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Multi-channel counter-current chromatography for high-throughput fractionation of natural products for drug discovery

Wu, Shihua, Yang, Lu, Gao, Yuan, Liu, Xiaoyue, Liu, Feiyan
Journal of chromatography 2008 v.1180 no.1-2 pp. 99-107
Solidago canadensis, Suillus, Trichosanthes kirilowii, medicinal plants, secondary metabolites, antineoplastic agents, plant extracts, fractionation, countercurrent chromatography, metabolomics
A multi-channel counter-current chromatography (CCC) method has been designed and fabricated for the high-throughput fractionation of natural products without complications sometimes encountered with other conventional chromatographic systems, such as irreversible adsorptive constituent losses and deactivation, tailing of solute peaks and contamination. It has multiple independent CCC channels and each channel connects independent separation column(s) by parallel flow tubes, and thus the multi-channel CCC apparatus can achieve simultaneously two or more independent chromatographic processes. Furthermore, a high-throughput CCC fractionation method for natural products has been developed by a combination of a new three-channel CCC apparatus and conventional parallel chromatographic devices including pumps, sample injectors, effluent detectors and collectors, and its performance has been displayed on the fractionation of ethyl acetate extracts of three natural materials Solidago canadensis, Suillus placidus, and Trichosanthes kirilowii, which are found to be potent cytotoxic to tumor cell lines in the course of screening the antitumor candidates. By combination of biological screening programs and preparative high-performance liquid chromatography (HPLC) purification, 22.8mg 6β-angeloyloxykolavenic acid and 29.4mg 6β-tigloyloxykolavenic acid for S. canadensis, 25.3mg suillin for S. placidus, and 6.8mg 23,24-dihydrocucurbitacin B for T. Kirilowii as their major cytotoxic principles were isolated from each 1000mg crude ethyl acetate exctract. Their chemical structures were characterized by electrospray ionization mass spectrometry, one- and two-dimensional nuclear magnetic resonance. The overall results indicate the multi-channel CCC is very useful for high-throughput fractionation of natural products for drug discovery in spite of the solvent balancing requirement and the lower resolution of the shorter CCC columns.