| Potentilla fruticosa L. is a species of hardy deciduous flowering shrub in the Potentilla genus of the family Rosaceae and has been confirmed to possess relatively high concentrations of phenolic acids and flavonoids with powerful radical scavenging capacity. In previous studies, we have found that there is an obvious antioxidant synergistic interaction in the combination of P. fruticosa leaves extracts and Ginkgo Biloba extracts. To further develop and utilize P. fruticosa, and screen out the more potent antioxidants, we researched the interaction effects and possible mechanisms of P. fruticosa combined with commercial antioxidants in a variety of oxidation systems. The main results were as follows:1.The antioxidant capacities of P. fruticosa extracts(PFE) + green tea polyphenol(GTP), PFE+ curcumin, PFE+ resveratrol were measured. There was an excellent synergistic interaction in PFE+GTP, especially at the ratio of 3:1(PFE: GTP), the interaction indexs of ABTS and FRAP were 1.35 and 1.29 respectively. Most combinations of PFE + curcumin and PFE + resveratrol showed simple additive effects on antioxidant capacity.2. We detected the contents of phenolic compounds in PFE and GTP by HPLC. Results showed that PFE contained high amounts of hyperoside(64.49±1.11 mg/g),(+)-catechin(25.11±0.93 mg/g) and ellagic acid(5.94±0.09 mg/g), while GTP contained high amounts of EGC(69.98±1.31 mg/g),(+)-catechin(11.03±0.15 mg/g), EGCG(350.60±3.45 mg/g), EC(60.90±0.77 mg/g) and ECG(103.30±2.46 mg/g. Besides, we found that no new peaks appeared in the chromatogram and no existing peaks disappeared, indicating that compositional changes did not occur. However, we determined that the(+)-catechin content decreased significantly while the EGC and EGCG content increased.3. Combinations of PFE and 5 phenolic compounds in GTP(EGC,(+)-catechin, EGCG, EC and ECG) were evaluated. Results showed that the combination at a ratio of 5:1(PFE: EGC) exhibited the strongest synergy in ABTS(γ=1.20), FRAP(γ=1.15) and DPPH(γ=0.86). Then EGC was added to the other 3 phenolics in PFE((+)-catechin, hyperoside and ellagic acid). Results showed hyperoside + EGC exhibited the greatest synergistic effect in various ratios. The combination at a ratio of 3:1 exhibited strong synergism in the ABTS(γ=1.11), FRAP(γ=1.16) and DPPH(γ=0.86).4. The H2O2 production rate and protective effect on H2O2-induced E.coli of PFE+EGC and hyperoside + EGC were measured. In combination of PFE+GTP, the ratio of 1:1 showed the strongest synergy in H2O2 production(γ=1.10) and the ratio of 3:1 showed the strongest synergy in protective effect on H2O2-induced E.coli(γ=1.18). While in combination of hyperoside+EGC, there is no any obivious syngergy, no matter in the H2O2 production or protective effect on H2O2-induced E.coli. Therefore, interaction of EGC and hyperoside should not take responsible for the synergy effect between PFE and GTP on the H2O2 production and the growth rate of E.coli.5.The influence of PFE+GTP、EGC+hyperoside on activities of 4 antioxidant enzymes(CAT、POD、SOD and GSH) in E.coliwere evaluated.From the results, we found that PFE+GTP can greatly help promote activities CAT and SOD, especially at ratio of 3:1, the interaction indexs were 1.15 and 1.14 repectively; but has no influence on activities of POD and GSH. Meanwhile, EGC+hyperoside have not any influence on activities of all the 4 antioxidant enzymes.6. The influence of PFE+GTP、EGC+hyperoside on expression of CAT, SODa, SODb and SODc genes were evaluated. In combination of PFE+GTP, the ratio of 3:1 also showed great synergy in expression of CAT(γ=1.11) and the ratio of 5:1 showed great synergy in expression of SODa(γ=1.10); but has no influence on expression of SODb and SODc. Meanwhile, EGC+hyperoside have not any influence on expression of all the 4 genes. |
PDF Full Text Request