Oligolignans in the wood of Picea obovata Ledeb.
We studied the chemical composition of the phenolic complex and the structure of oligomeric lignans in Siberian spruce (Picea obovata Ledeb.). We used the wood of Siberian spruce collected near the city of Irkutsk. The extractives were isolated from ground wood (particle size: 10–15 mm; humidity: 5.9%) by three-stage acetone extraction. The extract was separated by consecutive treatment with the solvents with increasing polarity: hexane, ethyl acetate and n-butanol. The main amount of phenolic compounds (lignans) was concentrated in the ethyl acetate fraction and it was 0.7% in absolutely dry wood (adw).The ethyl acetate fraction of spruce wood extract was separated by silica gel column; a chloroform-acetone mixture was used as the eluent (the concentration of acetone in the mixture was increased from 0 to 100%). Monomeric lignans (~60–65% of the ethyl acetate fraction of spruce wood extract), oligomeric lignans (~20–25%), and polymer lignans (~12–15%) were isolated.We also obtained 13C nuclear magnetic resonance (NMR) spectra for the main monomeric, oligomeric and polymeric lignan compounds of phenolic complexes. It was found that oligomeric and polymeric fractions contain monomeric lignan units with the butyrolactone cycle, primarily, the fragments with hydroxymatairesinol structure. Oligomeric lignans contain the fragments with a pinoresinol and lariciresinol structure. All the monomeric structural units are characterized by the guaiacyl substitution type of the aromatic cycles.A preliminary study has been performed on the antiviral and antioxidant activity of the ethyl acetate fraction of acetone extract of Siberian spruce wood. It was found that the lignan complex is active against Coxsackie B4 virus in cell culture and in the pancreatitis model in white mice, reducing the activity of enteroviruses in the cell culture approximately 100 times. The antioxidant activity rate of polyphenol complex of Siberian spruce wood is comparable to that of a known antioxidant dihydroquercetin.
Investigation of the main practically important extractive substances of the Larix cajanderi Mayr. Heartwood
The extractive substances of the wood of Cajander larch (Larix cajanderi Mayr.) growing in the areas of Magadan oblast under various climatic conditions have been investigated. It has been found that the investigated wood contains up to 4.5% of flavonoids and up to 15.5% of water-soluble polysaccharide arabinogalactan that defines the perspective of its application for the industrial production of these valuable biologically active substances.
Developmental aphasia: The perception of brief vowels and extended stop consonants
Abstract Developmental dysphasics and matched controls were examined for their ability to discriminate (a) two synthesized vowel-vowel syllables and (b) two synthesized consonant- vowel syllables. For both vowels and consonants, dysphasics were impaired when the discriminable components of the two stimuli were brief (43 msec) but unimpaired when these components were 95 msec or longer. It is concluded that developmental dysphasics have no difficulty in discriminating transitional auditory information as such and that their impaired discrimination of synthesized stop consonants is attributable solely to the brief duration of the discriminable components.