- Synthesis, structural elucidation and antiradical activity of a copper (II) naringenin complex
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Coupling the extraction and derivatization of flavonoids to the Citrus processing industry is attractive from both the environmental and economic points of view. In the present work, the flavonoid naringin, obtained by “green” extraction with a water:ethanol mixture from waste grapefruit industry, was hydrolyzed to obtain naringenin. This flavonoid was used to synthesize the complex trans-di(aqua) bis(7-hydroxy-2-(4-hydroxyphenyl)-4-oxo-5-chromanolato) copper (II). This compound was characterized by spectroscopic techniques (UV/Vis, IR, Raman, NMR and EPR), and by thermal analysis (TG and DSC). Then, a monocrystal of the complex obtained by dissolution and recrystallization in DMF was analyzed by single crystal X-ray diffraction. This is the first report of the crystal structure of a Citrus flavonoid complex. Additionally, its antiradical activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) was determined and compared with that for naringenin, demonstrating that coordination to copper enhances the antiradicalar activity of naringenin. According to the Mulliken population analysis conducted, by copper favors the delocalization and stabilization of the produced radical, since it acts as an electronic density acceptor.
- Celiz, Gustavo,Suarez, Sebastián A.,Arias, Analía,Molina, José,Brondino, Carlos D.,Doctorovich, Fabio
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- Development and evaluation of an HPLC method for accurate determinations of enzyme activities of naringinase complex
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An HPLC method that can separate naringin, prunin, and naringenin was used to help accurately measure the activities of naringinase and its subunits (α-l-rhamnosidase and β-d-glucosidase). The activities of the naringinase and β-d-glucosidase were determined through an indirect calculation of the naringenin concentration to avoid interference from its poor solubility. The measured enzymatic activities of the naringinase complex, α-l-rhamnosidase, and β-d-glucosidase were the as same as their theoretical activities when the substrates' (i.e., naringin or prunin) concentrations were 200 μg/mL, and the enzyme concentrations were within the range of 0.06-0.43, 0.067-0.53, and 0.15-1.13 U/mL, respectively. The β-d-glucosidase had a much higher Vmax than either naringinase or α-l-rhamnosidase, implying the hydrolysis of naringin to prunin was the limiting step of the enzyme reaction. The reliability of the method was finally validated through the repeatability test, indicating its feasibility for the determinations of the naringinase complex.
- Ni, Hui,Xiao, An-Feng,Wang, Ya Qi,Chen, Feng,Cai, Hui-Nong,Su, Wen-Jun
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- Sulfation of naringenin by Cunninghamella elegans
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A new flavonoid sulfate, naringenin-7-sulfate, was obtained by fermentation of naringenin using the fungus Cunninghamella elegans NRRL 1392 in 23% yield. Structural elucidation of the metabolite was achieved using EIMS, UV, IR, 1D and 2D NMR spectroscopy beside acid and enzyme hydrolyses. (C) 2000 Elsevier Science Ltd.
- Ibrahim, Abdel-Rahim S.
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- GLUCOSYLATED FLAVONOIDS AND OTHER PHENOLIC COMPOUNDS FROM SORGHUM
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The principal tannin constituents of sorghum are proanthocyanidins or condensed tannins.Analysis of the methanolic extract of a Hungarian sorghum (szegedi toerpe) containing 6percent catechin equivalents of tannins resulted in the separation and purification of 4 procyanidins having the basic formula epicatechin-(epicatechin)n-catechin and one procyanidin trimer corresponding to epicatechin-catechin-epicatechin.Apart from these procyanidins, the monomeric flavonoids eriodictyol 5-glucoside and (+)-taxifolin 7 glucoside together with their aglycones eriodictyol and taxifolin were found.Glucosylated dimeric and trimeric flavanoids with eriodictyol or eriodictyol 5-glucoside as the lower unit were also identified with the help of negative ion FABMS.Polymeric flavonoids formed between a chalcone and a flavonoid, as yet not identified, are also present in the grain. Key Word Index - Sorghum; Gramineae; flavanoids; glycosides; new oligomer glucosides; procyanidins; chalchone identification.
- Gujer, Rene,Magnolato, Daniele,Self, Ron
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Read Online
- Design, synthesis, and cholinesterase inhibition assay of liquiritigenin derivatives as anti-Alzheimer's activity
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The marine environment is a rich resource for discovering functional materials, and seaweed is recognized for its potential use in biology and medicine. Liquiritigenin has been isolated and identified from Sargassum pallidum. To find new anti-Alzheimer's activity, we designed and synthesized thirty-two 7-prenyloxy-2,3-dihydroflavanone derivatives (3a-3p) and 5-hydroxy-7-prenyloxy-2,3-dihydro-flavanone derivatives (4a-4p) as cholinesterases inhibitors based on liquiritigenin as the lead compound. Inhibition screening against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) indicated that all synthesized compounds possessed potent AChE inhibitory activity and moderated to weak BuChE inhibitory activity in vitro. Kinetic studies demonstrated that compound 4o inhibited AChE via a dual binding site ability. In addition, all compounds displayed the radical scavenging effects. Finally, the molecular docking simulation of 4o in AChE active site displayed good agreement with the obtained the pharmacological results.
- Guan, Liping,Jia, Jinjing,Jiang, Haiying,Peng, Dingxin,Zhang, Li
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- Flavanone compound as well as preparation method and application thereof
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The invention belongs to the technical field of medicines, and particularly relates to a flavanone compound as well as a preparation method and application thereof. Specifically disclosed is a compound represented by formula (I) or a pharmaceutically acceptable salt thereof. The compound shown in the formula (I) can target hURAT1 and/or GLUT9, so that uric acid excretion is promoted, and the effect of reducing uric acid is achieved. The compound can be used for preparing medicines for treating and/or preventing and/or delaying and/or adjunctively treating and/or treating diseases related to hURAT1/GLUT9 activity, and has a good application prospect in preventing or treating diseases (such as gout, gouty arthritis, uric acid kidney stone and the like) related to hyperuricemia.
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Paragraph 0202-0205
(2021/04/17)
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- Discovery of Novel Bacterial Chalcone Isomerases by a Sequence-Structure-Function-Evolution Strategy for Enzymatic Synthesis of (S)-Flavanones
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Chalcone isomerase (CHI) is a key enzyme in the biosynthesis of flavonoids in plants. The first bacterial CHI (CHIera) was identified from Eubacterium ramulus, but its distribution, evolutionary source, substrate scope, and stereoselectivity are still unclear. Here, we describe the identification of 66 novel bacterial CHIs from Genbank using a novel Sequence-Structure-Function-Evolution (SSFE) strategy. These novel bacterial CHIs show diversity in substrate specificity towards various hydroxylated and methoxylated chalcones. The mutagenesis of CHIera according to the substrate binding models of these novel bacterial CHIs resulted in several variants with greatly improved activity towards these chalcones. Furthermore, the preparative scale conversion catalyzed by bacterial CHIs has been performed for five chalcones and revealed (S)-selectivity with up to 96 % ee, which provides an alternative biocatalytic route for the synthesis of (S)-flavanones in high yields.
