Results 151 to 160 of about 15,004 (205)

Chromatography of Proanthocyanidins

1989
Current trends in chromatographic isolation and analyses of proanthocyanidins are reviewed. Preparative isolations by low pressure column chromatography can be carried out using a variety of gel types. Often, repeated separations are required to obtain pure compounds, and it has been found advantageous to alternate each separation with a different gel ...
Joseph J. Karchesy, Youngsoo Bae, Linda Chalker-Scott, Richard F. Helm, L. Yeap Foo   +4 more
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Proanthocyanidins in the Apple

Journal of Food Science, 1966
SUMMARY A study was conducted on the acetone‐ and ethyl‐acetate‐extractable flavan polyphenols of Waldhöfler apples, an astringent‐tasting juice variety. The extracts were examined by cellulose thin‐layer chromatography with 5% n‐butanol and n‐butanol—acetic acid—water (BAW) as the developing solvents ...
J. P. VAN BUREN, G. SENN, H. NEUKOM
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Biosynthesis of proanthocyanidins

Journal of the Chemical Society, Chemical Communications, 1975
The incorporation of 4′,5,7-trihydroxydihydroflavonol into the dimeric procyanidin B-4 in Rubus idaeus indicates that both flavan-3,4-diols and flavan-3-ols are derived biogenetically from dihydroflavonols.
Edmon Wong, Edward J. Birch
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Conformations of Proanthocyanidins

1992
The application of high resolution 1H-NMR and empirical (MM2, MMX) as well as semiempirical (MNDO, AMI, PM3) theoretical methods in the conformational analysis of proanthocyanidins have been the subject of much study. The E:A (B-ring equatorial or axial) ratios calculated for 4-arylflavan-3-ol model compounds, carefully selected to incorporate all ...
Jan P. Steynberg, E. Vincent Brandt, Matthiam J. H. Hoffman, Richard W. Hemingway, Daneel Ferreira   +4 more
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Plant proanthocyanidins. Part II. Proanthocyanidin-A2 and its derivatives

Journal of the Chemical Society, Perkin Transactions 1, 1974
The 2,7″-epoxy-4,8″-biflavan structure (1) has been deduced for the natural proanthocyanidin-A2 on the basis of spectroscopic (13C and 1H n.m.r.) and chemical evidence. Spectroscopic data are also outlined which lead, in association with biogenetic arguments, to a proposal (1a) for the absolute stereochemistry of the natural product.
David Jacques, Edwin Haslam, Geoffery R. Bedford, David Greatbanks   +3 more
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Proanthocyanidins ofPolygonum coriarium. IV. Structures of proanthocyanidins T3 and T4

Chemistry of Natural Compounds, 1997
Two oligomeric proanthocyanidins have been isolated from the roots ofPolygonum coriarium. By a study of their physical properties and spectral characteristics and analysis of the results of chemical transformations, the chemical structures of these compounds have been established as: (−)-epicatechin-77[O-β-D-glucopyranosyl]3\(\xleftarrow{6}\) O-²-D ...
B. M. Keneshov, Z. A. Kuliev, A. D. Vdovin, N. D. Abdullaev, A. A. Nishanov   +4 more
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Proanthocyanidins ofPolygonum coriarium III. Structures of proanthocyanidins T1 and T2

Chemistry of Natural Compounds, 1997
The roots ofPolygonum coriarum have yielded two oligomeric proanthocyanidins, T1 and T2, and their structures have been established: 3-O-galloyl-7-O-[O-(6-O-galloyl)-β-D-glucopyranosyl]-(−)-epigallocatechin-(4β-8)-(−)-epicatechin-(4β-8)-(−)-epicatechin-(4β-8)-(−)-epigallocatechin 3-O-gallate (T1) and (−)-epicatechin-(4β-8)-[3-O-galloyl ...
B. M. Keneshov, Z. A. Kuliev, A. D. Vdovin, N. D. Abdullaev, A. B. Makhmatkulov, A. A. Nishanov   +5 more
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Variation of Proanthocyanidins in Lotus Species

Journal of Chemical Ecology, 2006
The proanthocyanidin (PA) chemistry of 12 Lotus species of previously unknown PA content was examined in comparison with agricultural cultivars of L. pedunculatus, L. corniculatus, and L. tenuis and a "creeping" selection of L. corniculatus. Herbage harvested in winter 2000 and again in spring had extractable PA concentrations, estimations of which ...
Subathira, Sivakumaran, William, Rumball, Geoff A, Lane, Karl, Fraser, Lai Y, Foo, Min, Yu, Lucy P, Meagher   +6 more
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Phytochemistry of proanthocyanidins

Phytochemistry, 1975
Abstract Procyanidin A from Aesculus hippocastanum differs from the B type procyanidin in that it is difficultly soluble in water, gives a higher yield of cyanidin when heated in butanolic HCl and the production of cyanidin continues beyond the 2 hr period sufficient for maximum production in the case of B type procyanidin. Anthocyanidin production
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Biflavonoids and Proanthocyanidins

1989
The biflavonoids and proanthocyanidins constitute the two major classes of oligomeric flavonoids found in plants (126, 136). The biflavonoids are oxidative coupling products leading to biflavones, flavanone-flavones, and biflavanones. These compounds always carry carbonyl functions at the C-4 positions (126).
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