OBJECTIVE: The purpose of this study was to explore the exact efficacy of different extracts from Ilex cornuta in the treatment of hyperuricemia in vitro and in vivo, and to explore its pharmacological mechanism, so as to bring new ideas for the development of new drugs for reducing uric acid (UA) and anti-gout.
METHODS: Five crude extracts from Ilex cornuta leaves were extracted by different methods. Then, the xanthine oxidase inhibitory activity and antioxidant capacity of 5 extracts in vitro were compared to screen the extract with the most UA regulating potential. In vivo experiment, hyperuricemia model of mice was established by intragastric administration of potassium oxonate and feeding high yeast diet. Biochemical indexes such as serum UA level, xanthine oxidase activity, liver and kidney index of mice in each group were detected. The pathological sections of kidney and liver tissues were also observed and compared. The mechanism of Ilex cornuta leaves (western blotting, and RT-qPCR) in the treatment of hyperuricemia was further explored by targeting UA transporters ABCG2, GLUT9, and URAT1.
RESULTS: The in vitro results of inhibitory activity of xanthine oxidase showed that the crude saponin extract was the best, followed by crude flavonoids extract. Then, the in vivo results reflected that both crude saponins and crude flavonoids extracts could significantly reduce the serum UA level, inhibit the activity of xanthine oxidase in serum and liver, and maintain serum urea nitrogen and creatinine at normal level. Meanwhile, there was no liver and kidney injury in mice. Through the comparison of the mechanism results, it was found that both extracts could up-regulate the expression of ABCG2 protein and mRNA related to UA excretion, and down-regulate the expression of GLUT9 and URAT1 protein and mRNA.
CONCLUSIONS: The crude flavonoids and saponins of Ilex cornuta leaves not only inhibited XOD activity in vitro, but also significantly controlled XOD activity and reduced UA level in hyperuricemia mice in vivo. One of the potential mechanisms was to regulate UA level in vivo by regulating ABCG2, GLUT9, and URAT1 transporters directly related to UA transport, thus achieving the effect of intervening hyperuricemia. This study provided a preliminary experimental basis for the development of new drugs of Ilex cornuta leaves for treating hyperuricemia.
目的:本研究的目的是探讨山茱萸不同提取物在体内外治疗高尿酸血症的确切疗效,并探讨其药理机制,从而为降低尿酸(UA)和抗痛风新药的开发带来新的思路。
方法:采用不同方法提取了5种玉米叶粗提物。然后,比较5种提取物的体外黄嘌呤氧化酶抑制活性和抗氧化能力,筛选出最具UA调节潜力的提取物。体内实验,用高尿酸钾灌胃和高酵母饮食建立小鼠高尿酸血症模型。生化指标,如血清UA水平,黄嘌呤氧化酶活性,检测各组小鼠的肝肾指数。同时观察并比较肾脏和肝脏组织的病理切片。矢车菊叶的机制(蛋白质印迹,和RT-qPCR)通过靶向UA转运蛋白ABCG2,GLUT9和URAT1来进一步探索高尿酸血症的治疗。
结果:黄嘌呤氧化酶抑制活性的体外实验结果表明,粗皂苷提取物效果最好,其次是粗黄酮提取物。然后,体内实验结果反映了粗皂苷和粗黄酮提取物均能显著降低血清UA水平,抑制血清和肝脏中黄嘌呤氧化酶的活性,维持血清尿素氮和肌酐正常水平。同时,小鼠无肝肾损伤。通过机理结果的比较,发现两种提取物都可以上调ABCG2蛋白和与UA排泄相关的mRNA的表达,并下调GLUT9和URAT1蛋白和mRNA的表达。
结论:玉竹叶的粗黄酮和皂苷不仅抑制了XOD活性,但也显著控制XOD活性和降低体内高尿酸血症小鼠的UA水平。潜在的机制之一是通过调节与UA转运直接相关的ABCG2,GLUT9和URAT1转运蛋白来调节体内UA水平,从而达到干预高尿酸血症的效果。本研究为山茱萸叶治疗高尿酸血症新药的研制提供了初步的实验依据。