Aim:To investigate and compare the antioxidant activities of salvianolic acid B(SalB)and Ginkgo biloba extract(EGb 761)in aqueous solution,rat microsomesand the cellular system.Methods:Superoxide anion(O_2~-)was generated usingxanthine/xanthine oxidase system and phenazine methosulate/NADH system,andthe effects of SalB and EGb 761 on the generation of O_2~- were achieved by spectro-photometric measurement of the product formed on reduction of nitro bluetetrazolium.Two different methods were used to assess the scavenging effects ofthe extracts on hydroxyl radical(.OH):HPLC method was used for quantitation of.OH by oxy-radical trapping of 5,5-dimethyl- 1-pyrroline-N-oxide(DMPO)to formDMPO-OH adducts in Fe~(2+)-EDTA-H_2O_2 system.To confirm the HPLC data,.OHwas also measured by spectrophotometry using a commercial detection kit.Theanti-lipid peroxidation effects of the extracts in microsomes of rat brain,liver andkidney induced by ascorbate-NADPH were determined by thiobarbituric acid(TBA)method.The protective effects of the extracts on peroxide hydrogen(H_2O_2)-induced oxidative damage in SH-SY5Y cells were investigated by assessing cellviability assay,the level of lipid peroxidation,and the lactate dehydrogenase(LDH)release.Results:Both SalB and EGb 761 were able to scavenge O_2~- and.OH,inhibit lipid peroxidation of microsomes,and protect SH-SY5Y ceils againstH_2O_2-induced oxidative damage.However,the concentration of SalB was far lowerthan that of EGb 761 when a similar effect was obtained.Conclusion:The antioxi-dant efficiency of SalB was greater than that of EGb 761.These results suggestthat SalB,like EGb 761,has promising potential in treating oxidative damage-derived neurodegenerative disorders. Aim: To investigate and compare the anti activities of salvianolic acid B(SalB) and Ginkgo biloba extract(EGb 761) in aqueous solution,rat microsomes and the cellular system.Methods:Superoxide anion(O_2~-)was generated usingxanthine/xanthine oxidase system And phenazine methosulate/NADH system,andthe effects of SalB and EGb 761 on the generation of O_2~- were achieved by spectro-photometric measurement of the product formed on reduction of nitro bluetetrazolium.Two different methods were used to assess the scavenging effects of the extracts On hydroxyl radical(.OH):HPLC method was used for quantitation of.OH by oxy-radical trapping of 5,5-dimethyl- 1-pyrroline-N-oxide(DMPO) to formDMPO-OH adducts in Fe~(2+ )-EDTA-H_2O_2 system.To confirm the HPLC data,.OHwas also measured by spectrophotometry using a commercial detection kit.The anti-lipid peroxidation effects of the extracts in microsomes of rat brain,liver andkidney induced by ascorbate-NADPH were determined by thiobarbituric Acid(TBA )Method.The protective effects of the extracts on radioactive hydrogen(H_2O_2)-induced oxidative damage in SH-SY5Y cells were investigated by assessing cell viability assay,the level of lipid peroxidation,and the lactate dehydrogenase(LDH)release.Results:Both SalB And EGb 761 was able to scavenge O_2~- and.OH,inhibit lipid peroxidation of microsomes,and protect SH-SY5Y ceils againstH_2O_2-induced oxidative damage.However, the concentration of SalB was far lowerthan that of EGb 761 when a similar effect was obtained.Conclusion:The antioxi-dant efficiency of SalB was greater than that of EGb 761.These results suggestedthat SalB,like EGb 761,has promising potential in treating oxidative damage-derived neurodegenerative disorders.