Flavonoids isolated from the leaves of Melicope triphylla and their extracellular-superoxide dismutase-inducing activity

► We isolated two novel polymethoxyflavonoids from Melicope triphylla (Rutaceae). ► Four 7-O-prenyloxyflavonoids were evaluated for their antioxidant properties. ► The tested flavonoids induced the expression of EC-SOD in U937 cells. ► This is the first report of the natural flavonoids inducing EC-SOD expression.