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Kaempferol
Terms modified by Kaempferol Selected AbstractsStudy of the reaction products of flavonols with 2,2-diphenyl-1-picrylhydrazyl using liquid chromatography coupled with negative electrospray ionization tandem mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 12 2004Erlend Hvattum Abstract The products obtained after the reaction between flavonols and the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH,) in both methanol and acetonitrile were characterized using liquid chromatography coupled with negative electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) and NMR spectroscopy. The flavonols studied were quercetin, kaempferol and myricetin. In methanol, two reaction products of oxidized quercetin were identified using LC/ESI-MS/MS and NMR. Quercetin was oxidized through a transfer of two H-atoms to DPPH, and subsequently incorporated either two CH3OH molecules or one CH3OH- and one H2O molecule giving the products 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-2,3-dimethoxy-2,3-dihydrochromen-4-one and 2-(3,4-dihydroxyphenyl)-3,3,5,7-tetrahydroxy-2-methoxy-2,3-dihydrochromen-4-one, respectively. LC/ESI-MS/MS analysis revealed that in methanol, kaempferol and myricetin also gave rise to methoxylated oxidation products similar to that identified for quercetin. Kaempferol, in addition, also exhibited products where a kaempferol radical, obtained by a transfer of one H-atom to DPPH,, reacted with CH3OH through the addition of CH3O,, yielding two isomeric products. When the reaction took place in acetonitrile, LC/ESI-MS/MS analysis showed that both quercetin and myricetin formed stable isomeric quinone products obtained by a transfer of two H-atoms to DPPH,. In contrast, kaempferol formed two isomeric products where a kaempferol radical reacted with H2O through the addition of OH,, i.e. similar to the reaction of kaempferol radicals with CH3OH. Copyright © 2004 John Wiley & Sons, Ltd. [source] Identification of Kaempferol as a Monoamine Oxidase Inhibitor and Potential Neuroprotectant in Extracts of Ginkgo Biloba LeavesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2000B. D. SLOLEY The effects of Ginkgo biloba leaf extract on rat brain or livermonoamine oxidase (MAO)-A and -B activity, biogenic amine concentration in nervous tissue, N -methyl- d -aspartate (NMDA)- and N -(2-chloroethyl)- N -ethyl-2-bromobenzylamine (DSP-4)-induced neurotoxicity and antioxidant activity was investigated to determine the effects of the extract on monoamine catabolism and neuroprotection. Ginkgo biloba leaf extract was shown to produce in-vitro inhibition of rat brain MAO-A and -B. The Ginkgo biloba extract was chromatographed on a reverse-phase HPLC system and two of the components isolated were shown to be MAO inhibitors (MAOIs). These MAOIs were identified by high-resolution mass spectrometry as kaempferol and isorhamnetin. Pure kaempferol and a number of related flavonoids were examined as MAOIs in-vitro. Kaempferol, apigenin and chrysin proved to be potent MAOIs, but produced more pronounced inhibition of MAO-A than MAO-B. IC50 (50% inhibition concentration) values for the ability of these three flavones to inhibit MAO-A were 7 times 10,7, 1 times 10,6 and 2 times 10,6m, respectively. Ginkgo biloba leaf extract and kaempferol were found to have no effect ex-vivo on rat or mouse brain MAO or on concentrations of dopamine, noradrenaline, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid. Kaempferol was shown to protect against NMDA-induced neuronal toxicity in-vitro in rat cortical cultures, but did not prevent DSP-4-induced noradrenergic neurotoxicity in an in-vivo model. Both Ginkgo biloba extract and kaempferol were demonstrated to be antioxidants in a lipid-peroxidation assay. This data indicates that the MAO-inhibiting activity of Ginkgo biloba extract is primarily due to the presence of kaempferol. Ginkgo biloba extract has properties indicative of potential neuroprotective ability. [source] Assigning glucose or galactose as the primary glycosidic sugar in 3- O -mono-, di- and triglycosides of kaempferol using negative ion electrospray and serial mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2009Geoffrey C. Kite Kaempferol 3- O - , -glucopyranoside, kaempferol 3- O - , -galactopyranoside and higher glycosides of these two flavonoids with , -rhamnose at C-2 and/or C-6 of the primary sugar were studied by negative ion electrospray ionisation and serial mass spectrometry in a three-dimensional (3D) ion trap mass spectrometer. Kaempferol 3- O - , -glucopyranoside and kaempferol 3- O - , -rhamnopyranosyl(1,6)- , -glucopyranoside could be distinguished from their respective galactose analogues by differences in the ratio of the radical aglycone ion [Y0 , H],, to the rearrangement aglycone ion Y following MS/MS of the deprotonated molecules. Kaempferol 3- O -rhamnopyranosyl(1,2)- , -glucopyranoside and kaempferol 3- O - , -rhamnopyranosyl(1,2)[, -rhamnopyranosyl(1,6)]- , -glucopyranoside could be distinguished from their respective galactose analogues by differences in the product ion spectra of the [(M , H) , rhamnose], ion following serial mass spectrometry. In the triglycoside, it was deduced that this ion resulted from the loss of the rhamnose substituted at 2-OH of the primary sugar by observing that MS/MS of deprotonated kaempferol 3- O - , -glucopyranosyl(1,2)[, -rhamnopyranosyl(1,6)]- , -glucopyranoside showed the loss of glucose and not rhamnose. Thus the class of sugar (hexose, deoxyhexose, pentose) at C-2 and C-6 of the primary sugar can be determined. These observations aid the assignment of kaempferol 3- O -glycosides, having glucose or galactose as the primary glycosidic sugar, in LC/MS analyses of plant extracts, and this can be done with reference to only a few standards. Copyright © 2009 John Wiley & Sons, Ltd. [source] Characterization of phenolic compounds in the Chinese herbal drug