Inhibition of histamine-induced gastric secretion by flavone-6-carboxylic acids

Twenty-five flavone-6-carboxylic acids were synthesized and tested as to their ability to inhibit histamine-induced gastric acid secretion in the rat. 3-Isopropoxy-4'-methoxyflavone-6-carboxylic acid (41) showed consistent oral activity while being devoid of any other noteworthy pharmacological effects. In vitro, this compound was found to be inactive as a histamine H2 antagonist, and its mode of action remains unknown.