Isolation and Purification of Kudinosides from Kuding Tea by Semi-Preparative HPLC Combined with MCI-GEL Resin

Abstract

Background: Kuding tea, a Traditional Chinese drink, has a history of thousands of years in China. Triterpenoid saponins in Kuding tea are regarded as one of the major functional ingredients. Objective: The aim of this paper was to establish separation progress for the isolation and purification of five triterpenoid saponins (kudinoside A, C, D, F, G) from Kuding tea. Methods: Nine types of resins, including seven macroporous resins and two MCI-GEL resins, were firstly used for purifying triterpenoid saponins by the adsorption and desorption tests. Further dynamic adsorption/desorption experiments were carried out to obtain the optimal parameters for the five targeted saponins. Then the purification of five triterpenoid saponins (kudinoside A, C, D, F, G) was completed by semi-preparative high-performance liquid chromatography (semi-pHPLC). Results: As of optimized results, the HP20SS MCI-GEL was selected as the optimal one. The data also showed that 65.24 mg of refined extract including 7.04 mg kudinoside A, 3.52 mg kudinoside C, 4.04 mg kudinoside D, 4.13 mg kudinoside F, and 34.45 mg kudinoside G, could be isolated and purified from 645.90 mg of crude extract in which the content of five saponins was 81.51% and the average recovery reached 69.76%. The final contents of five saponins increased 6.91-fold as compared to the crude extract. Conclusion: The established separation progress was highly efficient, making it a potential approach for the large-scale production in the laboratory and providing several markers of triterpenoid saponins for quality control of Kuding tea or its processing products.