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Purification of Epothilones A and B with Column Chromatography on a Sephadex LH-20

A simplified and efficient method was developed for the large-scale purification of the epothilone A and B from fermentation products of Sorangium cellulosum after organic solvent extraction in this paper. Extractant from XAD-16 resin with tetrachloromethane containing epothilones was concentrated under vacuum, subjected to Sephadex LH-20 column chromatography, and eluted with several solvents. Fractions containing epothilones are pooled, concentrated, and applied to a second cycle of column chromatography with other solvents. Result showed that elution with acetone gave the best purity of epothilones [78.1% by high-performance liquid chromatography (HPLC) than that with pure methanol, pure ethanol, 70% (v/v) aqueous methanol or methanol-dichloromethane (1:1, v/v).] Then, when flow rate was 0.2 mL/min and sample amount (epoA) was 1 mg in second cycle, elution with methanol was resulted in complete separation between epothilone A and B, and further improved separately the purity of epothilone A and B to 90.27% and 77.34%. This simplified purification scheme avoided the loss of expensive epothilones in the common silica gel separation process and achieved the separation of epothilone A and B, significantly reduce the cost of the production without preparative liquid chromatography, or other equipment.