Tu-Si-Zi by liquid chromatography coupled to electrospray ionization mass spectrometry,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2005Min Ye Phenolic compounds are the major bioactive constituents of the Chinese herbal drug Tu-Si-Zi, which is prepared from the seeds of Cuscuta chinensis. However, seeds of C. australis also are offered under the name of this drug in the herb market. In order to make a comparison of their chemical constituents, the phenolic compounds of these two Cuscuta species were analyzed by high-performance liquid chromatography/diode-array detection/electrospray ion trap tandem mass spectrometry (HPLC/DAD/ESI-MSn). A total of 50 compounds were observed in the methanol extracts, including 23 flavonoids, 20 lignans and 7 quinic acid derivatives. These compounds were separated on a C18 column and identified or tentatively characterized based on UV spectra and MS fragmentation behavior. In contrast to previous reports, the phenolic patterns of these two Cuscuta species were found to be very different. Kaempferol and astragalin were the predominant constituents of C. australis, while hyperoside was the major compound in C. chinensis. Most of the identified compounds, especially the acylated flavonoid glycosides, have not previously been reported from Cuscuta species. In addition, a 30,Da neutral loss observed for flavonols was investigated and could be used to differentiate flavonoid isomers such as kaempferol and luteolin. The ESI-MS fragmentation behavior of furofuran lignans was also investigated, and a characteristic pathway is proposed. The large differences observed between the phenolic constituents of C. chinensis and C. australis strongly encouraged further comparison of the bioactivities of these two species. Copyright © 2005 John Wiley & Sons, Ltd. [source] Inhibition of fatty acid amide hydrolase by kaempferol and related naturally occurring flavonoidsBRITISH JOURNAL OF PHARMACOLOGY, Issue 2 2008L Thors Background and purpose: Recent studies have demonstrated that the naturally occurring isoflavone compounds genistein and daidzein inhibit the hydrolysis of anandamide by fatty acid amide hydrolase (FAAH) in the low micromolar concentration range. The purpose of the present study was to determine whether this property is shared by flavonoids. Experimental approach: The hydrolysis of anandamide in homogenates and intact cells was measured using the substrate labelled in the ethanolamine part of the molecule. Key results: Twenty compounds were tested. Among the commonly occurring flavonoids, kaempferol was the most potent, inhibiting FAAH in a competitive manner with a Ki value of 5 ,M. Among flavonoids with a more restricted distribution in nature, the two most active toward FAAH were 7-hydroxyflavone (IC50 value of 0.5,1 ,M depending on the solvent used) and 3,7-dihydroxyflavone (IC50 value 2.2 ,M). All three compounds reduced the FAAH-dependent uptake of anandamide and its metabolism by intact RBL2H3 basophilic leukaemia cells. Conclusions and implications: Inhibition of FAAH is an additional in vitro biochemical property of flavonoids. Kaempferol, 7-hydroxyflavone and 3,7-dihydroxyflavone may be useful as templates for the synthesis of novel compounds, which target several systems that are involved in the control of inflammation and cancer. British Journal of Pharmacology (2008) 155, 244,252; doi:10.1038/bjp.2008.237; published online 16 June 2008 [source] A prospective study of dietary flavonoid intake and incidence of epithelial ovarian cancerINTERNATIONAL JOURNAL OF CANCER, Issue 10 2007Margaret A. Gates Abstract Flavonoids are antioxidant compounds found in plants, including fruits, vegetables and tea. No prior prospective studies have examined the association between intake of flavonoids in the flavonol and flavone subclasses and ovarian cancer risk. We analyzed the association between intake of 5 common dietary flavonoids and incidence of epithelial ovarian cancer among 66,940 women in the Nurses' Health Study. We calculated each participant's intake of myricetin, kaempferol, quercetin, luteolin and apigenin from dietary data collected at multiple time points, and used Cox proportional hazards regression to model the incidence rate ratio (RR) of ovarian cancer for each quintile of intake. Our analysis included 347 cases diagnosed between 1984 and 2002, and 950,347 person-years of follow-up. There was no clear association between total intake of the 5 flavonoids examined and incidence of ovarian cancer (RR = 0.75 for the highest versus lowest quintile, 95% confidence interval [CI] = 0.51,1.09). However, there was a significant 40% decrease in ovarian cancer incidence for the highest versus lowest quintile of kaempferol intake (RR = 0.60, 95% CI = 0.42,0.87; p -trend = 0.002), and a significant 34% decrease in incidence for the highest versus lowest quintile of luteolin intake (RR = 0.66, 95% CI = 0.49,0.91; p -trend = 0.01). There was evidence of an inverse association with consumption of tea (nonherbal) and broccoli, the primary contributors to kaempferol intake in our population. These data suggest that dietary intake of certain flavonoids may reduce ovarian cancer risk, although additional prospective studies are needed to further evaluate this association. If confirmed, these results would provide an important target for ovarian cancer prevention. © 2007 Wiley-Liss, Inc. [source] The chain-breaking antioxidant activity of phenolic compounds with different numbers of O-H groups as determined during the oxidation of styreneINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 2 2009Ivan Tikhonov The technique based on monitoring oxygen consumption was applied to test 18 polyphenols (PP) and model phenolics as a chain-breaking antioxidant during the oxidation of styrene initiated by 2,2,-azobis(2,4-dimethylvaleronitril) at 37°C. The chain-breaking capability of PP was characterized by two parameters: the rate constant k1 for the reaction of