DOUGLAS-FIR POLYPHENOLS AND HEARTWOOD FORMATION

Phenolic extractives have been isolated from Douglas-fir sapwood and h eartwood and identified by NMR and mass spectroscopy. Pinocembrin, [5, 5']-bisdihydroquercetin and two lignans, pinoresinol and roxymethyl-5- (3-hydroxypropyl)-7-methoxybenzofuran are reported for the first time in these tissues. The chemical structures of these phenolic extractive s show that heartwood formation is characterized by both primary (bios ynthetic) and secondary reactions. Secondary reactions include hydroly sis of phenol glucosides and oxidative polymerization. (C) 1997 Elsevi er Science Ltd. All rights reserved.