- Total synthesis of luteolin
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Luteolin is a naturally-occurring polyphenolic flavonoid compound which has received considerable attention because of its wide range of biological and pharmacological properties. Efficient methods are reported for preparing luteolin, based on the acylation of 1,3,5-trimethoxybenzene and condensation with 3,4-dimethoxybenzaldehyde or the reaction of 3,4-dimethoxycinnamic acid with 1,3,5-trimethoxybenzene. The first of these is the better method.
- Zhang, Ji,Liu, Man,Cui, Wei,Yang, Jian,Yang, Bo
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- Ovipositional deterrent in the sweet pepper, Capsicum annuum, at the mature stage against Liriomyza trifolii (Burgess)
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Liriomyza trifolii (Burgess), the American serpentine leafminer fly, is well known as a serious pest throughout the world. This insect attack over 21 different plant families including solanaceae plants. The mature sweet pepper, Capsicum annuum (Solanaceae), however, shows resistance to this leafminer fly. This resistance is based on the ovipositional deterrent in the sweet pepper leaf against the fly species. Based on bioassay-guided fractionation, luteolin 7-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside was isolated and identified as the ovipositional deterrent against this insect species. This compound completely deterred L. trifolii females from laying their eggs on a host plant leaf treated at 4.90 μg/cm2.
- Kashiwagi, Takehiro,Horibata, Yoh,Mekuria, Daniel Bisrat,Tebayashi, Shin-Ich,Kim, Chul-Sa
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- Anti-inflammatory effect of luteolin is related to the changes in the gut microbiota and contributes to preventing the progression from simple steatosis to nonalcoholic steatohepatitis
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Increasing intestinal barrier function is one of the basic methods to suppress inflammation in the progression from simple steatosis (SS) to nonalcoholic steatohepatitis (NASH). Luteolin exists widely in vegetables, fruits and natural herbs and has various biological activities, including benefits on nonalcoholic fatty liver disease (NAFLD). However, its regulatory effects on the gut microbiota and involvement in its biological activities remain to be investigated. We fed rats a high-fat diet containing 0.5% luteolin for 12 weeks and determined the effects of luteolin on lipid metabolism, inflammation, and the gut microbiota. Supplementation with luteolin for 12 weeks significantly reduced blood lipids and hepatic lipid levels and improved liver fat accumulation and inflammation. Moreover, supplementation with luteolin led to the significant enrichment of more than 10% of gut bacterial species, which contributed to increase the abundance of ZO-1, reduce intestinal permeability, reduce plasma lipopolysaccharide, and inhibit the TLR4/NF-κB pathway. In summary, the anti-inflammatory effect of luteolin might be related to changes in the gut microbiota and contribute to preventing the progression from SS to NASH. Our research provides new insights into the anti-inflammatory mechanism of luteolin and supports its use as a dietary supplement for NAFLD patients.
- Sun, Wen-Long,Yang, Jing-Wen,Dou, Hao-Yue,Li, Gu-Qing,Li, Xin-Yu,Shen, Liang,Ji, Hong-Fang
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- Flavonoids from the aerial part of Vicia subvillosa
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The new flavone glucoside viscioside, luteolin-4-O-β-D- galactopyranoside, in addition to the known flavonoids apigenin, luteolin, quercetin, cinaroside, luteolin-4-O-β-D-glucoside, and isoquercitrin were isolated from the aerial part of Vicia subvillosa. Springer Science+Business Media, Inc. 2007.
- Yuldashev,Muminova,Drenin,Botirov
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- Flavonoids of carthamus tinctorius flowers
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The known flavonoids luteolin, cinaroside, 5-O-methylluteolin, azaleatin (3,7,3′,4′-tetrahydroxy-5-methoxyflavone), and the new natural product 3,7,3′,4′-tetrahydroxy-5-methoxyflavone 7-O-β- Dglucopyranoside (safloroside) were isolated from Carthamus tinctorius flowers and characterized by PMR and UV spectroscopy and mass spectrometry.
- Kurkin,Kharisova
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Read Online
- COSMETIC COMPOSITION FOR SKIN IMPROVEMENT COMPRISING GREEN BARLEY EXTRACT
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Provided is a cosmetic composition for skin improvement including a green barley extract.
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- Discovery of Novel Apigenin-Piperazine Hybrids as Potent and Selective Poly (ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors for the Treatment of Cancer
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Poly (ADP-ribose) polymerase-1 (PARP-1) is a potential target for the discovery of chemosensitizers and anticancer drugs. Amentoflavone (AMF) is reported to be a selective PARP-1 inhibitor. Here, structural modifications and trimming of AMF have led to a series of AMF derivatives (9a-h) and apigenin-piperazine/piperidine hybrids (14a-p, 15a-p, 17a-h, and 19a-f), respectively. Among these compounds, 15l exhibited a potent PARP-1 inhibitory effect (IC50 = 14.7 nM) and possessed high selectivity to PARP-1 over PARP-2 (61.2-fold). Molecular dynamics simulation and the cellular thermal shift assay revealed that 15l directly bound to the PARP-1 structure. In in vitro and in vivo studies, 15l showed a potent chemotherapy sensitizing effect against A549 cells and a selective cytotoxic effect toward SK-OV-3 cells through PARP-1 inhibition. 15l·2HCl also displayed good ADME characteristics, pharmacokinetic parameters, and a desirable safety margin. These findings demonstrated that 15l·2HCl may serve as a lead compound for chemosensitizers and the (BRCA-1)-deficient cancer therapy.