antioxidants with the peroxy radical produced from styrene and the stoichiometric coefficient of inhibition, f, which shows how many kinetic chains are terminated by one molecule of PP. Rate constants k1 × 105 (in M,1 s,1) were found to be 10 (catechol), 27 (pyrogallol), 34 (3,6-di-tert-Bu-catechol), 4.3 (protocatechic acid), 12 (gallic acid), 15 (caffeic acid), <0.01 (chrysin), 1.3 (kaempferol), 19 (quercetin), 5.3 (baicalein), 16 (epicatechin), 32 (epigallocatechin), 9.0 (dihydroquercetin), 3.3 (resveratrol), and 16 (nordihydroguaiaretic acid). The value of k1 increases when going from one to two and three adjacent O-H groups in a benzene ring (catechol and pyrogallol derivatives, respectively). At the same time, two O-H groups in metaposition in a A-ring of flavonoids actually do not participate in the inhibition. For the majority of PP, f is near to 2 independent of the number of OH groups. The correlation of k1 with the structure of PP and the OH bond dissociation enthalpy has been discussed. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 92,100, 2009 [source] Tyrosinase inhibitors isolated from the roots of Paeonia suffruticosaINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2010H. -Y. J. Cosmet. Sci., 60, 347,352 (May/June 2009) Accepted for publication November 6, 2008. Synopsis The inhibition of mushroom tyrosinase by Paeonia suffruticosa root-derived materials was evaluated. Six tyrosinase inhibitors were isolated by ethanol extraction, n -hexane, ethyl acetate, n -BuOH, and water partition, silica gel column chromatography, Sephadex LH-20, Lobar PR-8, and high-performance liquid chromatography methods, and they were identified as kaempferol (I), quercetin (II), mudanpioside B (III), benzoyloxypaeoniflorin (IV), mudanpioside H (V), and pentagalloyl-,-D-glucose (VI) on the basis of spectroscopic evidence. The inhibitory activities of compounds I to VI against mushroom tyrosinase were determined with IC50 values of 0.120, 0.108, 0.368, 0.453, 0.324, and 0.063 mM, respectively. The kinetic study indicated that all purified inhibitors acted competitively for the L-dopa binding site of the enzyme, with an exception of compound VI, which acted non-competitively. [source] Differential mechanisms for the inhibition of human cytochrome P450 1A2 by apigenin and genisteinJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 4 2010Hideaki Shimada Abstract The inhibitory effects of flavonoids on the human cytochrome P450 1A2 (CYP1A2) were examined. Among flavonoids tested, galangin, kaempferol, chrysin, and apigenin were potent inhibitors. Although apigenin belonging to flavones and genistein belonging to isoflavones are similar in the chemical structures, the inhibitory potencies for CYP1A2 were distinguished markedly between these two flavonoids. In computer-docking simulation, apigenin interacted with the same mode of cocrystallized ,-naphthoflavone in the active site of CYP1A2, and then the B ring of apigenin was placed close to the heme iron of the enzyme with a single orientation. In contrast, the docked genistein conformation showed two different binding modes, and the A ring of genistein was oriented to the heme iron of CYP1A2. Furthermore, the binding free energy of apigenin was lower than that of genistein. These results demonstrate a possible mechanism that causes the differential inhibitory potencies of apigenin and genistein for CYP1A2. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 24:230,234, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.20328 [source] Influence of Cultivation System on Bioactive Molecules Synthesis in Strawberries: Spin-off on Antioxidant and Antiproliferative ActivityJOURNAL OF FOOD SCIENCE, Issue 1 2010L. D'Evoli ABSTRACT:, Strawberries (Fragaria ananassa,L., cv. favette) were studied to investigate the influence of cultivation practices (biodynamic, conventional) on the synthesis of bioactive molecules (ascorbic acid, ellagic acid, anthocyanins, flavonols) and to evaluate their antioxidant activity. Additionally, the,in vitro,bioactivity, in terms of antioxidant and antiproliferative activity, of the same strawberry samples in human colon carcinoma (Caco-2) cells was also studied. Compared to conventional strawberries, biodynamic fruits had a significantly higher content of ascorbic acid (P,< 0.01), pelargonidin-3-glucoside (P,< 0.05), cyanidin-3-glucoside (P,< 0.01), ellagic acid (P,< 0.01), quercetin, and kaempferol (both,P,< 0.01). Antioxidant activity of biodynamic strawberry crude extract was significantly higher than that of the conventional one (P,< 0.05); in addition, while the antioxidant activity of water-soluble fraction was very similar in both biodynamic and conventional strawberries, that of water-insoluble fraction of biodynamic fruits was significantly higher (P,< 0.05). The same crude extract of biodynamic strawberry samples effectively corresponded to an increase of bioactivity, in terms of both cellular antioxidant activity and antiproliferative activity, in Caco-2 cells differentiated to normal intestinal epithelia and in undifferentiated Caco-2, respectively. Further studies are needed to confirm whether the practice of biodynamic agriculture is likely to increase the bioactivity of other varieties of fruits and vegetables. [source] Flavonoids in Onion Cultivars (Allium cepa L.)JOURNAL OF FOOD SCIENCE, Issue 8 2008B. Rodríguez Galdón ABSTRACT:, Total phenol and flavonoid contents were analyzed by HPLC coupled with a diode array detector in 5 traditional onion cultivars from Tenerife (Guayonje, San Juan de la Rambla, Carrizal Alto, Carrizal Bajo, and Masca) and a commercial cultivar (Texas Early Grano 502). Five quercetin chemical species (isoquercetin, quercetin diglucoside, quercetin monoglucoside 1, quercetin monoglucoside 2, and free quercetin) and kaempferol were identified and quantified in the onion samples. Quercetin monoglucoside 1 and quercetin diglucoside were the major flavonoids accounting for 