Antioxidant activity of Mitragyna rotundifolia

Antioxidant activities of different extracts of Mitragyna rotundifolia Kuntze were evaluated by DPPH,FRAP and ABTS assay.The results were compared with those of positive controls PG,BHA and BHT.In six extracts of the leaves and barks,ethyl acetate extract from leaves had the highest DPPH and ABTS free radical scavenging activity(IC50=2.24 mg/L and IC50=1.165 mg/L respectively) which was higher than that of BHA(IC50=3.43 mg/L and IC50=1.675 mg/L respectively) and BHT(IC50=18.79 mg/L and IC50=4.555 mg/L respectively);The n-butanol extract from leaves exhibited the highest ferric reducing antioxidant power with FRAP value of 1 395.94 μmol TE/g,the n-butanol extract from barks(FRAP value=1 275.43 μmol TE/g) was slightly lower than that of the n-butanol extract from leaves,and both of them had ferric reducing antioxidant power higher than that of BHT(the FRAP value=238.11 μmol TE/g),lowered than that of PG(FRAP value=5 159.97 μmol TE/g) and BHA(FRAP value=2 573.96 μmol TE/g).Results showed that ethyl acetate extract and the n-butanol extract from leaves and barks of M.rotundifolia had high antioxidant activities,and the antioxidant activities of extract from leaves was higher than that from barks.The novelty of this work has been confirmed in Technology Novelty Search Report No.CX 2008007 provided by the library of Henan University on August 25,2008.