Showing papers on "Flavanone published in 2006"
TL;DR: In this paper, seven different extracts, fractions and residues of Navel sweet orange (Citrus sinensis) peel were evaluated for their radical scavenging activity by the DPPH and luminol induced chemiluminescence methods.
456 citations
TL;DR: The database provides information on several varieties of citrus and eight flavanone compounds, including hesperidin and narirutin, which constitute the majority of flavonoids in citrus fruits such as sweet and sour oranges and their near relatives—tangerines/mandarins and tangelos.
250 citations
TL;DR: In this article, the authors developed a database for flavanones, the dominant flavonoid class in the genus citrus, and relevant scientific literature on flavonoids in grapefruit, lemons and limes was searched, abstracted, documented, standardized by taxons and units (mg/100 g).
247 citations
TL;DR: The functional expression in Escherichia coli of a plant P450 flavonoid 3', 5'-hydroxylase (F3'5'H) as a fusion protein with a P450 reductase is presented, opening the possibility of the future production of several other hydroxylated flavonoids molecules in E. coli.
165 citations
TL;DR: The combinatorial biosynthesis of the flavones and flavonols in E. coli is promising for the construction of a library of various flavonoid compounds and un-natural flavonoids in bacteria.
Abstract: (2S)-Flavanones (naringenin and pinocembrin) are key intermediates in the flavonoid biosynthetic pathway in plants. Recombinant Escherichia coli cells containing four genes for a phenylalanine ammonia-lyase, cinnamate/coumarate:CoA ligase, chalcone synthase, and chalcone isomerase, in addition to the acetyl-CoA carboxylase, have been established for efficient production of (2S)-naringenin from tyrosine and (2S)-pinocembrin from phenylalanine. Further introduction of the flavone synthase I gene from Petroselinum crispum under the control of the T7 promoter and the synthetic ribosome-binding sequence in pACYCDuet-1 caused the E. coli cells to produce flavones: apigenin (13 mg/l) from tyrosine and chrysin (9.4 mg/l) from phenylalanine. Introduction into the E. coli cells of the flavanone 3β-hydroxylase and flavonol synthase genes from the plant Citrus species led to production of flavonols: kaempferol (15.1 mg/l) from tyrosine and galangin (1.1 mg/l) from phenylalanine. The combinatorial biosynthesis of the flavones and flavonols in E. coli is promising for the construction of a library of various flavonoid compounds and un-natural flavonoids in bacteria.
144 citations
TL;DR: The flavonoid profile of the peel consisted of characteristic Citrus species flavanone rutinosides and neohesperosides derived from naringenin, eriodictyol, and hesperetin.
Abstract: Bergamot peel is an underutilized byproduct of the essential oil and juice-processing industry. As with other Citrus peels, it still contains exploitable components, such as pectins and flavonoids. Commercial glycoside hydrolases, specifically a combination of pectolytic and cellulolytic enzymes, solubilized a high percentage of the material (81.94%). The flavonoid profile of the peel consisted of characteristic Citrus species flavanone rutinosides and neohesperosides derived from naringenin, eriodictyol, and hesperetin. In addition, a number of minor flavanone and flavone glycosides, not found in orange and lemon peels, were identified. The majority of flavonoids were extracted in the two 70% v/v EtOH extractions. Processing this material clearly has economic potential leading to low environmental impact.
127 citations
TL;DR: The results indicate that flavonoid 3-O-glucosyltransferase activity is not essential for redirection from flavanol to anthocyanin formation in strawberry.
Abstract: Flavonoids are important secondary metabolites in strawberry as they fulfill a wide variety of physiological functions. In addition, they are beneficial for human health. Previous studies have shown for selected enzymes from the flavonoid pathway that flavonoid biosynthesis shows two peaks during fruit development. We provide optimized protocols for the determination of the activities of the key flavonoid enzymes: phenylalanine ammonia lyase, chalcone synthase/chalcone isomerase, flavanone 3-hydroxylase, dihydroflavonol 4-reductase, flavonol synthase, flavonoid 3-O-glucosyltransferase, and flavonoid 7-O-glucosyltransferase. Using these protocols we were able to demonstrate two distinct activity peaks during fruit ripening at early and late developmental stages for all enzymes with the exception of flavonol synthase. The first activity peak corresponds to the formation of flavanols, while the second peak is clearly related to anthocyanin and flavonol accumulation. The results indicate that flavonoid 3-O-glucosyltransferase activity is not essential for redirection from flavanol to anthocyanin formation in strawberry.
