Loblolly pine bark flavanoids

Abstract

The inner bark of Pinus taeda L. contains (+)-catechin, the procyanidin 8.1 (a C-4 to C-8 linked (-)-epicatechin to (+)-catechin dimer), and three polymeric procyanidins that have distinctly different solubility and chromatographic properties. An ethyl acetate soluble polymer (0.20% of bark, Mn = 1200) was purified by chromatography on LH-20 Sephadex. A water-soluble tannin (6.3% of bark, Mn = 2100) and an acetone/water-soluble tannin (3.7% of bark, Mn = 2900) were purified by chromatography on cellulose columns. Despite differences in their physical properties, thiolysis with benzenethiol and 18C-NMR spectra indicated that the three polymeric procyanidins were composed of C-4 to C-8 (or C-6) linked (-)-epicatechin upper units (chain extenders) and that the lower unit (chain initiator) was (+)-catechin.

Citation

Karchesy, J.J.; Hemingway, R.W. 1980. Loblolly pine bark flavanoids. Journal of Agricultural and Food Chemistry 28:222-228