The hepatoprotective effect and chemical constituents of total iridoids and xanthones extracted from Swertia mussotii Franch.

ETHNOPHARMACOLOGICAL RELEVANCE: Total iridoids and xanthones (TIXS) were extracted from Swertia mussotii Franch, one of the most important eight Tibetan medicines in China, which was recorded in the book of Jingzhu Bencao and used for clinical treatment of cholestatic hepatitis for many years. Our aim was to study the hepatoprotective effect and chemical constituents of the TIXS. MATERIALS AND METHODS: Crude extracts were prepared using 90% ethanol, and individual fractions were collected following HPD-300 macroporous resin column chromatography. HPLC/MS was applied to qualitatively and quantitatively analyze the TIXS. Then, the alpha-naphthylisot hiocyanate-induced liver damage model was used to assess the hepatoprotective effect of the TIXS. RESULTS: A total of 12 compounds were identified by the fingerprint chromatography of the TIXS, and swertiamarin and swertianolin were shown to be its two main components. Oral administration of the TIXS at a dose of 35, 70 or 140 mg kg(-1), swertiamarin at a dose of 20 mg kg(-1) or swertianolin at a dose of 20 mg kg(-1), for 7 days in mice significantly reduced the alpha-naphthylisot hiocyanate-induced levels of alanine aminotransferase, aspartate aminotransferase and the total and direct bilirubins, and increased the bile flow (P<0.01). CONCLUSION: These findings suggest that the TIXS exhibits significant hepatoprotective effect in the liver damage model induced by alpha-naphthylisot hiocyanate. Its active constituents include swertiamarin and swertianolin.

Determination of swertianolin in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

A sensitive and rapid LC-MS/MS method has been developed and validated for quantifying swertianolin in rat plasma using rutin as an internal standard (IS). Following liquid-liquid extraction with ethyl acetate, chromatographic separation for swertianolin was achieved on a C18 column with a gradient elution using 0.1% formic acid as mobile phase A and acetonitrile as mobile phase B at a flow rate of 0.3 mL/min. The detection was performed on a tandem mass spectrometer using multiple reaction monitoring via an electrospray ionization source and operating in the negative ionization mode. The optimized mass transition ion pairs (m/z) for quantitation were 435.1/272.0 for swertianolin and 609.2/300.1 for IS. The lower limit of quantitation was 0.5 ng/mL within a linear range of 0.5-500 ng/mL. Intra-day and inter-day precision was less than 6.8%. The accuracy was in the range of -13.9 to 12.0%. The mean recovery of swertianolin was >66.7%. The proposed method was successfully applied in evaluating the pharmacokinetics of swertianolin after an oral dose of 50 mg/kg Swertia mussotii extract in rats.