Studies on the Constituents of Swertia japonica. II. Isolation. and Structure of New Flavonoid, Swertiajaponin.

Abstract

1. Swertiajaponin, C₂₂H₂₂O₁₁, m.p. 265° (decomp.), was newly isolated from the whole herb of Swertia japonica MAKINO (Gentianaceae), and identified as 6-C-β-D-glucopyranosylluteolin-7-methylether. 2. Iso-swertiajaponin, C₂₂H₂₂O₁₁, m.p. 258∼261° (decomp.) was obtained by the acidtreatment of swertiajaponin, and formulated as 8-C-β-D-glucopyranosylluteolin-7-methylether. 3. At the same time, it was found that they were interconvertible into each other by boiling with mineral acids, reminiscent of the interrelationship between swertisin and isoswertisin.