Key words: Hedysarum theinum Krasnob., Fabaceae, 8-hydroxydiadzein, 6″-O-acetylononin, (-)-catechin, (-)-epicatechin, protocatechoic acid.In continuation of research on the chemical composition of Hedysarum theinum Krasnob.[1], which has valuable medicinal properties, we studied the chemical composition of the low-molecular-weight fractions of the alcohol extract of roots of this plant.Roots of H. theinum were extracted successively multiple times with EtOAc and ethanol. The chemical composition of the EtOAc extract has been reported by us [1]. Alcohol extracts have previously been separated into fractions of monomeric and oligomeric compounds by dissolving the dried extract in water and then extracting successively with organic solvents, e.g., diethylether, EtOAc, and BuOH [2]. However, in our instance the use of this method led to formation of emulsions and a precipitate during the extraction by diethylether or CHCl 3 . This complicated the separation process. In order to avoid this step, which caused losses, we separated the dried ethanol extract by extraction in a Soxhlet apparatus successively by CHCl 3 , EtOAc, acetone, and ethanol. HPLC analysis showed the presence of low-molecular-weight compounds in the CHCl 3 and EtOAc fractions of the alcohol extract and practically none in the acetone and ethanol fractions.Column chromatography of the CHCl 3 fraction over silica gel and preparative TLC on silica gel isolated medicarpin (1), raspberry ketone (2), vestitol (3), and rhododendrol (4).The EtOAc fraction was separated by chromatography over polyamide into water-soluble compounds (water eluent) and aglycons (MeOH eluent). Preparative separation of the aglycon fraction using column adsorption chromatography over silica gel with subsequent rechromatography over reversed-phase sorbent (Diasorb C16T) isolated vestitol (3), formononetin (5), protocatechoic acid (6), the isoflavonoids 8-hydroxydiadzein (7) and 6″-O-acetylononin (8), and (-)-catechin (9) and (-)-epicatechin (10). The structures of 1-10 were proved by spectral analysis including PMR, 13 C NMR, IR, and UV spectroscopy in addition to GC-MS. The resulting spectra were similar to those reported in the literature.
