To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcoh...To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcohols and saccharides respectively to give the correspondingglycosylation products. The compounds were determined by ~1H NMR and ^(13)C NMR spectra. ResultsThe α-glu-co-pyranosides and related oligosaccharides were prepared in high yields. Conclusion The3, 5-dinitro-benzoyl group was found to be a good leaving group at the anomeric position andO-glucopyranosides and oligosaccharides were stereoselectively synthesized in good yield.展开更多
By means of variable temperature NMR spectra, conformation of 8-C-glucosyl prunetin, isolated from the leaves of Dalbergia hainanensis (Leguminosae), was studied. The restricted rotation around the C (sp3)-C (sp2) bo...By means of variable temperature NMR spectra, conformation of 8-C-glucosyl prunetin, isolated from the leaves of Dalbergia hainanensis (Leguminosae), was studied. The restricted rotation around the C (sp3)-C (sp2) bond in the C-glucosides isoflavonoid results in two main conformers (syn and anti). With the help of MM calculation, the preferred conformation A has H-1 gauche to the 7-OCH3. The barrier to rotation was 18.1 kcal/mol. This result agrees with the calculated value 16.2 kcal/mol of free energy of activation for the interconversion between the conformers.展开更多
Three new glucosylated caffeoylquinic acid isomers (1-3), along with six known compounds, have been isolated from an aqueous extract of the flower buds of Lonicera japonica. Structures of the new compounds were determ...Three new glucosylated caffeoylquinic acid isomers (1-3), along with six known compounds, have been isolated from an aqueous extract of the flower buds of Lonicera japonica. Structures of the new compounds were determined by spectroscopic and chemical methods as (-)-4-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (-)-3-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (2), and (-)-5-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (3), respectively. In the preliminary in vitro assays, two known compounds methyl caffeate and 2'-O-methyladenosine showed inhibitory activity against Coxsackie virus B3 with IC50 values of 3.70 mu mol/L and 6.41 mu mol/L and SI values of 7.8 and 12.1, respectively. (C) 2015 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.展开更多
As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O- glucosylation regulates the formation of important ag...As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O- glucosylation regulates the formation of important agronomic traits in rice by manipulating the expression of OscZOG1 gene, encoding a putative zeatin O-glucosyltransferase. We found that OscZOG~ was preferentially expressed in shoot and root meristematic tissues and nascent organs. The growth of lateral roots was stimulated in the overexpression lines, but inhibited in RNA interference lines. In shoots, knockdown of OscZOG1 expression by RNA interference significantly im- proved tillering, panicle branching, grain number per panicle and seed size, which are important agronomic traits for grain yield. In contrast, constitutive expression of OscZOG1 leads to negative effects on the formation of the grain-yielding traits with a marked increase in the accumulation levels of cis-zeatin O-glucoside （cZOG） in the transgenic rice plants. In this study,our findings demonstrate the feasibility of improving the critical yield-determinant agronomic traits, including tiller number, panicle branches, total grain number per panicle and grain weight by downregulating the expression level of OscZOG1. Our results suggest that modulating the levels of cytokinin glucosylation can function as a fine-tuning switch in regulating the formation of agronomic traits in rice.展开更多
文摘To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcohols and saccharides respectively to give the correspondingglycosylation products. The compounds were determined by ~1H NMR and ^(13)C NMR spectra. ResultsThe α-glu-co-pyranosides and related oligosaccharides were prepared in high yields. Conclusion The3, 5-dinitro-benzoyl group was found to be a good leaving group at the anomeric position andO-glucopyranosides and oligosaccharides were stereoselectively synthesized in good yield.
文摘By means of variable temperature NMR spectra, conformation of 8-C-glucosyl prunetin, isolated from the leaves of Dalbergia hainanensis (Leguminosae), was studied. The restricted rotation around the C (sp3)-C (sp2) bond in the C-glucosides isoflavonoid results in two main conformers (syn and anti). With the help of MM calculation, the preferred conformation A has H-1 gauche to the 7-OCH3. The barrier to rotation was 18.1 kcal/mol. This result agrees with the calculated value 16.2 kcal/mol of free energy of activation for the interconversion between the conformers.
基金Financial support from the National Natural Science Foundation of China (NNSFC,Nos.20772156 and 30825044)the Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT,No.IRT1007)the National Science and Technology Project of China (No.2012ZX09301002-002)
文摘Three new glucosylated caffeoylquinic acid isomers (1-3), along with six known compounds, have been isolated from an aqueous extract of the flower buds of Lonicera japonica. Structures of the new compounds were determined by spectroscopic and chemical methods as (-)-4-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (-)-3-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (2), and (-)-5-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (3), respectively. In the preliminary in vitro assays, two known compounds methyl caffeate and 2'-O-methyladenosine showed inhibitory activity against Coxsackie virus B3 with IC50 values of 3.70 mu mol/L and 6.41 mu mol/L and SI values of 7.8 and 12.1, respectively. (C) 2015 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.
基金supported in parts by the Ministry of Science and Technology of China(2012CB944802 and 2012AA101103)the National Natural Science Foundation of China(91317305)the Ministry of Agriculture of China(2014ZX08009-003)
文摘As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O- glucosylation regulates the formation of important agronomic traits in rice by manipulating the expression of OscZOG1 gene, encoding a putative zeatin O-glucosyltransferase. We found that OscZOG~ was preferentially expressed in shoot and root meristematic tissues and nascent organs. The growth of lateral roots was stimulated in the overexpression lines, but inhibited in RNA interference lines. In shoots, knockdown of OscZOG1 expression by RNA interference significantly im- proved tillering, panicle branching, grain number per panicle and seed size, which are important agronomic traits for grain yield. In contrast, constitutive expression of OscZOG1 leads to negative effects on the formation of the grain-yielding traits with a marked increase in the accumulation levels of cis-zeatin O-glucoside （cZOG） in the transgenic rice plants. In this study,our findings demonstrate the feasibility of improving the critical yield-determinant agronomic traits, including tiller number, panicle branches, total grain number per panicle and grain weight by downregulating the expression level of OscZOG1. Our results suggest that modulating the levels of cytokinin glucosylation can function as a fine-tuning switch in regulating the formation of agronomic traits in rice.
