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Antioxidant Activity of Isoflavones and Biflavones Isolated from Godoya antioquiensis

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Antioxidative Wirkung von Biflavonen und Isoflavonen aus Godoya antioquiensis Zwei Biflavone, Ochnaflavon (1) und 2'',3''-Dihydroochnaflavon (2), und zwei Isoflavone, 5,7,4'-Trihydroxy-3',5'-dimethoxyisoflavone (Piscigenin) (3) und 5,4'-Dihydroxy-7,3',5'-trimethoxyisoflavone (4), ein erstmals beschriebener Naturstoff, wurden aus Blättern von Godoya antioquiensis (Ochnaceae) isoliert. Die Strukturaufklärung erfolgte an Hand spektraler Daten und durch Vergleich mit Werten aus der Literatur. Die Radikalfänger-Wirkung der isolierten Substanzen wurde im NBT(Nitroblau-Tetrazolium)/Hypoxanthin-Superoxid- und im ·OH/Luminol-Chemilumineszenz-Assay gemessen. Die isolierten Isoflavone zeigten starke Hydroxyl-Radikalfänger-Aktivität und mäßige Inhibition des Superoxid-Anions, während die beiden Biflavone im Superoxid-Anion-Test inaktiv waren und eine leichte Hydroxyl-Radikalfänger-Aktivität aufwiesen.
... The chromatographic procedure with the extracts of Ouratea ferruginea afforded twenty three known compounds. Friedelin (1) [8], 3β-friedelinol (2) [9], a mixture of sitosterol (4), stigmasterol (5) and campesterol (6) [10], a mixture of sitosteryl-3-O-β-D-glucopyranoside (7) and stigmasteryl-3-O-β-D-glucopyranosides (8) [10], 5,4′-dihydroxy-7,5′,3′-trimethoxyisoflavone (9) [11], 7,3′-di-Omethylorobol (10) [12], piscigenin (11) [13], a mixture of 5-hydroxy-7,3′,4′,5′-tetramethoxyisoflavone (12) and (9), syringic aldehyde (16) [14], 2,6-dimethoxyhydroquinone (17) [15], ferulic aldehyde (18) [16], the mixture of vanillic acid (19), 1-hydroxy-2-methoxy-4-(1E-3-hydroxypropenyl)benzene (20) and 3,5-dimethoxy-4-hydroxydihydrocinamaldehyde (21) and 2,6-dimethoxybenzoquinone (23) [15], were identified from the stems extracts and a mixture of triterpenes, friedelin (1), 3β-friedelinol (2) and lupeone (3) [8], the steroids mixture sitosterol (4), stigmasterol (5) and campesterol (6) [10], 2R,3R-epicatechin (13) [17], amenthoflavone (14) [18], sequoiaflavone (15) [18] and syringic acid (22), from the leaves extracts. The structures of the compounds were proposed by 1 H-and 13 C-NMR and CD spectral data analysis and comparison with the literature data [8][9][10][11][12][13][14][15][16][17][18], including HPLC and GC-MS analysis. ...
... Friedelin (1) [8], 3β-friedelinol (2) [9], a mixture of sitosterol (4), stigmasterol (5) and campesterol (6) [10], a mixture of sitosteryl-3-O-β-D-glucopyranoside (7) and stigmasteryl-3-O-β-D-glucopyranosides (8) [10], 5,4′-dihydroxy-7,5′,3′-trimethoxyisoflavone (9) [11], 7,3′-di-Omethylorobol (10) [12], piscigenin (11) [13], a mixture of 5-hydroxy-7,3′,4′,5′-tetramethoxyisoflavone (12) and (9), syringic aldehyde (16) [14], 2,6-dimethoxyhydroquinone (17) [15], ferulic aldehyde (18) [16], the mixture of vanillic acid (19), 1-hydroxy-2-methoxy-4-(1E-3-hydroxypropenyl)benzene (20) and 3,5-dimethoxy-4-hydroxydihydrocinamaldehyde (21) and 2,6-dimethoxybenzoquinone (23) [15], were identified from the stems extracts and a mixture of triterpenes, friedelin (1), 3β-friedelinol (2) and lupeone (3) [8], the steroids mixture sitosterol (4), stigmasterol (5) and campesterol (6) [10], 2R,3R-epicatechin (13) [17], amenthoflavone (14) [18], sequoiaflavone (15) [18] and syringic acid (22), from the leaves extracts. The structures of the compounds were proposed by 1 H-and 13 C-NMR and CD spectral data analysis and comparison with the literature data [8][9][10][11][12][13][14][15][16][17][18], including HPLC and GC-MS analysis. The structures are shown in Figure 1. ...
... 5,4′-Dihydroxy-7,3′5′-trimethoxyisoflavone (9), 7,3′-di-O-methylorobol (10), piscigenin (11), and sequoiaflavone (15) were accurately weighed. Solutions were prepared at a concentration of 8 mg/mL using DMSO as a solvent. ...
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The chemical study of the extracts from leaves and stems of Ouratea ferruginea 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-O-b-D-glucopyranosides, 5,4'-dihydroxy-7,5',3'-trimethoxyisoflavone, 5,4'-dihydroxy-7,3'-di-methoxyisoflavone (7,3'-di-O-methylorobol), 5,7,4'-trihydroxy-3',5'-dimethoxyisoflavone (piscigenin), 2R,3R-epicatechin, syringic acid, 2,6-dimethoxybenzoquinone, 2,6-dimethoxyhydroquinone, syringic and ferulic aldehyde, a mixture of vanillic acid, 1-hydroxy-2-methoxy-4-(1E-3-hydroxy-1-propenyl)-benzene and 3,5-dimethoxy-4-hydroxy-dihydrocinamaldehyde, besides amenthoflavone and 7-O-methylamenthoflavone (sequoiaflavone) which are considered as chemotaxonomic markers of Ouratea. The structures were identified by IR, (1)H- and (13)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-O-methylorobol, piscigenin and 7-O-methylamenthoflavone on cytochrome P450-dependent 7-ethoxycoumarin O-deethylase (ECOD) and glutathione S-transferase (GST) were evaluated in vitro. 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.
... Cardiovascular consequences of excessive hydroxyl radical production in diabetic nephropathy may be explained in terms of their modification of fibrinogen molecule that becomes deposited in kidneys in the form of fibrin-like aggregates [43]. Protective effect against hydroxyl radical-induced damage in biological systems has been documented by the use of natural polyene and polyphenol class of substances, such as flavonoids, present mostly in fruits and vegetables [44,45]. Also, hydroxyl radicals scavenging of double bonds present in quercetin may explain its beneficial effects on the modification of LDL molecule [46], similarly to the action of phenolic compounds in virgin olive [47]. ...
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