Studies on the Constituents of Swertia japonica. IV.1) Isolation and Structure of Xanthones2)

Abstract

The chemical constituents of Swertia japonica MAKINO were studied. Three kinds of new natural xanthones, named norswertianin (I), swertianin (III) and methylswertianin (V), were isolated from the whole herb of this plant, together with desmethylbellidifolin (X) and bellidifolin (XII). I was identified as 1,3,7,8-tetrahydroxyxanthone. The direct isolation of I from natural source has never been published, although it has derived from decussatin (VII) and/or swertinin (VIII) by demethylation. The structure of III and V were shown to be l,7s8-trihydroxy-3-methoxyxanthone and l,8-dihydroxy-3,7-dimethoxyxanthone, respectively. At the same time, “swertianol” was revised the structure to 1,5,8-trihydroxy-3-methoxyxanthone, which was proved to be identical with bellidifolin. © 1969, The Pharmaceutical Society of Japan. All rights reserved.