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Abstract
A preparative high‐speed countercurrent chromatography (HSCCC) method for isolation and purification of didymin, nairutin, and clinopodiside A from Clinopodium chinensis (Benth) O. Kuntze (Duanxueliu in Chinese) was successfully established. The separation was performed in two steps with two different kinds of solvent systems. In the first step, ethyl acetate‐1‐butanol‐water (5:0.8:5, v/v) was used as the two‐phase solvent system; nairutin was purified, and didymin and clinopodiside A were eluted together. In the second step, ethyl acetate‐methanol‐water (5:1:5, v/v) was used as the two‐phase solvent system; didymin and clinopodiside A were separated and purified. After two‐step separation, 15.2 mg of nairutin, 39.1 mg of clinopodiside A, and 20.6 mg of didymin were obtained from 100 mg of crude extract with purities of 96.5%, 98.4%, and 99.1%, respectively, as determined by HPLC analysis. The chemical structures of the three components were confirmed by 1H NMR and 13C NMR.
