Vol. 45 No. 2 (225) (2011)

During the preparation of aqueous suspension of whiskers of cellulose by sulfuric acid hydrolysis some hydroxyl groups on the surface were sulfated. In order to determine the degree of sulfatation we have used the acid-basic and conductometric titration methods. It has been shown that these methods allow to determine the degree of sulfatation and the percent content of sulfur in the dry cellulose.

The action of folic acid (FA) has been studied on the reaction H₂O₂+HOO^–, which occurs in alkaline and H₂O₂+Fe(II), which occurs in acidic aqueous solutions. It has been established that in both cases FA decreases the rate ($W_{O_2}$) of H₂O₂ decomposition. The increase of [FA]₀ results in decrease of $W_{O_2}$ in alkaline medium. It is concluded that FA (its anion) acts on $W_{O_2}$ of H₂O₂ decomposition, which occurs by radical-chain mechanism. An unusual phenomenon is also noticed. During the reaction in alkaline medium approximately 1 min the reaction is stopped, then it begins to run again, but with a decreased rate. It is assumed that during the reaction a compound is formed by radical mechanism, which reacts with O₂. The tablets of FA which are for sale in pharmacies contain a definite quantity of starch. For this reason its influence on the reactions is studied too. It is established that it has no significant influence on the reactions’ rates in both cases.

Roentgen structural and optical (optical polarizing microscope) investiga-tions showed that potassium persulfate and cetylpyridinium bromide have crystal structure. The product of their interaction in contrast to the originals is an amorphous substance.

An efficient method of catalytic asymmetric synthesis of (S)-glutamic acid was elaborated. The synthesis was carried out via addition of diethyl ester of malonic acid to C=C bond of a achiral Ni^II complex derived from the Schiff base of dehydroalanine and achiral auxiliary reagent (2-benzoylphenyl)amidopyridyl-2-carboxylic acid. The dependency of enantioselectivity of asymmetric reactions from the nature and quantity of catalysts, solvents and bases, as well as from the temperature has been examined. It was shown that in the presence of 10 mol% of 3,3'-bis(diphenylhydroxymethyl)-1,1'-binaphthalenyl-2,2'-diol or its tetrapotassium derivative the stereoselectivity of the reaction reaches 76–80%, and the enantiomeric excess of obtained (S)-glutamic acid exceeds 80%.

New derivatives of lactone-contaning thioureas and amides of carboxy-lactones have been synthesized on the base of carboxylactones.

Investigation of binding podophyllotoxin and etoposide with DNA of different guanine-cytosine content has been carried out using the method of thermal denaturation. It has been revealed, that podophyllotoxin and etoposide have a destabilizing effect on DNA. It has been shown that both compounds are preferably bound to AT-rich sites of DNA.

The aim of this work has been the investigation of structure/activity dependence of new porphyrines to improve their radiosensitizing effects. In this work it was shown that the cytotoxicity of water-soluble porphyrines depends on the type of central metal atom and ranges in the following order: ZnTOEt4PyP>MnTOEt4PyP>AgTOEt4PyP>FeTOEt4PyP>H2TOEt4PyP>CoTOEt4PyP>CuTOEt4PyP. Only AgTOEt4PyP and CuTOEt4PyP porphyrines demonstrated the radiosensitizing activity (DMF=1.9). Thus, the radiosensitizing activity of porphyrines depends on the structure, and structure modifications can be a way to improve their anticancer activity and pharmacological features.

Folk medicine recommends medicinal herbs with antihypoxic properties for the respiratory system diseases such as bronchitis, bronchial asthma, cold. One of these herbs is Trifolium pratense L. Fam. Fabaceae. The animals fed by trifolium flowers could stand hypoxia on the altitude 7–8 thousand m. The experiment results suggest that the increase of organism stability happens both on the system (external respiration remains longer) and cell levels since simultaneously registered electrical activity of the respiratory centre neurons of medulla has shown high stability compared to screening group.

The influence of some mineral salts and hormonal substances on the synthesis of naphthaquinones in isolated tissues of Alkanna orientalis and Onosma sericea was studied. Exclusion of ammoniac salts from the nutrient medium as well as increasing of copper and BAP concentration intensified the synthesis of naphthaquinones in the isolated tissues of alkanet. NAA stimulated the growth of alkanet tissues, but suppressed biosynthetic processes.

We investigated the concentration of heavy metals in fruit bodies of 7 species (Agaricus bisporus (J.E. Lange) Imbach, Armillaria mellea (Vahl) P. Kumm., Chroogomphus rutilus (Schaeff.: Fr.) O.K. Mill., Hypholoma fasciculare (Huds.: Fr.) P.Kumm., H. sublateritium (Fr.) Quél., Phallus impudicus (L.: Pers.), Pleurotus pulmonaris (Fr.: Fr.) Quél.) of wild-growing mushrooms in “Dilijan” National Park. The data indicated high concentration of metals (Cu, Zn, Pb, Cd, Co, Ni, Fe, Mn) in the fruit bodies. From the toxicological point of view it is important to note the high concentration of Cd and Pb, on average 15.1 and 23.6 μg/g, respectively. Periodic use of studied edible mushrooms in food can cause intoxication.

New derivatives of 2,5-dihydro-2-oxofurans have been obtained by interaction of 2,5-dihydro-4-methyl-5,5-dimethyl(pentamethylen)-2-oxofuran-3-carboxamides with chloranhydrides of acetic, propionic, butyric acids and also with 2,5-dihydro-3-ethoxycarbonyl-4-brommethyl-5,5-dimethyl-2-oxofuran.

The genotoxicity of proline enriched polypeptide (PRP-1) was estimated in mice leucocytes depending on its action time in vivo by Comet assay. A high level of DNA damages compared with the control variants was revealed. As well as a small amount of DNA damage is revealed in comparison with the control and there is a tendency for decreasing the level of damage in DNA with the lapse of time after the introduction of PRP-1. Taking into consideration the low genotoxicity of PRP-1, we can conclude the safety of this drug demonstrated in the applied test-system.

In terms of industrial pollution of the RA the technogenic factor has got a decisive influence on the chemical composition of the water of the Debed River. As a result of the technogenic pollution, these waters have a very unique chemical composition that is different from river water, formed under the influence of natural factors. They are characterized by a high content of heavy metals and hence unsatisfactory irrigating properties. Irrigation, using such waters, leads to soil pollution by heavy metals.