Pegylated tetraarylporphyrin entrapped in liposomal membranes. A possible novel drug-carrier system for photodynamic therapy

A system of poly(ethylene glycol) bound tetraarylporphyrin entrapped in liposomal membranes was investigated. The interactions between the 5-(4-hydroxymethylphenyl)-10,15,20-tritolylporphyrin (Po) covalently attached to the poly(ethylene glycol) chain (PEG-Po), and phosphatidylcholine liposomes in the aqueous solution were studied. The adsorption of the investigated polymer to lipid vesicles was confirmed by measurements of dynamic light scattering and zeta potential. Experimental results demonstrate that the diameter of liposomes increased and the absolute value of the zeta potential decreased after addition of PEG-Po. The binding constants (K(b)) of Po chromophores to liposome in pH range from 5.2 to 9.0 were determined using fluorescence spectroscopy. The degree of binding was found to be pH-independent and the average value was 24.6 +/- 0.9 mg ml(-1). The acid-base properties of the porphyrin chromophores and their aggregation in an aqueous solution were also studied. pK values associated with imine-N protonation of the porphyrin core were found to be 2.59 and 0.68 at the ionic strength of 0.1 M. The equilibrium constant for dimerization, K(D), was found to be 5 x 10(3) M(-1).     

Charged states of α,ω-dicyano β,β'-dibutylquaterthiophene as studied by in situ ESR UV-vis NIR spectroelectrochemistry

The influence of the molecular structure on the stabilization of charged states was studied in detail by in situ ESR UV-vis NIR spectroelectrochemistry at a novel α,ω-dicyano substituted β,β'-dibutylquaterthiophene (DCNDBQT) and the electrochemically generated cation and anion radicals have been proved for the first time. The voltammetry of DCNDBQT results in two separate oxidation steps with the reversible first one. The experimental absorption maxima at 646 and 1052 nm together with the calculated ones (by DFT method) as well as an ESR signal at the first anodic step prove the presence of a radical cation. Three additional optical bands (554, 906, and 1294 nm for CT-transition) can be attributed to the formation of cation radical dimer. The dicationic structure formed in the second oxidation step is not stable. The stabilization proceeds via a dimer formation in two chemical follow-up reactions. The existence of the dimeric structures was proved by ex situ MALDI TOF mass spectrometry. As the substitution by cyano groups opens the route to cathodic reductions, DCNDBQT shows a single quasi-reversible reduction step. Here, the in situ ESR UV-vis NIR spectroelectrochemical measurements and theoretical calculations let us confirm the electrochemical generation of an anion radical. As we found a low number of anion radicals by quantitative ESR spectroelectrochemistry and an appearance of additional bands in the UV-vis NIR absorption spectra, the formation of dimeric structures must be considered and was corroborated by mass spectrometry. The role of dimerization in the reaction mechanism of the DCNDBQT oxidation and reduction are discussed in general. The experimental results were interpreted using the quantum chemical calculations based on density functional theory.     

Synthesis and X-ray structure of N-phenyl phenylglyoxamide

The title compound (C₁₄H₁₁NO₂) is monoclinic with a = 13.579(2), b = 5.297(1), c = 16.455(2) Å, = 98.11(2)°, Z = 4, and space group P2₁/n. The significant structural features lie in the two carbonyl groups of the glyoxamide which are oriented antiperiplanar to each other [–163.6(3)°]. The central bond C(1)–C(2) is 1.545(4) Å. The observed conformation is stabilized by intramolecular hydrogen bonds.     

Mössbauer studes of electrocodeposited cobalt—Tin alloys

Cobalt—tin alloys electrocodeposited from a mildly alkaline sulfate bath were studied using¹¹⁹Sn absorption and⁵⁷Co Emission Mössbauer Spectroscopy. The Results reveal that dissolved tin and cubic CoSn (not appearing in the phase diagram) are the components obtained from fresh plating solutions. Upon exhaustion, the formation of Co₃Sn₂ is favoured, with the eventual deposition of cobalt particles as a separated phase. A precipitate is formed during bath operation which is richer in Sn(II), contrasting to the mother solution which is richer in Sn(IV).     

Azinyl Sulfides. LXVII.

The title compound, C₆H₇NS, is planar, with endo‐C—N—C bond angles of 118.7 (2) and 118.8 (2)°, and C—S bond lengths of 1.697 (2) and 1.692 (2) Å for the two symmetrically independent mol­ecules. 1‐Methylpyridinium‐4‐thiol­ate is the major contributor to the molecular structure in the solid state.     

