Abstract: Aim To investigate the influence of tetramethylpyrazine (ligustrazine, Lig) on oxygen consumption and superoxide during the respiratory burst of human neutrophils. Methods It was observed by using ESR spin trapping, spin probe oxymetry and lumino-dependent chemiluminesence (CL). Results Lig had no influence on oxygen consumption during the respiratory burst of neutrophils (P > 0.05) but had remarkable inhibition on CL response generated by neutrophils (P <0 01), and had scavenging effect on $\mathop{{O}}_{2}^{{\mathop{}_{\ ·}^{-}}}$ and OH ° generated by neutrophils, which were demonstrated in xanthine/xanthine oxidase system and Fentons reaction(P <0.01). Conclusion Lig has no inhibiting effect on oxygen metabolic function of neutrophils, but protects tissue from injury caused by activated neutrophils through scavenging oxygen radicals.

Key words: pyrazines, ligustrazine, electron spin resonance, chemiluminescence, oxygen radicals, antioxidants