- Long, Huan,Hu, Xiaolong,Wang, Baolin,Wang, Quan,Wang, Rong,Liu, Shumeng,Xiong, Fei,Jiang, Zhenzhou,Zhang, Xiao-Qi,Ye, Wen-Cai,Wang, Hao
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p. 12089 - 12108
(2021/09/06)
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- Biocatalytic green alternative to existing hazardous reaction media: Synthesis of chalcone and flavone derivatives via the Claisen-Schmidt reaction at room temperature
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Owing to the increasing amount of waste materials around the globe, the conversion of waste or secondary by-products to value-added products for various applications has gained significant interest. Herein, two novel agro-food waste products, Musa sp. 'Malbhog' peel ash (MMPA) and Musa Champa Hort. ex Hook. F. peel ash (MCPA) are used as catalysts to promote an inexpensive, efficient and eco-friendly carbon-carbon bond forming crossed aldol reaction at room temperature in solvent free conditions. Furthermore, the resulting products were subjected to reactions with these promoters in an oxygen atmosphere and led to the formation of novel flavone derivatives. Moreover, the used catalysts were properly characterized using different sophisticated analytical techniques such as Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), Brunauer-Emmett-Teller analysis (BET), Raman spectroscopy, scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS), transition electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) along with element detection using atomic absorption spectroscopy and ion chromatographic methods. These two approaches are metal free, as well as being devoid of any extra additives, co-catalysts, harsh conditions, the use of column chromatography for purification and result in a higher yield of the product within a short space of time. The catalytic abilities of the promoter were also examined to synthesize important bioactive molecules such as butein and apigenin at room temperature. With gram scale synthesis of the chalcone derivatives, the used catalysts (MMPA and MCPA) were further reused for five cycles and did not demonstrate any loss in catalytic activity.
- Tamuli, Kashyap J.,Sahoo, Ranjan K.,Bordoloi, Manobjyoti
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supporting information
p. 20956 - 20965
(2020/12/31)
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- New Flavonoids and Turkesterone-2-O-Cinnamate from Leaves of Rhaponticum uniflorum
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Leaves of Rhaponticum uniflorum (L.) DC. (Asteraceae) afforded 46 compounds including seven new flavonoids that were identified using UV, IR, and NMR spectroscopy and mass spectrometry as 6-hydroxyluteolin-7-O-(2′-O-caffeoyl)-β-D-glucopyranoside (rhaunoside A, 1), 6-hydroxyluteolin-7-O-(6″-O-cinnamoyl)-β-D-glucopyranoside (rhaunoside B, 2), 6-hydroxyluteolin-4′-O-β-D-glucopyranoside (rhaunoside C, 3), nepetin-7-O-(6″-O-caffeoyl)-β-D-glucopyranoside (rhaunoside D, 4), nepetin-7-O-(6″-O-cinnamoyl)-β-D-glucopyranoside (rhaunoside E, 5), nepetin-3′-O-β-D-glucopyranoside (rhaunoside F, 6), and luteolin-7-O-(2″-O-caffeoyl)-β-D-glucopyranoside (rhaunoside G, 7) and the new ecdysteroid turkesterone-2-O-cinnamate (8).
- Olennikov,Kashchenko
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p. 256 - 264
(2019/05/06)
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- Enhanced antioxidant activity, antibacterial activity and hypoglycemic effect of luteolin by complexation with manganese(II) and its inhibition kinetics on xanthine oxidase
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The present study aims to improve the biological activities of luteolin by complexation with manganese(ii). UV-visible spectroscopy, infrared spectroscopy, thermogravimetric analysis and elemental analysis were adopted to assess the relevant interaction of luteolin and manganese(ii) ions and the chelation sites. The antioxidant activity, hypoglycemic effect and antimicrobial activity of luteolin-manganese(ii) complex with respect to its parent luteolin and the inhibition effect of which on xanthine oxidase were investigated and compared. The spectroscopic data indicated that luteolin reacts with manganese(ii) cations through the chelation sites of 5-hydroxy and 4-carbonyl in two luteolin molecules. Antioxidant and antibacterial activity were enhanced after the complexation of manganese(ii) cations with luteolin. An inhibition effect assay found that luteolin and luteolin-manganese(ii) complex reversibly inhibited xanthine oxidase in a competitive manner. Luteolin-manganese(ii) complex had a more remarkable hypoglycemic effect than luteolin by increasing the glucose consumption in liver tissue.
- Dong, Hao,Yang, Xiaocui,He, Jiapeng,Cai, Sheng,Xiao, Kaijun,Zhu, Liang
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p. 53385 - 53395
(2017/12/02)
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- An improved synthesis of apigenin and luteolin
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Apigenin and luteolin are the antioxidant flavonoids found in foods such as parsley, artichoke, basil and celery. Both of these compounds have shown the ability to protect cells against cancer and also to inhibit DNA oxidative damage. These flavonoids are part of many nutraceutical formulations available in the market. There is a need for the development of cost effective methodologies to produce them in large quantities. The synthetic process developed for both these compounds is general and can be applied for other flavonoids also. An industrially applicable high pure product, cost effective synthesis and general synthetic method has been developed and presented.