Numerical modelling of inclusion-type complexes formed by chiral 18-crown-6 ethers bearing sugar moieties with enantiomers of phenylalanine methyl ester cations

The crystal structure of α-d-mannosido-benzo-18-crown-6·KSCN (1) was solved by X-ray single crystal diffractometry. C₂₈H₃₆O₁₀·KSCN is orthorhombic, space groupP2₁2₁2₁ withZ=4,a=8.035(4),b=9.960(2),c=38.83(2) Å,M _r =629.8,V=3103.6 ų,D _x =1.347 g cm^?3, μ(CuKα)=2.53 mm^?1, λ=1.54178 Å,F(000)=1324. FinalR=0.043 for 1139 unique observed reflections measured at room temperature. The potassium ion is surrounded by a nearly planar hexagon of oxygen atoms of the macrocyclic ring and lies on the plane formed by those atoms. Hexagonal pyramidal coordination is completed by the nitrogen atom of the thiocyanate anion. The SCN ion was found on the face of the macrocyclic ring opposite that for the chiral mannopyranoside moiety. The molecular structure of α-d-mannosido-18-crown-6 (2) and the structure of molecular complexes of2 and α-d-glucosido-benzo-18-crown-6 (3) were studied by molecular mechanics methods. The results suggest enthalpy driven selectivity of complexation of the phenylalanine methyl ester (4) by2 and both enthalpy and entropy effects in selective complexation of4 by3.     

X-ray structure and NMR assignment of 4,4′-[3-oxa-1,5-pentanedi(ylthio)]-3,3′-diquinolinyl sulfide

The title compound (C₂₂H₁₈N₂OS₃) is monoclinic, with a=20.7446(5), b=8.332(1), c=24.393(7)°, β=112.12(1)° and space group P2₁/n. There are two independent molecules in the unit cell. Two quinoline moieties are nearly perpendicular to each other (76.9(1)°) and (72.0(2)°). Both S-methylene fragments are trans-orientated with respect to the C(3)−S(1)−C(13) plane. Two pairs of sulfur atoms in ortho-positions are in very close contact with sulfide preserving a skew conformation. The central 12-membered ring adopts an unusual conformation. Part XLIII in the series of Azinyl Sulfides. Part XLII: Maślankiewicz, M.J.; Maślankiewicz, A.J. Heterocycl. Chem. 1996,33, 1989.     

Bioactive Molecules of Mandarin Seed Oils Diminish Mycotoxin and the Existence of Fungi

Mandarin is a favorite fruit of the citrus family. Mandarin seeds are considered a source of nontraditional oil obtained from byproduct materials. This investigation aimed to assess the biomolecules of mandarin seeds and evaluated their antimycotic and antimycotoxigenic impact on fungi. Moreover, it evaluated the protective role of mandarin oil against aflatoxin toxicity in cell lines. The two types of extracted oil (fixed and volatile) were ecofriendly. The fatty acid composition, tocopherol, sterols, and carotenoids were determined in the fixed oil, whereas volatiles and phenolics were estimated in the essential oil. A mixture of the two oils was prepared and evaluated for its antimicrobial impact. The reduction effect of this mixture was also investigated to reduce mycotoxin secretion using a simulated experiment. The protective effect of the oil was evaluated using healthy strains of cell lines. Fixed oil was distinguished by the omega fatty acid content (76.24%), lutein was the major carotenoid (504.3 mg/100 g) and it had a high β-sitosterol content (294.6 mg/100 g). Essential oil contained limonene (66.05%), α-pinene (6.82%), β-pinene (4.32%), and γ-terpinene (12.31%) in significant amounts, while gallic acid and catechol were recorded as the dominant phenolics. Evaluation of the oil mix for antimicrobial potency reflected a considerable impact against pathogenic bacteria and toxigenic fungi. By its application to the fungal media, this oil mix possessed a capacity for reducing mycotoxin secretion. The oil mix was also shown to have a low cytotoxic effect against healthy strains of cell lines and had potency in reducing the mortality impact of aflatoxin B₁ applied to cell lines. These results recommend further study to involve this oil in food safety applications.     

Homotopy Conley index for discrete multivalued dynamical systems

We define an index of Conley type for a certain class of upper semicontinuous multivalued dynamical systems. We use the Szymczak functor and apply techniques introduced by Reineck, Mrozek and Srzednicki for the index over the base. Moreover we introduce the notion of the homotopy partial functor for the usc maps. We show that the index possesses Wa?ewski and homotopy properties. We also give four examples that exhibit the benefits of our index over the cohomological index defined by Mrozek and Kaczyński.