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: uperoxide anion (O2•^－) was generated using xanthine/xanthine oxidase system and phenazinemethosulate/NADHsystem, and the effects of SalB and EGb 761 on the generation of O2•^－ 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 (•OH): HPLCmethod was used for quantitation of •OHby oxy-radical trapping of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) to form DMPO-OH adducts in Fe²⁺-EDTA-H₂O₂ system. To confirm the HPLC data, •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 byascorbate-NADPHwere 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 O2•^－ and •OH, inhibit lipid peroxidation ofmicrosomes, and protect SH-SY5Y cells against H₂O₂-induced oxidative damage. However, the concentration of SalBwas 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 damagederived neurodegenerative disorders.