Showing papers on "Flavanone published in 2002"
TL;DR: All the isolated compounds exhibited DPPH radical scavenging activity: quercetin derivatives showed the strongest action, while the flavanone 8-hydroxy-naringenin and kaempferol 3-O-alpha-rhamnoside had the lowest.
522 citations
TL;DR: Comparison of flavonoid profiles and gene expression data between tomato leaves and fruit indicates that the absence of anthocyanins in LC/C1 fruit is attributable primarily to an insufficient expression of the gene encoding flavanone-3′5′-hydroxylase, in combination with a strong preference of the tomato dihydroflavonol reductase enzyme to use the Flavonoid reaction product dihydromyricetin as a substrate.
Abstract: Flavonoids are a group of polyphenolic plant secondary metabolites important for plant biology and human nutrition. In particular flavonols are potent antioxidants, and their dietary intake is correlated with a reduced risk of cardiovascular diseases. Tomato fruit contain only in their peel small amounts of flavonoids, mainly naringenin chalcone and the flavonol rutin, a quercetin glycoside. To increase flavonoid levels in tomato, we expressed the maize transcription factor genes LC and C1 in the fruit of genetically modified tomato plants. Expression of both genes was required and sufficient to upregulate the flavonoid pathway in tomato fruit flesh, a tissue that normally does not produce any flavonoids. These fruit accumulated high levels of the flavonol kaempferol and, to a lesser extent, the flavanone naringenin in their flesh. All flavonoids detected were present as glycosides. Anthocyanins, previously reported to accumulate upon LC expression in several plant species, were present in LC/C1 tomato leaves but could not be detected in ripe LC/C1 fruit. RNA expression analysis of ripening fruit revealed that, with the exception of chalcone isomerase, all of the structural genes required for the production of kaempferol-type flavonols and pelargonidin-type anthocyanins were induced strongly by the LC/C1 transcription factors. Expression of the genes encoding flavanone-3'-hydroxylase and flavanone-3'5'-hydroxylase, which are required for the modification of B-ring hydroxylation patterns, was not affected by LC/C1. Comparison of flavonoid profiles and gene expression data between tomato leaves and fruit indicates that the absence of anthocyanins in LC/C1 fruit is attributable primarily to an insufficient expression of the gene encoding flavanone-3'5'-hydroxylase, in combination with a strong preference of the tomato dihydroflavonol reductase enzyme to use the flavanone-3'5'-hydroxylase reaction product dihydromyricetin as a substrate.
442 citations
TL;DR: The strong antiproliferative activities of the polymethoxylated flavones suggest that they may have use as anticancer agents in humans.
Abstract: Citrus fruits contain high concentrations of several classes of phenols, including numerous hydroxycinnamates, flavonoid glycosides, and polymethoxylated flavones. The latter group of compounds occurs without glycosidic linkages and has been shown to inhibit the proliferation of a number of cancer cell lines. This antiproliferative property was further demonstrated against additional human cancer cell lines, and the antiproliferative actions of a series of synthetic methoxylated flavones were also studied. Similar to the naturally occurring compounds, the synthetic compounds exhibited strong antiproliferative activities. In many cases the IC(50) values occurred below 10 microm. Other hydroxylated flavone and flavanone aglycons also exhibited antiproliferative activities against the cancer cell lines, with the flavones showing greater activities than the flavanones. Glycosylation of these compounds removed their activity. The strong antiproliferative activities of the polymethoxylated flavones suggest that they may have use as anticancer agents in humans.
344 citations
TL;DR: It was found that these three flavonoids exhibited comparable antioxidant activities against different oxidants leading to the conclusion that the presence of ortho -catechol group (3',4'-OH) in the B-ring is determinant for a high antioxidant capacity.
Abstract: The antioxidant and prooxidant activities of flavonoids belonging to several classes were studied to establish their structure-activity relationships against different oxidants. Special attention was paid to the flavonoids quercetin (flavone), taxifolin (flavanone) and catechin (flavanol), which possess different basic structures but the same hydroxylation pattern (3,5,7,3'4'-OH). It was found that these three flavonoids exhibited comparable antioxidant activities against different oxidants leading to the conclusion that the presence of ortho-catechol group (3',4'-OH) in the B-ring is determinant for a high antioxidant capacity. The flavone kaempferol (3,5,7,4'-OH), however, in spite of bearing no catechol group, also presents a high antioxidant activity against some oxidants. This fact can be attributed to the presence of both 2,3-double bond and the 3-hydroxyl group, meaning that the basic structure of flavonoids becomes important when the antioxidant activity of B-ring is small.
