Identification Of Synergistic Antioxidant Components In Huangqi And Shengma And Investigation Of Their Synergistic Mechanism

Chinese traditional medicine play a very important role in the development of functional foods due to their clear pharmacological effects and safety. Traditional herbs are commonly used in the form of combination due to the complex interaction between phytochemicals. Many researches indicated that reducing oxidative stress is one of the most important mechanism for the therapeutic or preventable function of natural active components. In this paper, screening of synergistic antioxidant compounds from the combination of Huangqi and Shengma based on in vitro antioxidant activity assay and the research on synergistic mechanism may provide some theoretical basis for the purported synergistic efficiency of Huang-qi and Sheng-ma as functional foods, dietary supplements and medicinal drugs. The following lists were the major results:1. The phenolic/flavonoid content of Huangqi, Shengma and different solvent-extracted fractions of them were measured, and the correlation between the phenolic/flavonoid increments and antioxidant activity were studied. Results indicated that the phenolic/flavonoid increments of different extracts were closely related to the enhancement of their antioxidant activity, and phenolic/flavonoid compounds are important antioxidants in Huangqi and Shengma.2. The vitro antioxidant assay (DPPH and ABTS radical scavenging assay, FRAP assay) was applied to evaluate the antioxidant capacity of samples. Chromatographic isolation was performed on thin layer chromatography, silica gel, Sephadex LH-20 columns and HPLC, and consequently to yield formononetin, calycosin in AME-CF and ferulic acid, isoferulic acid in CFO-CF, which were identified by their retention time, UV ?,max, MS and MS/MS data.3. DPPH radical scavenging ability of formononetin, calycosin, ferulic acid, isoferulic acid were measured, and the synergistic combination in scavenging DPPH radicals were screened: calycosin and isoferulic acid. In order to observe whether the dose ratio could affect the synergistic effect between calycosin and isoferulic acid, different dose ratios were tested and the strongest synergy in scavenging DPPH radicals was observed at a dose ratio of 1:1.4. ABTS radical scavenging ability and ferric reducing antioxidant capacity of these four potential synergistic antioxidant compounds were also measured in order to evaluate their synergistic effects from different aspects. In FRAP assay, the synergistic effect was observed in the combination of isoferulic acid and calycosin. While, as for ABTS radical scavenging assay, the combination of isoferulic acid and calycosin only showed additive effect. These results indicated that not a single method can give a comprehensive prediction of antioxidant efficacy.5. The combination of calycosin and isoferulic acidwere examined for their synergistic effects on protecting cells against H2O2 induced oxidative damage. The similar synergy was observed in this combination. This result was contribute to better elucidate the mechanism behind the antioxidant synergism of natural product.