RELATIONSHIP BETWEEN THE B-RING HYDROXYLATION PATTERN OF CONDENSED TANNINS AND THEIR PROTEIN-PRECIPITATING CAPACITY

A series of condensed tannin derivatives with non-, mono-, di- and tri-hydroxylated B-rings were synthesized starting from ph1oroglucinol and benzaldehyde derivatives. The protein-prec ipitating capacity of these condensed tannin derivatives showed 1) A condensed tannin with only a 4'-hydroxylated B-ring has almost the same protein-precipitating capacity as that of a condensed tannin with 3',4' -dihydroxy lated or 3',4',5'-trihydroxylated B-rings. 2) The complexing ability of phenolic hydroxyl groups in the B-ring are effective in the order of P- > m- > O-positions. © 1990, Taylor & Francis Group, LLC. All rights reserved.