Pinosylvin and monomethylpinosylvin, constituents of an extract from the knot of Pinus sylvestris, reduce inflammatory gene expression and inflammatory responses in vivo.

Scots pine (Pinus sylvestris) is known to be rich in phenolic compounds, which may have anti-inflammatory properties. The present study investigated the anti-inflammatory effects of a knot extract from P. sylvestris and two stilbenes, pinosylvin and monomethylpinosylvin, isolated from the extract. Inflammation is characterized by increased release of pro-inflammatory and regulatory mediators including nitric oxide (NO) produced by the inducible nitric oxide synthase (iNOS) pathway. The knot extract (EC50 values of 3 and 3 µg/mL) as well as two of its constituents, pinosylvin (EC50 values of 13 and 15 µM) and monomethylpinosylvin (EC50 values of 8 and 12 µM), reduced NO production and iNOS expression in activated macrophages. They also inhibited the production of inflammatory cytokines IL-6 and MCP-1. More importantly, pinosylvin and monomethylpinosylvin exerted a clear anti-inflammatory effect (80% inhibition at the dose of 100 mg/kg) in the standard in vivo model, carrageenan-induced paw inflammation in the mouse, with the effect being comparable to that of a known iNOS inhibitor L-NIL. The results reveal that the Scots pine stilbenes pinosylvin and monomethylpinosylvin are potential anti-inflammatory compounds.

Novel Lignan and stilbenoid mixture shows anticarcinogenic efficacy in preclinical PC-3M-luc2 prostate cancer model.

Prostate cancer is the most common cancer of men in the Western world, and novel approaches for prostate cancer risk reduction are needed. Plant-derived phenolic compounds attenuate prostate cancer growth in preclinical models by several mechanisms, which is in line with epidemiological findings suggesting that consumption of plant-based diets is associated with low risk of prostate cancer. The objective of this study was to assess the effects of a novel lignan-stilbenoid mixture in PC-3M-luc2 human prostate cancer cells in vitro and in orthotopic xenografts. Lignan and stilbenoid -rich extract was obtained from Scots pine (Pinus sylvestris) knots. Pine knot extract as well as stilbenoids (methyl pinosylvin and pinosylvin), and lignans (matairesinol and nortrachelogenin) present in pine knot extract showed antiproliferative and proapoptotic efficacy at ≥ 40 µM concentration in vitro. Furthermore, pine knot extract derived stilbenoids enhanced tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induced apoptosis already at ≥ 10 µM concentrations. In orthotopic PC-3M-luc2 xenograft bearing immunocompromized mice, three-week peroral exposure to pine knot extract (52 mg of lignans and stilbenoids per kg of body weight) was well tolerated and showed anti-tumorigenic efficacy, demonstrated by multivariate analysis combining essential markers of tumor growth (i.e. tumor volume, vascularization, and cell proliferation). Methyl pinosylvin, pinosylvin, matairesinol, nortrachelogenin, as well as resveratrol, a metabolite of pinosylvin, were detected in serum at total concentration of 7-73 µM, confirming the bioavailability of pine knot extract derived lignans and stilbenoids. In summary, our data indicates that pine knot extract is a novel and cost-effective source of resveratrol, methyl pinosylvin and other bioactive lignans and stilbenoids. Pine knot extract shows anticarcinogenic efficacy in preclinical prostate cancer model, and our in vitro data suggests that compounds derived from the extract may have potential as novel chemosensitizers to TRAIL. These findings promote further research on health-related applications of wood biochemicals.

Separation of polymeric galactoglucomannans from hot-water extract of spruce wood.

Two methods for separation of polymeric galactoglucomannans (GGMs) from a hot-water extract of spruce wood, i.e., membrane filtration and precipitation in ethanol-water, were compared. Filtration through a series of membranes with different pore sizes separated GGMs of different molar masses, from polymers to oligomers. Only polysaccharides were precipitated in ethanol-water. With the optimal water content of 5-15%, the precipitated amount was about 6% on wood basis. The average molar mass of the precipitated polysaccharides was 10-12kDa with a molar mass range of 4-20kDa. GGMs comprised about 80% of the precipitated hemicelluloses. Other precipitated polysaccharides were mainly arabinoglucuronoxylans and pectins (rhamnogalacturonans). Analysis of a lignin-free, ethanol-precipitated GGM preparation by (13)C NMR spectroscopy verified that it was structurally almost identical with a GGM-rich ethanol precipitate obtained from spruce wood by extraction at much milder conditions, 90°C for 60min.

Effects of pH control with phthalate buffers on hot-water extraction of hemicelluloses from spruce wood.

