Galina P. Skvortsova

Extraction of betulin from birch bark and study of its physico-chemical and pharmacological properties

Betulin-containing products were obtained in a yield of about 40% from absolutely dry birch bark. The content of betulin in the products was 74–75% or 85–89% depending on the presence of sodium or potassium hydroxide, respectively. The one-step method of extraction of high-purity betulin (97.7%) is presented. Betulin was identified by physic-chemical methods, i.e., elemental analysis, IR and NMR spectroscopy, and electron scanning microscopy. The thermal characteristics of betulin were also studied. It was shown that betulin exhibits gastroprotective, hepatoprotective, and capillary-strengthening properties.

Influence of mechanical treatment on the properties of betulin, betulin diacetate, and their mixture with water-soluble polymers

The influence of mechanical treatment on the properties of betulin, betulin diacetate, and their mixture with water-soluble polymers was studied. It was shown that mechanical treatment in a planetary mill-activator disordered the crystalline structure of betulin and betulin diacetate. Composites of betulin with polyvinylpyrrolidone (PVP) and polyethyleneglycol (PEG) that gave an increased betulin concentration upon dissolution in water were prepared. It was shown that H-bonds formed between betulin and PVP upon mechanical activation of their mixtures.

Sulfation of arabinogalactan by sulfamic acid in dioxane

The sulfation of arabinogalactan (AG) by sulfamic acid in the presence of urea in dioxane has been studied. The degree of AG sulfation increases as the sulfation temperature increases from 70 to 95°C. As indicated by 13C NMR spectroscopy, the sulfate groups in sulfated AG are in the C2 and C4 positions of the main galactan chain and the C6 position of the terminal galactose units of the main and the side chains of AG. The sulfation of AG by the complex sulfamic acid–urea in dioxane medium makes it possible to increase the ecological safety and the efficiency of the process compared with the known methods of sulfation.

Synthesis of the Betulin Dipropionate from the Upper Birch Bark

A one-step synthesis of the betulin dipropionate directly from the birch bark without a separate stage of the betulin preparation is described in this paper. Extracts with different content of the betulin dipropionate were shown to form depending on the conditions of acylation of the upper birch bark with propionic acid. The product with the maximum content of the betulin dipropionate was prepared from the starting fraction of 2–5 mm of the upper birch bark and the fraction of 10–20 mm that was preliminarily activated with superheated water vapor. The upper bark extract was analyzed by gas chromatography. The structure of betulin dipropionate was confirmed by element analysis, 1H NMR, 13C NMR, and FTIR spectroscopy.

Modification of Sulfated Arabinogalactan with Amino Acids by Ion Exchange Method

The new method of sulfated arabinogalactan modification by amino acids (glycine and ornithine) based on the ion exchange procedure was developed. The composition and structure of the reaction products obtained by interaction of sulfated arabinogalactan with amino acids were studied by elemental analysis and FTIR spectroscopy.

СИНТЕЗ И ИЗУЧЕНИЕ МЕДЬСОДЕРЖАЩИХ ПОЛИМЕРОВ НА ОСНОВЕ СУЛЬФАТОВ МИКРОКРИСТАЛЛИЧЕСКОЙ ЦЕЛЛЮЛОЗЫ ИЗ ДРЕВЕСИНЫ ЛИСТВЕННИЦЫ

Some somatostatine analogs were synthesized and tested for cytotoxic activity in comparison with sandostatine and octreotide in cell cultures, expressing somatostatine receptors: human prostate carcinoma cell line LNCap, LNCap-LN3, LNCap-clon FGC and human neuroblastoma cell line SH-SY5Y.

Synthesis and Study of Copper-Containing Polymers Based on Sulfated Arabinogalactan

Synthesis of water-soluble copper-containing sulfates of arabinogalactan was carried out for the first time by the ion exchange method. Their composition and structure were studied by the methods of elemental and chemical analysis, X-ray spectral microanalysis, atomic force microscopy (AFM), infrared spectroscopy (FTIR), and electron paramagnetic resonance (EPR). According to the AFM data, the surface of copper-containing polymer films does not have inclusions and consists of homogeneous crystallites of a spherical and slightly elongated shape and transverse dimensions of about 100 nm. The composition of copper- containing polymers was studied by the chemical method and X-ray spectral microanalysis. The absence of nitrogen in the obtained polymer indicates the complete replacement of ammonium cations in the ammonium salt of AG sulfate with the copper cations. The IR spectrum of copper-containing AG sulfate is similar to that of the sodium salt of sulfated arabinogalactan. Superposition of two signals was observed in the EPR spectrum of copper-containing AG sulfate. One of them belongs to isolated Cu2+ ions; another, to associated Cu2+ ions in the salt-like compounds. The integral intensity of isolated Cu2+ ion signals (anisotropic signal) and associated ions (isotropic signal) depends on the copper content in the polymer. Water-soluble coppercontaining polymers of AG sulfates have prospects for their use in medicine.

Effect of Lignin on the Properties of Organic and Carbon Gels from Polyphenols of the Larch Bark

The influence of lignin on the properties of organic and carbon gels synthesized by sol-gel polymerization of a mixture of formaldehyde and polyphenols isolated by various solvents from the larch bark was investigated. The porous structure and adsorption properties of polymer gels synthesized from mixtures of formaldehyde and ethanol extracts of bark by varying the pH value of initial solutions in the range of 4 to 12 were studied by BET and SEM methods. It was shown that an increase in pH value leads to the formation of organic gels with a more compacted texture and narrow pores. Carbonization of organic gels at 900 °C promotes the significant development of the specific surface area (up to 477 m2/g) of the obtained carbon gels. It was found that the addition of lignin in an amount of 10 % wt. to the polyphenols extracted by water from the larch bark improves the texture characteristics of the obtained organic and carbon gels and increases theirs elasticity and strength. But the increase of the lignin content to 20-30 % wt. reduces the total porosity and the total pore volume of the obtained gels. The effect of lignin on the properties of gels, obtained with the use of polyphenols extracted from larch bark by water–alkaline solution, is less pronounced.

Synthesis of Sulfated Arabinogalactan Derivatives with Histidine and Arginine

Natalia Yu. Vasilyevaa,b, Alexander V. Levdanskya, Alexander S. Kazachenkoa, Galina P. Skvortsovaa, Boris N. Kuznetsov*а,b, Laurent Djakovitchc and Catherine Pinelc aInstitute of Chemistry and Chemical Technology SB RAS FRC “Krasnoyarsk Science Center SB RAS” 50/24 Akademgorodok, Krasnoyarsk, 660036 Russia bSiberian Federal University 79 Svobodny, Krasnoyarsk, 660041 Russia cIRCELYON 2 Albert Einstein av., F-69626 Villeurbanne Cedex, Lyon, France