Phytochemical analysis and bioactivities of Swertia mussotii Franch, a tibetan traditional medicinal plant

The herbal medicine of Gentianaceae known under the common name “zangyinchen” are well- known and used in Tibetan traditional medicine for diabetes, hepatitis, and hepatobaliary diseases. Swertia mussotii Franch is one of the most widely used species in Tibet region. Ethanol extracts of S. mussotii were partitioned successively into petroleum ether fraction, ethyl acetate fraction (EAF) and butanol fractions (BF). Eighteen compounds were obtained from the two active fractions using bioassay-guided isolation, EAF and BF, including seven xanthones, four iridoids, two flavonoids, three phenolic acids, an alkaloid and a coumarin. The hepatoprotective activities of EAF and BF were assayed on CCl₄-injured HL7702 hepatocytes in vitro respectively at four different concentrations: 10µg/ml, 1 µg/ml,10^-1 µg/ml, and 10^-2 µg/ml. The hepatoprotective profiles were evaluated by assays from hepatocyte morphology, hepatocytes viability, and enzyme concentration of AST, ALT, LDH and MDA in cell culture. The antioxidant activities of compounds were evaluated by DPPH assay, along with four xanthones and an iridoid showing high activities. The EAF and BF were evaluated for the inhibition on α-glucosidase in vitro. The IC₅₀ values were 1.48 and 1.52 mg/mL compared to 1.24 mg/mL of acarbose (a positive control). The results support the Tibetan ethnomedicinal usage of S. mussotii. Acknowledgment: financial support by project of NSFC-81373765, SEAC-12ZYZ019, NCET-12 – 0578 and “111”-B08044.