Flavan-3-ols and procyanidins from the bark of Salix purpurea L.
From a commercial aqueous ethanolic extract obtained from the bark of Salix purpurea L. the flavan-3-ols catechin, epicatechin, gallocatechin, catechin-3-O-(1-hydroxy-6-oxo-2-cyclohexene-1-carboxylic acid)-ester, the dimeric procyanidins B1, B3 and the trimeric procyanidins epicatechin-(4B-->8)-catechin-(4alpha-->8)-catechin and epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-catechin were isolated. Structure elucidation was performed by NMR, CD, MS, degradation and optical rotation methods. A fraction containing higher oligomeric procyanidins was investigated by 13C NMR. Data indicate an average degree of oligomerization of 4 to 5 flavan-3-ol units with dihydroxylated B-rings and predominance of 2,3-cis-stereochemistry.
Jürgenliemk
G
G
Institute of Pharmaceutical Biology and Phytochemistry, Westfälische Wilhems-University, Münster, Germany.
Petereit
F
F
Nahrstedt
A
A
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D044948:Flavonols / Q000032:analysis*; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D009904:Optical Rotation; D024301:Plant Bark / Q000737:chemistry; D044945:Proanthocyanidins / Q000032:analysis*; D032108:Salix / Q000737:chemistry*
D044948:Flavonols; D007202:Indicators and Reagents; D044945:Proanthocyanidins