linoleic-acid and 10-10--dimethyl-9-9--biacridinium

The xanthine/xanthine oxidase dependent chemiluminescence was enhanced both by lucigenin and linoleate to create a sensitive, specific, and rapid chemiluminescent method for superoxide dismutase (SOD) activity determination. A pH optimum at around 10.0 was found both for the chemiluminescence and its inhibition by SOD. At this pH, a linear inhibition response to concentrations from 0.01 to 100 ng/ml of bovine Cu,Zn SOD could be established, with a 50% inhibitory concentration of 0.75 ng/ml. As little as 0.17 fmol of Cu,Zn SOD per test can be detected. With a slightly lower sensitivity, the method is operative at pH 7.4, too. Both Cu,Zn SOD and Mn SOD can be assayed. The rationale of the assay is in combining a superoxide-producing enzymatic system with linoleate amplification to enhance the sensitivity of the chemiluminescence to inhibition by SOD activity. Applicability of the method to biological samples was tested with a standard addition experiment.

Topics: Acridines; Animals; Free Radicals; Glutathione Peroxidase; Hydrogen-Ion Concentration; Linoleic Acid; Linoleic Acids; Luminescent Measurements; Rats; Selenium; Sodium Selenite; Superoxide Dismutase; Xanthine; Xanthine Oxidase; Xanthines

Co-oxidation of chlorogenic acid, caffeic acid, aesculetin and lucigenin with linoleic acid and egg phosphatidyl choline leads to the formation of fluorescent polymer materials. The fluorescent products are more lipophylic, they have lower elution volumes on Sephadex LH-20 column than related phenols and they differ by their fluorescence and chromatographic properties considerably from polymer lipid peroxidation products. From the presence in the excitation fluorescence spectra of a band corresponding to the phenols it was concluded that the fluorophoric groups were similar in both cases. The data are discussed in terms of liquid phase peroxidation and the appearance of the fluorescent species are attributed to the production of molecular adducts as a result of lipid and phenoxyl radical recombination. The characteristics of products obtained are compared with properties of fluorescent "plant ageing" pigments accumulated in aged and damaged plant cells.

Topics: Acridines; Caffeic Acids; Chlorogenic Acid; Free Radicals; Linoleic Acid; Linoleic Acids; Lipid Metabolism; Lipid Peroxides; Oxidation-Reduction; Phenols; Phosphatidylcholines; Pigments, Biological; Plant Physiological Phenomena; Spectrometry, Fluorescence; Umbelliferones