- Rambabu,Kumari,Baby Ramana,Ramani,Subbaraju,Hari Babu
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p. 1139 - 1143
(2016/03/01)
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- Novel synthesised flavone derivatives provide significant insight into the structural features required for enhanced anti-proliferative activity
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With many cancers showing resistance to current chemotherapies, the search for novel anti-cancer agents is attracting considerable attention. Natural flavonoids have been identified as useful leads in such programmes. However, since an in-depth understanding of the structural requirements for optimum activity is generally lacking, further research is required before the full potential of flavonoids as anti-proliferative agents can be realised. Herein a broad library of 76 methoxy and hydroxy flavones, and their 4-thio analogues, was constructed and their structure-activity relationships for anti-proliferative activity against the breast cancer cell lines MCF-7 (ER +ve), MCF-7/DX (ER +ve, anthracycline resistant) and MDA-MB-231 (ER -ve) were probed. Within this library, 42 compounds were novel, and all compounds were afforded in good yields and >95% purity. The most promising lead compounds, specifically the novel hydroxy 4-thioflavones 15f and 16f, were further evaluated for their anti-proliferative activities against a broader range of cancer cell lines by the National Cancer Institute (NCI), USA and displayed significant growth inhibition profiles (e.g. compound-15f: MCF-7 (GI50 = 0.18 μM), T-47D (GI50 = 0.03 μM) and MDA-MB-468 (GI50 = 0.47 μM) and compound-16f: MCF-7 (GI50 = 1.46 μM), T-47D (GI50 = 1.27 μM) and MDA-MB-231 (GI50 = 1.81 μM)). Overall, 15f and 16f exhibited 7-46 fold greater anti-proliferative potency than the natural flavone chrysin (2d). A systematic structure-activity relationship study against the breast cancer cell lines highlighted that free hydroxyl groups and the B-ring phenyl groups were essential for enhanced anti-proliferative activities. Substitution of the 4-CO functionality with a 4-CS functionality, and incorporation of electron withdrawing groups at C-4′ of the B-ring phenyl, also enhanced activity. Molecular docking and mechanistic studies suggest that the anti-proliferative effects of flavones 15f and 16f are mediated via ER-independent cleavage of PARP and downregulation of GSK-3β for MCF-7 and MCF-7/DX cell lines. For the MDA-MB-231 cell line, restoration of the wild-type p53 DNA binding activity of mutant p53 tumour suppressor gene was indicated.
- Ravishankar, Divyashree,Watson, Kimberly A.,Greco, Francesca,Osborn, Helen M. I.
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p. 64544 - 64556
(2016/07/21)
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- CATECHOL DERIVATIVES PREPARED BY USING TYROSINASE, METHOD FOR PREPARATION THEREOF, AND APPLICATION THEREOF
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The present invention refers to using tyrosinase and pyrocatechole type structural material technology and exclusively on the basis of the response in the biosynthesis of, melanocyte secondary oxidation reaction by effectively inhibiting, mono phenol type primary structural material optionally catalyst only complex induced a are defined.. The present invention refers to using the same variety of functional pyrocatechole type materials, with high productivity and. there is provided a technique for production yield. (by machine translation)
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Page/Page column 14
(2016/12/12)
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- Dracopalmaside, a New Flavonoid from Dracocephalum palmatum
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Phytochemical studies of the aerial part of Dracocephalum palmatum (Lamiaceae) isolated the new flavonoid dracopalmaside that was identified based on UV, MS, and NMR spectral data as luteolin-7,4′-di-O-α -Lrhamnopyranosyl-(1→6)-β-D-glucopyranoside (luteolin-7,4′-di-O-rutinoside) and the two known compounds cynarotriside and luteolin-7,4′-di-O-glucoside.
- Olennikov,Chirikova
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p. 1067 - 1069
(2016/02/18)
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- Modified syntheses of the dietary flavonoid luteolin
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Two novel syntheses of the flavone luteolin are described. In the first, 3,5-dimethoxyphenol was converted to 2-hydroxy-4,6-dimethoxyacetophenone and then by condensation with 3,4-dimethoxybenzaldehyde to 2'-hydroxy-3,4,4',6'-tetramethoxychalcone. In the second, the chalcone step was prepared in which 3,5-dimethoxyphenol was acylated with 3,4-dimethoxycinnamoyl chloride. The chalcone was then cyclised with iodine and demethylated with pyridine hydrochloride to form luteolin in 47% and 40% overall yield, respectively. Several disadvantages of previous syntheses like long reaction time, harsh reaction conditions and low overall yield have been overcome.
