Occurrence of "mammalian" lignans in plant and water sources.

Enterolignans, also called "mammalian" lignans because they are formed in the intestine of mammals after ingestion of plant lignans, were identified for the first time in extracts of four tree species, i.e., in knot heartwood of the hardwood species Fagus sylvatica and in knot or stem heartwood of the softwood species Araucaria angustifolia, Picea smithiana, and Abies cilicia.

Antioxidant activity of knotwood extractives and phenolic compounds of selected tree species.

The antioxidant potency and the radical scavenging capacity of superoxide and peroxyl radicals were assessed for 13 hydrophilic knotwood extracts of commercially important wood species, or fractions thereof, as well as for five pure wood-derived lignans and the flavonoid taxifolin. The chemical composition of the knotwood extracts was determined by gas chromatography combined with mass spectrometry. Most of the investigated wood species were rich in hydrophilic extractives (10-20% of the dry wood) with one or a few compounds dominating in each extract.

Phenolic extractives in Salix caprea wood and knots.

Salix caprea stemwood and knots were found to contain the phenolic extractives vanillic acid, 3-p-coumaryl alcohol, coniferyl alcohol, sinapylaldehyde, dihydrokaempferol, catechin, naringenin, gallocatechin, dihydromyrcetin and taxifolin. The knots contained larger quantities of flavonoids than did stemwood of the same tree.