Gallocyanine as a fluorogen for the identification of NADPH-dependent production of superoxide anion radical by blood cells

Abstract

Abstract. The interaction of the oxazine dye gallocyanine with reactive oxygen (•O2−,⋅Н2О2) and halogen (HOCl) species has been studied by spectrophotometry, mass spectrometry, and spectrofluorimetry. It has been shown that gallocyanine reacts with HOCl and •O2− (but not with Н2О2) to form fluorescent products. It has been found using the inhibition assay that, both in the xanthine/xanthine oxidase system and in activated human blood neutrophils, the main contribution to the conversion of gallocyanine to a fluorophore comes from its reaction with •O2−. The results obtained suggest that gallocyanine can act as a fluorogenic chemosensor and be used for estimating the activation of neutrophils and the NADPH-dependent production of superoxide anion radical by neutrophils and other blood cells, as well as for testing antioxidant drugs designed with the aim to correct diseases associated with oxidative stress.

Keywords: gallocyanine, reactive oxygen species, reactive halogen species, oxidative stress, superoxide anion radical, hypochlorous acid, fluorescence