicated that 1 had two phenylpropanoid units. 16,17) Significant HMBC correlations were also observed between H-7/C-5′ and H-8/C-4′. Therefore, it could be concluded that two phenylpropanoids formed a 7,8-dihydro-8-hydroxymethyl-7-phenyl-1′-benzofuranpropanol skeleton.…”

“…17,18) Accordingly, the structure of 1 was identified as (7S,8S)-7,8-dihydro-8-hydroxymethyl-7-(4-hydroxy-3-methoxyphenyl)-1′-benzofuranpropanol 2′-O-β-D-glucopyranoside, named akeqintoside A, as drawn in Fig. 1 14) The…”

“…Therefore, it could be concluded that two phenylpropanoids formed a 7,8-dihydro-8-hydroxymethyl-7-phenyl-1′-benzofuranpropanol skeleton. 16,17) In the 1 H-1 H-correlation spectroscopy (COSY) spectrum, the oxymethine proton at δ H 5.52 showed coupling with H-8, in addition methylene protons at δ H 2.62 showed coupling with H-8′ and H-9′. The glycosidic linkage was identified at C-2′ by nuclear Overhauser enhancement spectroscopy (NOESY) experiment and HMBC correlations as shown in Fig.…”

“…The relative configuration of H-7 and H-8 was identified as cis form from the distinct NOE correlation between H-7 and H-8, H-8 and H-2/H-6, also based on the reported NMR data. 17,18) The absolute stereochemistry at C-7…”

“…The CD spectrum of 2 showed a positive Cotton effect at 246 and 291 nm, which indicated the absolute configurations of 2 to be 7R,8R-configurations. 17,18) Accordingly, the structure of 2 was identified as (7R,8R)- (Table 1), 25 carbon signals appeared besides those of the sugar unit, including one carbonyl carbon at δ C 169.2 (C-9′), two oxygenated methine carbons at δ C 75.6 (C-7) and 75.6 (C-8), olefinic carbons at δ C 147.4 (C-7′) and 114.9 (C-8′), and one oxygenated methylene carbon at δ C 72.8 (C-9). Based on the 1 H-and 13 C-NMR data, the structure of 3 was closely related to guaiacylglycerol 4-O-β-D-glucopyranoside, which was isolated from Osmanthus asiaticus 8) except for the presence of a caffeoyl group in the sugar unit and the different location of the sugar in 3.…”