Ground spruce wood was extracted with water at 170 °C at four different pH levels (3.8, 4.0, 4.2 and 4.4) achieved by using phthalate buffers. Static batch extractions were carried out in an accelerated solvent extractor (ASE-300). The extracted non-cellulosic carbohydrates, predominantly galactoglucomannans (GGMs), were characterised mainly by sugar unit analysis and molar mass determination. Compared to extraction with plain water, extractions with phthalate buffer solutions gave similar yields of non-cellulosic carbohydrates, but gave up to 70% less monosaccharides, and consequently higher molar masses of extracted GGMs. Moreover, at these pH levels, the hydrolysis of acetyl groups were decreased by 40% compared to extraction with plain water, thus maintaining the water solubility of GGMs. It is concluded that hot water extraction of hemicelluloses in high-molar-mass form (average Mw about 10 kDa) from wood in good yields (8% of wood) demands appropriate control of pH, to a level of about 4.

A novel antioxidant phenyl disaccharide from Populus tremula knotwood.

The complete characterization of two compounds obtained from the acetone extract of Populus tremula knotwood has been was achieved using LC-DAD-MS, MS/MS, IR and NMR. The new compounds were unequivocally identified as a mixture of the ester isomers of the (E) and (Z) p-coumarate of 1-O-rutinose. The isomers showed the capacity to inhibit lipid peroxidation induced by tert-butylhydroperoxide and to trap peroxyl radicals, as determined by a chemiluminescence method. These new phenyl disaccharides also showed a significant ORAC (oxygen radical absorbance capacity) value, i.e. 11.7 microM TE (Trolox Equivalents).

Quantification of a broad spectrum of lignans in cereals, oilseeds, and nuts.

Twenty-four plant lignans were analyzed by high-performance liquid chromatography-tandem mass spectrometry in bran extracts of 16 cereal species, in four nut species, and in two oilseed species (sesame seeds and linseeds). Eighteen of these were lignans previously unidentified in these species, and of these, 16 were identified in the analyzed samples. Four different extraction methods were applied as follows: alkaline extraction, mild acid extraction, a combination of alkaline and mild acid extraction, or accelerated solvent extraction. The extraction method was of great importance for the lignan yield. 7-Hydroxymatairesinol, which has not previously been detected in cereals because of destructive extraction methods, was the dominant lignan in wheat, triticale, oat, barley, millet, corn bran, and amaranth whole grain. Syringaresinol was the other dominant cereal lignan. Wheat and rye bran had the highest lignan content of all cereals; however, linseeds and sesame seeds were by far the most lignan-rich of the studied species.

Antimicrobial and cytotoxic knotwood extracts and related pure compounds and their effects on food-associated microorganisms.

Knotwood or bark extracts prepared from 30 species of hard and soft wood trees as well as selected pure compounds (lignans, stilbenes and flavonoids) were assayed for their antimicrobial activity against a battery of both gram positive and negative bacteria, yeasts, and filamentous fungi (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Lactobacillus plantarum, Escherichia coli, Salmonella infantis, Pseudomonas fluorescens, Candida albicans, Saccharomyces cerevisiae, Aspergillus fumigatus and Penicillium brevicompactum). By far the most consistent antibacterial and antifungal properties were associated with extracts of Pinus species. These extracts showed also cytotoxicity against a mouse hepatoma cell line. Both antimicrobial and cytotoxic properties correlated with the stilbene content of the extracts. Purified stilbenes showed the most consistent antimicrobial and cytotoxic activities, while purified lignans had marginal effects, only. The results suggest that stilbenes account both for the antimicrobial and cytotoxic properties of Pinus knotwood extracts.

A new lariciresinol-type butyrolactone lignan derived from hydroxymatairesinol and its identification in spruce wood.

When the natural lignan hydroxymatairesinol (1) was treated with an alkaline aqueous solution, it partially rearranged to isomeric forms of a lariciresinol-type butyrolactone lignan. The two major diastereomers formed (2 and 3) were isolated by column and medium-pressure chromatography, and their structures were elucidated by MS and NMR techniques. These previously unknown butyrolactone lignans were identified as naturally occurring in spruce knotwood by GC, GC-MS, and HPLC-ESI MS/MS analyses. The formation of isohydroxymatairesinol (2) and epi-isohydroxymatairesinol (3) from hydroxymatairesinol (1), and their detection in rat urine after administration of 1, is discussed.

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. All extracts had a high antioxidative potency and/or radical scavenging capacity as compared to the well-known antioxidants Trolox and butylated hydroxyanisole. The pure wood-derived lignans and taxifolin also had a high antioxidative potency and/or radical scavenging capacity. However, the antioxidant potency and/or radical scavenging capacity of several of the hydrophilic knotwood extracts were higher than that of the dominating compounds in pure form.

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.