- Wang, Qian,Zhang, Ji,Liu, Man,Yang, Jian,Zhang, Xiang-Ming,Zhou, Lei,Cao, Lang,Liao, Xia-Li
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p. 550 - 552
(2015/11/27)
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- Hydnocarpin-Type Flavonolignans: Semisynthesis and Inhibitory Effects on Staphylococcus aureus Biofilm Formation
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A new, efficient, and general semisynthesis of hydnocarpin-type flavonolignans was developed and optimized, enabling gram-scale production of hydnocarpin D (2). Moreover, the syntheses of optically pure hydnocarpin isomers [(10R,11R)-hydnocarpin (1a), (10R,11R)-hydnocarpin D (2a), and (10S,11S)-hydnocarpin D (2b)], as well as the synthesis of isohydnocarpin (8), were achieved for the first time utilizing this new method. The synthesis is based on the two-step transformation of the readily available flavonolignans from milk thistle (Silybum marianum), accessible by isolation from the commercial extract silymarin. The first step relies on the regioselective formylation of the C-3 hydroxy group of the dihydroflavonol-type precursor using the Vilsmeier-Haack reagent, followed by formic acid elimination by triethylamine in the second step. The synthesized compounds were effective inhibitors of Staphylococcus aureus biofilm formation, with (10S,11S)-hydnocarpin D (2b) being the most potent inhibitor. Furthermore, the effect of glucose on biofilm formation was tested, and glucose decreased the biofilm inhibitory activity of 2b. Moreover, 2b increased the susceptibility of Staph. aureus to enrofloxacin. (Chemical Equation Presented).
- Vimberg, Vladimir,Kuzma, Marek,Stodu?lková, Eva,Novák, Petr,Bednárová, Lucie,?ulc, Miroslav,Ga?ák, Radek
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p. 2095 - 2103
(2015/09/08)
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- Exploring quercetin and luteolin derivatives as antiangiogenic agents
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The formation of new blood vessels from the pre-existing vasculature (angiogenesis) is a crucial stage in cancer progression and, indeed, angiogenesis inhibitors are now used as anticancer agents, clinically. Here we have explored the potential of flavonoid derivatives as antiangiogenic agents. Specifically, we have synthesised methoxy and 4-thio derivatives of the natural flavones quercetin and luteolin, two of which (4-thio quercetin and 4-thio luteolin) had never been previously reported. Seven of these compounds showed significant (p 0.05) antiangiogenic activity in an in vitro scratch assay. Their activity ranged from an 86% inhibition of the vascular endothelium growth factor (VEGF)-stimulated migration (observed for methoxyquercetin at 10 μM and for luteolin at 1 μM) to a 36% inhibition (for thiomethoxy quercetin at 10 μM). Western blotting studies showed that most (4 out of 7) compounds inhibited phosphorylation of the VEGF receptor-2 (VEGFR2), suggesting that the antiangiogenic activity was due to an interference with the VEGF/VEGFR2 pathway. Molecular modelling studies looking at the affinity of our compounds towards VEGFR and/or VEGF confirmed this hypothesis, and indeed the compound with the highest antiangiogenic activity (methoxyquercetin) showed the highest affinity towards VEGFR and VEGF. As reports from others have suggested that structurally similar compounds can elicit biological responses via a non-specific, promiscuous membrane perturbation, potential interactions of the active compounds with a model lipid bilayer were assessed via DSC. Luteolin and its derivatives did not perturb the model membrane even at concentrations 10 times higher than the biologically active concentration and only subtle interactions were observed for quercetin and its derivatives. Finally, cytotoxicity assessment of these flavonoid derivatives against MCF-7 breast cancer cells demonstrated also a direct anticancer activity albeit at generally higher concentrations than those required for an antiangiogenic effect (10 fold higher for the methoxy analogues). Taken together these results show promise for flavonoid derivatives as antiangiogenic agents.
- Ravishankar, Divyashree,Watson, Kimberly A.,Boateng, Samuel Y.,Green, Rebecca J.,Greco, Francesca,Osborn, Helen M.I.
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p. 259 - 274
(2015/05/27)
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- A new synthesis for acacetin, chrysoeriol, diosmetin, tricin and other hydroxylated flavones by modified Baker-Venkataraman transformation
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Baker-Venkataraman (BV) rearrangement is the method of choice for the synthesis of flavones. The major limitation of BV is that it requires extensive protections and deprotections of hydroxyl groups which make the process lengthy and cumbersome. In the present study, a three step efficient method has been developed using simple protecting groups and easily available starting materials. New syntheses for acacetin, chrysoeriol, diosmetin, tricin and other hydroxylated flavones are described.
- Pandurangan
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p. 225 - 229
(2014/05/20)
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- PROCESS FOR PREPARATION OF LUTEOLIN
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The present invention provides a process for preparation of Luteolin by deprotection of the corresponding ethers using Lewis acid mediated Ionic complexes, and to compositions containing the same.
