积雪草中积雪草酸的分离、纯化及其含量测定

目的分离纯化积雪草中积雪草酸,并建立高效液相色谱法(high-performance liquid chromatography,HPLC)测定积雪草酸的含量。方法超声提取积雪草中积雪草酸,将粗提物用石油醚-丙酮体系在硅胶柱上梯度洗脱,HPLC法测定积雪草酸的含量。色谱条件:采用Waters Symmetry C18色谱柱(4.6 mm×250 mm,5μm),流动相为乙腈-10 mmol.L-1乙酸铵溶液(38∶62,V/V),检测波长为210 nm,流速为1.0 mL.min-1,柱温25℃,进样体积为20μL。结果积雪草酸在浓度10～200 mg.L-1线性关系良好(R2=0.999 5),其日内、日间RSD均小于5.4%,回收率为100.5%。积雪草中积雪草酸含量为0.99 g.kg-1。经提取、分离、纯化得到积雪草酸白色粉末,纯度为79.0%。结论本实验所用分析方法简便、准确、重复性好,可用于积雪草酸的含量测定;所用提取分离及纯化积雪草酸的方法可使中药中积雪草酸得到有效富集。

Purification of asiatic acid from centella asiatica and its determination by RP-HPLC

Objective To establish a rapid separation and purification method of asiatic acid from centella asiatical(L.) Urban and to develop a reversed-phase high-performance liquid chromatography(HPLC) method with UV-vis detection for the quantitative determination of asiatic acid. Methods Crude extract separated and purified by silica gel column chromatography with gradient elution of petroleum ether-acetone system was first extracted with ethanol from centella asiatical(L.) urban and then done by ethyl acetate. TLC was used as the monitor during the process. HPLC separation was achieved on a Symmetry C₁₈ column(4.6 mm×250 mm, 5 μm) with a solvent system of acetonitrile -10 mmol·L^-1 ammonium acetate(38∶62). The wavelength of detector was set at 210 nm, the flow rate was 1 mL·min^-1, the column temperature was set at 25 ℃, and the injection volume was 20 μL. Results A calibration curve ranging from 10 to 200 mg·L^-1 was shown to be linear(R²=0.999 5), and the lower limit of quantification(LLOQ) was 10 mg·L^-1. The inter- and intra-day RSD% which were determined by three different concentration(25, 100, 200 mg·L^-1) were lower than 5.4%. The content of asiatic acid in centella asiatical(L.) Urban was 0.99 g·kg^-1. Conclusion The method was successfully applied to the separation, purification and the quantitative determination of AA.