Douglas-fir polyphenols and heartwood formation

Phenolic extractives have been isolated from Douglas-fir sapwood and heartwood and identified by NMR and mass spectroscopy. Pinocembrin, [5,5′]-bisdihydroquercetin and two lignans, pinoresinol and 2,3-dihydro-2-(4′- O-β-glucopyranosyl-3′-methoxyphenyl)-3-hydroxymethyl-5-(3-hydroxypropyl)-7-methoxy-benzofuran are reported for the first time in these tissues. The chemical structures of these phenolic extractives show that heartwood formation is characterized by both primary (biosynthetic) and secondary reactions. Secondary reactions include hydrolysis of phenol glucosides and oxidative polymerization. © 1997 Elsevier Science Ltd. All rights reserved