Resveratrol-3,5,4′-trihydroxystilbene-possesses antioxidant activitiesin vitro. Western blot analysis documented that N-f-5HT in concentrations of 10 and 10. N-feruloyl-serotonin (N-f-5HT) inhibited dose-dependently oxidative burst of human whole blood and isolated neutrophils in vitro stimulated with phorbol-myristate-acetate (PMA) as measured by luminol/isoluminol enhanced chemiluminescence.In isolated neutrophils stimulated with PMA, N-f-5HT was effective against extracellular as well as intracellular reactive oxygen species. In this study we analysed the effect of a crystalline complex fraction of four N-feruloyl-serotonin isomers isolated from the seeds of Leuzea carthamoides on the mechanism of oxidative burst of human neutrophils in vitro. When appropriately stimulated, they undergo dramatic physiological and biochemical changes resulting in phagocytosis, chemotaxis and degranulation with the activation of reactive oxygen species (ROS) production known as the respiratory burst. These findings suggest that more than one mechanism exists for activation of the respiratory burst oxidase in human neutrophils, and that the neutrophil possesses at least one oxidase that is not an ectoenzyme.Neutrophil leukocytes and macrophages represent professional phagocytic cells. The PMA-activated enzyme was susceptible to inhibition of directly exposed to DASA in this particulate fraction. Membrane-rich particulate fractions from neutrophils have been shown to contain NADPH-dependent oxidative activity that is presumably responsible for the phagocytosis-associated respiratory burst of intact cells. The inhibition by DASA of O2- production did not appear to be caused by interference with binding of the affected stimuli, since pretreatment with DASA did not inhibit release of the lysosomal enzymes lysozyme and myeloperoxidase induced by concanavalin A or FMLP. DASA reproducibly inhibited activities of two known surface enzymes Mg++-ATPase and alkaline phosphatase, by 45-55% and 60-70%, respectively. Pretreatment with DASA inhibited oxygen uptake stimulated by FMLP, but not oxygen uptake stimulated by PMA.
or the ionophore A23187 was not inhibited by DASA.
Production of superoxide anion (O2-) stimulated by concanavalin A or the chemotactic peptide formyl-methionyl-leucyl-phenylalanine FMLP was inhibited by DASA pretreatment, whereas O2- production stimulated by phorbol myristate acetate (PMA), sodium fluoride. Alteration of the surface of human neutrophils with the nonpenetrating, protein-inactivating agent p-diazobenzenesulfonic acid (DASA) was found to prevent activation of the respiratory burst by some stimuli, but not others.
0 kommentar(er)
