Antioxidant Activity and Antioxidant Mechanism of Brazilin and Neoprotosappanin from Caesalpinia sappan Lignum

The compounds, brazilin and neoprotosappanin, have been isolated from Caesalpinia sappan Lignum. The structures were charaterized by NMR spectra. The antioxidant activity of brazilin and neoprotosappanin were evaluateded by using free radical scavenging assays, namely 1,1'-diphenyl-2-picrylhydrazyl. The IC50 values of brazilin and neoprotosappanin are 0.067 and 0.375 mu g/mL, respectively, much higher than the IC50 of vitamin C, 0.542 mu g/mL. The result shows that brazilin and neoprotosappanin possess powerful antioxidant activity, which can be used as function-rich antioxidants and whose application promising are very extensive.