Bioactive flavone dimers from Ouratea multiflora (Ochnaceae)

Abstract

Chromatographic fractionation of the organic extract from leaves of Ouratea multiflora afforded the flavone dimers heveaflavone, amentoflavone-7′, 4‴-dimethyl eter, podocarpusflavone-A and amentoflavone. Their structures were elucidated from spectral data, including 2D-NMR experiments of the natural substances. Biological activities of all isolates were evaluated, using antimicrobial assay against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, cytotoxicity assay against mouse lymphoma (L5178) and KB cell lines, TLC screening for acetylcholinesterase inhibitors and antioxidant activity measured by DPPH test.