118 citations
TL;DR: In this paper, the authors used powder-XRD technique in combination with scanning and transmission electron microscopy to detect hydrogen bonds between polyvinylpyrrolidone (PVP) carbonyl groups and hydroxyl groups of both aglycones.
Abstract: Polyvinylpyrrolidone (PVP) and poly(ethylene glycol) (PEG) solid dispersion systems with flavanone glycosides, naringin and hesperidin, and their aglycones, naringenin and hesperetin, were prepared, using solvent evaporation method, to enhance their dissolution rates that may affect their bioavailability. Drug release of both flavanone glycosides and their aglycones was directly affected by the physical state of solid dispersions. Powder-XRD technique in combination with scanning and transmission electron microscopy revealed that PVP polymer formed amorphous nanodispersion systems with flavanone aglycones, while such systems could not be formed with their glycosides, which are bulkier molecules. Fourier transform infrared spectra suggest the presence of hydrogen bonds between PVP carbonyl groups and hydroxyl groups of both flavanone aglycones. These interactions prevent the crystallization of naringenin and hesperetin aglycones in PVP matrix. On the other hand, the ability of PEG carrier to form hydrogen bonds with flavanone glycosides or aglycones was limited, and as a result both flavanone glycosides and their aglycones remain in the crystalline form. For this reason, the solubility enhancement of PEG solid dispersions was lower than when PVP was used as drug carrier. At pH 6.8, the % release of naringenin and hesperetin from PVP/naringenin–hesperetin (80/20 w/w) solid dispersion was 100% while in PEG solid dispersions, it was not higher than 60–70%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 460–471, 2006
102 citations
TL;DR: The results showed that some bacteria considered to be responsible for bad odours at the armpit and feet levels, were destroyed at 200 microg ml-1 (MBC), a concentration sparing most of the useful saprophytic microflora.
87 citations
TL;DR: The antioxidative properties of five prenylated flavonoids, including new flavanone, from the root bark of Cudrania tricuspidata were examined against the ABTS, DPPH, and hydroxyl radicals.
Abstract: The antioxidative properties of five prenylated flavonoids, including new flavanone (2), from the root bark of Cudrania tricuspidata were examined against the ABTS, DPPH, and hydroxyl radicals. In most of the assays to determine their antioxidative properties, the ABTS activity was strongly correlated with DPPH because both methods are responsible for the same chemical property of hydrogen- or electron-donation to the antioxidant. On the other hand, the prenylated flavonoids (1-5) acted differently with both methods; namely, all the prenylated flavonoids strongly scavenged the ABTS radical (IC(50) 300 microM). Even though isolated 5,7,2',4',-tetrahydroxy-6,5'-diprenylflavanone (3) showed weak reducing power (746 mV) by cyclic voltammetry when compared to quercetin (394 mV), both had similar ABTS activity (IC(50) < 5 microM).
73 citations
TL;DR: Other interesting transformations include the formation of flavonoids through an ortho-quinone methide (o-QM) cycloaddition-oxidation sequence and regioselective β-glycosidations of several unprotected flavanones suggesting a likely synthesis of 2 from the aglycone 33.
TL;DR: Bioassay-guided fractionation of an EtOAc-soluble extract of the root bark of Erythrina mildbraedii, using an in vitro PTP1B inhibitory assay, resulted in the isolation of three new isoprenylated flavonoids, abyssinone-IV-4'-O-methyl ether, which may be considered as a new class of P TP1B inhibitors.
