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An exopolysaccharide (EPS_B3) produced by a Leuconostoc mesenteroides strain isolated from a semi-hard Italian cheese was chemically and biologically characterized. HPLC-SEC, NMR, FT-IR and monosaccharide composition experiments were performed. Antimicrobial, antibiofilm, bifidogenic, antioxidant, and DNA-protective activity of EPS_B3 were also studied. Results revealed that EPS_B3 was a mixture of two high-molecular-weight dextran with low branching degree. Moreover, EPS_B3 displayed significant antibacterial activity against eight foodborne pathogens and inhibited biofilm formation by Listeria monocytogenes. EPS_B3 also evidenced bifidogenic activity, stimulating the growth of three probiotic bifidobacteria, and improving the tolerance of Bifidobacterium animalis subsp. lactis to oxygen stress. It also protected plasmid DNA from hydrogen peroxide damage. Only limited antioxidant capacity was observed. In conclusion, data suggest that EPS_B3 might be exploited in the context of functional foods especially for its marked antimicrobial activity as well as for the ability to improve the viability of bifidobacteria in probiotic foods. However, further studies should be carried out to assess the ability of EPS_B3 to reach intact the target site (i.e., gastrointestinal tract) to consider the possibility of use it as a new functional ingredient in foods. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: We have recently described the synthesis of two porphyrogenic macrocycles: 20-phenyl-2,13-dimethyl-3,7,8,12-tetraethyl-[24]iso-pentaphyrin (1) and 20-phenyl-2,13-dimethyl-3,7,8,12-tetraethyl-[22]pentaphyrin (2) (J. Med. Chem. 2006, 49, 196–204). We found that the structure of iso-pentaphyrin is influenced by the acidity of the medium. By adjusting the TFA concentration, we solved two isomers of iso-pentaphyrin: 1 and 1A. At high TFA concentration iso-pentaphyrin is present only as 1, which is slowly oxidized into the aromatic macrocycle 2 upon exposure to air. The correlation between acidic conditions, isomer structures, and oxidation is discussed. [Copyright &y& Elsevier]

The kinetics and the thermodynamics of the oxygenation reaction of Co(trien)2+ complex (trien=1,4,7,10-tetraazadecane) have been studied in dimethylsulfoxide (dmso) at 298 K and in a medium adjusted to 0.1 mol dm−3 with Et4NClO4 by means of UV–Vis spectrophotometric technique. The reaction mechanism is consistent with the fast formation of an initial CoL–O2 species, followed by a rate determining step which gives the final (CoL)2O2 adduct. The results are compared with similar data in water and discussed considering the effects of ligand/solvent substitution. The catalytic activity of Co(trien)2+ as well as that of other diamine complexes, CoL2 (L=ethylenediamine (en), N,N′-dimethylethylenediamine) has also been tested towards the aerobic oxidation of 2,6-di-tert-butylphenol in mild conditions and the results are discussed in term of both catalytic ability and selectivity. [Copyright &y& Elsevier]

A new utility for multipurpose analysis, SOLVERSTAT, taking advantage of the versatility of spreadsheets is here described. By means of this tool advanced statistical tests have introduced in Microsoft Excel Solver thus allowing regression diagnostic and discrimination between different models. The utility is here applied to the determination, by UV-Vis spectroscopy, of the stability constant for the uptake of molecular dioxygen by the 1:2 complex of Co(II) with N,N′-dimethylethylenediamine (dmen) in the aprotic solvent dimethylsulfoxide (dmso) at 298 K and in a medium adjusted to 0.1 mol dm−3 with Et4NClO4. The reliability of the model and parameters obtained are discussed and the results compared with those obtained by Dynafit, a different software package, and by independent voltammetric measurements. The validity of SOLVERSTAT has been also examined applying it to the discrimination between different models already discussed in the literature. [Copyright &y& Elsevier]

The interactions of lanthanide(III) ions with the following oxygen- and mixed oxygen–nitrogen-donor ligands: 2-methoxyethylamine (L1), 2-aminoethanol (L2), 2-methoxyethylether (L3), di(ethyleneglycol) (L4), 2,2′-oxydiethylamine (L5) and 1,5-diaminopentane (L6) have been investigated in dimethylsulfoxide (DMSO) at 298 K and I=0.1 mol dm−3 (Et4NClO4). Calorimetric and 1H NMR results show that L1–L4 and L6 are not able to complex Ln(III) ions. L5 is shown to be able to bind heavier Ln(III) ions (Ln&z.dbnd6;Ho&z.sbnd;Lu). Potentiometric and calorimetric measurements have been carried out to obtain the Ln(III)–L5 thermodynamic parameters of complexation. All the complexes are formed in exothermic reactions being the entropy terms generally negative or slightly positive. Comparison between the complexing abilities of L1 and L5 shows that at least two &z.sbnd;CH2CH2NH2 side-arms added to an ether function are needed to promote effective interaction between an ether O atom and Ln(III) ions in the high coordinating solvent DMSO. The results are discussed in terms of different donor properties and solvation of &z.sbnd;NR&z.sbnd; and &z.sbnd;O&z.sbnd; groups towards metal ions. A comparison with data previously obtained in DMSO for the complex formation of Ln(III) with the purely N donor diethylenetriamine (dien) is made. [Copyright &y& Elsevier]