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Page/Page column 9-10
(2013/08/15)
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- Chemo-enzymatic transformation of naturally abundant naringin to luteolin, a flavonoid with various biological effects
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Luteolin [3′,4′,5,7-tetrahydroxyflavone], having multiple biological effects such as anti-inflammation, anti-allergy and anti-cancer, was prepared by chemo-enzymatic synthesis from naringin, a naturally abundant flavonoid glycoside. On the occasion of Candida antarctica lipase B (Novozym 435)-catalyzed transesterification on peracetylated form of naringin, an acetate on C-4′ was exclusively deprotected to give the key intermediate. The oxidation with 2-iodoxybenzoic acid (IBX) followed by the reductive workup provided regioselectively C-3′and C-4′ catechol functionality. After protection of the above-mentioned diol with methoxymethyl (MOM) groups and subsequent hydrolysis of all acetyl groups, a dehydrogenative introduction of double bond between C-2 and C-3 was done by the treatment with I2. Acid-catalyzed simultaneous removal of MOM groups and glycoside provided luteolin in total 8 steps and 36% overall yield from the starting material. Throughout the synthesis, diglycoside side chain effectively worked as the protective group on C-7 hydroxy group.
- Kobayashi, Ryohei,Itou, Takasi,Hanaya, Kengo,Shoji, Mitsuru,Hada, Noriyasu,Sugai, Takeshi
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- Hydrolysis of flavonoid glycosides by propolis β-glycosidase
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Flavonoids generally occur as O-glycosides with sugars bound in nature, while aglycones and their derivatives are the main flavonoids in propolis. The objective of this work was to study the propolis β-glycosidase activities toward flavonoid β-glycosides and their conjugated forms. β-Glycosidase was extracted from propolis, incubated with avonoid glycosides, and analysed for aglycone formation by HPLC. The results demonstrated that glucose conjugates were rapidly hydrolysed, but not conjugates with other sugars, i.e. rutin and naringin. The rate and extent of deglycosylation depends on the structure of the avonoid and the position of the sugar substituitions. Quercetin 3-O-glucoside had the highest percent of hydrolysis, while quercetin 7-O-glucoside was the least hydrolysed. The Km values for hydrolysis of apigenin 7-glucoside and luteolin-7-O-glucoside were 13M and 20M, respectively.
- Zhang, Cui-Ping,Liu, Gang,Hu, Fu-Liang
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scheme or table
p. 270 - 273
(2012/03/27)
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- Flavonoid constituents of Cakile maritima (scope) growing in Egypt and their biological activity
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The study of the flavonoidal constituents isolated from the chloroform, ethyl acetate and butanol fractions of aqueous alcoholic extract of Cakile maritima (family Crucifereae) revealed the isolation and identification of quercetin, quercetin-3-O-rhamnoside, kaempferol-7-O-glucoside, luteolin, luteolin-7-O-glucoside and caffeic acid. Identification of the isolated compounds was carried out by spectroscopic analysis viz UV, MS, NMR, TLC, PC and acid hydrolysis of the glycoside compounds. The radical scavenging effects of the tested extracts and isolated compounds on DPPH free radical were observed, in which the flavonoidal compounds showed a strong antioxidant activity. Molluscidal activity of different fractions and isolated compounds of Cakile maritime was carried out against Biomphalaria alexandrina snails, in which luteolin-7-O-glucoside, kaempferol-7-O-glucoside and quercetin-3-O-rhamnoside showed significant molluscicidal activity (LC50 24, 37 and 40, respectively). It was also found that the quercetin, luteolin and caffeic acid had showed moderate activity.
- Shams, Khaled A.,Radwan, Hany M.,Tawfik, Wafaa A.,Habib, Amira A.,Soliman, Abdel-Mohsen M.
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experimental part
p. 3981 - 3988
(2010/11/18)
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- Selective and efficient oxidative modifications of flavonoids with 2-iodoxybenzoic acid (IBX)
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2-Iodoxybenzoic acid (IBX), a mild and efficient hypervalent iodine oxidant, has been utilised in different reaction conditions to perform several efficient oxidative modifications of flavonoids. Fine-tuning of the reaction conditions allowed remarkably selective modifications of these compounds. At room temperature, IBX proved to be an excellent reagent for a highly regioselective aromatic hydroxylation of monohydroxylated flavanones and flavones, generating the corresponding catecholic derivatives showing high antioxidant activity. At 90 °C, IBX efficiently dehydrogenated a large panel of methoxylated flavanones to their corresponding flavones exhibiting anticancer activity. IBX polystyrene has also been utilised to increase the recovery of highly polar compounds. Following the first oxidation, the reagent was recovered and reused in several runs without loss of efficiency and selectivity. The first example of an application of IBX polystyrene in a dehydrogenation reaction has been described.
- Barontini, Maurizio,Bernini, Roberta,Crisante, Fernanda,Fabrizi, Giancarlo
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experimental part
p. 6047 - 6053
(2010/09/11)
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- Flavone synthase II (CYP93B16) from soybean (Glycine max L.)
