Bioassay-guided Separation of Anti-tumor Components from Euphorbia kansui by Means of Two-dimensional Preparative High Performance Liquid Chromatography and Real-time Cell Analysis.

A new strategy for the convergence of two-dimensional preparative high performance liquid chromatography (HPLC) and real-time cell analysis (RTCA) was developed for rapidly separating and screening anti-tumor components from the ethyl acetate extract of the traditional Chinese medicine (TCM), Euphorbia kansui. Eight compounds: esulone A (1), kansuinin A (2), (3β,11β)-3,11-dihydroxylanosta-8,24-dien-7-one (3), kansuinin E (4), kansuinin B (5), isoscopoletin (6), kansuinin D (7) and kansuinin G (8) were efficiently isolated with purity above 97%. Of all the compounds, esulone A has been isolated from this plant for the first time. The structures were identified by NMR spectroscopy and comparisons were made with the data in previous literature. The anti-tumor bioassay was performed on A549 (human lung cancer cells) and Hep-G2 (human liver cancer cells) with a newly developed RTCA system. The result revealed that compounds 1, 3, 7 and 8 almost entirely inhibited the proliferation of A549 cells and that compound 8 was also thought to be the most active compound against Hep-G2 cells. The method provided considerable assistance for the efficient separation of different polar compounds and rapid screening of anti-tumor active compounds.