2-2--azino-di-(3-ethylbenzothiazoline)-6-sulfonic-acid and hydroxide-ion

Topics: Antioxidants; Benzothiazoles; Biphenyl Compounds; Chitosan; Gold; Green Chemistry Technology; Hydroxides; Iron; Metal Nanoparticles; Picrates; Sulfonic Acids

Topics: Analgesics; Animals; Anti-Inflammatory Agents; Antioxidants; Benzothiazoles; Biphenyl Compounds; Edema; Hydroxides; Inflammation; Male; Methanol; Mice; Ononis; Phytotherapy; Picrates; Plant Extracts; Plant Roots; Rats; Rats, Sprague-Dawley; Skin; Sulfonic Acids; Wound Healing

Cinnamoylphenethylamine (CNPA) derivatives including feruloylphenethylamine (FRPA), caffeoylphenethylamine (CFPA), cinnamoyltyramine (CNTA), feruloyltyramine (FRTA) and caffeoyltyramine (CFTA) were synthesized in order to investigate the influence of the number and position of hydroxyl group on Cu(2+)/glutathione (GSH) and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced oxidation of DNA. The radical-scavenging properties of these CNPA derivatives were also evaluated by trapping 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonate) cationic radical (ABTS(+•)), 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH) and galvinoxyl radical. In addition, these CNPA derivatives were tested by linoleic acid (LH)-β-carotene-bleaching experiment. The chemical kinetic was employed to treat the results from AAPH-induced oxidation of DNA and gave the order of antioxidant ability as CFTA > CFPA > FRTA > FRPA. CFTA and CFPA also possessed high abilities to inhibit Cu²(+)/GSH-mediated degradation of DNA, whereas FRPA and FRTA can protect LH against the auto-oxidation efficiently. Finally, CFPA and FRPA exhibited high activity in trapping ABTS(+•), DPPH and galvinoxyl radicals. Therefore, the cinnamoyl group bearing ortho-dihydroxyl or hydroxyl with ortho-methoxyl benefited for CNPA derivatives to protect DNA, while hydroxyl in tyramine cannot enhance the radical-scavenging abilities of CNPA derivatives.

Topics: Amidines; Antioxidants; Benzhydryl Compounds; Benzothiazoles; beta Carotene; Biphenyl Compounds; Cinnamates; Copper; DNA; Free Radical Scavengers; Glutathione; Hydroxides; Linoleic Acid; Oxidation-Reduction; Phenethylamines; Picrates; Solutions; Structure-Activity Relationship; Sulfonic Acids

The polyphenol quercetin (Q) that has a high antioxidant capacity is a lead compound in the design of antioxidants. We investigated the possibility of modifying quercetin while retaining its antioxidant capacity as much as possible. To this end, the antioxidant capacities of Q, rutin, monohydroxyethyl rutinoside (monoHER) and a series of synthesized methylated Q derivatives were determined. The results confirm that the electron donating effect of the hydroxyl groups is essential. It was also found that the relatively planar structure of Q needs to be conserved. This planar conformation enables the distribution of the electron donating effect through the large conjugated π-system over the entire molecule. This is essential for the cooperation between the electron donating groups. Based on the activity of the compounds tested, it was concluded that structural modification at the 5 or 7 position is the most optimal to retain most of the antioxidant capacity of Q. This was confirmed by synthesizing and testing Q5OMe (Q6) and Q7OMe (Q7) that indeed displayed antioxidant capacities closest to Q.

Topics: Animals; Antioxidants; Benzothiazoles; Humans; Hydroxides; Molecular Structure; Oxidation-Reduction; Quercetin; Rutin; Sulfonic Acids

A detailed study of the effect of pH, temperature, and pressure on the reaction of hydrogen peroxide with [Fe(III)(P(8-))](7-), where P(8-) represents the octa anionic porphyrin, was performed using stopped-flow techniques. Depending on the pH, different high valent iron-oxo species were formed. At pH < 9 formation of a two-electron oxidized species [(porphyrin(+*))Fe(IV)=O] was observed. In contrast, at pH > 9 only the one electron oxidized species [(porphyrin)Fe(IV)=O] was found to be present in solution. Under selected conditions at pH 8 it was possible to determine rate constants for both the coordination of hydrogen peroxide and subsequent heterolytic cleavage of the O-O bond. At pH 11 a composite rate constant for coordination of H(2)O(2) and homolytic cleavage of the O-O bond could be measured. In addition, it was possible to determine the activation parameters for the overall reaction sequence leading to the formation of [(porphyrin)Fe(IV)=O]. Careful analysis of the obtained data supports an associatively activated mechanism for the coordination of hydrogen peroxide. The catalytic properties of [Fe(III)(P(8-))](7-) in the presence of H(2)O(2) were also investigated. Both high valent iron-oxo species turned out to be able to oxidize diammonium-2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) to the radical cation ABTS(+*). At higher hydrogen peroxide concentrations a reduced yield of ABTS(+*) was observed because of increased catalase activity of [Fe(III)(P(8-))](7-). At high pH disproportionation of ABTS(+*) to ABTS and ABTS(2+) occurred, which could be suppressed by an excess of unreacted ABTS. In slightly basic to acidic solutions this reaction did not play a role.

Topics: Benzothiazoles; Catalysis; Ferric Compounds; Hydrogen Peroxide; Hydrogen-Ion Concentration; Hydroxides; Kinetics; Metalloporphyrins; Oxidation-Reduction; Pressure; Sulfonic Acids; Temperature; Water