The thermodynamic functions for the complexation of Ag(I) by the following diamines: N,N-dimethyldiethylenediamine (N,N-dmen), N,N-dimethyl-1,3-propanediamine (N,N-dmtn) and N,N,N′,N′-tetramethyl-1,3-propanediamine (tmtn) have been determined in dimethylsulfoxide (dmso) by potentiometric and calorimetric techniques at 298 K and 0.1 mol dm−3 ionic strength (NEt4ClO4). Only mononuclear complexes are formed (AgLj +, j=1, 2) where the ligands act as monodentate or chelate agents. All the complexes are enthalpy stabilized whereas the entropy changes counteract the complexation. The different basicities and steric requirements of both the ligands and complexes formed together with the size of the chelate rings are taken into account to discuss the results presented here. [Copyright &y& Elsevier]

The search for novel exopolysaccharides (EPS) with targeted functionalities is currently a topic of great interest. This study aimed to investigate the chemical characteristics and technological properties of a novel EPS (named EPS_O) from Leuconostoc mesenteroides. EPS_O was a high-molecular-weight dextran (>6.68 × 105 g/mol) characterized by high water-holding capacity (785 ± 73%) and high water solubility index (about 99%). EPS_O in water (<30 mg/mL) formed viscous solutions, whereas at concentrations >30 mg/mL, it formed weak gels. Notably, lower concentrations (4–5 mg/mL) exhibited antimicrobial activity against various foodborne pathogens, antibiofilm activity against Listeria monocytogenes , and radical-scavenging activity. These properties are significant for maintaining food quality and promoting health. Based on these findings, EPS_O presents itself as a promising food ingredient that could elevate food quality and confer health benefits to consumers. [Display omitted] • Leuconostoc mesenteroides DSA_O produced a high-molecular-weight dextran (EPS_O). • EPS_O displayed strong antimicrobial and antibiofilm activity. • The dextran exhibited radical scavenging ability. • Weak gels were formed by EPS_O at concentration > 3%. • The properties of EPS_O may be exploited in functional foods. [ABSTRACT FROM AUTHOR]

Abstract: Photodynamic therapy (PDT) is an emerging cancer treatment modality based on the excitation of a nontoxic photosensitizer with harmless visible light to produce reactive-oxygen species (ROS) that induce apoptosis and/or necrosis in cancer cells. As the efficacy of this therapy strongly depends of the nature of the photosensitizer, there is a great interest to develop new photoactive molecules. Here we report for the first time the synthesis, characterization and bioactivity of metal complexes between the non-aromatic expanded porphyrin, namely 20-[[4′-(Trimethylsilyl)ethoxycarbonyl]phenyl-2,13-dimethyl-3,12-diethyl-[24] iso-pentaphyrin (PCRed) and Zn(II) [Zn(II)–PCRed] or Lu(III) [Lu(III)–PCRed]. The complexation of these two diamagnetic heavy metal ions to PCRed improved the properties of the free photosensitizer as a PDT drug. We discovered that the 1:1 complex between PCRed and Lu(III) significantly increases the cellular uptake, ROS production and antiproliferative capacity in four cancer cell lines. Our study shows that metal complexation is a useful strategy to potentiate iso-pentaphyrin as a PDT drug. [ABSTRACT FROM AUTHOR]

[Display omitted] • PVC-based composites as active materials for photodynamic pathogens inactivation. • Composition, structure, stability, and bioactivity correlations are discussed. • At best, composites kill 108 CFU mL-1 of S. aureus after 60 min irradiation. Synthesis, chemical, and biological characterization of composite polyvinyl chloride (PVC)-based materials to be applied in the photodynamic inactivation (PDI) of pathogen microorganisms are reported. Different blends of PVC, plasticizers, and photosensitizers have been tested in their photokilling ability vs. Staphylococcus aureus , after irradiation using a multi-LED blue lamp at a fluence rate of 50 W/m2. Four common adipates, namely: dibutyl hexanedioate [di(n-butyl) adipate, BA, 1 ], bis(2-ethylhexyl) hexanedioate [bis(2-ethylhexyl) adipate, EA, 2 ], dioctyl hexanedioate (dioctyl adipate, OA, 3), and didecyl hexanedioate (dicapryl adipate, DA, 4), have been employed in this investigation, in combination with two photosensitizers: 5-(4-carboxy-phenyl)-10,15,20-triphenyl-21H,23H-porphyrin (TPP, 5), and the expanded porphyrin 20-(4-carboxyphenyl)-2,13-dimethyl-3,12-diethyl-[21]pentaphyrin (PCox, 6). The experimental evidence has established the essential role of the addition of a plasticizer to the polymer/photosensitizer mixture in transforming PVC into a photoactive material, being bactericidal properties dependent upon the type and amount of additive. Long-chain linear adipates were found more efficient in imparting the desired bactericidal activity to the final material, reaching in one case the complete abatement of the initial bacterial solution (108 CFU/ml) in 60 min. The obtained polymeric films proved to be stable over time and under oxidation conditions; in addition, no release of toxic components was observed over the experiments, definitely demonstrating that the bactericidal action was effectively due to the ROS generated by photosensitizers immobilized into the material. Moreover, SEM and FT-IR analyses proved that no photodegradation of the film took place during the irradiation experiment. [ABSTRACT FROM AUTHOR]