80% of the total quercetin content. The mean quercetin monoglucoside 1: quercetin diglucoside ratio (QMG/QDG) was 1: 2.2. There were differences between the onion cultivars in the cases of total phenol, quercetin diglucoside, isoquercetin, QMG/QDG ratio, and kaempferol. The Texas cultivar had a higher QMG/QDG ratio and a higher kaempferol content than the traditional cultivars. The correlation study showed significant correlations between the analyzed phenolic components. [source] Study of the reaction products of flavonols with 2,2-diphenyl-1-picrylhydrazyl using liquid chromatography coupled with negative electrospray ionization tandem mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 12 2004Erlend Hvattum Abstract The products obtained after the reaction between flavonols and the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH,) in both methanol and acetonitrile were characterized using liquid chromatography coupled with negative electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) and NMR spectroscopy. The flavonols studied were quercetin, kaempferol and myricetin. In methanol, two reaction products of oxidized quercetin were identified using LC/ESI-MS/MS and NMR. Quercetin was oxidized through a transfer of two H-atoms to DPPH, and subsequently incorporated either two CH3OH molecules or one CH3OH- and one H2O molecule giving the products 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-2,3-dimethoxy-2,3-dihydrochromen-4-one and 2-(3,4-dihydroxyphenyl)-3,3,5,7-tetrahydroxy-2-methoxy-2,3-dihydrochromen-4-one, respectively. LC/ESI-MS/MS analysis revealed that in methanol, kaempferol and myricetin also gave rise to methoxylated oxidation products similar to that identified for quercetin. Kaempferol, in addition, also exhibited products where a kaempferol radical, obtained by a transfer of one H-atom to DPPH,, reacted with CH3OH through the addition of CH3O,, yielding two isomeric products. When the reaction took place in acetonitrile, LC/ESI-MS/MS analysis showed that both quercetin and myricetin formed stable isomeric quinone products obtained by a transfer of two H-atoms to DPPH,. In contrast, kaempferol formed two isomeric products where a kaempferol radical reacted with H2O through the addition of OH,, i.e. similar to the reaction of kaempferol radicals with CH3OH. Copyright © 2004 John Wiley & Sons, Ltd. [source] Potent anti-amyloidogenic and fibril-destabilizing effects of polyphenols in vitro: implications for the prevention and therapeutics of Alzheimer's diseaseJOURNAL OF NEUROCHEMISTRY, Issue 1 2003Kenjiro Ono Abstract Cerebral deposition of amyloid ,-peptide (A,) in the brain is an invariant feature of Alzheimer's disease (AD). A consistent protective effect of wine consumption on AD has been documented by epidemiological studies. In the present study, we used fluorescence spectroscopy with thioflavin T and electron microscopy to examine the effects of wine-related polyphenols (myricetin, morin, quercetin, kaempferol (+)-catechin and (,)-epicatechin) on the formation, extension, and destabilization of ,-amyloid fibrils (fA,) at pH 7.5 at 37°C in vitro. All examined polyphenols dose-dependently inhibited formation of fA, from fresh A,(1,40) and A,(1,42), as well as their extension. Moreover, these polyphenols dose-dependently destabilized preformed fA,s. The overall activity of the molecules examined was in the order of: myricetin = morin = quercetin > kaempferol > (+)-catechin = (,)-epicatechin. The effective concentrations (EC50) of myricetin, morin and quercetin for the formation, extension and destabilization of fA,s were in the order of 0.1,1 µm. In cell culture experiments, myricetin-treated fA, were suggested to be less toxic than intact fA,, as demonstrated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Although the mechanisms by which these polyphenols inhibit fA, formation from A,, and destabilize pre-formed fA,in vitro are still unclear, polyphenols could be a key molecule for the development of preventives and therapeutics for AD. [source] Identification of Kaempferol as a Monoamine Oxidase Inhibitor and Potential Neuroprotectant in Extracts of Ginkgo Biloba LeavesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2000B. D. SLOLEY The effects of Ginkgo biloba leaf extract on rat brain or livermonoamine oxidase (MAO)-A and -B activity, biogenic amine concentration in nervous tissue, N -methyl- d -aspartate (NMDA)- and N -(2-chloroethyl)- N -ethyl-2-bromobenzylamine (DSP-4)-induced neurotoxicity and antioxidant activity was investigated to determine the effects of the extract on monoamine catabolism and neuroprotection. Ginkgo biloba leaf extract was shown to produce in-vitro inhibition of rat brain MAO-A and -B. The Ginkgo biloba extract was chromatographed on a reverse-phase HPLC system and two of the components isolated were shown to be MAO inhibitors (MAOIs). These MAOIs were identified by high-resolution mass spectrometry as kaempferol and isorhamnetin. Pure kaempferol and a number of related flavonoids were examined as MAOIs in-vitro. Kaempferol, apigenin and chrysin proved to be potent MAOIs, but produced more pronounced inhibition of MAO-A than MAO-B. IC50 (50% inhibition concentration) values for the ability of these three flavones to inhibit MAO-A were 7 times 10,7, 1 times 10,6 and 2 times 10,6m, respectively. Ginkgo biloba leaf extract and kaempferol were found to have no effect ex-vivo on rat or mouse brain MAO or on concentrations of dopamine, noradrenaline, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid. Kaempferol was shown to protect against NMDA-induced neuronal toxicity in-vitro in rat cortical cultures, but did not prevent DSP-4-induced noradrenergic neurotoxicity in an in-vivo model. Both Ginkgo biloba extract and kaempferol were demonstrated to be antioxidants in a lipid-peroxidation assay. This data indicates that the MAO-inhibiting activity of Ginkgo biloba extract is primarily due to the presence of