Isolation of biflavonoids with analgesic activity from Rheedia gardneriana leaves

Some phytoconstituents present in the R. Gardneriana Pl. Tr. leaves, a Brazilian medicinal plant, were isolated by column chromatography. Their preliminary analgesic effects were evaluated against formalin-induced pain in mice. The results demonstrated that four biflavonoids, identified as volkensiflavone, GB-2 a, fukugetin and fukugeside are the main active components of the ethyl acetate fraction. Such compounds exhibited significative analgesic activity in relation to the second phase (inflammatory pain) of the formalin test, suggesting that they are the compounds responsible for the pharmacological effects previously observed for the hydroalcoholic extract of this plant.