Studies On Chemical Composition Of Burdock Root&Influence On Mice Ua From Aqueous Extracts

Objective:To isolate, purify and identify the chemical composition of ethanol extracts of burdock root; to duplicate mice models of urgent and chronic hyperuricemia; to study the influence of ethanol extracts of burdock root on hyperuricemia.Methods:1. Identify the chemical composition of burdock root:respectively, with petroleum ether, chloroform, ethyl acetate, normal butanol, extract the burdock root extracts (have been extracted by ethanol95%). Isolate and purify the extracts with column chromatography methods like silicagel column, C18column and Sepadex-LH20, then identify the structures of compounds via comparing their physicochemical properties with the reference substance and with modern spectrum analysis methods like ESI-MS,1H NMR,13C NMR and IR.2.2.1Model experiment of mice suffered with chronic hyperuricemia:Duplicate mice model of chronic hyperuricemia via feeding (gavage) mice with the extract for continuous14days. The experiment was set with blank controlled group, model group, aqueous extracts group of burdock root in high, medium and low doses (6.67,3.33and1.67g·kg-1), positive group of allopurinol (40mg·kg-1). Start administration via gavage at the six day after model duplicating (qd×9d). Collect blood sample one hour later of the last administration. Test the UA level.2.2Model experiment of mice suffered with acute hyperuricemia:duplicate model of mice suffered with hyperuricemia via hypoxanthine intraperitoneal injection. The designation of experiment is same with above. After continuous administration via gavage(qd×10d), intraperitoneal injection with hypoxanthine is conducted one hour later of the last administration to duplicate mice model. Test the UA level.2.3Experiment on normal mice:the experiment is designed with blank controlled group, aqueous extract group of burdock root in high dose, and positive drug group of allopurinol. After continuous administration via gavage(qd×10d), collect blood sample one hour later of the last administration. Test the UA level. Process all the data via software SPSS13.0. One-way anova is employed. The result is shown with x±s. P<0.05means statistically significant.Results:1. Ten compounds are identified, including four compounds located in petroleum ether:(β-sitosterol (NBG-1), oleanolic acid (NBG-2a), ursolic acid (NBG-2b), and2-hydroxyl pentacosane acid (NBG-3); four compounds located in chloroform:β-sitosterol (NBG-1), daucosterol (NBG-4), syringaresinal (NBG-5), ethyl-(3-D-pyran fructoside (NBG-6); one compound is located in ethyl acetate:1,5-O-dicaffeoylquinic acid (NBG-7); and two compounds are located in normal butanol:succinic acid (NBG-8), 5-hydroxyl maltol (NBG-9).2.2.1Model experiment of mice suffered with chronic hyperuricemia:compared to model group, both aqueous extract group of burdock root in high dose and positive drug group of allopurinol reduced UA levels with significant differences (P<0.05, P<0.01), while aqueous extract group of burdock root in low and medium dose showed no significant difference (P>0.05); compared to blank controlled group, positive drug group of allopurinol reduces UA of mice to normal levels (P>0.05), while aqueous extract group of burdock root in all doses failed to reduce UA to normal levels (P<0.05).2.2Model experiment of mice suffered with acute hyperuricemia:compared to model group, both aqueous extract group of burdock root in high dose and positive drug group of allopurinol reduced UA levels with significant differences (P<0.05, P<0.01), while aqueous extract group of burdock root in low and medium dose showed no significant difference (P>0.05); compared to blank controlled group, positive drug group of allopurinol reduces UA of mice to normal levels (P>0.05), while aqueous extract group of burdock root in all doses failed to reduce UA to normal levels (P<0.05).2.3Experiment on normal mice:compared to blank controlled group, positive drug group of allopurinol reduced UA to normal levels (P<0.05), while aqueous extract group of burdock root in high dose showed no significant difference(P>0.05).Conclusions:This study firstly discover following compounds in burdock root: oleanolic acid (NBG-2a), ursolic acid (NBG-2b),2-hydroxyl pentacosane acid (NBG-3), syringaresinol (NBG-5), ethyl-β-D-pyran fructoside (NBG-6), succinic acid (NBG-8),5-hydroxyl maltol (NBG-9); the ethanol extracts of burdock root is active to reduce the UA level of mice suffered with hyperuricemia.