[Droplet countercurrent chromatography to isolate ecdysteroids from the herb Silene tatarica (L>)]

Our research project was to isolate ecdysteroids from Silene tatarica (L.) Pers., which plant belongs to Caryophyllaceae family. This plant as a species of the Silence genus has been considered as a good potential source of ecdysteroids, including new, hitherto never identified natural product(s). The raw material of isolation was the herba of Silene tatarica (L.) Pers. that was cultivated in the fields of the Ecological and Botanical Research Institute of the Hungarian Academy of Sciences (Vácrátót, Hungary) and the plants were collected in June of 1994. The isolation procedure started with methanol extraction of the ground and milled herba. To improve the recovery, the extraction was done with boiling methanol under reflux for 20 minutes. The crude extract was purified using simple techniques, such as fractioned precipitation (with acetone), solvent-solvent partition (benzene-aqueous methanol). Further purification includes droplet counter-current chromatography (chloroform-methanol-water, 65:20:20, v/v/v) and straight-phase HPLC (silica stationary phase, dichloromethane-150 propanol-water. 125:25:2 v/v/v, mobile phase). Structural identification was done by using mass spectrometry and NMR spectroscopy. Three of the isolated ecdysteroids were identified as 20-hydroxyecdysone, 2-deoxy-20-hydroxyecdysone and 20-hydroxyecdysone-22-benzoate these compounds have never been detected in Silene tatarica (L.) Pers. Structural elucidation of the fourt isolated ecdysteroid resulted in a new natural product with the chemical structure of 2-deoxy-20-hydroxyecdysone 22-benzoate.