Triterpenoids from swallow roots--a convenient HPLC method for separation.

A convenient semi-preparative high-performance liquid chromatography (HPLC) method for separating a mixture of triterpenoids (alpha-amyrin, beta-amyrin, and lupeol) and their corresponding acetates from the swallow roots (Decalepis hamiltonii Wight and Arn), which are known to have potential bioactive properties, is described. The swallow roots are found to be one of the richest natural sources for these compounds. The hexane extract of the dried spent root on column chromatography yields mixtures (i.e., triterpenoids and their acetates) containing at least three compounds in each. These could not be further separated using the routine chromatographic techniques, such as classical column chromatography and preparative thin-layer chromatography using various solvent systems. Therefore, the optimal conditions are determined on reversed-phase HPLC for their separation and are characterized using spectral data, particularly by nuclear magnetic resonance with physical and chemical properties.