kaempferol. Ginkgo biloba extract has properties indicative of potential neuroprotective ability. [source] A novel solid phase for selective separation of flavonoid compoundsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2007Yong-qing Xia Abstract A novel straightforward approach to selective separation for flavonoid compounds was reported. The solid phase material was prepared by copolymerization using allyl-bromide-modified chitosan as macromonomer, and ethylene glycol dimethacrylate as cross-linker. The material was evaluated by chromatographic analysis; it exhibited high selectivity separation for quercetin and its structural analogues using different mobile phases. The material could directly trap a specific class of compounds including quercetin and kaempferol from the hydrolyzate of Ginkgo biloba extract. These results demonstrated the possibility of direct extraction of certain constituents from herb using this material. [source] Compositional changes induced by UV-B radiation treatment of common bean and soybean seedlings monitored by capillary electrophoresis with diode array detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 4 2007Giovanni Dinelli Abstract In this work, a new CE method with diode array detection (DAD) was developed for the monitoring and quantitation of flavonoids in different beans treated and untreated with UV-B radiation. Flavonoid concentration was monitored in UV-B-treated and untreated sprouts of three common beans (Zolfino ecotype, cv. Verdone, cv. Lingua di Fuoco) and one soybean (cv. Pacific). After acid hydrolysis of extracts, the CE-DAD method provides reproducible quantitative determinations of daidzein, glycitein, genistein, and kaempferol at ppm level in these natural matrices within a relatively short time (less than 16 min). Total flavonoid content determined by CE-DAD was 159 ± 8, 26 ± 2, 13 ± 1, and 1.3 ± 0.3 ,g/g fresh weight for untreated sprouts of Pacific soybean, Verdone bean, Zolfino bean, and Lingua di Fuoco bean, respectively. UV-B treatment caused no significant quantitative effect on Pacific soybean sprouts, whereas it enhanced the total isoflavone content by 1.5, 1.8, and 3.2-fold in Verdone, Zolfino, and Lingua di Fuoco beans, respectively. The proposed method shows (i) the potentialities of bean sprouts as a natural source of bioactive compounds (antioxidants); (ii) the technological role of UV-B treatment for sprout isoflavone enrichment; and (iii) the good capabilities of CE-DAD to monitor this process. [source] Phenolic compounds, lycopene and antioxidant activity in commercial varieties of tomato (Lycopersicum esculentum)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2002Isabel Martínez-Valverde Abstract Nine commercial varieties of tomato (Rambo, Senior, Ramillete, Liso, Pera, Canario, Durina, Daniella and Remate) produced in Spain were analysed for their lycopene content, content of phenolic compounds and antioxidant capacity. The phenolic compounds were characterised as flavonoids (quercetin, kaempferol and naringenin) and hydroxycinnamic acids (caffeic, chlorogenic, ferulic and p -coumaric acids). Antioxidant activity was measured using the DPPH and ABTS assays. The concentrations of lycopene and the various phenolic compounds as well as the antioxidant activity were significantly influenced by the tomato variety. Quercetin, the most abundant flavonoid, was found in concentrations ranging between 7.19 and 43.59,mg,kg,1 fresh weight, while naringenin levels were lower than 12.55,mg,kg,1. The most abundant hydroxycinnamic acid was chlorogenic acid, with values ranging from 14 to 32,mg,kg,1 fresh weight, followed by caffeic acid, while p -coumaric and ferulic acids showed similar concentrations lower than 5,mg,kg,1. The highest content of lycopene was found in Ramillete, Pera and Durina (>50,mg,kg,1 fresh weight), while the concentration in the other varieties was between 50 and 30,mg,kg,1, with the exception of Liso (less than 20,mg,kg,1). The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used. Individual compounds found to be significantly related to antioxidant capacity were lycopene and ferulic and caffeic acids, but not quercetin and chlorogenic acid. © 2002 Society of Chemical Industry [source] HPLC flavonoid profiles as markers for the botanical origin of European unifloral honeysJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2001Francisco A Tomás-Barberán Abstract The HPLC phenolic profiles of 52 selected unifloral honey samples produced in Europe were analysed to detect possible markers for the floral origin of the different honeys. Lime-tree (five markers), chestnut (five markers), rapeseed (one marker), eucalyptus (six markers) and heather (three markers) honeys had specific markers with characteristic UV spectra. In addition, the flavanone hesperetin was confirmed as a marker for citrus honey, as well as kaempferol for rosemary honey and quercetin for sunflower honey. Abscisic acid, which had been reported to be a possible marker for heather honey, was also detected in rapeseed, lime-tree and acacia honeys. Ellagic acid in heather honey and the hydroxycinnamates caffeic, p -coumaric and ferulic acids in chestnut, sunflower, lavender and acacia honeys were also detected. The characteristic propolis-derived flavonoids pinocembrin, pinobanksin and chrysin were present in most samples in variable amounts. © 2001 Society of Chemical Industry [source] Total antioxidant capacity and content of flavonoids and other phenolic compounds in canihua (Chenopodium pallidicaule): An Andean pseudocerealMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 6 2008J. Mauricio Peńarrieta Abstract Total antioxidant capacity (TAC), total phenolic compounds (TPH), total flavonoids (TF) and individual phenolic compounds were determined in canihua collected at approx. 