The content of astilbin and taxifolin in concentrated extracts of Rhizoma Smilacis Glabrae and turtle jelly vary significantly

Extract of Rhizoma Smilacis Glabrae (RSG) is one of the main ingredients in turtle jelly, which is a traditional functional food in Southern China and Hong Kong. A capillary electrophoresis method was successfully developed for determination of astilbin and taxifolin in turtle jelly and RSG concentrated extract samples. For six determinations of astilbin and taxifolin at concentrations of 20 μg ml−1, the relative standard deviations of migration time were 0.62% and 0.87%, while those of the peak area ratios were 2.17% and 3.62%, respectively. Eighteen turtle jelly samples manufactured in mainland China and Hong Kong were collected for analysis. The results show that astilbin and taxifolin were all from the RSG ingredient. The contents of astilbin and taxifolin in turtle jelly were distinctly different between brands, and some were found not to contain these substances.