LAUSR

Abstract The composition of sapwood, transition zone and heartwood extracts from Pseudotsuga menziesii was studied using LC/ESI–MS/MS. Based on retention times, and MS fragmentation patterns, 40 phenolic compounds, 11 terpenes and 7 fatty and organic acids were identified or accordingly characterized. The flavonoids taxifolin-O-hexoside and the corresponding aglycon taxifolin, dihydrokaempferol, pinocembrin, pinobanksin, quercetin and flavan-3-ols, catechin and epicatechin were the main compounds detected in wood collected in the fall. Taxifolin derivatives were identified as monomers, dimers and flavonolignans. Comparative metabolite profiling of the three zones showed differences in metabolite distribution. Flavonoids were distributed in the 3 zones. Lignans, flavonolignans, phenolic acid derivatives and terpenes accumulated mainly in the transition zone while tannins were detected only in sapwood. Fatty and organic acids were present in sapwood and the transition zone. Multiple Reaction Monitoring (MRM) was used for the quantification of main metabolites of extracts in order to observe seasonal variations in the wood. The relative quantity of 35 selected compounds in each zone was discussed. The lowest metabolite content was usually observed in winter whereas flavonoids were found in high quantities in heartwood either in spring or autumn.