XANTHONES FROM HYPERICUM-JAPONICUM AND HYPERICUM-HENRYI

From the aerial part of Hypericum japonicum, one new xanthone glycosid e, 1,5-dihydroxyxanthone-6-O-beta-D-glucoside, one novel dimer xanthon e, bijaponicaxanthone, and the first natural prenylated xanthone, 1,3, 5,6-tetrahydroxy-4-prenylxanthone, were isolated together with the fou r known xanthones, 1,5,6-trihydroxyxanthone, isojacereubin, 6-deoxyiso jacareubin and dihydro-1,5,6-trihydroxy-4',4',5'-tri-methylfurano (2', 3':4,5) xanthone. Five previously known xanthones, kielcorin, cadensin , 1,7,-dihydroxyxanthone, 1,5-dihydroxy-4-methoxyxanthone and 1,2,5-tr ihydroxyxanthone were also found in the dichoromethane extract of the stems and leaves of H. henryi. Their structures were elucidated by spe ctroscopic and chemical methods. Some of the compounds from H. japonic um were found to exert an interesting coagulant activity in an in vitr o test. The chemotaxonomic value of xanthones is discussed briefly. (C ) 1998 Elsevier Science Ltd. All rights reserved.