- Bornscheuer, Uwe T.,Brückner, Stephan I.,Gei?ler, Torsten,Gross, Egon,Hartmann, Beate,Ley, Jakob P.,Meinert, Hannes,R?ttger, Carsten,Schuiten, Eva,Yi, Dong,Zirpel, Bastian
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supporting information
p. 16874 - 16879
(2021/07/06)
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- Covalent Immobilization of Naringinase over Two-Dimensional 2D Zeolites and its Applications in a Continuous Process to Produce Citrus Flavonoids and for Debittering of Juices
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The crude naringinase from Penicillium decumbens and a purified naringinase with high α-L-rhamnosidase activity could be covalently immobilized on two-dimensional zeolite ITQ-2 after surface modification with glutaraldehyde. The influence of pH and temperature on the enzyme activity (in free and immobilized forms) as well as the thermal stability were determined using the specific substrate: p-nitrophenyl-alpha-L-rhamnopyranoside (Rha-pNP). The crude and purified naringinase supported on ITQ-2 were applied in the hydrolysis of naringin, giving the flavonoids naringenin and prunin respectively with a conversion '90 percent and excellent selectivity. The supported enzymes showed long term stability, being possible to perform up to 25 consecutive cycles without loss of activity, showing its high potential to produce the valuable citrus flavonoids prunin and naringenin. We have also succeeded in the application of the immobilized crude naringinase on ITQ-2 for debittering grapefruit juices in a continuous process that was maintained operating for 300 h, with excellent results.
- Carceller, Jose Miguel,Martínez Galán, Julián Paul,Monti, Rubens,Bassan, Juliana Cristina,Filice, Marco,Yu, Jihong,Climent, María J.,Iborra, Sara,Corma, Avelino
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p. 4502 - 4511
(2020/06/08)
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- Novel chromenone derivatives having substituted biphenyl group and a pharmaceutical composition for prevention or treatment of allergic diseases compring the same
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The present invention relates to: a novel chromenone derivative compound capable of effectively suppressing an allergic immune response by inhibiting signal transduction mediated by thymic stromal lymphopoietin (TSLP); and a pharmaceutical composition capable of fundamentally preventing or treating various allergic diseases by using the same.COPYRIGHT KIPO 2021
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Paragraph 0157-0164; 0166-0170
(2020/11/26)
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- Site-selective synthesis of acacetin and genkwanin through lipase-catalyzed deacetylation of apigenin 5,7-diacetate and subsequent methylation
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Candida antarctica lipase B-catalyzed deacetylation proceeded with high site-selectivity on the C-4′ acetyl group in apigenin triacetate to give apigenin 5,7-diacetate. Methylation of the liberated hydroxy group with the combination of trimethyloxonium tetrafluoroborate (Meerwein reagent) and 1,8-bis(dimethylamino)naphthalene (proton sponge) in CH2Cl2 proceeded in a quantitative manner to give the product methylated at the C-4′ hydroxy group (acacetin 5,7-diacetate). Even with the same precursor, a different methylation product at the C-7 hydroxy group (genkwanin 4′,5-diacetate) was obtained in 86% yield by applying iodomethane and Cs2CO3 in dimethyl sulfoxide (DMSO). The methylated products were deprotected to form acacetin and genkwanin. We inferred that the latter unexpected methylation was ascribable to the intermolecular migration of an acetyl group from C-7 to C-4′. DFT calculations indicated that the C-7 phenoxide ion was 12.6 kJ/mol more stable than the initially formed C-4′ phenoxide ion.
- Fujita, Rie,Hanaya, Kengo,Higashibayashi, Shuhei,Mandal, Susanta,Shoji, Mitsuru,Sugai, Takeshi
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p. 638 - 648
(2019/07/31)
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- Chiral separation of novel iminonaringenin derivatives
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A series of 4-iminonaringenin derivatives 2-6 have been prepared in good overall yields from a condensation reaction between naringenin and primary amines. The structures of all products were confirmed by ultraviolet, infrared, proton nuclear magnetic resonance, and carbon-13 nuclear magnetic resonance spectroscopic techniques. These derivatives were analyzed by high-performance liquid chromatography using polysaccharide-based chiral stationary phases, namely, Chiralpak IB and Chiralcel OD, using various mobile phases. 2-Propanol showed a high enantioselectivity for naringin and its derivatives using achiral column containing immobilized polysaccharides (Chiralpak IB).
- Bouanini, Meriem,Belboukhari, Nasser,Menéndez, J. Carlos,Sekkoum, Khaled,Cheriti, Abdelkarim,Aboul-Enein, Hassan Y.
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p. 484 - 490
(2018/04/02)
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- Purification and characterization of an intracellular α-L-rhamnosidase from a newly isolated strain, Alternaria alternata SK37.001
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A strain, Alternaria alternata SK37.001, which produces an intracellular α-L-rhamnosidase, was newly isolated from citrus orchard soil. The molecular mass of the enzyme was 66 kDa, as evaluated by SDS-PAGE and 135 kDa, as determined by gel filtration, which indicated that the enzyme is a dimer. The enzyme had a specific activity of 21.7 U mg?1 after step-by-step purification. The optimal pH and temperature were 5.5 and 60 °C, respectively. The enzyme was relatively stable at a pH of 4.0–8.0 and a temperature between 30 and 50 °C compared with other pH levels and temperatures investigated. The enzyme activity was accelerated by Ba2+ and Al3+ but inhibited by Ni2+, Cu2+ and Co2+, especially Ni2+. The kinetic parameters of Km and Vmax were 4.84 mM and 53.1 μmol mg?1 min?1, respectively. The α-L-rhamnosidase could hydrolyze quercitrin, naringin and neohesperidin, hesperidin and rutin rhamnose-containing glycosides but could not hydrolyze ginsenoside Rg2 or saiko-saponin C.