3850 m altitude. The TAC values varied among samples from 2.7 to 44.7 by the ferric reducing antioxidant power (FRAP) method and from 1.8 to 41 by the 2,2,-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method expressed as ,mol of Trolox equivalents/g dw. The content of TPH was 12.4,71.2 ,mol gallic acid equivalents/g dw and that of the TF ranged between 2.2 and 11.4 ,mol of catechin equivalents/g dw. The data obtained by the four methods showed several significant correlations. Prior to analysis by HPLC, the samples were subjected to acid hydrolysis and in the water-soluble extracts this led to an up to 20-fold increase in the TAC values in comparison with the values of the nonhydrolysed samples. HPLC analysis showed the presence of eight major compounds identified as catechin gallate, catechin, vanillic acid, kaempferol, ferulic acid, quercetin, resorcinol and 4-methylresorcinol. Their estimated contribution to the TAC value (FRAP method) indicated that resorcinols contributed most of the antioxidant capacity of the water-soluble extract. The results show that canihua is a potential source of natural antioxidant compounds and other bioactive compounds which can be important for human health. [source] Characterisation of new oligoglycosidic compounds in two Chinese medicinal herbsPHYTOCHEMICAL ANALYSIS, Issue 4 2002Sandra Apers Abstract A series of caffeic acid derivatives (3,5-dicaffeoyl-quinic acid, 3,4-dicaffeoyl-quinic acid, and 4,5-dicaffeoyl-quinic acid), and the new compound ,,3,4-trihydroxyphenethyl- O -[,-apiofuranosyl-(1,4)-,-rhamnopyranosyl-(1,3)]-(4- O -caffeoyl)-,-glucopyranoside (wedelosin), as well as three known flavonoid glycosides (quercetin 3- O -,-glucoside, kaempferol 3- O -,-apiosyl-(1-2)-,-glucoside, and astragalin or kaempferol 3- O -,-glucoside) were isolated from the Chinese medicinal herb Wedelia chinensis. Wedelosin showed an inhibitory activity on both the classical and the alternative activation pathway of the complement system. Another Chinese medicinal herb, Kyllinga brevifolia, yielded two known flavonoid glycosides [kaempferol 3- O -,-apiosyl-(1-2)-,-glucoside and isorhamnetin 3- O -,-apiosyl-(1-2)-,-glucoside], and a new quercetin triglycoside [quercetin 3- O -,-apiofuranosyl-(1,2)-,-glucopyranoside 7- O -,-rhamnopyranoside]. The latter compound showed a moderate anti-viral activity. Copyright © 2002 John Wiley & Sons, Ltd. [source] Antiinflammatory activities of flavonoids and a triterpene caffeate isolated from Bauhinia variegataPHYTOTHERAPY RESEARCH, Issue 7 2008Yerra Koteswara Rao Abstract In the continuing search for novel antiinflammatory agents, six flavonoids, namely kaempferol (1), ombuin (2), kaempferol 7,4,-dimethyl ether 3- O - , - d -glucopyranoside (3), kaempferol 3- O - , - d -glucopyranoside (4), isorhamnetin 3- O - , - d -glucopyranoside (5) and hesperidin (6), together with one triterpene caffeate, 3, - trans -(3,4-dihydroxycinnamoyloxy)olean-12-en-28-oic acid (7) were isolated from the non-woody aerial parts of Bauhinia variegata. Compounds 1,7 were evaluated as inhibitors of some macrophage functions involved in the inflammatory process. These seven compounds significantly and dose dependently inhibited lipopolysaccharide (LPS) and interferon (IFN)- , induced nitric oxide (NO), and cytokines [tumor necrosis factor (TNF)- , and interleukin (IL)-12]. The concentration causing a 50% inhibition (IC50) of NO, TNF- , and IL-12 production by compounds 1, 2 and 7 was approximately 30, 50 and 10 µM, respectively, while at 50, 200 and 40 µM compounds 3, 4, and 5, 6 showed 15,30% inhibition, respectively. On the other hand, compounds 3 and 7 showed no inhibitory effect, while compounds 1, 4,6 reduced by around 10,30% the synthesis of NO by macrophages, when inducible NO synthase was already expressed with LPS/IFN- , for 24 h. These experimental findings lend pharmacological support to the suggested folkloric uses of the plant B. variegata in the management of inflammatory conditions. Copyright © 2008 John Wiley & Sons, Ltd. [source] Moringa oleifera: a food plant with multiple medicinal usesPHYTOTHERAPY RESEARCH, Issue 1 2007Farooq Anwar Abstract Moringa oleifera Lam (Moringaceae) is a highly valued plant, distributed in many countries of the tropics and subtropics. It has an impressive range of medicinal uses with high nutritional value. Different parts of this plant contain a profile of important minerals, and are a good source of protein, vitamins, , -carotene, amino acids and various phenolics. The Moringa plant provides a rich and rare combination of zeatin, quercetin, , -sitosterol, caffeoylquinic acid and kaempferol. In addition to its compelling water purifying powers and high nutritional value, M. oleifera is very important for its medicinal value. Various parts of this plant such as the leaves, roots, seed, bark, fruit, flowers and immature pods act as cardiac and circulatory stimulants, possess antitumor, antipyretic, antiepileptic, antiinflammatory, antiulcer, antispasmodic, diuretic, antihypertensive, cholesterol lowering, antioxidant, antidiabetic, hepatoprotective, antibacterial and antifungal activities, and are being employed for the treatment of different ailments in the indigenous system of medicine, particularly in South Asia. This review focuses on the detailed phytochemical composition, medicinal uses, along with pharmacological properties of different parts of this multipurpose tree. Copyright © 2006 John Wiley & Sons, Ltd. [source] Rat lens aldose reductase inhibitory constituents of Nelumbo nucifera stamensPHYTOTHERAPY RESEARCH, Issue 10 2006Soon Sung Lim Abstract Aldose reductase, the principal enzyme of the polyol pathway, has been shown to play an important role in the complications associated with diabetes. A methanol extract of the stamens of Nelumbo nucifera Gaertn. was shown to exert an inhibitory effect on rat lens aldose reductase (RLAR), and thus was fractionated using several organic solvents, including dichloromethane, ethyl acetate and n -butanol. The ethyl acetate-soluble fraction, which manifested potent RLAR-inhibitory