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

Abstract

The heartwood of two European larch trees was examined for the content of hydrophilic extractives. Ethanol was used as a solvent for extractions of adequately pretreated samples, while gas chromatography with flame ionisation detection (GC-FID), gas chromatography coupled to mass spectrometry (GC-MS) and high performance size exclusion chromatography (HPLC-SEC) were applied for analyses. Different phenolic compounds, such as flavonoids and lignans were identified and quantitatively evaluated. The most abundant flavonoids were taxifolin and dihydrokaempferol, while the main lignan was secoisolariciresinol. Contents of flavonoids and lignans, measured at different stem heights, varied between 10.6 and 15.7 mg/g. At lower and medium heights flavonoids prevailed, while at upper stem positions the concentrations of lignans significantly increased. In addition, some trimeric and tetrameric phenolic structures were also detected. There was very little variation in the composition of hydrophilics between the two examined trees. The identified flavonoids and lignans are classified as very strong antioxidants.

Keywords

• European larch
• heartwood
• hydophilic extractives
• fl avonoids
• lignans
• chromatographic techniques