- Zhang, Tao,Yuan, Wenbo,Li, Mengli,Miao, Ming,Mu, Wanmeng
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- New C-2 diastereomers of flavanone glycosides conjugated with 3-hydroxy-3-methylglutaric acid from the pericarp of Citrus grandis (L.) Osbeck
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Two new 3-hydroxy-3-methylglutaryl (HMG) flavanone 7-O-diglycosides, cigranosides A and B (1 and 2), the known naringenin 7-(2′′-α-rhamnosyl-6′′-(3′′′′-hydroxy-3′′′′-methylglutaryl)-glucoside (melitidin, 3), their common biosynthetic precursor flavanone 7-O-diglycoside (naringin, 4), and one known flavone 7-O-diglycoside (rhoifolin, 5) were isolated from the pericarp of Citrus grandis (L.) Osbeck. The structures of these compounds were elucidated by spectroscopic and chemical techniques. The relative ratios and absolute configurations of the C-2 diastereomers of compounds 1, 2 and 4 were determined by online normal-phase HPLC-CD using a Chiralcel column. The absolute configuration of the HMG fragment in compounds 1–3 was assigned to be S through spectroscopic analysis of the mevalonamide obtained by amidation and reduction of the HMG moiety. The NO inhibitory activities of compounds 1–5 were evaluated using lipopolysaccharide-induced RAW264.7 cells. Compounds 1–5 were not cytotoxic to RAW264.7 cells at 10 μM.
- Ma, Shuang-Gang,Wang, Ru-Bing,Li, Wen-Rui,Liu, Yun-Bao,Qu, Jing,Li, Yong,Wang, Xiao-Jing,Xu, Song,Yu, Shi-Shan
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p. 519 - 524
(2018/07/25)
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- 5,7-Dihydroxy-2-(4-hydroxyphenyl)chroman-4-one (naringenin): X-ray diffraction structures of the naringenin enantiomers and DFT evaluation of the preferred ground-state structures and thermodynamics for racemization
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The R- and S-enantiomers of naringenin were separated by chiral supercritical fluid (SCF) and the absolute configuration of each enantiomer was established by X-ray crystallography. The solid-state data is in agreement with the reported circular dichroism spectra. Both enantiomers crystallize in the monoclinic crystal system in the space group P21 with two independent molecules in the asymmetric unit. In all molecules, the pyrone ring adopts a flattened chair-like conformation in which the C1 atom deviates from the plane drawn through the remaining five atoms of this heterocycle. The 4-hydroxyphenyl substituent located at C1 of the pyrone ring occupies an equatorial position and lies in a plane that is almost perpendicular to the aromatic platform associated with the heterocyclic portion of the molecule. Strong intramolecular O-H?O hydrogen bonding exists between the carbonyl moiety and the aryl hydroxyl group at C5. In both enantiomers, a favorable mutual orientation of two independent molecules promotes the formation of intermolecular O-H?O hydrogen bonds that link them into dimers. There are additional long-range intermolecular O-H?O hydrogen bonds and weak C-H?O contacts within the unit cell of each enantiomer that connect dimers in an extended network. DFT calculations have been performed and the thermodynamics for naringenin racemization via an acyclic chalcone have been computed. Eight energetically accessible conformations have been verified for S-naringenin.
- Nesterov, Volodymyr V.,Zakharov, Lev N.,Nesterov, Vladimir N.,Calderon, Jose G.,Longo, Antonella,Zaman, Khadiza,Choudhury, Feroza Kaneez,Farrell, William,Shulaev, Vladimir,Richmond, Michael G.
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p. 994 - 1000
(2016/12/18)
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- Enantioselective modulatory effects of naringenin enantiomers on the expression levels of miR-17-3p involved in endogenous antioxidant defenses
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Naringenin is a flavanone present in citrus fruit as a mixture of chiral isomers. The numerous biological properties attributed to this compound include antioxidant and anti-inflammatory activities, even though the molecular mechanisms of these remain unknown. This study aims to evaluate the effects of racemic and enantiomeric naringenin on the expression levels of miR-17-3p, miR-25-5p and relative mRNA targets, to elucidate the mechanisms underlying these antioxidant and anti-inflammatory properties. Caco-2 cells, a well characterized in vitro model which mimics the intestinal barrier, were treated with subtoxic concentrations of racemate and enantiomers. The expression levels of miR-17-3p and miR-25-5p were determined by Real-Time PCR and were found to be decreased for both miRNAs. miR-17-3p behavior was in agreement with the increased levels of target mRNAs coding for two antioxidant enzymes, manganese-dependent superoxide dismutase (MnSOD) and glutathione peroxidase 2 (GPx2), while expression levels of miR-25-5p were not in agreement with its target mRNAs, coding for two pro-inflammatory cytokines, Tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6). These results lead to the conclusion that naringenin could exert its antioxidant activity through epigenetic regulation operated by miRNAs, while anti-inflammatory activity is regulated by other miRNAs and/or mechanisms.
- Curti, Valeria,Di Lorenzo, Arianna,Rossi, Daniela,Martino, Emanuela,Capelli, Enrica,Collina, Simona,Daglia, Maria
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- Functionalities tuned enantioselectivity of phenylcarbamate cyclodextrin clicked chiral stationary phases in HPLC
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The mixed chloro- and methyl- functionalities can greatly modulate the enantioselectivities of phenylcarbamate cyclodextrin (CD) clicked chiral stationary phases (CSPs). A comparison study is herein reported for per(4-chloro-3-methyl)phenylcarbamate and per(2-chloro-5-methyl)phenylcarbamate β-CD clicked CSPs (i.e., CCC4M3-CSP and CCC2M5-CSP). The enantioselectivity dependence on column temperature was studied in both normal-phase and reversed-phase mode high performance liquid chromatography (HPLC). The thermodynamic study revealed that the stronger intermolecular interactions can be formed between CCC4M3-CSP and chiral solutes to drive the chiral separation. The higher enantioselectivities of CCC4M3-CSP were further demonstrated with the enantioseparation of 17 model racemates in HPLC.
- Tang, Jian,Lin, Yuzhou,Yang, Bo,Zhou, Jie,Tang, Weihua
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p. 566 - 573
(2017/08/26)
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- Macroporous resin auxiliary various glycoside hydrolysis to prepare their aglycon, secondary glucoside method
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Various glycoside compounds and particularly glycoside compounds which are unstable, easy to oxidize and difficult to dissolve in water and an organic solvent are hydrolyzed under the actions of adsorption, dispersion, curing and settlement of macroporous adsorption resin to generate aglycone or a mixture of the aglycone and secondary glucoside, and the macroporous adsorption resin is secondarily eluted or primarily eluted by using an organic solvent to obtain aglycone, secondary glucoside and a mixture of the aglycone and the secondary glucoside. The invention provides a universal method for preparing the aglycone and the secondary glucoside by using the various glycoside compounds, the method is simple in operation, almost integrated in hydrolysis and separation, high in product purity, good in product yield, free of expensive reagent, capable of realizing repeated utilization of hydrolysate and the macroporous adsorption resin, environment-friendly, easy for realizing industrial production and low in cost and has great advantages as comparison with an enzyme hydrolysis method, a fermentation method and the like. By taking the hydrolysis of the total saponin of panax ginseng as an example, through the hydrolysis of acetic acid and other acids, more prosapogenins Rh2 of panax ginseng and protopanaxadiol aglycones are obtained, but a C17 side chain cyclization product is not obvious.