Abstract: Inhibition of protein tyrosine phosphatase-1B (PTP1B) has been proposed as a therapy for treatment of type-2 diabetes and obesity. Bioassay-guided fractionation of an EtOAc-soluble extract of the root bark of Erythrina mildbraedii, using an in vitro PTP1B inhibitory assay, resulted in the isolation of three new isoprenylated flavonoids, abyssinone-IV-4'-O-methyl ether (2), 7-hydroxy-4'-methoxy-3'-(3-hydroxy-3-methyl-trans-but-1-enyl)-5'-(3-methylbut-2-enyl)flavanone (3), and abyssinone-VI-4-O-methyl ether (6), along with six known flavonoids, abyssinone-V-4'-O-methyl ether (1), abyssinone-V (4), abyssinone-IV (5), sigmoidin E (7), 4'-hydroxy-5,7-dimethoxyisoflavone (8), and alpinumisoflavone (9). Compounds 1 and 2, 4-7, and 9 inhibited PTP1B activity, with IC50 values ranging from 14.8 +/- 1.1 to 39.7 +/- 2.5 microM. On the basis of the data obtained, flavanones and chalcones with isoprenyl groups may be considered as a new class of PTP1B inhibitors.
TL;DR: The lower concentration of flavanones in the TuB rats suggests that disease and more particularly cancer, may affect the bioavailability of flavonoids.
TL;DR: The effect of buffer systems containing mixtures of cyclodextrin with either sodium dodecyl sulfate or sodium cholate upon the chiral recognition of flavanones and flavanone-7-O-glycosides as well as the variation of the background electrolyte, and its influence on the resolution factor Rs was investigated.
Abstract: The stereoisomeric separation of several flavanones and flavanone-7-O-glycosides has been achieved with capillary electrophoresis by adding native cyclodextrins or cyclodextrin derivatives to the background electrolyte. As an alternative method, micellar electrokinetic chromatography with sodium cholate as a chiral surfactant has been used for the epimeric separation of two flavanone-7-O-glycosides. The effect of buffer systems containing mixtures of cyclodextrin with either sodium dodecyl sulfate or sodium cholate upon the chiral recognition of flavanones and flavanone-7-O-glycosides as well as the variation of the background electrolyte (concentration of buffer and surfactant, pH value, organic modifier), and its influence on the resolution factor Rs was investigated. Temperature- and pH-dependent enantiomerization or epimerization barriers of several flavanones (naringenin, homoeriodictyol) and flavanone-7-O-glycosides (naringin, neohesperidin, prunin, narirutin) in basic media (pH values of 9−11) have...
TL;DR: In this paper, a new drug delivery system for both flavanone glycosides and their aglycones based on solid-dispersion systems was presented, using PVP, PEG and mannitol as drug carrier matrices.
Abstract: Purposes of this paper were to prepare and study new drug delivery systems for both flavanone glycosides and their aglycones based on solid-dispersion systems. These compounds are poor water soluble drugs, so an enhancement of their dissolution is a high priority. Solid-dispersion systems were prepared using PVP, PEG and mannitol as drug carrier matrices. Characterizations of these dispersions were done by differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The glass transition (Tg) temperature of PVP was only recorded in the DSC thermograms of PVP solid-dispersions of both flavanone glycosides and their aglycones, while in case of PEG and mannitol solid-dispersions endotherms of both glycosides and aglycones were noticed with low peak intensity, indicating that high percent of drug is in amorphous state. The XRD patterns of all PVP solid-dispersions of aglycones show typical amorphous materials, but XRD patterns of their glycosides reveal the presence of crystalline material. However, in all solid dispersions shifts in Tg of PVP as well as Tm of PEG were observed, indicating the existence of some interactions between drugs and matrices. SEM and TEM microscopy revealed that PVP/aglycone flavanone compounds are nanodispersed systems while all the other solid dispersions are microcrystalline dispersions. The solubility of both flavanone glycosides and their aglycones was directly affected by the new physical state of solid dispersions. Due to the amorphous drug state or nano-dispersions in PVP matrices, the solubility was enhanced and found to be 100% at pH 6.8 in the nano-dispersion containing 20 mass% of aglycones. Also solubility enhancement was occurred in solid dispersions of PEG and mannitol, but it was lower than that of PVP nano-dispersions due to the presence of the drug compounds in crystalline state in both matrices.
