Antioxidant C-glucosylxanthones from the leaves of Arrabidaea patellifera.

Chemical investigation of the methanol extract from the leaves of Arrabidaea patellifera, a Bignoniaceae from Panama, afforded mangiferin, isomangiferin, and six new derivatives (3'-O-p-hydroxybenzoylmangiferin, 3'-O-trans-coumaroylmangiferin, 6'-O-trans-coumaroylmangiferin, 3'-O-trans-cinnamoylmangiferin, 3'-O-trans-caffeoylmangiferin, and 3'-O-benzoylmangiferin). All these compounds had antioxidant and radical-scavenging activities, and four of them were relatively active in vitro against Plasmodium falciparum. The structures were determined by spectrometric and chemical methods, including 1D and 2D NMR experiments and MS analysis.