[show abstract][hide abstract] ABSTRACT: Two new benzophenones were isolated from the leaves of Hypericum carinatum. Their structures were established on the basis of 2D NMR spectroscopic analyses and mass spectrometry as cariphenone A (6-benzoyl-5,7-dihydroxy-2,2,8-trimethyl-2H-chromene) (1) and cariphenone B (8-benzoyl-5,7-dihydroxy-2,2,6-trimethyl-2H-chromene) (2). Five known compounds, the phloroglucinol derivative uliginosin B (3), 1-eicosanol, sitosterol, stigmasterol, and campesterol, were also characterized. Compounds 1-3 were evaluated for their total antioxidant capacity through a total radical-trapping parameter assay. Only compound 1 showed moderate antioxidant activity, exhibiting inhibition of chemiluminescence similar to that of quercetin at the same concentration.
Journal of Natural Products 06/2005; 68(5):784-6. · 3.29 Impact Factor