Comparison of antioxidant activities between salvianolic acid B and Ginkgo biloba extract (EGb 761)

Aim: To investigate and compare the antioxidant 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 using xanthine/xanthine oxidase system and phenazine methosulate/NADH system, and the effects of SalB and EGb 761 on the generation of O-2(-) were achieved by spectrophotometric measurement of the product formed on reduction of nitro blue tetrazolium. Two different methods were used to assess the scavenging effects of the extracts on hydroxyl radical (center dot OH): HPLC method was used for quantitation of center dot OH by oxy-radical trapping of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) to form DMPO-OH adducts in Fe 2, -EDTA-H2O2 system. To confirm the HPLC data, center dot OH was also measured by spectrophotometry using a commercial detection kit. The anti-lipid peroxidation effects of the extracts in microsomes of rat brain, liver and kidney induced by ascorbate-NADPH were determined by thiobarbituric acid (TBA) method. The protective effects of the extracts on peroxide hydrogen (H2O2)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 were able to scavenge O-2(-) and center dot OH, inhibit lipid peroxidation of microsomes, and protect SH-SY5Y cells against H2O2-induced oxidative damage. However, the concentration of SalB was far lower than that of EGb 761 when a similar effect was obtained. Conclusion: The antioxidant efficiency of SalB was greater than that of EGb 761. These results suggest that SalB, like EGb 761, has promising potential in treating oxidative damage-derived neurodegenerative disorders.