Separation and determination of flavone and xanthone glycosides in Tibetan folk medicinal species Swertia mussotii and S-franchetiana by capillary electrophoresis

The contents of five pharmacologically active flavone and xanthone glycosides, namely, swertianolin, swertisin, isoorientin, mangiferin, and 7-O-[alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-xylopyranosyl]-1,8-dihydroxy-3-methoxyxanthone, extracted from Tibetan folk medicinal species Swertia mussotii and S. franchetiana were determined by capillary electrophoresis with diode-array detection. The separation of five components has been optimized with a capillary column with a total length of 48.5 cm and effective length of 40 cm (50 mu m i.d). The influence of the running buffer, the sodium dodecyl sulfonate (SDS) concentration, organic modifier, etc. on the resolution was evaluated. The background electrolyte contained 30 mM borate buffer, 28 mM SDS, 1.0% (v/v) acetonitrile, and was adjusted to pH 9.0 with 0.1 M NaOH. A good baseline resolution was obtained for the separation of five components within 5 min with the working voltage of 24 kV and a column temperature of 25 degrees C. The established method was rapid and reproducible for the separation and determination of five flavone and xanthone glycosides from the extracts of S. mussotii and franchetiana plant samples.