Chemical characterization and extractives composition of heartwood and sapwood from Quercus faginea

Abstract

Heartwood and sapwood of Quercus faginea were evaluated in relation to summative chemical composition and non-polar and polar extracts composition, including an assessment of antioxidant properties (DPPH and FRAP). Twenty trees from two sites in Portugal were analysed. Heartwood had approximately two times more solvent extractible compounds than sapwood (on average 19.0% and 9.5%). The lipophilic extractible compounds were below 1%, and most of them were polar e.g. ethanol-soluble compounds corresponded to 65% of total extractives in heartwood and 43% in sapwood. Lignin content was similar in sapwood and heartwood (28.1% and 28.6% of extractive-free wood respectively) as well as the sugar composition. Site did not influence the chemical composition. The lipophilic extractible compounds from both sapwood and heartwood included mainly saturated fatty acids (23.0% and 36.9% respectively) and aromatic compounds were also abundant in sapwood (22.9%). The ethanol-water extractibles had a high content of phenolic substances (558.0 and 319.4 mg GAE/g extract, respectively of heartwood and sapwood). The polyphenolic composition was similar in heartwood and sapwood with higher content of ellagitannins (168.9 and 153.5 mg tannic acid/g of extract in sapwood and heartwood respectively) and very low content of condensed tannins. The antioxidant activity was very high with IC50 of 2.6 μg/ml and 3.3 μg/ml for sapwood and heartwood respectively, as compared to standard antioxidants (IC50 of 3.8 μg/ml for Trolox). The ferric reducing ability was 2.8 and 2.0 mMol Trolox equivalents/g extract of heartwood and sapwood respectively. The variability between trees was low and no differences between the two sites were found. Q. faginea showed a very good potential for cooperage and other applications for which a source of compounds with antioxidant properties is desirable.

Variation of Ring Width and Wood Density in Two Unmanaged Stands of the Mediterranean Oak Quercus faginea

“…As tension and knot wood were avoided in the present measurements, it is the extractives content that should explain the density variations in Q. faginea wood between sites and between trees per site. However, the total heartwood extractives were approximately the same at both sites (19%) [4], suggesting that it does not explain per se the wood density variability found between these sites. Within-tree extractives content might be important to explain heart-and sapwood differences in wood density.…”

“…In Portugal, its present area is very restricted because of the past intensive utilization [1]. The species shows favorable characteristics for wood processing and performance, and is considered a good potential timber species for structural and flooring components, and cooperage [2][3][4][5].…”

The effect of tree age on the chemical composition of the wood of silver birch (Betula pendula Roth.) in Poland

“…The cited research by the above-mentioned authors confirms the impact of tree age on the content of structural compounds and extractives in wood. The results reported in the literature refer to specific studies and tree growing conditions, as well as their age, species, and the parts of the tree from which samples are taken (Bao et al 2001;Cown and McConchie 1982;Dietrichs 1972;Han and Rowell 1997;Hytönen and Nurmi 2015;Miranda et al 2017;Mohammadi et al 2011;Morais and Pereira 2012;Piispanen and Saranpää 2001;Rencoret et al 2011;Uprichard and Lloyd 1980;Waliszewska et al 2015). These results cannot be generalised, and it is not possible to formulate on their basis a general rule for the dependence of the chemical composition of wood on tree age for all species and for the entire range of ages, from young saplings to 100-year-old trees.…”

“…The proportions of particular components in wood tissue depend on the species, the habitat conditions, the climate, the part of the tree from which samples are taken (trunk, branches, roots, sapwood or heartwood, bark, juvenile, or mature wood), the time of year, and the health of the tree (Bikovens et al 2013;Miranda et al 2017;Szczepkowski et al 2007;Zobel and Sprague 1998). Another factor for the variation of the chemical structure of wood and its possible uses is the age of the tree, as has been documented for certain species (Berrocal et al 2004;Fidelis et al 2013;Healey et al 2016;Miranda and Pereira 2002;Rencoret et al 2011;Uprichard and Lloyd 1980).…”

Chemical analysis and antioxidant properties of orange‐tree (Citrus sinensis L.) biomass extracts obtained via different extraction techniques

“…Other studies on woody forest material have analyzed the secondary metabolites present in the wood and bark. Their extraction uses different techniques and they can be used in different industrial sectors, especially in chemistry …”