Chemical composition of extractives of different wood compartments of Pinus merkusii and their potential implication in wood durability
A Wijayanto, S Dumarçay, R Kartika Sari, W Syafii, P Gérardin, C Gérardin-Charbonnier
Amounts and nature of extractives differ strongly according to the compartment of wood and to the nature of the wood species. Previous studies reported that knotwood of several European Pinus sp. contains extractives contents much higher than stemwood consisting mainly of lignans which may find valuable applications in cosmetic, nutraceutic or pharmaceutic sectors. Different explanations have been proposed to explain these high amounts of lignans: the first one concerns their potential implications in the lignification process to reinforce knot tissues involved in branches support; the second one their role in wood durability and protection against biotic and abiotic agents. During the course of our studies concerning the identification of new sources of molecules with potential interest, we were interested in the characterization of knotwood extractives of Pinus merkusii a tropical wood species for which no data on the nature of extractives have been reported up to now. Determination of extractives amounts present in sapwood, heartwood and knotwood of Pinus merkusii has been performed and their chemical composition analyzed using GC-MS and LC-MS. Antioxidant and antifungal activities were also evaluated by DPPH method and growth inhibition method, respectively. The results showed that knotwood contains more extractives than heartwood, the latter containing more extractives than sapwood. Knotwood extracts contain mainly lignans, especially nortrachelogenin, stilbenes and resin acids, while heartwood extracts were constituted mainly of stilbenes, especially pinosylvin monomethyl ether, pinosylvin and pinosylvin dimethyl ether and of flavonoid like pinocembrin. Acetone knotwood extract presents the higher antioxidant activity, while acetone heartwood extract possesses the higher antifungal activities against the two tested fungi Trametes versicolor and Poria placenta.