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Flavonoids are a very diverse group of plant secondary metabolites with a wide array of activities in plants, as well as in nutrition and health. All flavonoids are derived from a limited number of flavanone intermediates, which serve as substrates for a variety of enzyme activities, enabling the generation of diversity in flavonoid structures. Flavonoids can be characteristic metabolites, like isoflavonoids for legumes. Others, like flavones, occur in nearly all plants. Interestingly, there exist two fundamentally different enzymatic systems able to directly generate flavones from flavanones, flavone synthase (FNS) I and II. We describe an inducible flavone synthase activity from soybean (Glycine max) cell cultures, generating 7,4′-dihydroxyflavone (DHF), which we classified as FNS II. The corresponding full-length cDNA (CYP93B16) was isolated using known FNS II sequences from other plants. Functional expression in yeast allowed the detailed biochemical characterization of the catalytic activity of FNS II. A direct conversion of flavanones such as liquiritigenin, naringenin, and eriodictyol into the corresponding flavones DHF, apigenin and luteolin, respectively, was demonstrated. The enzymatic reaction of FNS II was stereoselective, favouring the (S)- over the (R)-enantiomer. Phylogenetic analyses of the subfamily of plant CYP93B enzymes indicate the evolution of a gene encoding a flavone synthase which originally catalyzed the direct conversion of flavanones into flavones, via early gene duplication into a less efficient enzyme with an altered catalytic mechanism. Ultimately, this allowed the evolution of the legume-specific isoflavonoid synthase activity.
- Fliegmann, Judith,Furtw?ngler, Katarina,Malterer, Georg,Cantarello, Corrado,Schüler, G?de,Ebel, Jürgen,Mith?fer, Axel
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experimental part
p. 508 - 514
(2010/06/17)
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- Polyphenolic Bioprecursors
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Cosmetic and therapeutic, in particular dermatological bioprecursors have the formula [A]n—PP—[B]m wherein PP is a polyphenol radical in which each hydroxyl function is protected by a group A or a group B, A is a saturated or unsaturated, substituted or unsubstituted alkyl radical having 1 to 20 carbon atoms which is bonded to the polyphenol, n is an integer not less than 1, and B is a precursor of a biologically active molecule, which is also bonded to the polyphenol, and m is an integer also not less than 1.
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Page/Page column 9-10
(2009/09/07)
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- Flavonoids of Zizyphus rugosa
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Three flavonolds - kaempferol-4′-methylether, luteolin and luteolin-7-O-glucoside have been isolated from the barks of Zizyphus rugosa and their structures were established by spectral evidences. This is the first report of these flavonoids from Z. rugosa.
- Singh,Pandey,Singh, Sarita,Singh,Singh
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experimental part
p. 177 - 178
(2010/04/05)
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- A new iridoid glycoside from Vitex negundo Linn (Verbenacea)
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Five compounds have been isolated from the leaves of Vitex negundo Linn (Verbenacea) and their structures established by spectral analysis. Compound 1 has been identified and characterised as a new iridoid with a novel structure which has never before been reported in literature from Vitex or any other source. Its structure has been established as 1,4a,5,7a-tetrahydro-1 - β-D-glucosyl-7-(3′,4′-dihydroxybenzoyloxymethyl) -5-ketocyclopenta[c]pyran-4-carboxylic acid. Other compounds, 2, 3, 4 and 5, have been identified as luteolin-7-O -β- D glucoside, nishindaside, negundoside, and agnuside, respectively. Compound 2, a flavone-O-glycoside, is being reported from this plant for the first time, and compounds 3, 4 and 5 are structurally known iridoids.
- Sharma, Rattan L.,Prabhakar, Anil,Dhar, Kanaya L.,Sachar, Anand
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experimental part
p. 1201 - 1209
(2010/04/23)
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- Microbial metabolism part 9.1 Structure and antioxidant significance of the metabolites of 5,7-dihydroxyflavone (chrysin), and 5- and 6-hydroxyflavones
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5,7-Dihydroxyflavone (chrysin) (1) when fermented with fungal cultures, Aspergillus alliaceous (ATCC 10060), Beauveria bassiana (ATCC 13144) and Absidia glauco (ATCC 22752) gave mainly 4′-hydroxychrysin (4), chrysin 7-O-β-D-4-O-methylglucopyranoside (5) and chrysin 7-sulfate (6), respectively. Mucore ramannianus (ATCC 9628), however, transformed chrysin into six metabolites: 4′-hydroxy-3′-methoxychrysin (chrysoeriol) (7), 4′-hydroxychrysin (apigenin) (4) 3′,4′-dihydroxychrysin (luteolin) (8), 3′-methoxychrysin 4′-O-α-D-6- deoxyallopyranoside (9), chrysin 4′-O-α-D-6-deoxyallopyranoside (10), and luteolin 3′-sulfate (11). Cultures of A. alliaceous (ATCC 10060) and B. bassiana (ATCC 13144) metabolized 5-hydroxyflavone (2) into 5,4′-dihydroxyflavone (12) and 4′-hydroxyflavone 5-O-β-D-4-O-methylglucopyranoside (13), respectively. 6-Hydroxyflavone (3) was transformed into 6-hydroxyflavanone (14), flavone 3-O-β-D-4-O- methylglucopyranoside (15) and (±)-flavanone 6-O-β-D-4-O- methylglucopyranoside (16) by cultures of Beauveria bassiana (ATCC 13144). The structures of the metabolic products were elucidated by means of spectroscopic data. The significance of the metabolites as antioxidants in relation to their structure is briefly discussed.
