Separation and Analysis of Ginsenoside Rg1: An Experiment for the Separation and Analysis of Natural Products

A comprehensive experiment for third-year undergraduate students in pharmaceutical engineering is described. Students had previously completed courses in analytical chemistry, chemistry of natural products, and bioseparation engineering and had background knowledge in purification, quantitative analysis, packed column chromatography, high-performance liquid chromatography (HPLC), thin layer chromatography (TLC), and so on. Students were arranged into groups of four to six, and each student group completed the whole experiment independently. Extracts of Panax ginseng stems and leaves were used as raw materials. Students used HPLC to analyze the contents of Rg1 in the raw materials and the purified products by the area normalization method and the absolute content method, respectively; students then calculated the yield. During silica gel column chromatography, TLC was used to quickly monitor the chromatographic fractions to accurately collect fractions containing Rg1. The pure Rg1 obtained was quantitatively analyzed by HPLC with an external standard method. Conducting this experiment, students can gain conceptual understanding as well as practical skills and understanding of separation techniques from the analytical level to the preparative level and from rapid qualitative monitoring to quantitative analysis.