- Labdane diterpenes and flavonoids from Leonurus japonicus
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Chemical investigation of the aerial part of Leonurus japonicus led to the isolation and characterization of a new labdane-type diterpene, named 3α-acetoxy-15-O-methylleopersin C (3), and a new acylated rutin derivative, named 2?-syringylrutin (9), along with seven known compounds, including a labdane-type diterpene and six flavonoids. The structures of the new compounds were established by spectroscopic methods.
- Seo, Hyun Kyu,Kim, Ju Sun,Kang, Sam Sik
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- READILY WATER-SOLUBLE ISOQUERCITRIN COMPOSITION
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Disclosed is a method for improving the solubility of isoquercitrin in water. Also disclosed is a readily water-soluble isoquercitrin composition which has improved solubility in water due to the method. Specifically disclosed is a method for preparing an isoquercitrin inclusion product, which comprises including isoquercitrin in γ-cyclodextrin in the proportion of 2 to 10 mol of γ-cyclodextrin to 1 mol of isoquercitrin.
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- Recovery of isoquercetin from bioflavanoid pastes
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The invention relates to a method for recovering high-purity isoquerectin from bioflavonoid pastes, that is from mother-liquor residues which are produced during the recovery of flavonoids, by extraction with a solvent mixture of methyl acetate and water.
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Page column 3-4
(2008/06/13)
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- Pharmaceutical compounds for treating copd
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Use of an MPO inhibitor for the treatment of COPD.
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- Ume extract having medicinal effects and compositions containing the same
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Extracts are prepared from a leaf and a stem of ume, a kernel of ume, and an ume flower, using methanol in an amount of 5 times the volume thereof. These extracts have anti-oxidation action, gastric mucosa injury inhibiting action, aldose reductase inhibiting action, blood glucose level elevation inhibiting action, platelet agglutination accelerating action, alcohol absorption inhibiting action, anti-inflammatory action, and the like.
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- Reduction potentials of flavonoid and model phenoxyl radicals. Which ring in flavonoids is responsible for antioxidant activity?
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Model phenoxyl and more complex flavonoid radicals were generated by azide radical induced one-electron oxidation in aqueous solutions. Spectral, acid-base and redox properties of the radicals were investigated by the pulse radiolysis technique. The physicochemical characteristics of the flavonoid radicals closely match those of the ring with the lower reduction potential. In flavonoids which have a 3,5-dihydroxyanisole (catechins), or a 2,4-dihydroxyacetophenone (hesperidin, rutin, quercetin)-like A ring and a catechol- or 2-methoxyphenol-like B ring, the antioxidant active moiety is clearly the B ring [reduction potential difference between the model phenoxyls is ΔE(A-B ring models) > 0.1 V]. In galangin, where the B ring is unsubstituted phenyl, the antioxidant active moiety is the A ring. Even though the A ring is not a good electron donor, E7, > 0.8/NHE V, it can still scavenge alkyl peroxyl radicals, E7, = 1.06 V, and the Superoxide radical, E7 > 1.06 V. Quercetin is the best electron donor of all investigated flavonoids (measured E10.8 = 0.09 V, and calculated E7 = 0.33 V). The favourable electron-donating properties originate from the electron donating O-3 hydroxy group in the C ring, which is conjugated to the catechol (B ring) radical through the 2,3-double bond. The conjugation of the A and B rings is apparently minimal, amounting to less than 2.5% of the substituent effect in either direction. Thus, neglecting the acid-base equilibria of the A ring, and using those of the B ring and the measured values of the reduction potentials at pH 3,7 and 13.5, the pH dependence of the reduction potentials of the flavonoid radicals can be calculated. In neutral and slightly alkaline media (pH 7-9), all investigated flavonoids are inferior electron donors to ascorbate. Quercetin, E7 = 0.33 V, and gallocatechins, E7 = 0.43 V, can reduce vitamin E radicals (assuming the same reduction potential as Trolox C radicals, E7 = 0.48 V). Since all investigated flavonoid radicals have reduction potentials lower than E7 = 1.06 V of alkyl peroxyl radicals, the parent flavonoids qualify as chain-breaking antioxidants in any oxidation process mediated by these radicals.
- Jovanovic, Slobodan V.,Steenken, Steen,Hara, Yukihiko,Simic, Michael G.
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p. 2497 - 2504
(2007/10/03)
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- A FLAVONOL TRIGLYCOSIDE FROM BACCHARIS THESIOIDES
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Five flavonols have been isolated from the aerial parts of Baccharis thesioides.On the basis of spectroscopic analysis the structure of a new flavonol triglycoside has been elucidated as quercetin 3-O-2)α-L-rhamnopyranosyl (1->6)>-β-D-glucopyranoside.Four known flavonols were identified as rutin, hyperoside, isoquercetin and quercetin.
- Liu, Yong-Long,Timmermann, Barbara N.,Hoffmann, Joseoh J.,McLaughlin, Steven P.
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p. 1549 - 1551
(2007/10/02)
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