- Herath, Wimal,Mikell, Julie Rakel,Hale, Amber Lynn,Ferreira, Daneel,Khan, Ikhlas Ahmad
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experimental part
p. 418 - 422
(2009/04/11)
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- An NADPH and FAD dependent enzyme catalyzes hydroxylation of flavonoids in position 8
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Yellow flavonols contribute to flower pigmentation in Asteraceae. In contrast to common flavonols, they show additional hydroxyl groups in position 6 and/or 8 of the aromatic A-ring in addition to the basic 5,7-hydroxylation pattern. An enzyme introducing a hydroxyl group in position 8 of flavonols and flavones was demonstrated for the first time with enzyme preparations from petals of Chrysanthemum segetum. Flavanones, dihydroflavonols and glucosylated flavonols and flavones were not accepted as substrates. The enzyme was localized in the microsomal fraction and uses NADPH and FAD as cofactors. Experiments with carbon monoxide/blue light and with antibodies specific for cytochrome P450 reductase did not indicate the involvement of a classical cytochrome P450 dependent monooxygenase in the reaction. Thus, the flavonoid 8-hydroxylase represents a novel type of hydroxylating enzyme in the flavonoid pathway. Apart from flavonoid 8-hydroxylase activity, the presence of all enzymes involved in the formation of flavonoid 7-O-glucosides in C. segetum was demonstrated. The pathway leading to 8-hydroxyflavonoids in C. segetum has been derived from enzyme activities and substrate specificities observed.
- Halbwirth, Heidrun,Stich, Karl
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p. 1080 - 1087
(2008/02/10)
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- Flavonoids from Cephalaria gigantea flowers
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Luteolin, quercetin, cinaroside, quercimeritrin, and the new flavonol bioside gigantoside A were isolated from Cephalaria gigantea (Ledeb.) Bobr. (Dipsacaceae) flowers. Spectral properties and chemical transformations established that gigantoside A had the structure quercetin-7-O-[α-L- arabinopyranosyl(1→6)]-β-D-glucopyranoside.
- Movsumov,Garaev,Isaev
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p. 677 - 680
(2008/02/08)
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- Structural and mechanistic studies on anthocyanidin synthase catalysed oxidation of flavanone substrates: The effect of C-2 stereochemistry on product selectivity and mechanism
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During the biosynthesis of the tricyclic flavonoid natural products in plants, oxidative modifications to the central C-ring are catalysed by Fe(II) and 2-oxoglutarate dependent oxygenases. The reactions catalysed by three of these enzymes; flavone synthase I, flavonol synthase and anthocyanidin synthase (ANS), are formally desaturations. In comparison, flavanone 3β-hydroxylase catalyses hydroxylation at the C-3 pro-R position of 2S-naringenin. Incubation of ANS with the unnatural substrate (±)-naringenin results in predominantly C-3 hydroxylation to give cis-dihydrokaempferol as the major product; trans-dihydrokaempferol and the desaturation product, apigenin are also observed. Labelling studies have demonstrated that some of the formal desaturation reactions catalysed by ANS proceed via initial C-3 hydroxylation followed by dehydration at the active site. We describe analyses of the reaction of ANS with 2S- and 2R-naringenin substrates, including the anaerobic crystal structure of an ANS - Fe-2-oxoglutarate-naringenin complex. Together the results reveal that for the 'natural' C-2 stereochemistry of 2S-naringenin, C-3 hydroxylation predominates (>9:1) over desaturation, probably due to the inaccessibility of the C-2 hydrogen to the iron centre. For the 2R-naringenin substrate, desaturation is significantly increased relative to C-3 hydroxylation (ca. 1:1); this is probably a result of both the C-3 pro-S and C-2 hydrogen atoms being accessible to the reactive oxidising intermediate in this substrate. In contrast to the hydroxylation-elimination desaturation mechanism for some ANS substrates, the results imply that the ANS catalysed desaturation of 2R-naringenin to form apigenin proceeds with a syn-arrangement of eliminated hydrogen atoms and not via an oxygenated (gem-diol) flavonoid intermediate. Thus, by utilising flavonoid substrates with different C-2 stereochemistries, the balance between C-3 hydroxylation or C-2, C-3 desaturation mechanisms can be altered. The Royal Society of Chemistry 2005.
- Welford, Richard W.D.,Clifton, Ian J.,Turnbull, Jonathan J.,Wilson, Stuart C.,Schofield, Christopher J.
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p. 3117 - 3126
(2007/10/03)
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- Method for producing luteolin and luteolin derivatives
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Disclosed is a method for producing compounds of formula (I), wherein R1represents H or (CH2)mOH, R2represents H or (CH2)nOH, R3represents H or (CH2)pOH and m, n and p represent 2-8 independently from one another. Said compounds are particularly suitable for use as food supplements. They are highly suitable for use in cosmetic formulations as UV filters, for instance.
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- Novel use of flavones
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A pharmaceutical composition for inhibiting COX-2 biosynthesis comprising a therapeutically effective amount of the compound of formula I and a pharmaceutrically acceptable carrier. wherein R1 and R4 represent either Hydrogen or together a bond R5, R6, R7, R8 represent independently of each other Hydrogen, Hydroxy or Methoxy; in addition R7 represents a sugar substituent like glucoside, rutinosid, manno gluco pyransyl, aprosylglucoside R2 and R3 represent Hydrogen, Hydroxy, Methoxy or wherein R2′, R3′, R4′, R5′ and R6′ are independently or each other Hydrogen, Hydroxy or Methoxy with the proviso, that R2 or R3 is represented by the optionally substituted Phenylring.
