Extraction and isolation of dictamnine, obacunone and fraxinellone from Dictamnus dasycarpus Turcz. by supercritical fluid extraction and high-speed counter-current chromatography

Abstract

Supercritical fluid extraction was used to extract active compounds from the Chinese traditional medicinal D. dasycarpus under the pressure of 30 MPa and temperature of 45 °C. Further separation and purification was established by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.8:1.3:0.9, volume ratio). The separation yielded a total of 47 mg of dictamnine, 24 mg of obacunone and 83 mg of fraxinellone from 1.0 g of the crude extract in one step separation with the purity of 99.2, 98.4 and 99.0%, respectively, as determined by HPLC. The chemical structures of these compounds were identified by ESI-MS, IR, 1H-NMR and 13C-NMR.