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Paragraph 0030-0033
(2017/08/23)
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- Biomimetic synthesis and HPLC-ECD analysis of the isomers of dracocephins A and B
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Starting from racemic naringenin ((±)-1), a mixture of dracocephin A stereoisomers 6-(2″-pyrrolidinone-5″-yl)naringenin (±)-2a-d and its regioisomer, dracocephin B 8-(2″-pyrrolidinone-5″-yl)naringenin (±)-3a-d originally isolated from Dracocephalum rupestre, have been synthesized in a one-pot reaction. The separation of 2a-d and 3a-d was achieved by preparative HPLC. The four stereoisomers of each natural product were separated by analytical chiral HPLC and their absolute configuration was studied by the combination of HPLC-ECD measurements and TDDFT-ECD calculations. The synthesized flavonoid alkaloids were further characterized by physicochemical and in vitro pharmacological studies.
- Ilkei, Viktor,Spaits, András,Prechl, Anita,Szigetvári, áron,Béni, Zoltán,Dékány, Miklós,Szántay, Csaba,Müller, Judit,K?ncz?l, árpád,Szappanos, ádám,Mándi, Attila,Antus, Sándor,Martins, Ana,Hunyadi, Attila,Balogh, Gy?rgy Tibor,Kalaus, Gy?rgy,B?lcskei, Hedvig,Hazai, László,Kurtán, Tibor
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p. 2523 - 2534
(2016/12/07)
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- MICROBIAL PRODUCTION OF THE FLAVONOIDS GARBANZOL, RESOKAEMPFEROL AND FISETIN
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The invention provides a genetically modified micro-organism comprising one or more transgene for the production of one or more of the flavonoids garbanzol, resokaempferol and fisetin. The micro-organism may be a bacterial or yeast cell engineered to express a metabolic pathway for garbanzol, resokaempferol and/or fisetin biosynthesis. The invention further provides a method for producing garbanzol, resokaempferol and/or fisetin employing the genetically modified micro-organism of the invention. The genetically modified micro- organism may be used to convert a number of substrates and/or co-substrates into fisetin via a fisetin biosynthetic pathway.
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Page/Page column 39; 40
(2016/06/01)
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- Method for preparing a naringenin
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The invention provides a preparation method of naringenin. The preparation method of the naringenin comprises the steps that naringin is mixed with a hydrochloric acid solution to be hydrolyzed, solids are separated out, and wet crude naringenin is obtained through washing after the solids are treated with suction filtration; acetum is added, stirring is carried out twice, the solids are washed with water after being filtered and pass through a neutral alumina chromatographic column after being dissolved by means of ethyl alcohol, activated carbon is added to achieve decoloration and then filtering is carried out, obtained filter liquor is heated and concentrated, distilled water is added when the filter liquor is hot to enable the filter liquor to be cooled and crystallized to obtain wet fine naringenin, and the wet fine naringenin is recrystallized and then is dried to obtain the naringenin. According to the preparation method of the naringenin, due to the fact that the hydrochloric acid is used as the solvent during acid hydrolysis, cost is saved, and operation processes are simplified; due to the fact that the acetic acid is used for washing and impurities are absorbed by means of the neutral aluminium oxide chromatographic column in the postprocessing process, the naringenin with the content more than 99% is obtained through recrystallization once, the quality standard of a naringenin comparison product is met, the naringenin content is high, and the yield is high.
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Paragraph 0017-0020
(2017/02/23)
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- Preparation method of flavone aglycone or monoglycoside from aluminum-salt-flavonoid-glycoside complex through hydrolysis
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Disclosed is a preparation method of flavone aglycone or monoglycoside from aluminum-salt-flavonoid-glycoside complex through hydrolysis. The problems that flavonoid glycosides neither dissolve in water nor are hard to dissolve in a common organic alcohol solution, and flavone aglycone prepared from hydrolysis has slow hydrolysis speed, needs a large amount of an organic solvent, and cannot be totally hydrolyzed are solved. A complex product from complexation of aluminum salt and flavonoid glycosides is easy to dissolve in alcohol, hydrogen chloride generated by the complex product is utilized with addition of hydrochloric acid or sulfuric acid, and hydrolysis is carried out at a certain temperature to prepare aglycone or a mixture of aglycone and monoglycoside. After the reaction is over, phosphoric acid or phosphate is added to break complexation of aluminum ions and flavone to obtain flavone aglycone, or the mixture of flavone aglycone and flavone monoglycoside, or a mixture of flavone aglycone, flavone monoglycoside, and flavonoid glycoside. The method is simple and easy to operate, relatively high in yield and purity, and extremely low in cost, and is suitable for massive industrial production of flavone aglycone or the mixture of flavone aglycone and flavone monoglycoside.
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Paragraph 0017
(2016/10/31)
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- Practical synthesis of naringenin
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Two routes for the synthesis of the flavanone naringenin are described. In the first, 3,5-dimethoxyphenol is converted to 2-hydroxy- 4,6-dimethoxyacetophenone and then by condensation with anisaldehyde to 2′-hydroxy-4,4′,6′-trimethoxychalcone. The chalcone is then cyclised with aqueous hydrochloric acid and demethylated with pyridine hydrochloride to form naringenin in 45% overall yield. The condensation of 2-hydroxy-4,6-dimethoxyacetophenone with anisaldehyde could also directly produce 4′,5,7-trimethoxyflavanone, which was then converted into naringenin in 60% overall yield. In the second route, a single step for the preparation of the chalcone is used in which 1,3,5-trimethoxybenzene is acylated with p-methoxycinnamic acid. Although the synthesis of naringenin is achieved in a lower overall yield of 29%, the process is simpler.
- Wang, Qian,Yang, Jian,Zhang, Xiang-Ming,Zhou, Lei,Liao, Xia-Li,Yang, Bo
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p. 455 - 457
(2015/11/03)
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- A novel synthesis of naringenin and related flavanones
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Efficient methods are reported for the preparation of naringenin (4',5,7-trihydroxyflavanone) which could be easily scaled-up. They have been applied to three other flavanones (6.hydroxyflavanone, 6,4'-dihydroxyflavanone, 6,3',4'-trihydroxyflavanone) suitably.