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- Cyclodehydrogenation of 2'-Hydroxychalcones with Hypervalent Iodine Reagent: A New Synthesis of Flavones
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A new synthesis of chrysin (1) and luteolin (4) was accomplished by the cyclodehydrogenation of the appropriately substituted 2'-hydroxychalcones 21 and 22 in the presence of iodosobenzene diacetate/potassium hydroxide in methanol.The scope and limitation of this transformation is discussed. - Keywords: Cyclodehydrogenation / 2'-Hydroxychalcones / Flavones / Iodosobenzene diacetate
- Litkei, Gyoergy,Gulasci, Katalin,Antus, Sandor,Blasko, Gabor
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p. 1711 - 1716
(2007/10/02)
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- Synthesis of 3-Acyl- and 3-Carbamoylflavones
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Routes to 3-acyl-, 3-carboxamido- and polyhydroxylated flavones have been devised by application of isoxazole methodology and Heck-Stille couplings.Reductive ring opening of 3-alkoxyisoxazoles gives β-keto carboxamides in contrast with 3-alkoxy-2-isoxazolines, which give β-hydroxy esters.
- Ellemose, Steen,Kure, Niels,Torsell, Kurt B. G.
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p. 524 - 529
(2007/10/02)
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- FLAVONOID 5-GLUCOSIDES FROM PRUNUS CERASUS BARK AND THEIR CHARACTERISTIC WEAK GLYCOSIDIC BONDING
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Pinostrobin 5-glucoside, a novel flavanone glycoside, was isolated from the bark of Prunus cerasus.As it was not found in P. avium, the substance is useful to distinguish these two species.Apigenin 5-glucoside, genkwanin 5-glucoside and neosakuranin were also isolated from the bark of P. cerasus.They occur in both species as minor components.These 5-glucosides together with genistein 5-glucoside, prunetin 5-glucoside, sakuranin, tectochrysin 5-glucoside and luteolin 5-glucoside were hydrolysed in malic acid.The isoflavone and flavone 5-glucosides were shown to be hydrolysed more rapidly than the flavanone 5-glucosides, whereas no hydrolysis was observed with the corresponding 7-glucosides under the same conditions.The chalcone 2'-glucoside neosakuranin was transformed at first to the corresponding flavanone 5-glucoside, which was hydrolysed thereafter. Key Word Index - Prunus cerasus; Prunus avium; Rosaceae; bark; pinostrobin 5-glucoside; flavonoid 5-glucosides; hydrolysis.
- Geibel, Martin,Feucht, Walter
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p. 1519 - 1521
(2007/10/02)
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- A Short and Facile Synthetic Route to Hydroxylated Flavones. New Syntheses of Apigenin, Tricin, and Luteolin
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Reaction of lithium polyanions generated from o-hydroxyacetophenones 3a-f with O-silyloxylated benzoates 2a-d gave 1-aryl-3-(2-hydroxyphenyl)-1,3-propanediones 4a-n, which on treatment with acetic acid containing 0.5percent H2SO4 at 95 - 100 deg C afforded hydroxylated flavones 5-18 in high yields (76 - 92percent).
- Nagarathnam, Dhanapalan,Cushman, Mark
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p. 4884 - 4887
(2007/10/02)
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- Flavonoid lactates from leaves of Marrubium vulgare
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The new natural lactoyl (2-hydroxypropionyl) flavonoids, luteolin and apigenin 7-lactates together with their 2″-O-β-glucuronides and 2″-O-β-glucosides were isolated from the leaves of Marrubium vulgare. The known flavonoids, vicenin II, vitexin, luteolin 7-glucoside, apigenin 7-glucoside, apigenin 7-(6″-p-coumaroyl)glucoside, luteolin, chrysoeriol and apigenin were also found. The structures were established by conventional methods of analysis and confirmed by 1H, 13C NMR and MS analysis. 2D-chemical shift correlation NMR was applied in the case of the new flavonoids.
- Nawwar, Mahmoud A.M.,El-Mousallamy, Amany M.D.,Barakat, Heba H.,Buddrus, Joachim,Linscheid, Michael
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p. 3201 - 3206
(2007/10/02)
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- TWO LUTEOLIN O-GLUCURONIDES FROM PRIMARY LEAVES OF SECALE CEREALE
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Two luteolin O-glucuronides have been located exclusively in the photosynthetically active mesophyll of primary leaves of rye (Secale cereale).Their structures have been elucidated as luteolin 7-O2)β-D-glucuronide>-4'-O-β-D-glucuronide and luteolin 7-O-2)β-D-glucuronide>.The former glycoside is a new natural compound. - Key Word Index - Secale cereale; Poaceae; rye; luteolin glucuronides.
- Schulz, Margot,Strack, Dieter,Weissenboeck, Gottfried,Markham, Kenneth R.,Dellamonica, Georgette,Chopin, Jean
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p. 343 - 346
(2007/10/02)
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