properties, was then purified further via repeated measures of silica gel and Sephadex LH-20 column chromatography. Thirteen flavonoids: kaempferol (1) and seven of its glycosides (2,9), myricetin 3,,5,-dimethylether 3- O - , - d -glucopyranoside (10), quercetin 3- O - , - d -glucopyranoside (11) and two isorhamnetin glycosides (12, 13) were isolated from N. nucifera, as well as four non-flavonoid compounds: adenine (14), myo -inositol (15), arbutin (16) and , -sitosterol glucopyranoside (17). These compounds were all assessed with regard to their RLAR-inhibitory properties. Among the isolated flavonoids, those harboring 3- O - , - l -rhamnopyranosyl-(1,6)- , - d -glucopyranoside groups in their C rings, including kaempferol 3- O - , - l -rhamnopyranosyl-(1,6)- , - d -glucopyranoside (5) and isorhamnetin 3- O - , - l -rhamnopyranosyl-(1,6)- , - d -glucopyranoside (13), were determined to exhibit the highest degree of rat lens aldose reductase inhibitory activity in vitro, evidencing IC50 values (concentration required for a 50% inhibition of enzyme activity) of 5.6 and 9.0 µm, respectively. Copyright © 2006 John Wiley & Sons, Ltd. [source] Additional antiprotozoal constituents from Cuphea pinetorum, a plant used in Mayan traditional medicine to treat diarrhoeaPHYTOTHERAPY RESEARCH, Issue 8 2005Fernando Calzada Abstract In addition to kaempferol and quercetin already found in the roots from Cuphea pinetorum, bioassay-guided fractionation of the crude extract of the aerial part of this species gave four flavonoid glycosides, quercetin-3- O - , -rhamnopyranoside, luteolin-7- O - , - d -glucopyranoside, apigenin-7- O - , - l -rhamnopyranoside and apigenin-7- O - , - d -glucopyranoside, as well as squalen and , -sitosterol. In vitro antiamoebic and antigiardial activities of isolated compounds indicated that kaempferol is the principal antiprotozoal agent in C. pinetorum. Based on finding this antiprotozoal inhibitor, flavonoids were studied in order to elucidate structure-activity relationships. These data suggest that kaempferol may play an important role in antidiarrhoeal activity of C. pinetorum. Copyright © 2005 John Wiley & Sons, Ltd. [source] Flavonoids from the leaves of Litsea japonica and their anti-complement activityPHYTOTHERAPY RESEARCH, Issue 4 2005Sun-Young Lee Abstract Four flavonoids, epicatechin (1), afzelin (2), quercitrin (3), and tiliroside (4), were isolated from the leaves of Litsea japonica (Thunb.) Jussieu (Lauraceae). The structures of compounds were identified by comparing their chemical and spectral data with those previously reported. The flavonoids (1,4) were tested for their anti-complement activity against classical pathway of complement system. Compounds 2,4 showed inhibitory activity against complement system with IC50 values of 258, 440, and 101 µm, respectively, whereas 1 was inactive. For the evaluation of the structure-activity relationship of 5,7-dihydroxyflavones, myricitrin (5) from Juglans mandshurica also tested for it's anti-complement activity and is inactive in this assay system. Furthermore, compounds 2, 3, and 5 were hydrolyzed with naringinase to give kaempferol (2a), quercetin (3a), and myricetin (5a), and these were also tested for their activity. Of the three aglycones, 2a exhibited anti-complement activity with an IC50 value of 730 µM, while 3a and 5a were inactive. The inhibitory potencies of 2, 2a, 3, 3a, 5, and 5a against complement activity increased in inverse proportion to number of free hydroxyls on B-ring of 5,7-dihydroxyflavone. Of the compounds tested, 4 showed the most potent inhibitory activity against the complement system. Copyright © 2005 John Wiley & Sons, Ltd. [source] Chemoprotective effect of plant phenolics against anthracycline-induced toxicity on rat cardiomyocytes.PHYTOTHERAPY RESEARCH, Issue 7 2004Part III. Abstract Flavonoids are found universally in plants and act as free radical scavenging and chelating agents with antiin,ammatory, antiischemic, vasodilating and chemoprotective properties. In this study, the antilipoperoxidative and cytoprotective effects of apigenin, baicalein, kaempferol, luteolin and quercetin against doxorubicin-induced oxidative stress were investigated in isolated rat heart cardiac myocytes, mitochondria and microsomes. After preincubation of cardiomyocytes with the test compounds for 1 h the cardiomyocytes were treated with the toxic agent, doxorubicin (100 µM for 8 h). Cardiomyocyte protection was assessed by extracellular LDH and cellular ADP and ATP production. Cytoprotection was concentration dependent for baicalein > luteolin , apigenin > quercetin > kaempferol. All test compounds had signi,cantly better protective effects than dexrazoxan, an agent currently used for adjuvant therapy during anthracycline antibiotic therapy. In microsomes/mitochondria the IC50 values of lipid peroxidation inhibition for quercetin, baicalein, kaempferol, luteolin, and apigenin were 3.1 ± 0.2/8.2 ± 0.6, 3.3 ± 0.3/9.6 ± 0.5, 3.9 ± 0.3/10.1 ± 0.8, 22.9 ± 1.7/18.2 ± 0.7, and 338.8 ± 23.1/73.1 ± 6.4 mM, respectively. The antilipoperoxidative activity of apigenin differed from its cytoprotective effects, but correlated with the free radical scavenging of 2,2-diphenyl-1-picrylhydrazyl radical and half peak oxidation potential (Ep/2). Apigenin was the least effective of the ,avonoids studied in all models except the cardiomyocyte model where its cardiomyocyte cytoprotective effect was comparable to other compounds. Copyright © 2004 John Wiley & Sons, Ltd. [source] Engineered native pathways for high kaempferol and caffeoylquinate production in potatoPLANT BIOTECHNOLOGY JOURNAL, Issue 9 2008Caius M. Rommens Summary Flavonols and caffeoylquinates represent important groups of phenolic antioxidants with health-promoting activities. The genetic potential of potato (Solanum tuberosum) to produce high levels of these dietary compounds has not been realized in currently available commodity varieties. In this article, it is