Application of Cyclodextrins to the Extraction of Antioxidant Compounds from Olive Oil

Olive oil contains powerful antioxidant compounds which impart stability, contribute to various properties of it, and are valuable from the nutritional point of view. Their extraction with as mild conditions as possible led to its investigation using cyclodextrins as a tool. The inclusion ability of α-, β-, and γ-CD was estimated, and it has been demonstrated that the small cavity of α-CD as well as the wide one of γ-CD could enclose less effectively the antioxidant compounds of olive oil than the intermediate in shape cavity of β-CD. The highest yields of antioxidant compounds were achieved when olive oil was mixed with a 2%aqueous solution of β-CD and the resulting precipitate was treated with ethyl alcohol.__________Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 18–21, January–February, 2005.     

壳聚糖-氨基酸体系中碳酸钙模拟生物矿化的研究

本文选取壳聚糖与氨基酸作为碳酸钙模拟生物矿化的有机基质,研究并比较了侧链带不同电荷的氨基酸对碳酸钙生物矿化的调制作用,发现侧链带负电荷的酸性氨基酸能改变壳聚糖体系中原有的晶种模板,使能量比较高的球霰石型碳酸钙得以生成,而单纯的壳聚糖体系中只能得到方解石型碳酸钙;在形貌上则改变了球霰石型碳酸钙原有的球状堆积,出现了两头小、中间大椭球状的特殊形貌。     

Post-column oxidative derivatization for the liquid chromatographic determination of phenothiazines

A first post-column chemical derivatization method for the liquid chromatographic determination of phenothiazines is presented. Peroxyacetic acid is introduced as a derivatizing agent for phenothiazines, yielding the colored radical cations or fluorescent sulfoxides, depending on reaction conditions. Both reaction products were successfully employed for the detection of the phenothiazines after their liquid chromatographic separation. The fluorescence spectroscopic detection of the sulfoxides proved to be the more robust and sensitive method. Limits of detection ranged from 4 nM for triflupromazine and trimeprazine to 300 nM for phenothiazine for the fluorescence spectroscopic detection of the sulfoxide and from 0.3 μM for phenothiazine and triflupromazine to 2 μM for trifluperazine for the UV–Vis spectroscopic detection of the radical cation. The calibration functions for the fluorimetric sulfoxide determination ranged from two to more than three decades, starting at the limit of quantification.     

Characterisation of botulinum toxins type C, D, E, and F by matrix-assisted laser desorption ionisation and electrospray mass spectrometry

In a follow-up of the earlier characterisation of botulinum toxins type A and B (BTxA and BTxB) by mass spectrometry (MS), types C, D, E, and F (BTxC, BTxD, BTxE, BTxF) were now investigated. Botulinum toxins are extremely neurotoxic bacterial toxins, likely to be used as biological warfare agent. Biologically active BTxC, BTxD, BTxE, and BTxF are comprised of a protein complex of the respective neurotoxins with non-toxic non-haemagglutinin (NTNH) and, sometimes, specific haemagglutinins (HA). These protein complexes were observed in mass spectrometric identification. The BTxC complex, from Clostridium botulinum strain 003-9, consisted of a 'type C1 and D mosaic' toxin similar to that of type C strain 6813, a non-toxic non-hemagglutinating and a 33 kDa hemagglutinating (HA-33) component similar to those of strain C-Stockholm, and an exoenzyme C3 of which the sequence was in full agreement with the known genetic sequence of strain 003-9. The BTxD complex, from C. botulinum strain CB-16, consisted of a neurotoxin with the observed sequence identical with that of type D strain BVD/-3 and of an NTNH with the observed sequence identical with that of type C strain C-Yoichi. Remarkably, the observed protein sequence of CB-16 NTNH differed by one amino acid from the known gene sequence: L859 instead of F859. The BTxE complex, from a C. botulinum isolated from herring sprats, consisted of the neurotoxin with an observed sequence identical with that from strain NCTC 11219 and an NTNH similar to that from type E strain Mashike (1 amino acid difference with observed sequence). BTxF, from C. botulinum strain Langeland (NCTC 10281), consisted of the neurotoxin and an NTNH; observed sequences from both proteins were in agreement with the gene sequence known from strain Langeland. As with BTxA and BTxB, matrix-assisted laser desorption/ionisation (MALDI) MS provided provisional identification from trypsin digest peptide maps and liquid chromatography-electrospray (tandem) mass spectrometry (LC-ES MS) afforded unequivocal identification from amino acid sequence information of digest peptides obtained in trypsin digestion.     

A Flexible Approach to the γ－Amino－β－hydroxy Acid Moiety of Hapalosin

A flexible approach to ethyl (3R,4S)-N-Boc-4-amino-3-hydroxy-5-phenylpentanoate (N-Boc-AHPPA-OEt), the γ-amino-β-hydroxy acid moiety of hapalosin is described. The synthetic method features a ring-opening ethanolysis of an activated N-Boc-lactam, which is obtained via a diastereoselective reductive-alkylation of (R)-malimide derivative. The flexibility of the method resides in the introduction of the alkyl side chain by Grignard reagent addition.     

