Antinociceptive activity of 13,118-binaringenin, a biflavonoid present in plants of the guttiferae

This paper describes the antinociceptive action of 13,II8-binaringenin (GB- 1a), a biflavonoid isolated from Clusia columnaris and present in several p lants of the family Guttiferae, in a writhing test and a formalin test. It was found that it exhibits potent and dose-related antinociceptive action i n both experimental models, with ID50 values of 22 mu mol/kg against the wr ithing test and 28 mu mol/kg against the second phase of the formalin test. It was more potent than some well-known analgesic drugs used as reference. Based on a hot-plate test its mechanism of action seems to be unrelated wi th the opioid receptors.