Studies on the Constituents of Swertia japonica.I. On the Structures of Swertisin and Isoswertisin

Abstract

Swertisin, C22H22O10, m. p. 243[degree] (decomp. ), was isolated in a pure state from the whole plant, Swertia japonica (Gentianacea), and identified as 6-C-[beta]-D-glucopyranosylgenkwanin. Isoswertisin, C22H22O10, m. p. 295[degree] (decomp. ), was obtained by the acid-treatment of swertisin, and for-mulated as 8-C-[beta]-D -glucopyranosylgenkwanin. At the same time, it was found that they were interconvertible with each other, reminis-cent of the relationship between vitexin and isovitexin.