Xanthine oxidase inhibitory activity of paraguayan myrtaceae

Abstract Nineteen Myrtaceae collections belonging to 15 species, 12 of which are used in Paraguayan folk medicine, were assayed for inhibitory activity towards the enzyme xanthine oxidase. Most leaf and stem extracts were active showing IC 50 values ranging from 3.0 to 50 μg/ml. The reported activities support existing ethnobotanical data concerning their use for the treatment of gout.