340 citations
TL;DR: Electrospray mass spectrometry has been used to study metal ion interactions with a set of flavonoids from different classes, establishing for flavones and for the flavanone naringenin that the binding metal sites are preferentially at the 5-hydroxyl and 4-oxo groups.
294 citations
TL;DR: The functional and structural studies support the proposal that CHI accelerates the stereochemically defined intramolecular cyclization of chalcones into biologically active (2S)-flavanones by selectively binding an ionized chalcone in a conformation conducive to ring closure in a diffusion-controlled reaction.
149 citations
TL;DR: In the course of screening phytoestrogen in medicinal plants, six Glycyrrhiza phenols exhibited the binding affinities for the bovine uterine estrogen receptor, and the affinity of a dihydrostilbene with two 3-methyl-2-butenyl (prenyl) groups, gancaonin R, was higher than those of isoflavone phy toestrogens in dietary foods.
Abstract: The genus Glycyrrhiza consists of about 30 species in which G. glabra, G. uralensis, G. inflata, G. aspera, G. korshinskyi, and G. eurycarpa are generally recog- nized as licorice because of their sweet taste. Except G. korshinskyi, we examined iso- prenoid-substituted phenols of these licorices. Each plant could be characterized by some isoprenoid phenols. We also investigated the biological activities of the Glycyrrhiza phe- nols. In the course of screening phytoestrogen in medicinal plants, six Glycyrrhiza phenols exhibited the binding affinities for the bovine uterine estrogen receptor. The affinity of a dihydrostilbene with two 3-methyl-2-butenyl (prenyl) groups, gancaonin R, was higher than those of isoflavone phytoestrogens (genistein and daidzein) in dietary foods. The affini- ties of the other five phenols, a flavanone (liquiritigenin), two prenylflavanones (isobavachin and sigmoidin B), a prenylated coumestan (glycyrol), and a pyranoisoflav-3-ene (glabrene), were similar to that of the dietary isoflavone, genistein or daidzein. Cytotoxic activities of the Glycyrrhiza phenols against human oral tumor cell lines and HIV-infected MT-4 cells were also reviewed.
132 citations
TL;DR: Two new flavanone glycosides were found to show inhibitory activity for rat lens aldose reductase and a new phenylbutanoid glycoside, (2S, 3S)-1-phenyl-2,3-butanediol 3-O-beta-D-glucopyranoside, were isolated from the flowers of Chrysanthemum indicum L. cultivated in China together with eight flavonoids.
Abstract: Two new flavanone glycosides, (2S)- and (2R)-eriodictyol 7-O-β-D-glucopyranosiduronic acids, and a new phenylbutanoid glycoside, (2S, 3S)-1-phenyl-2,3-butanediol 3-O-β-D-glucopyranoside, were isolated from the flowers of Chrysanthemum indicum L. cultivated in China together with eight flavonoids. The absolute stereostructures of the new compounds were determined on the basis of chemical and physicochemical evidence. Both of the new flavanone glycosides were found to show inhibitory activity for rat lens aldose reductase.
131 citations
TL;DR: Three new flavanone glucosides, myrciacitrins III, IV, and V, were isolated from the leaves of Brazilian Myrcia multiflora and were found to show potent inhibitory activity on aldose reductase.
Abstract: Following the characterization of myrciacitrins I and II and myrciaphenones A and B, three new flavanone glucosides, myrciacitrins III, IV, and V, were isolated from the leaves of Brazilian Myrcia multiflora. The structures of new myrciacitrins were elucidated on the basis of physicochemical and chemical evidence. Myrciacitrins were found to show potent inhibitory activity on aldose reductase.
93 citations
TL;DR: Two new flavanone glucosides, (2R)- and (2S)-5-O-beta-D-glucopyranosyl-7,4'-dihydroxy-3',5'-dimethoxyflavanone[pervianoside I (3), peruvianoside II(4)] and a new flavonol glycoside, quercetin 3-O-[alpha-L-rhamnopyranoyl
Abstract: Two new flavanone glucosides, (2R)- and (2S)-5-O-β-D-glucopyranosyl-7,4′-dihydroxy-3′,5′-dimethoxyflavanone[pervianoside I (3), peruvianoside II (4)] and a new flavonol glycoside, quercetin 3-O-{β-D-glucopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside} (peruvianoside III, 13) were isolated from the leaves of Thevetia peruviana SCHUM., together with nine known flavonol glycosides and two known iridoid glucosides. The structures of all compounds were determined on the basis of chemical and spectroscopic methods. Their inhibitory effects against HIV-1 reverse transcriptase and HIV-1 integrase were also investigated.
