| Eucommia ulmoides Oliv., which is an ancient species of economical trees of the genus Eucommia and the family Eucommiaceae, is well-known as a kind of old-line therapeutic herbal medicine material for2000years. According to modern research results, Eucommia ulmoides Oliv was used in ancient China because of their biological efficacies like pressure releasing, lowering blood fat, removing free radicals and etc.. In this paper Eucommia ulmoides leaves were chosen to be the major object. The content of the total flavonoids and phenolic content, in vitro antioxidant activities, in vitro xanthine oxidase inhibitory activity, preventive and therapeutic effects on hyperuricemia were investigated by applying modern analytical and research methods. The main results obtained in this research are summarized as follows.1. The lipid compositions were removed from the Eucommia ulmoides leaves by ether reflux, then the flavonoids were extracted by60%ethanol, following the remanent compositions were abstracted by the previous ethanol extraction through the different organic solvents. Finally, each fraction was concentrated under reduced pressure. Six fractions were obtained as ether fraction, ethanol fraction, chloroform fraction, ethyl acetate fraction, n-butanol fraction and residual fraction. The extraction yield, the total flavonoid and phenolic content of the six fractions were measured respectively. The experiment results showed that ethyl acetate fraction possesses the highest flavonoid and phenolic content,376.63mg/g and461.2mg/g respectively.2. The in vitro antioxidant of the extraction in Eucommia ulmoides leaves was studied with the abilities of DPPH scavenging radicals assay, β-carotene/linoleic acid bleaching assay and oxygen radical absorbance capacity assay. The results showed that the ethyl acetate fraction fraction possess the highest ability of antioxidant activities of the six fractions,3. The in vitro xanthine oxidase inhibitory activity of the Eucommia ulmoides Leaves extractions were evaluated, and it was found that all of the fractions had abilities of restraining xanthine oxidase, but the abilities exist significant distinction. Among the fractions test, ethyl acetate fraction exhibited highest potency (IC50 2.47mg/mL).4. To establish the hyperuricemia model with oxonic acid potassium salt in SD rats, the different dosage sample groups (low and high) of ethyl acetate fraction and n-butanol fraction on hyperuricemia in rats were studied. The experiment results showed that the high dosage group of ethyl acetate fraction(74.7mg/kg) showed the best preventive and therapeutic effects. |
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