[Determination of absolute configuration of a new triterpenic acid in leaves of Ilex hainanensis].

This study aimed to explore the triterpenic acid components in leaves of Ilex hainanensis. Alkaline water extraction, macroporous resin adsorption, and high performance liquid chromatography were used to separate and purify the triterpenic acid components in leaves of I. hainanensis. The physical and chemical property analysis, MS, NMR spectroscopy, and literature comparison were performed to identify the structures, and a new triterpene acid compound was discovered:(3S, 4R, 5R, 8R, 9R, 10R, 14S, 17S, 18S, 19R)-3,19-dihydroxyursa-12,20(30)-diene-24,28-dioic-acid, and named ilexhainanin F. In addition, according to its structural characteristics, the ~(19)F-NMR Mosher method was further employed to study its absolute configuration. By comparison of the ~(19)F-NMR chemical shifts of Mosher esters, it was determined that the absolute configuration of the 3-position chiral center of the compound was the S configuration.