90 citations
TL;DR: Mentha longifolia (Lamiaceae), an aromatic herb yielded a new halogenated chloro-derivative of menthone (longifone), two new derivatives of beta-sitosterol glycoside (longiside-A and -B) and a new flavanone-glycosides (longitin).
TL;DR: Two prenylated flavonoid derivatives were isolated from an ethyl acetate-soluble extract of the leaves of Macaranga conifera using an in vitro activity-guided fractionation procedure based on the inhibition of cyclooxygenase-2 and their structures were determined using spectroscopic methods.
TL;DR: The stem bark of Feronia limonia yielded (-)-(2S)-5,3'-dihydroxy-4'-methoxy-6",6"-dimethylchromeno-(7,8,2",3")-flavanone along with several known compounds including an alkaloid, five coumarins, a flavanone, a lignan, three sterols and a triterpene.
TL;DR: Two new acylated flavanone glycosides were isolated from the leaves and branches of Phyllanthus emblica together with a new phenolic glycoside, 2-(2-methylbutyryl)phloroglucinol 1-O-(6"-O-beta-D-apiofuranosyl)-beta- D-glucopyranoside, as well as 22 known compounds.
Abstract: Phyllanthus emblica L. (Euphorbiaceae) is a shrub or tree native to subtropical and tropical areas of China, India, Indonesia and the Malay Peninsula. The fruit has been widely used for antiinflammatory and antipyretic treatment. The root, leaves and bark are also used for the treatment of indigestion, diarrhea or dysentery, eczema and wart. As a continuation of investigation on the constituents of this plant, 1—5) we chemically examined its leaves and branches, and two new acylated flavanone glycosides, a new phenolic glycoside, and 22 known compounds were isolated. This paper describes the isolation and structural elucidation of these com
TL;DR: The X-ray crystal structures of the T48A and Y106F mutants support the assertion that the observed kinetic effects result from the loss of key hydrogen bonds at the CHI active site, and are consistent with a reaction mechanism for CHI in which Thr48 polarizes the ketone of the substrate and Tyr106 stabilizes a key catalytic water molecule.
Abstract: In flavonoid, isoflavonoid, and anthocyanin biosynthesis, chalcone isomerase (CHI) catalyzes the intramolecular cyclization of chalcones into (S)-flavanones with a second-order rate constant that approaches the diffusion-controlled limit. The three-dimensional structures of alfalfa CHI complexed with different flavanones indicate that two sets of hydrogen bonds may possess critical roles in catalysis. The first set of interactions includes two conserved amino acids (Thr48 and Tyr106) that mediate a hydrogen bond network with two active site water molecules. The second set of hydrogen bonds occurs between the flavanone 7-hydroxyl group and two active site residues (Asn113 and Thr190). Comparison of the steady-state kinetic parameters of wild-type and mutant CHIs demonstrates that efficient cyclization of various chalcones into their respective flavanones requires both sets of contacts. For example, the T48A, T48S, Y106F, N113A, and T190A mutants exhibit 1550-, 3-, 30-, 7-, and 6-fold reductions in kcat and...
TL;DR: In this paper, the absolute configurations of three flavanone-(3→8″)-flavone type biflavonoids, (+)-morelloflavone (1), (+)-volkensiflavone-7-sulfate (2 ), isolated from Rheedia acuminata, were confirmed by circular dichroism as 2 R,3 S, hence clarifying the literature confusion of 2 S,3 R absolute configuration for (+-morelloftlavone.
TL;DR: Results demonstrated that PGE2 is an important mediator in TPA‐induced proliferation, and MAPK phosphorylation was located at the upstream of COX‐2, c‐Jun, and ODC gene expressions in Tpa‐induced responses.