Nonideal mixing of 16-(9-anthroyloxy) palmitic acid and fatty acid in monolayer

The surface pressure-molecular area curve of the mixed monolayer of 16-(9-anthroyloxy) palmitic acid (16AP) and fatty acid (palmitic or stearic acids) showed various kink points which indicated the phase transitions of the monolayer. On the basis of the surface phase rule, the phase diagrams of the mixed monolayer were elucidated. The bifunctional molecule, 16AP, takes two orientations in a monolayer state, that is, horizontal and vertical ones. Horizontally oriented 16AP and vertically oriented fatty acid form a mixed monolayer but this exhibits deviation from the ideal mixing, which was interpreted in terms of the surface regular solution theory. On the other hand, the 16AP molecule in the vertical state was found to be immiscible with the fatty acid molecule in a monolayer de spite both molecules being vertical to the surface and parallel to each other. This was caused by the participation of the 9-anthroyloxy moiety of 16AP in the interaction of 16AP and fatty acid in the hydrophobic region of the monolayer.     

Kinetic Study of the Bromine-Catalyzed Isomerization of Methyl- and Chloro-Maleic Acids in Aqueous Ce(IV)-Br -H2SO4 Medium

Methylmaleic (citraconic, CTA) acid and methylfumaric (measaconic, MSA) acid in aqueous sulfuric acid solution undergo bromine-catalyzed reversible cis-trans isomerization in the presence of ceric and bromide ions. The positional isomerization of CTA or MSA to itaconic acid (ITA) is not observed. The method of high performance liquid chromatography (HPLC) was applied to study the kinetics of this catalyzed isomerization. The major catalytic species is best expressed as the Br^?₂ · radical anion. Under suitable catalytic conditions, there is a tendency for the [MSA]/[CTA] ratio to reach an equilibrium value of 4.10 at 25° for the CTA+Br^?₂ · ? MSA+Br^?₂ · reaction. Chloromaleic (CMA) and chlorofumaric (CFA) acids undergo similar isomerization with an equilibrium [CFA]/[CMA] ratio of 10.3 at 25°. The isomerization of maleic acid (MA) to fumaric acid (FA) is essentially irreversible with 50 as the lower limit of the equilibrium [FA]/[MA] ratio. The substituent has an important effect on the reversibility of this catalyzed isomerization of butenedicarboxylic acids. The thermodynamic parameters ΔH° and ΔS° at 25° for the CTA+Br^?₂ · ? MSA+Br^?₂ · reaction were found to be ?5.1±0.7 kj/mol and ?6.0±3.3 J/mol K, respectively. The present method gives a plausible way to measure the differences in enthalpy and entropy between the trans- and cis-isomers of butenedicarboxylic acids (CRCO₂H=CR'CO₂H) in aqueous solution.     

The solid state reactions of o-aminobenzoic acid with Zn(Ⅱ), Cu(Ⅱ), Ni(Ⅱ), Mn(Ⅱ) acetate hydrate at room temperature

The solid-solid state reactions of o-aminobenzoic acid with Zn(OAc)2.2H2O, Cu(OAc)2 .H2O, Ni(OAc)2.4H2O and Mn(OAc)2.4H2O result in the formation of corresponding complexes M(OAB)2 (M = Zn(Ⅱ), Cu(Ⅱ), Ni(Ⅱ), Mn(IⅡ)). XRD, IR and elemental analysis methods have been used to characterize the solid products. The activation energies of these reactions, which are calculated from the kinetic data obtained by means of the isothermal electrical conductivity measurement method, have been found to increase in the order: Cu(OAc)2.H2O(37.7 kJ.mol-1)~Mn(OAc)2.4H2O (39.7kJ.mol-1) < Zn(OAc)2.2H2O (56.3 kJ.mol-1) < Ni(OAc)2.4H2O (85.2 kJ.mol-1). The trend is related to their crystal structures.     

Photochemical degradation of hyaluronic acid by singlet oxygen

Changes of the rheological properties of hyaluronic acid (sodium-magnesium salt) solutions after exposure to UV radiation indicate a vigorous decrease in their viscosity, but its still strong shear rate dependence. Whereas the presence of the singlet oxygen sensitizer (anthracene-1-sulphonic acid) brings about a loss of shear dependence; the studied solutions show newtonian behavior.     

Reaction of α-cyanoacrylic acid and cyanoacrylates with dialkyl and diaryl phosphites

-Cyanoacrylic acid and -cyanoacrylates add dialkyl and diaryl phosphites and diethyl thiophosphite at the C=C double bond in the absence of catalyst. This is an anti-Markovnikov reaction, which yields the corresponding phosphonates and thiophosphonates.A. N. Nesmeyanov Institute of Organometallic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1913–1915, August, 1992.