demonstrated that tuber-specific expression of the native and slightly modified MYB transcription factor gene StMtf1M activates the phenylpropanoid biosynthetic pathway. Compared with untransformed controls, transgenic tubers contained fourfold increased levels of caffeoylquinates, including chlorogenic acid (CGA) (1.80 mg/g dry weight), whilst also accumulating various flavonols and anthocyanins. Subsequent impairment of anthocyanin biosynthesis through silencing of the flavonoid-3,,5,-hydroxylase (F3,5,h) gene resulted in the accumulation of kaempferol-rut (KAR) to levels that were approximately 100-fold higher than in controls (0.12 mg/g dry weight). The biochemical changes were associated with increased expression of both the CGA biosynthetic hydroxycinnamoyl-CoA quinate hydroxycinnamoyl transferase (Hqt) gene and the upstream chorismate mutase (Cm) and prephenate dehydratase (Pdh) genes. Field trials indicated that transgenic lines produced similar tuber yields to the original potato variety Bintje. Processed products of these lines retained most of their phenylpropanoids and were indistinguishable from untransformed controls in texture and taste. [source] Abscisic acid is involved in the response of grape (Vitis vinifera L.) cv. Malbec leaf tissues to ultraviolet-B radiation by enhancing ultraviolet-absorbing compounds, antioxidant enzymes and membrane sterolsPLANT CELL & ENVIRONMENT, Issue 1 2010FEDERICO J. BERLI ABSTRACT We investigated the interactions of abscisic acid (ABA) in the responses of grape leaf tissues to contrasting ultraviolet (UV)-B treatments. One-year-old field-grown plants of Vitis vinifera L. were exposed to photosynthetically active radiation (PAR) where solar UV-B was eliminated by using polyester filters, or where PAR was supplemented with UV-B irradiation. Treatments combinations included weekly foliar sprays of ABA or a water control. The levels of UV-B absorbing flavonols, quercetin and kaempferol were significantly decreased by filtering out UV-B, while applied ABA increased their content. Concentration of two hydroxycinnamic acids, caffeic and ferulic acids, were also increased by ABA, but not affected by plus UV-B (+UV-B) treatments. Levels of carotenoids and activities of the antioxidant enzymes, catalase, ascorbate peroxidase and peroxidase were elevated by +ABA treatments, but only if +UV-B was given. Cell membrane , -sitosterol was enhanced by ABA independently of +UV-B. Changes in photoprotective compounds, antioxidant enzymatic activities and sterols were correlated with lessened membrane harm by UV-B, as assessed by ion leakage. Oxidative damage expressed as malondialdehyde content was increased under +UV-B treatments. Our results suggest that the defence system of grape leaf tissues against UV-B is activated by UV-B irradiation with ABA acting downstream in the signalling pathway. [source] First report of non-coloured flavonoids in Echium plantagineum bee pollen: differentiation of isomers by liquid chromatography/ion trap mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2010Federico Ferreres Apicultural products have been widely used in diet complements as well as in phytotherapy. Bee pollen from Echium plantagineum was analysed by high-performance liquid chromatography/photodiode-array detection coupled to ion trap mass spectrometry (HPLC-PAD-MSn) with an electrospray ionisation interface. The structures have been determined by the study of the ion mass fragmentation, which characterises the interglycosidic linkage in glycosylated flavonoids and differentiates positional isomers. Twelve non-coloured flavonoids were characterised, being kaempferol-3- O -neohesperidoside the major compound, besides others in trace amounts. These include quercetin, kaempferol and isorhamnetin glycosides, with several of them being isomers. Acetylated derivatives are also described. This is the first time that non-coloured flavonoids are reported from this pollen, with MS fragmentation proving to be most useful in the elucidation of isomeric structures. Copyright © 2010 John Wiley & Sons, Ltd. [source] Assigning glucose or galactose as the primary glycosidic sugar in 3- O -mono-, di- and triglycosides of kaempferol using negative ion electrospray and serial mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2009Geoffrey C. Kite Kaempferol 3- O - , -glucopyranoside, kaempferol 3- O - , -galactopyranoside and higher glycosides of these two flavonoids with , -rhamnose at C-2 and/or C-6 of the primary sugar were studied by negative ion electrospray ionisation and serial mass spectrometry in a three-dimensional (3D) ion trap mass spectrometer. Kaempferol 3- O - , -glucopyranoside and kaempferol 3- O - , -rhamnopyranosyl(1,6)- , -glucopyranoside could be distinguished from their respective galactose analogues by differences in the ratio of the radical aglycone ion [Y0 , H],, to the rearrangement aglycone ion Y following MS/MS of the deprotonated molecules. Kaempferol 3- O -rhamnopyranosyl(1,2)- , -glucopyranoside and kaempferol 3- O - , -rhamnopyranosyl(1,2)[, -rhamnopyranosyl(1,6)]- , -glucopyranoside could be distinguished from their respective galactose analogues by differences in the product ion spectra of the [(M , H) , rhamnose], ion following serial mass spectrometry. In the triglycoside, it was deduced that this ion resulted from the loss of the rhamnose substituted at 2-OH of the primary sugar by observing that MS/MS of deprotonated kaempferol 3- O - , -glucopyranosyl(1,2)[, -rhamnopyranosyl(1,6)]- , -glucopyranoside showed the loss of glucose and not rhamnose. Thus the class of sugar (hexose, deoxyhexose, pentose) at C-2 and C-6 of the primary sugar can be determined. These observations aid the assignment of kaempferol 3- O -glycosides, having glucose or galactose as the primary glycosidic sugar, in LC/MS analyses of plant extracts, and this can be done with reference to only a few standards. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||