Objective: To investigate the antioxidant effects of water extract of Carthamus tinctorius L. on injury of cardiomyocytes induced by hydrogen peroxide (H2O2) and to detect reactive oxygen species (ROS) for exploring the mechanisms. Methods: In cultured neonatal rat cardiomyocytes

the antioxidant effect of water extract of Carthamus tinctorius L. was investigated after H2O2 (1 mmol·L-1) induced damage. The spontaneous beating

the survival rate and release of LDH

MDA

SOD

NO

NOS

GSH-Px and XOD enzyme activity in supernatant were investigated

and cell suspension was collected for detecting reactive oxygen species (ROS) by electron spin resonance (ESR). Results: Preconditioning by water extract of Carthamus tinctorius L. increased the spontaneous beating and the survival rate

and decreased the release of LDH

MDA and SOD with the rise of SOD

NO

NOS and GSH-Px enzyme activity

while in the cell suspension ROS signal decreased significantly. Conclusion: Water extract of Carthamus tinctorius L. has antioxidative effect. The mechanisms are likely related with scavenging of free radicals

enhancing its clearance

enhancing endogenous antioxidant activity.