Total Flavonoids Extraction And Evaluation Of The Antioxidant,

Portulaca oleracea L, belongs to the genus Portulaca (Portulacaceae), is widely distributed weed. It has been used as folk medicine as heat-clearing and detoxifying and cooling blood and hemostasis. It exhibits a wide range of pharmacological effects, including antibacterial, antiatheroscloresis, skeletal muscle-relaxant, anti-inflammatory, analgesic, and wound-healing. Moreover, some findings also showed that Portulaca oleracea L. owns anti-hypoxia and anti-aging effects.As the difference of solubility of flavonoids depends on the different structure and existing state, it is necessary to determine the type of solvents and then take into account the scope of factors, such as percentage of solvent, solid to liquid ratio and time-influence. applied the orthogonal experiment and statistical analysis to optimize the percentage of solvent extraction temperature, extraction time and solvent volume in order to design best extraction way for flavonoids.applied HPD-600 macroporous resin gel to get the total flavonoids from the crude extract of Portulaca oleracea L and biological activity of total flavonoids was investigated through some in vitro systems, such as 1,1-diphenyll-2-2-pricylhydrazyl (DPPH) free radical scavenging activity, hydroxyl radical scavenging, and superoxide anion radical scavenging activity. The induced and non-induced systems were applied to determine products (MDA) in liver homogenate in order to evaluate the protection ability of lipid peroxidation induced by Fenton reaction. The protective ability on erythrocyte hemolysis was also investigated through AAPH caused free radical on erythrocytes.The ICR mice were subcuteneously injected with D-gal for 60 days. All mice were administered with PFE 300, 600, 1 200 mg/kg?d for 60 days, then sacrificed to collect serum, liver and brain tissue. The activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant activity (T-AOC) and the content of malondialdehyde (MDA) in serum and liver were determined. Likewise, the activity of SOD , Na⁺-K⁺-ATPase and content of MDA in the brain were assayed.Our findings showed that the optimum conditions for extraction is as follows: solvent (50% ethanol), extracting time (30 min), solid to liquid ratio (1:25), and times (two times). We found that the DPPH free radical scavenging ability was high in total flavonoids after purified by resin compared the crude extract. The IC₅₀ for DPPH·is 13.46 mg/L for total flavonoids, which is higher than standard antioxidants, VC and rutin. The total antioxidant ability is 225.7 U/mg, which is higher than VC. Nevertheless, the ability for scavenging hydroxyl radical is lower than Vc. The total flavonoids showed a dose-dependent protective activity on AAPH-induced erythrocyte hemolysis The total flavonoids also can inhibit the MDA level in mouse liver after stimulated with Fenton reaction with a certain range dose-dependent manner.Compared with the normal group, the activities of SOD, GSH-Px, CAT, and T-AOC in the D-galactose-induced aged mice were significantly decreased. Meanwhile, the content of MDA was dramatically increased. After perfused with different doses of PFE, the activities of SOD, GSH-Px, CAT and T-AOC in the serum, liver and brain tissues were increased, while the content of MDA in serum, liver and brain tissue were decreased,the activities of Na⁺-K⁺-ATPase was decreased.However, there is no significant difference between orally flavonoids extract and model group, suggesting flavonoids can significantly improve the antioxidant of subacute mice. The protection on brain remains to be further study.