TL;DR: Six flavonoids including two known and four novel compounds were successfully simultaneous purified by CCC and examined to inhibit human cancer cells' growth including A549, BEL-7402, SGC-7901, MCF-7, HT-29, K562 and A498 cell lines by MTT method in vitro.
TL;DR: In this paper, the effect of surface basicity of MgO on the heterogeneous synthesis of flavanone from benzaldehyde and 2′-hydroxyacetophenone was examined through a series of mgO samples modified with different anions.
Abstract: The effect of the surface basicity of MgO on the heterogeneous synthesis of flavanone from benzaldehyde and 2′-hydroxyacetophenone was examined through a series of MgO samples modified with different anions. CO 2 temperature programmed desorption (TPD) was used to characterize the basic properties of these samples. The results indicate that basic sites with different strengths exist on the MgO surface. Introduction of different anions completely eliminates the weak basic sites (i.e., those desorbing CO 2 in the 300–420 K range) and reduces substantially the number of medium strength sites (i.e., those desorbing CO 2 in the 420–650 K range). In contrast, no substantial effect was observed – with the exception of the chloride-treated sample – on the stronger basic sites (i.e., those desorbing CO 2 above 650 K). A strong correlation was observed between the number of basic sites of “medium” strength and the catalytic activity of these samples for the heterogeneous synthesis of flavanone. These sites are most likely involved in the activation of 2′-hydroxyacetophenone for the Claisen–Schmidt condensation with benzaldehyde, which represents the first step in the synthesis of flavanone.
TL;DR: The initial screening performed in this study enables the identification of compounds that exert significant effects on fibroblast function and show potential as starting material for pharmaceutical preparations targeted against various disorders centered around disturbed collagen metabolism.
Abstract: In this study, we discovered that flavonoids belonging to the subclasses: (flavanone, flavone, and flavonol) display differential effects on the synthesis of collagen in human dermal fibroblasts. At 80 μg/ml flavonoids quercetin-3,3′,4′, 5,7-pentahydroxyflavone, 3-methyl quercetin, and 7-hydroxyflavone significantly decreased the total protein concentration which was a direct consequence of their cytotoxic effect, while naringenin exhibited no effect on total collagen and total protein concentration. Quercetin-3,3′4′,7-tetramethyl ether, 4′-hydroxyflavanone, flavanone, and fisetin significantly decreased collagen concentration while morin, rutin, and chrysin increased collagen concentration without changing the overall protein concentration. The initial screening performed in this study enables the identification of compounds that exert significant effects on fibroblast function and show potential as starting material for pharmaceutical preparations targeted against various disorders centered around disturbed collagen metabolism.
TL;DR: Three-dimensional structure modeling showed that GbF3H had a jerry roll in the enzyme core consisted of β-sheet, a typical structure shared by all 2-oxoglutarate-dependent dioxygenases including F3Hs.
Abstract: Flavanone 3-hydroxylase (F3H) activity is necessary for the biosynthesis of flavonoids, the main ingredients of Gingko biloba extract. The full-length cDNA and genomic DNA sequences of F3H gene were isolated from G. biloba for the first time. The full-length cDNA of G. biloba F3H gene (designated as GbF3H) contained a 1071 bp open reading frame (ORF) encoding a 357-amino-acid protein with a calculated molecular weight of about 40 kDa and isoelectric point (pI) of 5.57. The genomic DNA analysis showed that GbF3H gene had three exons and two introns. The deduced GbF3H protein showed high identities to other plant F3Hs. The conserved amino acids ligating ferrous iron and residues participating in 2-oxoglutarate binding (R-X-S) were found in GbF3H at the similar positions like other F3Hs. Three-dimensional structure modeling showed that GbF3H had a jerry roll in the enzyme core consisted of β-sheet, a typical structure shared by all 2-oxoglutarate-dependent dioxygenases including F3Hs. Phylogenetic tree analysis revealed that GbF3H shared the same ancestor in evolution with other F3Hs and had a further relationship with other angiosperms species. Southern blot analysis indicated that GbF3H belonged to a multi-gene family. Transcription analysis revealed that GbF3H expressed in stem and leaf with the highest transcription level in leaf. The isolation and characterization of GbF3H gene will be helpful to further study the role of GbF3H gene in the biosynthesis of flavonoids in G. biloba.