Abstract: Biological functions of flavanones have been studied extensively, however, the structure-related activities of flavanones on 12-o-tetradecanoylphorbol 13-acetate (TPA)-induced promotive effects are still unclear. In this study, flavanone, 2'-OH flavanone, 4'-OH flavanone, 6-OH flavanone showed the most significant dose-dependent inhibition on TPA-induced proliferative effects among eight tested flavanones in NIH3T3 cells. TPA-induced mitogen activated protein kinases (MAPK) phosphorylation, ornithine decarboxylase (ODC), c-Jun, and cyclooxygenase 2 (COX-2) protein expressions in a time-dependent manner, and the maximal inductive time point is at 1 h for MAPK phosphorylation and 6 h for others. Flavanone, 2'-OH flavanone, 4'-OH flavanone, 6-OH flavanone showed the dose-dependent inhibition on TPA-stimulated MAPK phosphorylation, COX-2, ODC, c-Jun protein expressions. Induction of, prostaglandin E(2) (PGE(2)) production was detected in TPA-treated NIH3T3 cells, and flavanone, 2'-OH flavanone, 4'-OH flavanone, 6-OH flavanone inhibited significantly PGE(2) production induced by TPA. Addition of PGE(2) reverses the inhibitory activities of flavanone, 2'-OH flavanone, 4'-OH flavanone, 6-OH flavanone on TPA-induced proliferation. And, PD98059, a specific inhibitor of ERKs, inhibited TPA-induced MAPK phosphorylation, accompanied by decreasing COX-2, c-Jun, and ODC protein expression, and showed dose-dependent inhibition on TPA-induced proliferation in cells. These results demonstrated that PGE(2) is an important mediator in TPA-induced proliferation, and MAPK phosphorylation was located at the upstream of COX-2, c-Jun, and ODC gene expressions in TPA-induced responses. Furthermore, flavanone, 2'-OH flavanone, 4'-OH flavanone, 6-OH flavanone (100 microM) suppressed TPA-induced colony formation associated with blocking MAPK phosphorylation, ODC, c-Jun, and COX-2 proteins expression. And, 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay showed that flavanone, 2'-OH flavanone, 4'-OH flavanone, 6-OH flavanone did not perform potent anti-radical activities among these eight tested compounds. In conclusion, this study provided molecular evidences to demonstrate that flavanone, 2'-OH flavanone, 4'-OH flavanone, 6-OH flavanone were potent inhibitors on TPA-induced responses without notable cytotoxicity through suppression of PGE(2) production; and anti-radical activity of flavanones was not correlated with preventing the occurrence of tumor promotion. We proposed that blocking TPA-induced intracellular signaling responses might be involved in the anti-promotive mechanism of flavanones.
TL;DR: In this paper, the synthesis of flavanone was studied over a magnesium oxide solid catalyst in a batch reactor, where the reaction scheme consists of the Claisen-Schmidt condensation of 2-hydroxyacetophenone with benzaldehyde towards the formation of a 2'-hydroxychalcone intermediate and the subsequent isomerization of this intermediate to flavour.
Abstract: The synthesis of flavanone was studied over a magnesium oxide solid catalyst in a batch reactor. The reaction scheme consists of the Claisen–Schmidt condensation of 2'-hydroxyacetophenone with benzaldehyde towards the formation of a 2'-hydroxychalcone intermediate and the subsequent isomerization of this intermediate to flavanone. An initial parametric study yielded a range of values for key experimental parameters (i.e., catalyst particle size and weight percentage and stirring rate) for which the batch reactor system operates in the kinetic regime. The kinetic investigation that followed indicates that over the MgO catalyst studied the Claisen–Schmidt condensation reaction follows first-order kinetics in 2-hydroxyacetophenone and half-order kinetics in benzaldehyde, while the 2'-hydroxychalcone isomerization follows first-order kinetics; activation energies of 40 and 48 kJ/mol were obtained for the two reactions, respectively.
TL;DR: Flavanone (1) on oxidation with iodobenzene diacetate (PIDA) in the presence of sulfuric acid in trimethyl orthoformate (TMOF) undergoes a stereospecific ring contraction by an aryl shift to result in trans methyl 2-aryl-2,3-dihydrobenzo[b]furan-3-carboxylate (4a) as a major product.
TL;DR: Two (E)-pyridinyl-substituted flavanone derivatives were synthesized and UV irradiation of these compounds afforded a Z-enriched mixture, which had a substantial influence on the aromatase inhibitory activity since (E-isomers were found to be more active than (Z)-isomers.
TL;DR: In this article, an efficient enantiospecific synthesis of the (R)- and (S)-enantiomers of flavanone and 2-methylchromanone is described.
Abstract: An efficient enantiospecific synthesis of the (R)- and (S)-enantiomers of flavanone and 2-methylchromanone is described. The key steps are a C,C-bond formation by ring opening of a chiral epoxide with a dithiane anion, followed by a Mitsunobu cyclization. The products obtained have high enantiomeric purity.
TL;DR: Cell suspension cultures of Sophora flavescens produced large amounts of sophoraflavanone G, an 8-lavandulylated flavanone and lupalbigenin, a 6,3'-di-dimethylallylated isoflavone, by the simultaneous addition of cork tissues and methyl jasmonate.
