Lignans and Lipophilic Extractives in Norway Spruce Knots and Stemwood

Abstract

Summary The hydrophilic and lipophilic extractives in the heartwood of knots from 7 Norway spruce trees were analysed by GC, GC-MS and HPSEC. The knots contained extremely large amounts of lignans, 6–24% (w/w), with hydroxymatairesinol comprising 65–85% of the lignans. Even the knots of the young trees contained 4–8% (w/w) of lignans. The variation in the amount of lignans was large among knots, both within a single tree and between trees. In addition to the lignans, knots also contained 2–6% (w/w) of a complex mixture of lignan-like compounds with 3, 4 and even up to 6 phenyl propane units, here called oligolignans. The amounts of lignans in the knots were similar in the radial direction from the pith into the outer branch, but decreased dramatically outwards in the branch, almost disappearing after 10–20 cm. The ratio of the 2 epimers of hydroxymatairesinol differed between different knots and even within the knot. A new spruce lignan, nortrachelogenin, or its enantiomer, wikstromol, was detected in knots from trees in northern Finland as opposed to samples from southern Finland. The amount of lipophilic extractives was small compared to the amount of hydrophilic extractives in the knots. Five of the dead knots contained more resin acids and free diterpenyl alcohols than ordinary stemwood. In the other knots, the amount of lipophilic extractives was on the same level as stem heartwood. The stem sapwood contained larger amounts of esterified fatty acids than the knots.

Screening Analyses of Pinosylvin Stilbenes, Resin Acids and Lignans in Norwegian Conifers

“…The Finnish pine knots contained large amounts, 4.5-30 % (w/w), and the stemwood 1-3.5 % (w/w) of resin acids. Lower concentrations of resin acids in spruce (Picea abies) wood (<0.2 % w/w) and knots (<0.04 % w/w) were identified in our samples compared to Finnish spruce samples (< 0.2 and < 0.04 % w/w, respectively) [33]. The lignan content in living knots of the Norwegian spruce samples (Picea abies) was approx.…”

“…Sapwood tissue contains negligible amount of lignans. In general, only minor amounts of resin acids (< 2/< 0.5 % w/w in stemwood/knots) have been detected in spruce samples [29][30][31][32][33]. No lignans have been found in Salic caprea [34] and minor amounts of lignan glycosides have been isolated from the inner bark of Betula pendula [35].…”

“…These results are in accordance with previous reports from Finland. The content of lignans present in Finnish spruce knots has been reported to be 6-24 % (w/w) [33] with HMR comprising 65-85% of the lignans. No detectable amounts of lignans was found in the stemwood .…”

Hydrophilic Extractives in Heartwood of European Larch (Larix decidua Mill.)

“…The biological activity of taxifolin could be attributed to the relatively high content of phenolic hydroxyl groups in the right ring of its molecular structure, while on the other hand secoisolariciresinol is very effi cient antioxidant on account of its butanediol structure (Figure 7). Presence of higher trimeric and tetrameric phenols also positively affects antioxidative properties of extractives and thus biological resistance of wood tissues against rotting (Pietarinen et al 2006;Willför et al 2003;Scalbert, 1991;De Bruyne et al 1999).…”

The onset of hazel wood formation in Norway spruce (Picea abies [L.] Karst.) stems

“…Some lignans have potential antimicrobial, antifungal, antiviral, antioxidant, insecticidal, and antifeeding properties, and they probably play a notable role in plant defense against various biological pathogens and pests (Calvo-Flores et al 2015). A new and exceptionally rich source of lignans are the knots of P. abies which contain on average about 10% by weight of lignans of which hydroxymatairesinol makes up 70-85% (Willför et al 2003).…”