Procyanidins from the herb of Hypericum perforatum

From the aqueous acetone extract of the herb of Hypericum perforatum the fl avanols catechin (1) and epicatechin (2), and the procyanidins A2 (9), B1 ( 3), B2 (4), B3 (5), B5 (6), B7 (7) and C1 (8) were isolated. Their structur es were established as their peracetate derivatives, on the basis of chemic al and spectral evidence. The C-13 NMR spectrum of the higher molecular wei ght polymer fraction revealed a 3 ' ,4 ' -dihydroxylated B-ring oxidation p attern and the 2,3-cis relative stereochemistry of the constituent flavan-3 -ol units. The mean average molecular size of the polymers was estimated to be 4 to 5 flavan-3-ol units. The procyanidin pattern in comparison to that of Crataegus spec. is briefly discussed.