Suppression of oxidative burst in human neutrophils with the naturally occurring serotonin derivative isomer from Leuzea carthamoides.

OBJECTIVE: Neutrophil leukocytes and macrophages represent professional phagocytic cells. 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.

DESIGN: 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.

RESULTS: 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. Western blot analysis documented that N-f-5HT in concentrations of 10 and 100 µM significantly decreased PMA-induced phosphorylation of protein kinase C alpha/beta II.

CONCLUSION: The results suggest that N-f-5HT represents an effective naturally occurring substance with potent effect on the oxidative burst of human neutrophils and could be further investigated for its pharmacological activity against oxidative stress in ischaemia-reperfusion, inflammation and other pathological conditions.