Anti-ulcer effect of isoprenyl flavonoids. II. Synthesis and anti-ulcer activity of new chalcones related to sophoradin

To investigate the anti-ulcer activity of the isoprenyl chalcone, sophoradin, which is present in a Chinese crude drug, Guang-dou-gen (the root of Sophora subprostrata), 30 related chalcones (1-30) were newly synthesized by condensation between substituted acetophenones and benzaldehydes, and their anti-ulcer activities were examined using Shay's pylorus-ligated rats, and water-immersed and restraint stress rats. Twenty-seven chalcones were substituted with isoprenyl or isoprenyloxyl groups and two with geranyloxyl groups (13, 30), with or without a carboxymethoxyl group, and one chalcone was substituted with allyloxyl group (14). All the chalcones were found to be effective by both methods. Several chalcones (2, 3, 8, 10, 11, 12, 15, 17, 22), each having more than one isoprenyloxyl group, exhibited high inhibitory ratios by both methods. In particular, 2', 4'-dihydroxy-3'-(3-methyl-2-butenyl)-4-(3-methyl-2-butenyloxy) chalcone (2), 2'-hydroxy-4, 4'-bis (3-methyl-2-butenyloxy) chalcone (10), and 2'-carboxymethoxy-4, 4'-bis (3-methyl-2-butenyloxy) chalcone (15) exhibited very high inhibitory ratios (70-100%) by both methods, and were as potent as sophoradin.