- Cui, Wei,Zhang, Ji,Wang, Qian,Gao, Kai,Zhang, Wei,Yang, Jian
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p. 686 - 689
(2015/02/19)
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- Hydrolysis of scutellarin and related glycosides to scutellarein and the corresponding aglycones
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Scutellarein has been prepared by the hydrolysis of scutellarin with sulfuric acid to provide this biologically important rare flavone in up to > 90% yield and on the 5 g scale in minutes. This protocol has been applied to five other flavonoid glycosides (rutin, hesperidin, naringin, baicalin and diosmin) which are readily hydrolysed to their corresponding aglycones.
- Zhang, Wei,Yi, Dong,Gao, Kai,Liu, Manshuo,Yang, Jian,Liao, Xiali,Yang, Bo
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p. 396 - 398
(2014/08/05)
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- α-Rhamnosidase activity in the marine isolate Novosphingobium sp. PP1Y and its use in the bioconversion of flavonoids
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Crude protein extracts of Novosphingobium sp. PP1Y, a microorganism isolated from polluted marine waters in Pozzuoli (Italy), were analyzed for the presence of glycosidase activities. Particular attention was devoted to a α-L-rhamnosidase activity able to hydrolyze several flavonoids of interest for the pharmaceutical and food industries. This activity had an alkaline pH optimum and a moderate tolerance to the presence of organic solvents, appealing features for its possible biotechnological uses. An increase of the α-L-rhamnosidase activity in PP1Y crude extracts was induced by adding naringin to the growth medium, suggesting the possibility to use material from Citrus industrial waste to induce the glycosidase activity expressed by strain PP1Y and produce simultaneously high-added-value molecules from the hydrolysis of their flavonoids. In order to investigate on the enzymatic mechanism of PP1Y α-L-rhamnosidase activity, hydrolysis products of PNP-α-L- rhamnopyranoside were analyzed by 1H-NMR experiments. The kinetic behaviour clearly indicated an inverting mechanism of hydrolysis for this novel enzymatic activity.
- Izzo, Viviana,Tedesco, Pietro,Notomista, Eugenio,Pagnotta, Eduardo,Di Donato, Alberto,Trincone, Antonio,Tramice, Annabella
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- Semisynthesis of polymethoxyflavonoids from naringin and hesperidin
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Polymethoxyflavonoids (PMFs) possess important biological activities, notably as anticancer agents. Semisynthesis of a series of PMFs were performed by glycoside hydrolysis, dehydrogenation, bromination, aromatic nucleophilic substitution, O-methylation, dimethyldioxirane oxidation and regioselective demethylation, starting from abundant and inexpensive natural sources naringin and hesperidin. A new synthetic method for selective methylation using CuBr catalysed and microwave-assisted reaction was developed, and the dimethyl dioxirane oxidation of flavones to flavonols was much improved. The new semisynthetic route has the advantages of easy availability of starting materials, simple operation and good yields.
- Li, Yue,Cai, Shuanglian,He, Kailin,Wang, Qiuan
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p. 287 - 290
(2014/06/09)
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- Purification and characterization of a naringinase from Aspergillus aculeatus JMUdb058
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A naringinase from Aspergillus aculeatus JMUdb058 was purified, identified, and characterized. This naringinase had a molecular mass (MW) of 348 kDa and contained four subunits with MWs of 100, 95, 84, and 69 kDa. Mass spectrometric analysis revealed that the three larger subunits were β-d-glucosidases and that the smallest subunit was an α-l-rhamnosidase. The naringinase and its α-l-rhamnosidase and β-d-glucosidase subunits all had optimal activities at approximately pH 4 and 50 C, and they were stable between pH 3 and 6 and below 50 C. This naringinase was able to hydrolyze naringin, aesculin, and some other glycosides. The enzyme complex had a Km value of 0.11 mM and a kcat/Km ratio of 14 034 s-1 mM -1 for total naringinase. Its α-l-rhamnosidase and β-d-glucosidase subunits had Km values of 0.23 and 0.53 mM, respectively, and kcat/Km ratios of 14 146 and 7733 s -1 mM-1, respectively. These results provide in-depth insight into the structure of the naringinase complex and the hydrolyses of naringin and other glycosides.
- Chen, Yuelong,Ni, Hui,Chen, Feng,Cai, Huinong,Li, Lijun,Su, Wenjin
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p. 931 - 938
(2013/08/24)
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- An eco-friendly enantioselective access to (R)-naringenin as inhibitor of proinflammatory cytokine release
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(RS)-Naringenin is a flavanone well-known for its beneficial health-related properties, such as its anti-inflammatory activity. The preparative enantioselective chromatographic resolution of commercial (RS)-naringenin was performed on a Chiralpak AD-H column (500×50 mm i.d., dp 20 μm) using MeOH as eluent. The developed method is in accordance with the principles of green chemistry, since the environmental impact was lowered by recycling of the eluent, and allowed the production of gram amounts of each enantiomer with high purity (chemical purity >99%, enantiomeric excess (ee) >94%). Racemic and enantiomeric naringenin were subjected to an exhaustive in vitro investigation of anti-inflammatory activity, aimed at evaluating the relevance of chirality. The assay with cultured human peripheral blood mononuclear cells (hPBMC) activated by phytohemagglutinin A revealed that (R)-naringenin was more effective in inhibiting T-cell proliferation than the (S)-enantiomer and the racemate. Moreover, (R)-naringenin significantly reduced proinflammatory cytokine levels such as those of TNF-α and, with less potency, IL-6. These results evidenced the anti-inflammatory potential of naringenin and the higher capacity of (R)-naringenin to inhibit both in vitro hPBMC proliferation and cytokine secretion at non toxic doses. Thus, (R)-naringenin is a promising candidate for in vivo investigation. Copyright
- Gaggeri, Raffaella,Rossi, Daniela,Daglia, Maria,Leoni, Flavio,Avanzini, Maria Antonia,Mantelli, Melissa,Juza, Markus,Collina, Simona
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p. 1531 - 1538
(2013/09/12)
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- Cloning and structure-function analyses of quinolone- and acridone-producing novel type III polyketide synthases from citrus microcarpa
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Background:Type III polyketide synthases (PKSs) synthesize various polyketide and alkaloid scaffolds. Results:QNS synthesizes quinolone as the single product, whereas ACS produces acridone as the major product. Conclusion:QNS and ACS are novel quinolone- and acridone-producing type III PKSs, respectively. Significance:Structure-function analyses of QNS and ACS provide insights into molecular bases for alkaloid biosyntheses.
