ascorbic-acid and crocin

Laccases have a great potential for use in industrial and biotechnological applications. It has affinity towards phenolics and finds major applications in the field of bioremediation. Here, Surface Plasmon Resonance (SPR) as a biosensor with immobilized laccase on chip surface has been studied. Laccase was immobilized by thiol coupling method and compounds containing increasing number of hydroxyl groups were analyzed for their binding affinity at various concentrations in millimolar range. The small molecules like phloroglucinol (1.532×10(-8) M), crocin (3.204×10(-3) M), ascorbic acid (8.331×10(-8) M), kojic acid (6.411×10(-7) M) and saffron (3.466×10(-7) M) were studied and respective KD values are obtained. The results were also confirmed by inhibition assay and IC50 values were calculated. All these molecules showed different affinity towards laccase in terms of KD values. This method may be useful for preliminary screening and characterization of small molecules as laccase substrates, inhibitors or modulators of activity. This method will be useful for rapid screening of phenolics in waste water because of high sensitivity.

Topics: Ascorbic Acid; Biodegradation, Environmental; Biosensing Techniques; Carotenoids; Computer Systems; Crocus; Enzymes, Immobilized; Fungal Proteins; Inhibitory Concentration 50; Laccase; Phloroglucinol; Protein Binding; Pyrones; Substrate Specificity; Surface Plasmon Resonance; Trichophyton

The antioxidant properties of S-nitrosoglutathione, a nitric oxide-derived product were studied in different experimental systems. By using the crocin bleaching test, S-nitrosoglutathione, in the presence of copper ions, shows an antioxidant capacity about six times higher than that of Trolox c and referable to the interception of peroxyl radicals by nitric oxide. Copper alone shows a modest inhibitory action, which is about seven times lower than that of Trolox c. S-nitrosoglutathione prevents lipid peroxidation induced by the well-known Fe2+/ascorbate system (IC50 = 450 microM) and the inhibitory effect is strongly reinforced by the presence of copper ions (IC50 = 6.5 microM). In addition, cumene hydroperoxide-induced lipid peroxidation is markedly decreased by S-nitrosoglutathione, provided that copper ions, maintained reduced by ascorbate, are present. Decomposition of S-nitrosoglutathione through metal catalysis and/or the presence of reducing agents and the consequent release of nitric oxide are of crucial importance for eliciting the antioxidant power. In this way, copper ions and/or reducing species with low antioxidant potency are able to promote the formation of an extremely strong antioxidant species such as nitric oxide.

Topics: Animals; Antioxidants; Ascorbic Acid; Benzene Derivatives; Carotenoids; Chromans; Copper; Ferrous Compounds; Lipid Peroxidation; Microsomes, Liver; Nitric Oxide; Peroxides; Rats; Reducing Agents; S-Nitrosoglutathione; Thiobarbituric Acid Reactive Substances

Aqueous solutions of engine exhaust condensation products were derived from cars powered by diesel or four-stroke gasoline engines (with and without three-way catalytic converter). The cars were operated on a static test platform. Samples of the different exhaust solutions accumulated in a Grimmer-type distillation trap (VDI 3872) during standard test programs (Federal Test Procedure) were incubated with important biomolecules. As indicators of reactive oxygen species or oxidative destruction, ascorbic acid, cysteine, glutathione, serum albumin, the enzymes glycerinaldehyde phosphate dehydrogenase and xanthine oxidase, and the oxygen free-radical indicator keto-methylthiobutyrate were used. During and after the incubations, oxygen activation (consumption) and oxidative destruction were determined. Comparison of the oxidative activities of the different types of exhaust condensates clearly showed that the exhaust condensate derived from the four-stroke car equipped with a three-way catalytic converter exhibited by far the lowest oxidative and destructive power.

Topics: Antioxidants; Ascorbic Acid; Automobiles; Carotenoids; Ethylenes; Gasoline; Glyceraldehyde-3-Phosphate Dehydrogenases; Methionine; Oxidation-Reduction; Reactive Oxygen Species; Serum Albumin, Bovine; Sulfhydryl Compounds; Vehicle Emissions; Xanthine Oxidase