Xanthine Oxidase Inhibition by Aqueous Extract of Limonium brasiliense (Plumbaginaceae)

Limonium brasiliense (Boiss.) Kuntze (Plumbaginaceae) is a medicinal plant that is popularly used in the folk medicine. In this study, we examined xanthine oxidase (XO) inhibitory activity of the aqueous fraction of Limonium brasiliense extract and its polar bioactive constituents using the enzymatic hypoxanthine (HX)–XO system in vitro. Seven active compounds isolated from the aqueous extract proved to be strong XO inhibitors. Prodelphinidin B1-3,3′-digallate (1) showed the most potent inhibitory activity with an IC50 value of 6.61 µM, comparable to allopurinol. This study provides basis for the potential use of the aqueous fraction of L. brasiliense against hyperuricemia, displaying potent XO inhibitory activity with an IC50 value of 48.3 µg/mL. This inhibitory effect is compatible with the presence of (1) in this extract.