- Mori, Takahiro,Shimokawa, Yoshihiko,Matsui, Takashi,Kinjo, Keishi,Kato, Ryohei,Noguchi, Hiroshi,Sugio, Shigetoshi,Morita, Hiroyuki,Abe, Ikuro
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p. 28845 - 28858
(2013/10/22)
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- PREPARATION METHOD OF CHROMENONE DERIVATIVES USING RADIATION
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A preparation method of chromenone derivatives using radiation is provided. The preparation method exposes commercially-available silybin in reaction solvent to radiation, to thereby concurrently obtain both dehydrosilybin and apigenin compounds, which are chromenone compounds, in a simple reaction step and with high yield. Because the compounds are prepared at economic cost, the preparation method can be advantageously used particularly for the purpose of mass production. Further, in consideration of good cancer cell viability suppression effect thereof, dehydrosilybin and apigenin prepared according to the preparation method can be advantageously used as a pharmaceutical composition for prevention and treatment of cancer.
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Paragraph 0054; 0055
(2013/06/27)
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- Synthesis, structure-activity relationship analysis and kinetics study of reductive derivatives of flavonoids as Helicobacter pylori urease inhibitors
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In a continuing study for discovering urease inhibitors based on flavonoids, nineteen reductive derivatives of flavonoids were synthesized and evaluated against Helicobacter pylori urease. Analysis of structure-activity relationship disclosed that 4-deoxy analogues are more potent than other reductive products. Out of them, 4′,7,8-trihydroxyl-2-isoflavene (13) was found to be the most active with IC50 of 0.85 μM, being over 20-fold more potent than the commercial available urease inhibitor, acetohydroxamic acid (AHA). Kinetics study revealed that 13 is a competitive inhibitor of H. pylori urease with a Ki value of 0.641 μM, which is well matched with the results of molecular docking. Biological evaluation and mechanism study of 13 suggest that it is a good candidate for discovering novel anti-gastritis and anti-gastric ulcer agent.
- Xiao, Zhu-Ping,Peng, Zhi-Yun,Dong, Jing-Jun,He, Juan,Ouyang, Hui,Feng, Yu-Ting,Lu, Chun-Lei,Lin, Wan-Qiang,Wang, Jin-Xiang,Xiang, Yin-Ping,Zhu, Hai-Liang
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p. 685 - 695
(2013/07/25)
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- Cloning and functional characterization of a chalcone isomerase from trigonella foenum-graecum L
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Flavonoids belong to a group of plant natural products with variable phenolic structures and play important roles in protection against biotic and abiotic stress. Fenugreek (Trigonella foenum-graecum L.) seeds and stems contain flavonol glycosides and isoflavone derivatives. Up to now, the molecular features of fenugreek flavonoid biosynthesis have not been characterized. Here we present cloning of a cDNA encoding a chalcone isomerase (namely TFGCHI1) from the leaves of T. foenum-graecum which convert chalcones to flavanones in vitro. Transformation of Arabidopsis loss-of-function tt5 (chi) mutant with a TFGCHI1 cDNA complemented tt5 and produced higher levels of flavonol glycosides than wild-type Col-0. Georg Thieme Verlag KG Stuttgart · New York.
- Qin, Jian-Chun,Zhu, Lin,Gao, Ming-Jun,Wu, Xian,Pan, Hong-Yu,Zhang, Yan-Sheng,Li, Xiang
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experimental part
p. 765 - 770
(2012/03/11)
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- Enantiomers of naringenin as pleiotropic, stereoselective inhibitors of cytochrome P450 isoforms
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Interactions between naringenin and the cytochrome P450 (CYP) system have been of interest since the first demonstration that grapefruit juice reduced CYP3A activity. The effects of naringenin on other CYP isoforms have been less investigated. In addition
- Lu, Wenjie Jessie,Ferlito, Valentina,Xu, Cong,Flockhart, David Alastair,Caccamese, Salvatore
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experimental part
p. 891 - 896
(2012/07/13)
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- Chemical composition and biological activity of Citrus jambhiri Lush
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The fresh peel of Citrus jambhiri was extracted with aqueous methanol and the residue was fractionated using light petroleum, chloroform and ethyl acetate. The constituents of the extracts were separated by column chromatography employing solvents of different polarity. The chemical structure of the isolated compounds was then identified by MS and NMR. Column chromatography of the petroleum fraction resulted in the isolation of nobiletin, 5-O-demethylnobiletin, tangeretin, 5-hydroxy-3,6,7,8,3′,4′- hexamethoxyflavone, 3,5,6,7,8,3′,4′-heptamethoxyflavone, and a mixture of β-sitosterol and stigmasterol. The chloroform fraction afforded 6-demethoxynobiletin, 5,4′-dihydroxy-6,7,8,3′-tetramethoxyflavone, limonin and nomilin. The flavonoid glycosides naringin, hesperidin and neohesperidin were isolated from the ethyl acetate fraction. The chemical structure of the isolated compounds was established by MS and NMR (APT, COSY, HSQC, HMBC, and NOESY). LC-ESI-MS analysis of the ethyl acetate fraction afforded eight flavonoid glycosides, while the dichloromethane fraction of the defatted seeds contained seven limonoid aglycones. The chloroform fraction exerted the strongest DPPH* free radical scavenging activity in comparison to other fractions. The petroleum fraction showed a significant inhibition of lipoxygenase indicating an anti-inflammatory action (IC50 29 ± 1 μg/mL). Some of the isolated polymethoxyflavones exhibited strong cytotoxicity against COS7, HeLa and Caco-2 cell lines.
- Hamdan, Dalia,El-Readi, Mahmoud Zaki,Tahrani, Ahmad,Herrmann, Florian,Kaufmann, Dorothea,Farrag, Nawal,El-Shazly, Assem,Wink, Michael
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p. 394 - 403
(2013/01/09)
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- Active Compound Combinations
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Compositions comprising a (A) dithiino-tetracarboximide of formula (I) and at least one agriculturally beneficial biological control agent (B) are disclosed. A method for curatively or preventively controlling phytopathogenic fungi of plants or crops is disclosed. A method for treating seed and a method for protecting seed are disclosed.
