in vitro and in vivo antioxidant potentials of alchornea floribunda leaf extract, fractions and isolated bioactive compounds

objective: alchornea floribunda leaves are widely used in ethnomedicine for the management of immuno-inflammatory disorders. we investigated the in vivo and in vitro antioxidant activity of the leaf extract, fractions and isolated compounds of a. floribunda.materials and methods: the ethyl acetate fraction of the methanol leaf extract was subjected to several chromatographic separations to isolate compounds 1-4. the structures of the isolated compounds were elucidated by a combination of 1d and 2d nmr and mass spectrometry. oxidative stress was induced with carbon tetrachloride (ccl4). further analysis on the isolated phenolic compounds were done using 2,2-diphenyl-1-picrylhydrazyl (dpph), ferric reducing antioxidant power (frap) and hydrogen peroxide scavenging activity tests.results: the ethyl acetate fraction at 200 mg/kg produced significant (p<0.05) elevations of catalase enzyme activity and a significant (p<0.05) reduction in serum malondialdehyde. the chemical investigation of the ethyl acetate fraction led to the isolation of three flavans, (-) cathechin (1), (-) epicathechin (2), (+) epicathechin (3) and a flavanone, 2r, 3r dihydroquercitin (4). in hydrogen peroxide scavenging assay, (-) epicathechin exhibited an ec50 value of 8 μg/ml, similar to the standard ascorbic acid (ec50 = 8 μg/ml). (-) epicathechin showed scavenging of dpph radical with ec50 value of 19 μg/ml while in the frap assay, it had ec50 value of 46 μg/ml which was lower than that of the standard, ascobic acid (ec50 = 66 μg/ml).conclusion: the medicinal uses of a. floribunda may be due to the antioxidant activities of its phenolic compounds.