Phytochemical analysis and biological activity of the flavonoids from the Mongolian medicinal plant Dianthus versicolor Fisch.

Dianthus versicolor Fisch. is used in Traditional Mongolian Medicine against various liver diseases. Until now chrysoeriol-C-glycosides and triterpenoid saponines were found in the plant [1,2]. Aqueous (OWE) and methanolic extracts were tested in the isolated rat liver perfusion model [3] and both types of extracts showed a dose dependent increase of the bile flow. For preparation of the OWE aerial parts were powdered and extracted with water (pH 2, trifluoroacetic acid) for 1h by shaking gently. This simulates the traditional way of intake where the crude drug is taken together with a certain amount of water. The OWE was further fractionated by SPE yielding four fractions. The 40% methanolic fraction showed a dose-dependent effect on the bile flow which was – even though in higher concentrations – comparable to the liver-affecting cynarin. From this fraction six main flavonoids were isolated using CC, CPC and semi-preparative HPLC. Their structure elucidation (UV, MS, 1D- and 2D-NMR) revealed apigenin, luteolin and chrysoeriol C- and O-, di- and triglycosides. Three further flavonoids were characterized by UV and MS-data, one of them was identified as isovitexin-7-O-glucoside (saponarin). The nine flavonoids were quantified by HPLC on Aquasil C₁₈ using a MeCN/H₂O (pH 2.8, trifluoroacetic acid) gradient and quercetin-3-O-rutinoside (rutin) as internal standard. Additionally, the total flavonoid content was determined by establishing a UV-spectrophotometric method following the European Pharmacopoeia. Plant material of two different origins was compared. The total flavonoid content amounted to 0.75% and 1.19% in the crude drug; the two OWEs contained 1.78% and 3.59%, respectively.

References: [1] Boguslavskaya, L.I. et al. (1983) Khim. Prir. Soedin. 6:783–784.

[2] Ma, L. et al. (2009)J. Nat. Prod. 72:640–644.

[3] Glasl, S. et al. (2007) Planta Med. 73:59–66.