Quality evaluation of Codonopsis Radix and processed products based on the analysis of monosaccharides and oligosaccharides by liquid chromatography coupled with charged aerosol detector.

Introduction: Codonopsis Radix (CR) is an edible food and traditional Chinese herb medicine that is widely used in China and Southeast Asia. Saccharides, including fructo‐oligosaccharides (FOS) and polysaccharides, are among the most important active substances in CR. However, a quality evaluation of CR based on oligosaccharides has not been conducted. Objective: This study aimed to establish a high‐performance liquid chromatography coupled with charged aerosol detector method (HPLC‐CAD) for the quality evaluation of CR and processed products based on analysis of monosaccharides and oligosaccharides. Method: A sensitive and rapid HPLC‐CAD method for the simultaneous determination of two monosaccharides (D‐fructose and D‐glucose), sucrose, and FOS (GF2–GF6) was established to evaluate the quality of CR for the first time. In the present study, 65 batches of CR from three species of the genus Codonopsis were analysed using multivariate statistical techniques. Furthermore, the effects of cultivation management measures (plant growth retardants supply, harvesting time, and growth period) and primary process (drying methods) in the production areas on the target compounds were studied by analysing 34 batches of processed samples. Results: Different varieties of CR resulted in considerably different saccharide contents. Cultivation management measures and processing method remarkably affected the quality of CR. Low concentration of plant growth retardants was recommended. The best harvest time is in October after 4 years of growth. Dryer‐drying was suggested to meet the requirement for large‐scale processing. Conclusion: This method would provide an efficient analytical tool for monosaccharides and oligosaccharides of CR and contribute to the improvement of CR quality. An accurate and efficient HPLC‐CAD method for monosaccharides and oligosaccharides was established and demonstrated to be suitable to evaluate the quality of Codonopsis Radix and processed products. Results indicated that the content of oligosaccharides varied considerably among the specimens, not only inter‐species but also intra‐species. Besides cultivar type, other factors such as plant growth retardants supply, harvesting time, growth period, and drying methods would affect the saccharide accumulation. [ABSTRACT FROM AUTHOR]