Studies on the Constituents of Swertia japonica. V. : On the Xanthone Constituents of the Plants of Swertia spp.

We previously reported that norswertianin (I), swertianin (II), methylswertianin (IV), desmethylbellidifolin (VI), and bellidofolin (VII) were isolated from the whole herb of Swertia japonica MAKINO (Gentianaceae).1) Besides these compounds, methylbellidifolin (IX) has now been isolated and identified. At the same time, xanthone constituents were examined in six different kinds of Swertia SPP., the results are shown in Table II. A C-glucoside of Swertia chirata BUCH.-HAM. was identified as mangiferin (XI) from its physical properties and its ability to give norathyriol (XII) by action of hydriodic acid. In addition, the "swertianolin" structure was revised as being now a 1-O-glucoside of bellidifolin (X).