Translated Abstract
Gout is a metabolic disorder of purine compounds, which lead to lasting high serum uric acid level and urate crystal deposition by increasing production and reducing excretion of uric acid. In recent years, the incidence of gout is rising, and more and more younger patients are suffering from such disease. At present, widely used clinical drugs for the prevention and treatment of gout are uric acid synthesis inhibitors, which inhibit the activity of xanthine oxidase to reduce the production of uric acid. Therefore, screening of xanthine oxidase inhibitors from natural medicine will provide a theoretical basis for the research and development of anti-gout drugs.
This dissertation investigated main factors affecting the determination of xanthine oxidase inhibitory activity by UV spectrophotometry method and modified this method. The xanthine oxidase inhibitory activity of 154 medicinal species were tested by the modified method and the results showed that only 41 medicinal plants possessed xanthine oxidase inhibitory activity and Pinus tabulaeformis Carr showd the most impressive activity, with an inhibition rate of 69.6%.
This dissertation also established and validated TLC method to track the active compounds in plants with xanthine oxidase inhibitory activity. Using this method, active compounds in Belamcanda chinensis (L.) DC., Psoralea corylifolia L and Pinus tabulaeformis Carr, three plants that showed significant xanthine oxidase inhibitory activity, were tracked.
By column chromatograph method and recrystallization, five active compounds were obtained. Their chemical strctures were established on the basis of spectral data (ESI-MS, 1H-NMR and 13C-NMR), physical and chemical constants, and chemical identifications. They were irigenin, psoralen, isopsoralen, corylin and 1-heptacosanol, and their xanthine oxidase inhibition rates were 76.3%, 12.7%, 39.2%, 47.9% and 41.1% respectively. The results were consistent with that of active conpouds tracking experiment.
Adopted 5 kinds of coumarins as experimental subjects, studies of structure-activity relationship between coumarins and xanthine oxidase inhibitory activity were taken. The results showed that isocoumarins were more active than coumarins, pyran coumarins showed more impressive activity than simple coumarins, and xanthine oxidase inhibitory activity of angle-type pyran coumarins were stronger than that of linear- type pyran coumarins.
This dissertation conducted the screening of abundant amounts of natural medicine, tracked and isloated the active compounds which resulted in the discovery of xanthine oxidase inhibitors. This dissertation promotes the development of anti-gout drugs.
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