| Summary: | The chemical study of the extracts from leaves and stems of <em>Ouratea ferruginea</em> allowed the identification of a new isoflavone, 5-hydroxy-7,3′4′5′-tetramethoxyisoflavone, and twenty two known compounds, including friedelin, 3β-friedelinol, lupeone, a mixture of sitosterol, stigmasterol and campesterol, sitosteryl- and stigmasteryl-3-<em>O</em>-b-D-glucopyranosides, 5,4′-dihydroxy-7,5′,3′-trimethoxyisoflavone, 5,4′-dihydroxy-7,3′-di-methoxyisoflavone (7,3′-di-<em>O</em>-methylorobol), 5,7,4′-trihydroxy-3′,5′-dimethoxyisoflavone (piscigenin), 2<em>R</em>,3<em>R</em>-epicatechin, syringic acid, 2,6-dimethoxybenzoquinone, 2,6-dimethoxyhydroquinone, syringic and ferulic aldehyde, a mixture of vanillic acid, 1-hydroxy-2-methoxy-4-(1<em>E</em>-3-hydroxy-1-propenyl)-benzene and 3,5-dimethoxy-4-hydroxy-dihydrocinamaldehyde, besides amenthoflavone and 7-<em>O</em>-methylamenthoflavone (sequoiaflavone) which are considered as chemotaxonomic markers of <em>Ouratea</em>. The structures were identified by IR, <sup>1</sup>H- and <sup>13</sup>C-NMR and GC-MS, HPLC-MS, besides comparison with literature data. The inhibitory effects of 5,4′-dihydroxy-7,5′,3′-trimethoxyisoflavone, 7,3′-di-<em>O</em>-methylorobol, piscigenin and 7-<em>O</em>-methylamenthoflavone on cytochrome P450-dependent 7-ethoxycoumarin <em>O</em>-deethylase (ECOD) and glutathione <em>S</em>-transferase (GST) were evaluated <em>in vitro</em>. The 5,4′-dihydroxy-7,5′,3′-trimethoxy-isoflavone was the best inhibitor, inhibiting almost 75% of GST activity. Sequoiaflavone was the most potent inhibitor, inhibiting ECOD assay in 75%. These activities allow us to consider both these flavonoids as potential anticancer and chemopreventive agents.
|
|---|