[Effects of flavones extracted from Portulaca oleracea on ability of hypoxia tolerance in mice and its mechanism].
OBJECTIVE: To identify anti-hypoxia ingredients extracted from Portulaca oleracea and to find out the possible mechanism of its anti-hypoxia actions. METHODS: Seventy mice were randomly divided into seven groups which were untreated (normal saline), ginsenosides-treated, polysaccharide-treated, acidic components-treated, basic components-treated, alkaloids-treated and flavones-treated groups, and the ingredients of polysaccharide, acidic components, basic components, alkaloids and flavones were extracted from Portulaca olerace. The mice in each group were fed with corresponding ingredients for one week respectively. Then the survival time of mice in hypoxic conditions was observed. Another 90 mice were divided into 3 groups: untreated (normal saline), ginsenosides-treated and flavones-treated groups. The mice in each of these 3 groups were divided into 3 subgroups according to 12-, 24- and 36-hour exposure to hypoxia (10% oxygen and 90% nitrogen), respectively. After exposure to hypoxia, the red blood cell count (RBC), hemoglobin (Hb) concentration and hematocrit (HCT) in mice were determined. The plasma erythropoietin (EPO) levels of mice were detected by enzyme-linked immunosorbent assay (ELISA) and the relative values of EPO mRNA in renal tissue and pallium of mice were determined by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: The survival time of mice in hypoxic conditions in flavones-treated group was significantly longer than that in the untreated group. The RBC, Hb concentration, HCT, plasma EPO level and the relative values of EPO mRNA in renal tissue and pallium of mice were significantly higher in the flavones-treated group than those in the untreated group. CONCLUSION: The anti-hypoxia ingredients extracted from Portulaca oleracea are flavones and the anti-hypoxia effects may be obtained by improving the expression level of EPO and accelerating the generations of erythrocyte and Hb.