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- Pressure-enhanced activity and stability of α-l-rhamnosidase and β-d-glucosidase activities expressed by naringinase
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Naringinase is an enzyme complex, expressing α-l-rhamnosidase and β-d-glucosidase activities. The impact of high pressure and temperature on naringinase activity and stability were studied, in order to assess the potential of enzyme thermostability on glycosides hydrolyses. To a better understanding of these effects on naringinase enzyme complex, they were also evaluated over α-l-rhamnosidase and β-d-glucosidase activities, using specific substrates, p-nitrophenyl α-l-rhamnopyranoside (4-NRham) and p-nitrophenyl β-d-glucopyranoside (4-NGluc), respectively. Hydrolysis rate of 4-NRham and naringin increased with pressure from 0.1 to 150 MPa. The equilibrium constants for α-l-rhamnosidase and β-d-glucosidase reactions, at pressures of 0.1-200 MPa and 40 °C, were determined and best fitted with the model of Baliga and Whalley equation. Accordingly, reaction volumes of 93 and 64 mL mol-1 were obtained for α-l-rhamnosidase and β-d-glucosidase reactions, respectively. Reaction rate constants were also determined at the same experimental conditions and well fitted to the models of Golinkin, Laidlaw, Hyne and of Burris and Laidler. A negative ΔV≠ of -7.7 ± 1.5 and -20.0 ± 5.2 mL mol-1 were obtained for α-l-rhamnosidase and naringinase reactions, correspondingly, which reflect the accelerating effect of pressure on the biocatalysis. Moreover, the KM, kcat and kcat/KM values, on naringin hydrolysis under atmospheric (0.1 MPa) and high pressure (150 MPa) conditions at different temperatures (25-80 °C) were determined. A 3-fold and 4-fold increase on naringinase thermostability was observed under 150 MPa at 70 and 80 °C, respectively, compared to 0.1 MPa experiments. In addition, a 15-fold increase of kcat/kM values from experimental conditions of 0.1 MPa and 30 °C to 150 MPa and 70 °C was observed. In fact, high pressure showed to be a powerful tool to increase stability of naringinase against thermal denaturation. In conclusion, the effect of amplification of pressure effects on reaction rates by temperature could have a pragmatic use for accelerating enzymatic reactions.
- Vila-Real, Helder,Alfaia, Antonio J.,Phillips, Robert S.,Calado, Antonio R.,Ribeiro, Maria H.L.
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experimental part
p. 102 - 109
(2011/02/16)
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- Improvement of activity and stability of soluble and sol-gel immobilized naringinase in co-solvent systems
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The hydrolysis of naringin, a bitter flavonone glycoside, with naringinase leads to reducing sugars (rhamnose and glucose), to prunin and to the aglycone, naringenin. To overcome the low solubility of naringin in the enzymatic reaction media, the effect of different solvents was studied, in order to improve the productivity and yield of the system. The effect of increasing concentration of co-solvents on the stability of both soluble and immobilized naringinase expressing α-l-rhamnosidase and β-d-glucosidase activities was evaluated. The enzyme was immobilized onto sol-gel matrices of tetramethoxysilane and glycerol. Combining the higher naringin solubility, and the higher residual activity of both α-l-rhamnosidase and β-d-glucosidase expressed by naringinase, eight solvents were chosen for stability and activity studies: dimethyl sulfoxide, N,N-dimethylmethanamide, methanol, ethanol, acetone, tetrahydrofurane, 1,2-dimethoxyethane and 1,4-dioxane. Deactivation of soluble naringinase was analyzed according to a first-order kinetic model. For the sol-gel immobilized enzyme the two-step deactivation model, of Henley and Sadana, was adjusted. Sol-gel immobilization stables naringinase in all tested co-solvents systems. This effect was specially pronounced at higher co-solvent concentration (10%). The half-life of α-l-rhamnosidase and β-d-glucosidase expressed by naringinase even increased 21- and 59-fold, respectively, in aqueous co-solvation with tetrahydrofurane. These are high innovative and sounding results showing the protective effect of immobilization onto sol-gel (tetramethoxysilane + glycerol) matrices with naringinase in co-solvent systems, which is a great advantage for non-conventional biocatalysis.
- Vila-Real, Helder,Alfaia, Antonio J.,Calado, Antonio R.,Ribeiro, Maria H.L.
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experimental part
p. 91 - 101
(2010/11/19)
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- Biotransformation of naringin and naringenin by cultured Eucalyptus perriniana cells
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The biotransformation of naringin and naringenin was investigated using cultured cells of Eucalyptus perriniana. Naringin (1) was converted into naringenin 7-O-β-d-glucopyranoside (2, 15%), naringenin (3, 1%), naringenin 5,7-O-β-d-diglucopyranoside (4, 15
- Shimoda, Kei,Kubota, Naoji,Taniuchi, Koji,Sato, Daisuke,Nakajima, Nobuyoshi,Hamada, Hatsuyuki,Hamada, Hiroki
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experimental part
p. 201 - 205
(2010/05/17)
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- Statin-like principles of bergamot fruit (Citrus bergamia): Isolation of 3-hydroxymethylglutaryl flavonoid glycosides
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The 3-hydroxy-3-methylglutaryl neohesperidosides of hesperetin (brutieridin, 1) and naringenin (melitidin, 2) were isolated and detected from the fruits of bergamot (Citrus bergamia). The structures of these compounds were determined by spectroscopic and
- Di Donna, Leonardo,De Luca, Giuseppina,Mazzotti, Fabio,Napoli, Anna,Salerno, Raffaele,Taverna, Domenico,Sindona, Giovanni
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supporting information; experimental part
p. 1352 - 1354
(2009/12/29)
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- Medicinal flowers. xxvii.1) New flavanone and chalcone glycosides, arenariumosides i, ii, iii, and iv, and tumor necrosis factor-α inhibitors from everlasting, flowers of helichrysum arenarium
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The methanolic extract from the flowers of Helichrysum arenarium L. Moench was found to show inhibitory effect on tumor necrosis factor-α (TNF-α, 1 ng/ml)-induced cytotoxicity in L929 cells. From the methanolic extract, 50 constituents including four new
- Toshio Morikawa,Li-Bo Wang,Seikou Nakamura,Kiyofumi Ninomiya,Eri Yokoyama,Hisashi Matsuda,Osamu Muraoka,Li-Jun Wu,Yoshikawa, Masayuki
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experimental part
p. 361 - 367
(2009/12/26)
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- C-Glucosylflavonoid biosynthesis from 2-hydroxynaringenin by Desmodium uncinatum (Jacq.) (Fabaceae)
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[2′,3′,5′,6′-2H4]-2-Hydroxynaringenin is synthesised and incubated with commercially available UDP-glucose and the crude protein extract from Desmoduim uncinatum leaves. The organic extract produces isotopically labelled [2′,3′,5′,6′-2H4]-vitexin and [2′,3′,5′,6′-2H4]-isovitexin. Repeating the experiment with denatured protein or replacing the 2-hydroxynaringenin with [2′,3′,5′,6′-2H4]-apigenin or [2′,3′,5′,6′-2H4]-naringenin results in no observable incorporation. 2-Hydroxynaringenin is therefore the substrate for C-glucosylflavonoid biosynthesis in D. uncinatum.
- Hamilton, Mary L.,Caulfield, John C.,Pickett, John A.,Hooper, Antony M.