TL;DR: A new flavanone, euchrenone a 1 7 (1), along with eighteen known compounds, including glabrol, formononetin, vanillin, medicagol, octadecyl ferulate (15), (+)-syringaresinol (16), β-sitosteryl-D-glucoside (17), and a mixture of β-stosterol (18) and stigmasterol (19) were isolated from the methanolic extracts of the roots of Euchresta formosana.
Abstract: A new flavanone, euchrenone a 1 7 (1), along with eighteen known compounds, glabrol (2), euchrenone a 2 (3), formononetin (4), 7-methoxy-2',4'-dihydroxyisoflavone (5), 3-(3,4-dimethoxy-phenyl)-7,8-dihydroxy-chromon-4-one (6), 5,7,2'-trihydroxy-4'-methoxyisoflavone (7), 2'-hydroxygenistein (8), euchrenone b 1 (9), euchrenone b2 (10), euchrenone b 1 6 (11), vanillin (12), p-hydroxybenzoic acid (13), medicagol (14), octadecyl ferulate (15), (+)-syringaresinol (16), β-sitosteryl-D-glucoside (17), and a mixture of β-sitosterol (18) and stigmasterol (19), were isolated from the methanolic extracts of the roots of Euchresta formosana. The structures of these compounds were established by means of spectral analysis.
TL;DR: Four coumaronochromones, formosanatins A-D (-4), and a flavanone, euchrenone a(16), along with four known compounds, including euchretins E and G, and euchrestaflavanone A, and daidzein, were isolated from the roots of Euchresta formosana.
Patent•
04 Oct 2002TL;DR: In this article, the authors present nucleic acids and nucleic acid fragments encoding amino acid sequences for flavonoid biosynthetic enzymes in plants, and the use thereof for the modification of flavonoids biosynthesis in plants.
Abstract: Nucleic acids and nucleic acid fragments encoding amino acid sequences for flavonoid biosynthetic enzymes in plants, and the use thereof for the modification of flavonoid biosynthesis in plants.More particularly, the flavonoid biosynthetic enzyme is selected from the group consisting of chalcone isomerase (CHI), chalcone synthase (CHS), chalcone reductase (CHR), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin reductase (LCR), flavonoid 3', 5' hydrolase (F3'5'H), flavanone 3-hydroxylase (F3H), flavonoid 3'-hydroxylase (F3'H), phenylalanine ammonia-olyase (PAL) and vestitone reductase (VR), and functionally active fragments and variants thereof (62) Divided Out of 531985
30 Jun 2002
TL;DR: In this article, two new flavonoids, 4',5-dihydroxy-8-hydroxymethyl-6",6"-dimethylpyrano[2",3":7,6]flavanone (1), and 2",3"-dihdroxylupinifolin (2), were isolated from the stems of Derris reticulata.
Abstract: Two new flavonoids, 4',5-dihydroxy-8-hydroxymethyl-6",6"-dimethylpyrano[2",3":7,6]flavanone (1), and 2",3"-dihydroxylupinifolin (2) were isolated from the stems of Derris reticulata. Both compounds showed cytotoxic activity in the P-388 cell line. The structures were established by spectroscopic analysis and chemical transformations. The biosynthetic origin and the mechanism of formation of the hydroxymethyl group in compound (1) are proposed.
TL;DR: An isomerization of 2"-hydroxychalcones into the corresponding flavanones in ethanol in the presence of triethylamine is described.
Abstract: An isomerization of 2"-hydroxychalcones into the corresponding flavanones in ethanol in the presence of triethylamine is described.
TL;DR: The isolated flavonoids displayed antibacterial activities against a series of G +ve and G –ve bacteria and may provide good markers for chemotaxonomical studies of Citrus species.
Abstract: Six biologically active flavonoids were isolated from the fruit peels of Citrus deliciosa. Analysis off their spectral data (UV, MS, 1H, 13C and 2D NMR experiments) confirmed their structures as four polymethoxyflavones (5-0-demethylnobiletin 1; tangeritin 2; nobiletin 3 and 5,7,8,3’,4’-pentamethoxyflavone 4) as well as two flavanone glycosides (hesperetin-7-0-glucoside 5 and hesperidin 6). The IH NMR assignment of3 and the isolation of 5 from Rutaceae is reported for the first time. The isolated flavonoids displayed antibacterial activities against a series of G +ve and G –ve bacteria. The chemotaxonomic value of the present findings has been verified, and some of the isolated flavonoids may provide good markers for chemotaxonomical studies of Citrus species.