TL;DR: In this article, a well-ordered hexagonally arranged mesopores were synthesized by one-pot co-condensation of tetraethoxysilane and aminopropyl-functionalized SBA-15 materials.
TL;DR: Two new flavanone glucosides were isolated from the branches and leaves of Viscum coloratum NAKAI (Loranthaceae) and showed potent albeit varied degrees of antioxidative activities and the structure-activity relationship is discussed.
Abstract: Two new flavanone glucosides, (2S)-homoeriodictyol 7,4′-di-O-β-D-glucopyranoside (4) and (2R)-eriodictyol 7,4′-di-O-β-D-glucopyranoside (5) were isolated from the branches and leaves of Viscum coloratum (KOMAR) NAKAI (Loranthaceae), along with three known flavanone glucosides: (2S)-homoeriodictyol 7-O-β-D-glucopyranoside (1), (2S)-eriodictyol 7-O-β-D-glucopyranoside (2), and (2S)-naringenin 7-O-β-D-glucopyranoside (3). The structures of these compounds were elucidated using spectroscopic methods. The antioxidant activities of these isolated compounds were evaluated by colorimetric methods based on their scavenging effects on hydroxyl radicals and superoxide anion radicals, respectively. All the compounds showed potent albeit varied degrees of antioxidative activities and the structure–activity relationship is discussed.
TL;DR: Three naturally occurring di-C-glycosylflavonoids, phloretin (dihydrochalcone), naringenin (flavanone), and apigenin (Flavone) bis-6,8-C -beta-D-glucopyranosides (4, 5, and 6), were synthesized in total yields of 52.3%, 53.5%, and 36.4%, respectively.
TL;DR: Close structural similarity of cyclohexanediones and some pyridine dicarboxylic acids to flavonoid substrates was identified and all compounds found to be active as inhibitors may prove useful for studying the reaction mechanisms and substrate specificities of various 2-ODDs.
TL;DR: The bioassay-guided fractionation of the MeOH extract of the root barks of Cudrania tricuspidata furnished three hepatoprotective compounds, gerontoxanthone A, cudraflavone B, gericudranin E, and isocudraxanthone K, a new compound, which showed moderate hepatoprotsective effect against tacrine-induced cytotoxicity in Hep G2 cells.
Abstract: The bioassay-guided fractionation of the MeOH extract of the root barks of Cudrania tricuspidata furnished three hepatoprotective compounds, gerontoxanthone A (2), cudraflavone B (4), gericudranin E (5), together with four prenylated xanthones, cudraxanthone B (3), isocudraxanthone K (6), cudraxanthone C (7), cudraxanthone H (8), and a prenylated flavanone, euchrestaflavanone C (1). Compounds 4 and 5 showed significant hepatoprotective effects with the EC50 values of 37.39±0.4 and 39.87±0.7 μM, respectively, and compound 2 showed moderate hepatoprotective effect with an EC50 value of 125.9±1.5 μM, against tacrine-induced cytotoxicity in Hep G2 cells. Silybin as positive control showed an EC50 value of 84.76±0.5 μM. Isocudraxanthone K (6) is a new compound.
TL;DR: In this paper, the first report of a highly selective transformation of flavanones to 3-bromoflavones or flavones by microwave irradiation of the corresponding flavanone reactants and Nbromosuccinimide (NBS) in the presence of a catalytic amount of 2,2′-azobis(isobutyronitrile) (AIBN).
Abstract: This paper presents the first report of a highly selective transformation of flavanones to 3-bromoflavones or flavones by microwave irradiation of the corresponding flavanone reactants and N-bromosuccinimide (NBS) in the presence of a catalytic amount of 2,2′-azobis(isobutyronitrile) (AIBN). The combination of good to excellent yields, shorter reaction time (10 min), and high levels of functional group compatibility make this an attractive synthetic approach to 3-bromoflavones and flavones.
