RESUMEN
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.
Asunto(s)
Grano Comestible/química , Lignanos/análisis , Nueces/química , Aceites de Plantas/química , Semillas/química , Cromatografía Líquida de Alta Presión , Hidrólisis , Espectrometría de MasasRESUMEN
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.
Asunto(s)
4-Butirolactona/análogos & derivados , Lignanos/química , Picea/química , Plantas Medicinales/química , 4-Butirolactona/química , Animales , Lignanos/aislamiento & purificación , Lignanos/farmacología , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Ratas , Estereoisomerismo , Orina/química , MaderaRESUMEN
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.
Asunto(s)
Antioxidantes/análisis , Extractos Vegetales/química , Árboles/química , Madera , Depuradores de Radicales Libres/química , Cromatografía de Gases y Espectrometría de Masas , Peroxidación de Lípido/efectos de los fármacos , Peróxidos/química , Extractos Vegetales/farmacología , Superóxidos/químicaRESUMEN
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.