葛根总黄酮在乙醇-无机盐双水相体系中的萃取

Extraction of flavonids fromPueraria lobata using ethanol/inorganic salts aqueous two-phase system

根据乙醇/无机盐双水相体系的分相能力差异与葛根总黄酮在其中的分配差异,用双水相对葛根总黄酮进行萃取纯化.先在室温25℃下用浊点法分别绘制研究乙醇与氯化钠、碳酸钠、磷酸氢二钾、碳酸钾、硫酸铵5种盐所组成的双水相体系的相图,并计算萃取后葛根总黄酮在各体系中的分配系数和萃取率,筛选出乙醇/磷酸氢二钾体系为最佳体系.然后考察改变该体系中水与乙醇体积比和盐的量对体系相比以及葛根总黄酮的分配系数和萃取率的影响,确定最佳组成.最后考察了葛根粗提取液中葛根总黄酮浓度变化对其分配系数和萃取率的影响.结果表明乙醇质量分数为50.14%、磷酸氢二钾质量分数为22.67%的双水相体系是分离纯化葛根总黄酮的最佳条件;在一定质量浓度范围内,葛根总黄酮质量浓度越高,葛根总黄酮在双水相体系中的分配系数越大,当葛根粗提物质量浓度超过0.014g/mL后,分配系数减小;质量浓度的改变对萃取率影响不大;在最佳萃取条件下,葛根总黄酮在体系中的分配系数为35.99,萃取率高达99.23%.该双水相萃取技术操作简单、环保无害,并对葛根粗提取液中葛根总黄酮的分离纯化有较好的效果.

According to the diversity of phase separation ability and the distribution of target products in the ethanol/inorganic salts aqueous two-phase system （ATPS）, ATPS was used to extract and purify total flavonids of Pueraria lobata. The phase diagrams of ethanol/sodium chloride,ethanol/sodium car- bonate,ethanol/dipotassium hydrogen phosphate, ethanol/potassium carbonate and ethan01/ammonium sulfate ATPS were drawn and investigated at room temperature of 25 ℃ by the cloud point method,re- spectively. The ethanol/dipotassium hydrogen phosphate system was selected as the optimum system for the extraction of total flavonids after the distribution coefficient and the extraction yield was calcu- lated. Then the distribution coefficients and the extraction yield of puerariae flavonids were studied un- der the different proportion of ethanol to dipotassium hydrogen phosphate of ATPS, and the optimal composition was determined. Finally the effect of the concentration of total flavonids on the distribution coefficient and the extraction yield was investigated. The results show that the optimal extraction condi- tion of total flavonids is got as the ATPS with ethanol 50.14% （w/w） and dipotassium hydrogen phos- phate 22.67% （w/w） ;meanwhile the distribution coefficient increases with the total flavonids concen- tration increase;however the distribution coefficient begins to decrease when the concentration of crude extract of Pueraria lobata is over 0. 014 g/mL; finally, the distribution coefficient is 35.99 and the ex- traction yield of puerariae flavonids reaches 99. 23%, respectively. The aqueous two-phase extraction （ATPE） has a good effect on the separation and purification of total flavonids of Pueraria lobata.