TL;DR: Biotransformation kinetics indicated that the enzyme converted more than 80% of the apigenin, kaempferol, luteolin and quercetin substrates, which were added at concentration of 70 microM, into corresponding 7-methoxy compounds within 24 h.
TL;DR: In silico metabolic and toxicity study of the synthesized compounds were performed and the predicted result showed that the compound having hydroxyl functional group undergo sulfate and O-glucuronide conjugation reaction and methoxy derivatives undergo demethylation reaction.
Abstract: Flavones chemically are anthoxanthins, occur either in the free state or as glycosides associated with tannins (flavanoids). Flavanoids (derivatives of flavone) possess various pharmacological activities and due to its xanthine-oxidase enzyme inhibitory effect it also has superoxide-scavenging activities. A series of 2-phenyl-2,3-dihydrochromon-4-one derivatives (flavanone derivatives) were synthesized from chalcones by cyclization method and their activities were evaluated against some gram positive and gram-negative bacteria. IR, NMR and CHN analysis confirmed the structure of the synthesized compounds. The results of the antibacterial studies shows that compounds 2b, 2e, 2f and 2h possess activity against many bacterial strains. Among that the compound (2h) has remarkable activity against all strains viz. 25 microg/ml inhibitory concentration against S. aureus, S. sonnei, E. coli, S. typhimurium and V. cholerae. Compound 2f possess minimum inhibitory concentration of 200 microg/ml against E. coli and S. typhimurium and 25 microg/ml against S. sonnei, S. dysenteriae and V. cholerae. In silico metabolic and toxicity study of the synthesized compounds were performed and the predicted result showed that the compound having hydroxyl functional group undergo sulfate and O-glucuronide conjugation reaction and methoxy derivatives undergo demethylation reaction. The biologically active compounds are free of toxicity in oncogene, teratogen, sensitivity and immunotoxicity.
TL;DR: One new 1,3-diphenylpropane, viscolin, and one new flavanone, (2S)-7,4'-dihydroxy-5,3'-dimethoxyflavanone (2), together with thirty-nine known compounds, which included eleven known flavanones, two chromones, fourteen benzenoids, one inositol, two pyrimidines, four triterpenoids and five steroids, were isolated and characterized from Viscum coloratum.
Abstract: One new 1,3-diphenylpropane, viscolin (1), and one new flavanone, (2S)-7,4'-dihydroxy-5,3'-dimethoxyflavanone (2), together with thirty-nine known compounds, which included eleven known flavanones, two chromones, fourteen benzenoids, one inositol, two pyrimidines, four triterpenoids and five steroids, were isolated and characterized from Viscum coloratum. Structures of new compounds were determined by spectral analysis. Among them, viscolin (1) showed the most significant inhibition on superoxide anion generation by human neutrophils in response to fMLP (formyl-L-methionyl-L-leucyl-L-phenylalanine).
TL;DR: Flavanone and 6-hydroxyflavanone were subjected to transformation by means of Aspergillus niger strains and the biotransformation resulted in reduction of the carbonyl group and dehydrogenation at C-2 and C-3.
Abstract: Flavanone (1) and 6-hydroxyflavanone (2) were subjected to transformation by means of Aspergillus niger strains (one wild and three UV mutants). For both substrates the biotransformation resulted in reduction of the carbonyl group (products 5 and 7) and dehydrogenation at C-2 and C-3 (3 and 8). Additionally, for flavanone (1) reduction of C-4 together with hydroxylation at C-7 (6) and dehydrogenation at C-2, C-3 along with hydroxylation at C-3 (4) were observed.
TL;DR: A new flavanone glycoside, butin 4′-O-(2″-O-β-D-apiofuranosyl)-β -D-glucopyranoside (1), together with liquiritin (2), liquidiritin apioside (3), isoliquiritn apiosides (4), davidioside(5), quercetin...
Abstract: A new flavanone glycoside, butin 4′-O-(2″-O-β-D-apiofuranosyl)-β-D-glucopyranoside (1), together with liquiritin (2), liquiritin apioside (3), isoliquiritn apioside (4), davidioside (5), quercetin ...