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scheme or table
p. 5656 - 5659
(2011/02/24)
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- In vitro precursor-directed synthesis of polyketide analogues with coenzyme a regeneration for the development of antiangiogenic agents
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Polyketide analogues are produced via in vitro reconstruction of a precursor-directed polyketide biosynthetic pathway. Malonyl-CoA synthetase (MCS) was used in conjunction with chalcone synthase (CHS), thereby allowing efficient use of synthetic starter molecules and malonate as extender. Coenzyme-A was recycled up to 50 times. The use of a simple immobilization procedure resulted in up to a 30-fold higher yield of pyrone CHS products than that obtained with the free enzyme solutions.
- Kim, Moon I.I.,Kwon, Seok Joon,Dordick, Jonathan S.
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supporting information; experimental part
p. 3806 - 3809
(2009/12/09)
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- Site-specific fluorescent labeling approaches for naringenin, an essential flavonone in plant nitrogen-fixation signaling pathways
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(Chemical Equation Presented) In search of an appropriate position for the fluorescent labeling, six chemically available positions of the flavonone core of naringenin have been examined. A number of azido-containing naringenin derivatives were accordingly prepared in various site-specific fashions, and the mild Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition successfully served as the common "Click" labeling tool in the final steps. On the basis of the biological activities of the first batch of labeled compounds, further optimization at the C-6 position of naringenin finally afforded naringenin-flu (27), which acquired 20% of the potency of naringenin and presented good optical properties. Entry of naringenin-flu into living Rhizobium cells was demonstrated by in vitro fluorescent imaging experiments.
- Chen, Lei,Li, Feng-Qing,Hou, Bi-He,Hong, Guo-Fan,Yao, Zhu-Jun
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supporting information; experimental part
p. 8279 - 8285
(2009/04/11)
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- (±)-Diinsininone: made nature's way
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We report the synthesis of diinsininone (33), the aglycone of (±)-diinsinin (2). Thereby, we complete the first construction of a proanthocyanidin (PA) type-A compound incorporating a [3.3.1]-bicyclic ketal as its characteristic core. Our strategy utilizes a coupling between a benzopyrilium salt and a flavanone that proves applicable to other PA type-A compounds. During this undertaking, treatment of naringenin (9) with 2-iodoxybenzoic acid (IBX) followed by reductive work-up affords eriodictyol (10). This reactivity mirrors that of catechol hydroxylase (F3H) found in the flavonoid pathway. 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.
- Selenski, Carolyn,Pettus, Thomas R.R.
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p. 5298 - 5307
(2007/10/03)
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- Cyclohexanoid protoflavanones from the stem-bark and roots of Ongokea gore
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Phytochemical investigation of root and stem-bark of the West African medicinal plant Ongokea gore resulted in the isolation of four novel flavonoids with an unusual cyclohexyl substituent instead of the common aromatic ring B. The structures of the isolated compounds were elucidated by spectroscopic methods, mainly 1D and 2D NMR, and subsequently, the structures were corroborated by chemical conversion to (-)-(S)-sakuranetin. The absolute configurations, and preferred conformations were determined by NOE experiments and CD measurements.
- Jerz, Gerold,Waibel, Reiner,Achenbach, Hans
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p. 1698 - 1706
(2008/02/01)
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- O-demethylation and sulfation of 7-methoxylated flavanones by Cunninghamella elegans
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Metabolism of 7-O-methylnaringenin (sakuranetin) by Cunninghamella elegans NRRL 1392 yielded naringenin and naringenin-4′-sulfate. C. elegans also converted 5,3′,4′-trihydroxy-7-methoxyflavanone into eriodictyol-4′-sulfate. Furthermore, incubation of 5,4′
- Ibrahim, Abdel-Rahim Sayed,Galal, Ahmed Mohamed,Ahmed, Mohammed Shamim,Mossa, Gabir Salem
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p. 203 - 206
(2007/10/03)
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- Aromatase inhibitors from Broussonetia papyrifera
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A composition and method of cancer treatment is disclosed. The composition and method utilized the extract of B. papyrifera, or compounds included therein having aromatase inhibition properties, as active cancer chemopreventative and treating agents in mammals, including humans.
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- New potent antioxidative hydroxyflavanones produced with Aspergillus saitoi from flavanone glycoside in citrus fruit.
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Potent antioxidative hydroxyflavanones were produced with Aspergillus saitoi from hesperidin or naringin, which are flavanone glycosides in citrus fruit with weak antioxidative activity. The hydroxyflavanone produced from hesperidin was identified as 8-hydroxyhesperetin (8-HHE), a novel substance, and those from naringin were identified as carthamidin (6-hydroxynaringenin) and isocarthamidin (8-hydroxynaringenin) by FAB-MS, 1H-NMR and 13C-NMR analyses. The antioxidative activity of these hydroxyflavanones was examined by using the free radical-scavenging system of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the methyl linoleate oxidation system. The hydroxyflavanones (8-HHE, carthamidin, and isocarthamidin) exhibited stronger activity than the flavanone glycosides (hesperidin or naringin) and their aglycones (hesperetin or naringenin). The activity of 8-HHE and isocarthamidin was comparable to that of alpha-tocopherol, and that of carthamidin was weaker than that of isocarthamidin. The hydroxyflavanones, which were hydroxylated on A ring of flavanone by Aspergillus saitoi, were obtained as potent antioxidants.
- Miyake, Yoshiaki,Minato, Kenichiro,Fukumoto, Syuichi,Yamamoto, Kanefumi,Oya-Ito, Tomoko,Kawakishi, Syunro,Osawa, Toshihiko
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p. 1443 - 1450
(2007/10/03)
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- A simple synthesis of selinone, an antifungal component of Monotes engleri
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A new synthesis of racemic 5,7-dihydroxy-2-[4-(3-methyl-but-2-enyloxy)-phenyl]chroman-4-one (selinone) (rac-1a) isolated from Monotes engleri GILG was accomplished by two routes starting from MOM-protected phloracetophenone (2).
- Kenez, Agnes,Juhasz, Laszlo,Antus, Sandor
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p. 543 - 548
(2007/10/03)
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- ACYLATED FLAVANONE GLYCOSIDES FROM Ricinus communis
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Naringenin 7-O-(6''-O-p-coumaroyl-β-D-glucopyranoside) and new the flavanone naringenin 7-O-(2''-O-p-coumaroyl-β-D-glucopyranoside) have been isolated from the seeds of Ricinus communis L.The structures of the compounds isolated were established on the basis of the results of chemical transformations and spectral characteristics.
- Yuldashev, M. P.,Batirov, E. Kh.,Malikov, V. M.,Yuldashev, P. Kh.
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p. 303 - 305
(2007/10/02)
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