HETEROGENEITY OF INTERFLAVANOID BOND LOCATION IN LOBLOLLY PINE BARK PROCYANIDINS

Article abstract of DOI:10.1016/S0031-9422(00)80105-3

Procyanidins B-1 B-3 and B-7 were obtained from Pinus taeda phloem in yields of 0.076, 0.021 and 0.034percent of unextracted dry wt.Procyanidins B-1 and B-7 were produced in relative yields of 2.4:1 by biosynthetically patterned synthesis from catechin and loblolly pine tannins.Partial acid-catalysed thiolytic cleavage of loblolly pine phloem tannins produced (2R,3S,4S)-2,3-cis-3,4-trans-3,3',4',5,7-pentahydroxy-4-phenylthioflavan and both (2R,3R,4R)-2,3-cis-3,4-trans-3,3'4',5,7-pentahydroxy-4-<(2R,3S,4S)-2,3-cis-3,4-trans-3,3',4',5,7-pentahydroxy-4-phenylthioflavan-8-yl>flavan and (2R,3R,4R)-2,3-cis-3,4-trans-3,3',4',5,7-4-<(2R,3S,4S)-2,3-cis-3,4-trans-3,3',4',5,7-pentahydroxy-4-phenylthioflavan-6-yl>flavan in ratios of 3 : 1 demonstrating regio-isomerism of the interflavanoid linkage in the polymeric procyanidins of loblolly pine bark.Key Word Index - Pinus taeda; Pinaceae; loblolly pine; bark; phloem; procyanidins; condensed tannins; interflavanoid linkage; regio-isomerism.