Study of the interaction between oxygen and bile salts.

The interaction between molecular oxygen and bile salts, previously observed using chemiluminescence techniques, is studied in this paper by electrochemical techniques to further highlight the nature of the interaction. A shift of half-wave potential of the first polarographic wave for the reduction of molecular oxygen was observed in solutions in the presence of bile salts. The shift could be related to different phenomena, such as adsorption of bile salt molecules on the mercury electrode, irreversibility of the oxygen reduction reaction, pH of the solution.

Interactions between different selenium compounds and zinc, cadmium and mercury.

In this paper, we present a polarographic study of systems containing different inorganic and organic selenium compounds (sodium selenite, sodium selenate, seleno-methionine and seleno-urea) and metal ions (Zn2+, Cd2+ Hg2+) of the 12th group of elements in the periodic table. While zinc is a trace element known to be essential for plants and animals, cadmium and mercury are exogenous elements and are harmful pollutants that accumulate during aging; selenium is also recognized as an important micronutrient and is sometimes added to the diet. Experiments investigating the interactions were carried out using polarographic techniques in unbuffered systems.

Interaction between indomethacin and heavy metal ions in aqueous solution.

The interaction between indomethacin anions and heavy metal ions, such as cadmium, zinc and copper(II) ions, was studied in aqueous solution by polarographic techniques. Indomethacin anions form complexes with these heavy metal ions: the complex formed with cadmium ions is sparingly soluble, while more soluble and also stronger complexes are formed with zinc and copper(II). At high concentrations, where indomethacin anions undergo self-aggregation, these last compounds are solubilised.

Diclofenac interactions: tetrakis[mu-2-(2,6-dichloroanilino)phenylacetato]-1:2 kappa 8O:O'-diacetone-1 kappa O,2 kappa O-dicopper(II)(Cu-Cu) acetaldehyde solvate.

The structure of the centrosymmetric dimeric copper(II) title compound, [Cu2(C14H10Cl2NO2)4(C3H6O)2] C2H4O, has been determined and compared with the structures of analogous O-bridged CuII dimers. Polarographic experiments on aqueous solutions containing a mixture of the CuII ion and diclofenac have been used to determine both the formation constant [1 (1) x 10(8)] and the solubility product [2 (1) x 10(-12)] of the complex.

Antioxidant properties of bile salt micelles evaluated with different chemiluminescent assays: a possible physiological role.

The antioxidant activity of a representative series of free, glycine- and taurine-conjugated bile acids was evaluated by two different chemiluminescent assays: (a) the enhanced chemiluminescence system based on horseradish peroxidase and luminol/oxidant/enhancer reagent, and (b) the hypoxanthine/xanthine oxidase/Fe(2+)-EDTA/luminol system. Bile acids were studied at final concentrations ranging from 1 to 28 mmol/L. All of the bile acids studied inhibited the steady-state chemiluminescent reaction and the extent of inhibition depended upon the structure of the bile acids, whereas the duration was related to bile acid concentration.