Biol. Pharm. Bull. 28(4) 667—670 (2005)

drug for arthritis for thousands of years in China. ST has been reported to have anti-inflammatory and immunosuppressive properties in vitro and in experimental animals. This study was performed to clarify the role of ST from an antioxidative point of view. In the present study, we examined the effects of ST on scavenging activities of reactive oxygen species (ROS) by means of electron spin resonance (ESR) method, and on red blood cell (RBC) hemolysis induced by an azo free-radical initiator in healthy volunteers. The ESR method was used for the measurement of O2 · and HO· scavenging activities of ST. RBC hemolysis was used for determination of the antioxidative effect of ST, and the influence of ST on RBCs, which have the most important role in hemorrheology. Furthermore, we hypothesized that ingestion of ST extract (ST.E) would further strengthen the antioxidative effect of plasma, which already has a function of reducing the free radical-induced tissue damage in cerebrovascular disease and ischemic heart disease, if the responsible compounds in ST could be absorbed and circulated in blood. Therefore, the present study examined the effect on plasma antioxidative activity after a gavage-dose of ST.E in rats.