Identification de xanthones et de nouveaux arabinosides de C-glucosides flavoniques dans Swertia perennisL.

Identification of xanthones and new arabinosides of flavone C-glucosides from Swertia perennis L. – Seven tetraoxygenated xanthones [1,3,7,8-tetrahydroxy-xanthone ( 1 ); 1,8-dihydroxy-3,7-dimethoxy-xanthone ( 2 ); 1,7-dihydroxy-3,8-dimethoxy-xanthone ( 3 ); 1-hydroxy-3,7,8-trimethoxy-xanthone ( 4 ); 3,7,8-trihydroxy-xanthone-xanthone-1-0-β-glucoside ( 5 ); 3,7,8-trimethoxy-xanthone-1-0-primeveroside ( 6 ); 8-hydroxy-3,7-dimethoxy-xanthone-1-0-primeveroside ( 7 )] have been isolated chromatographically, using polyamide columns, from roots of Swertia perennis L . From leaves and stems of the same plant, six xanthones [1,5,8-trihydroxy-3-methoxy-xanthone ( 8 ); 1,5-dihydroxy-3-methoxy-xanthone-8-0-β-glucoside ( 9 ); mangiferin ( 10 ); 1 ; 4 ; 5 ] and four flavone C-glycosides [iso-orientin ( 11 ); isovitexin ( 12 ); iso-orientin-6″-arabinoside ( 13 ); isovitexin-6″-arabinoside ( 14 )] have also been isolated. Among these compounds, 7 , 13 and 14 were not encountered before in nature. In the last two compounds, the position of arabinose on the C-glucoside moiety of the flavone was established by ¹³C-NMR. spectroscopy.