Gram-Scale Purification of Two Sesquiterpene Lactones from Chartolepsis Intermedia Boiss.
Résumé
Two sesquiterpene lactones, grosheimin and cynaropicrin, present in the aerial part of the Chartolepis intermedia Boiss. plant can be obtained from the ethyl acetate solid extract of the dried plant. A large-scale purification processing 16 kg of dry plant is presented. The first liquid-liquid extraction step of the 16 kg produced 550 g of dry extract that were divided in two equal portions. A classical low-pressure chromatography method can produce from 275 g of dry extract 13.8 g of grosheimin and 52.3 g of cynaropicrin 95 % pure lactones in 110 h using large amounts of organic solvents and 8 kg of silica gel. Another purification method employing countercurrent chromatography, with a modern hydrostatic column, and reversed phase preparative liquid chromatography were used with the second 275 g dry extract portion. It could produce 17.9 g of 99.4 % pure grosheimin and 68 g of 98.7 % pure cynaropicrin lactones in 95 h, with better yields and minimized losses in chromatographic columns, and using smaller solvent volumes than the classical method. The two purification processes are fully described and compared.