- Study on the structure-activity of dihydromyricetin and its new production: Myricetin by using ESR and spectroscopic techniques
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Myricetin (MY) was firstly synthesized from dihydromyricetin (DMY), and its antioxidant activity was analyzed. FTIR, NMR, and TG measurements confirmed that the DMY turned to MY. Scanning electron microscope observation showed that the 2,3-single bond offered great flexibility on the stage of crystallization to form imperfect crystalline regions; hence, DMY tends to form larger columnar crystals than MY. It has been found that the antioxidative efficiency of DMY was superior to MY, based on the measurement of radical scavenging activity by DPPH and the oxidation induction time of PP-antioxidant samples. The 2,3-double bond in MY structure, known as one of the characteristic determinants, was not an important requirement for antioxidant capacity or even negative correlation observed. Such a deduction was further supported by UV-Vis absorption spectra change when the pH was raised to pH 9. It was concluded that the ortho-trihydroxyl group in the B ring provides an antioxidant defense, and the 2,3-single band of C ring provides the structural stability.
- Xin, Mingliang,Ma, Yujie,Lin, Weihong,Xu, Kai,Chen, Mingcai
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- Preparation method of 3,5,7,3',4',5'-hexahydroxy flavone
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The invention provides a preparation method of 3,5,7,3',4',5'-hexahydroxy flavone, aims at solving the problems that an existing method is low in yield, complicated to operate and not suitable for industrial production. Dihydromyricetin is used as an initial raw material, an oxidation reaction is carried out under the combined action of high temperature and high pressure, an alkaline environment and iodine catalysis to prepare dihydromyricetin, a product with the myricetin content larger than or equal to 98% can be obtained through a one-step reaction, no organic reagent participates in the reaction process, and no problem of safety accidents due to the need to add a catalyst in the reaction process exists; therefore, compared with the prior art, the method disclosed by the invention is simple to operate, high in yield, green and environment-friendly, and suitable for industrial production.
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Paragraph 0026; 0028-0043
(2021/06/26)
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- Continuous flow microchannel synthesis process of flavonoid compounds
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The invention provides a continuous flow microchannel synthesis process of flavonoid compounds. According to the process, hesperidin and iodine elementary substance are used as raw materials and react in a continuous flow microchannel reactor in the presence of a reaction solvent to synthesize the flavonoid compound as shown in a formula A. Compared with a traditional kettle-type preparation process, the process disclosed by the invention has the advantages that the preparation time is obviously shortened, and the conversion rate of raw materials and the yield of products are obviously improved; and especially, when the diosmin is prepared under optimal process conditions of continuous flow microchannel synthesis, the conversion rate of the raw material hesperidin is as high as 96.48%, and the yield of the product diosmin is as high as 81.96%. The continuous flow micro-channel synthesis process provided by the invention is beneficial to realizing safe, efficient and rapid industrial production of flavonoid compounds, and has a wide application prospect.
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Paragraph 0050-0059; 0061
(2021/06/22)
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- Synthesis method of myricetin
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The invention discloses a synthesis method of myricetin. The method includes the steps of: adding an alkaline solution into a dihydromyricetin aqueous solution, and then performing heating under a reflux state; adding a selenium dioxide aqueous solution, then stirring at a reflux temperature for reaction, and then performing cooling to room temperature; adding acid to adjust the pH value, conducting stirring and rotary evaporation, and then performing stirring and filtering; adding an ethanol aqueous solution into a filter cake, performing pulping and filtering, flushing the filter cake with an ethanol aqueous solution, collecting the filter cake, and performing drying to obtain red selenium; combining an organic phases, and performing spin-drying till no ethanol smell, precipitating a large amount of solid, performing filtering, and flushing the filter cake with an ethanol aqueous solution to obtain a yellow solid, i.e. myricetin. The method has the advantages that: 1, the reaction issimple and easy to operate; 2, water and a small amount of ethanol are mainly used as the solvent, and the emission of three wastes is low; 3, red selenium with economic value can be recovered; 4, the obtained myricetin is high in purity; and 5, the method can achieve multiple purposes, has very good economic benefits, and is suitable for large-scale production.
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Paragraph 0029-0052
(2020/01/12)
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- Myricitrin preparation method
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The invention belongs to the technical field of pharmaceutical chemical synthesis, in particular relates to a preparation method of the slots. The invention the equivalent preparation method is as follows: a, in order to 1 - 1 as shown in the compound as a raw material, with the methoxy second grade nitrile under acidic conditions in the acylation reaction to obtain 1 - 3 as shown in the; second, 1 - 3 is shown with the compound 3, 4, 5 - trimethoxy benzoic anhydride generating rearrangement reaction to 1 - 5 as shown in the; three, 1 - 5 shown BBr3 compound in the dichloromethane solution takes place in the demethylation reaction generating 3 - 1 compound of formula, is myricetin. The invention relates to a fully synthetic routes proceed from the phloroglucinol, by the three-step reaction, to 60% of the total yield has succeeded in synthesizing myricetin. With cheap raw material, mild reaction conditions, synthetic route is short, and the yield is high, the operation is simple, and little environmental pollution and the like.
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Paragraph 0038-042
(2019/01/08)
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- Isolation of Flavonoids and Flavonoid Glycosides from Myrsine africana and Their Inhibitory Activities against Mushroom Tyrosinase
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Bioassay-guided fractionation of the methanol extract of the shoots of Myrsine africana led to the isolation of the new compound myricetin 3-O-(2″,4″-di-O-acetyl)-α-l-rhamnopyranoside (9) and 11 known compounds. The known compounds quercetin 3-O-(3″,4″-di-O-acetyl)-α-l-rhamnopyranoside (8), rutin (10), quercetin 3-O-α-l-rhamnopyranoside (11), and myricetin 3-O-α-l-rhamnopyranoside (12) are reported for the first time from the methanol extract of the shoots of M. africana. Compounds 10 and 12 showed significant inhibition of tyrosinase with 50% inhibition (IC50 values) of the enzyme at 0.13 ± 0.003 and 0.12 ± 0.002 mM, respectively, which was supported by the docking fitness scores obtained through molecular docking analysis. In addition, compounds 1-12 displayed significant antioxidant activity with IC50 values ranging 1.90 to 3.90 μM.
- Kishore, Navneet,Twilley, Danielle,Blom Van Staden, Analike,Verma, Praveen,Singh, Bikram,Cardinali, Giorgia,Kovacs, Daniela,Picardo, Mauro,Kumar, Vivek,Lall, Namrita
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- A cytotoxic flavonol glycoside from Melaleuca leucadendra leaves extract with immunostimulant activity
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Leaves of Melaleuca leucadendra contain the novel flavonol glycoside, myricetin 3-O-β-4C1-galactopyranuronoid. In addition, known fifteen phenolics were identified. All isolates are characterized for the first time from this plant. Structures were established by conventional methods and confirmed by spectral methods of analysis, including one and two-dimensional nuclear magnetic resonance spectroscopy (1D and 2D-NMR) and high resolution electro-spray ionization mass spectrometry (HRESIMS), as well. Assessment of some immunological and biological efficacy, of the extract in combination with a parallel cytotoxicity evaluation, using the method of cellular reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) technique was carried out. Besides, evaluation of the antioxidant effectiveness, using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the oxygen radical absorption capacity (ORAC) methods was performed. In addition, the cytotoxicity against liver (Huh-7), breast (MCF-7) and prostate (PC-3) cancers using the neutral red assay (NRU) technique for the extract and the new flavonol glycoside also, was assessed.
- Hashim,Swilam,Moustafa,Bakry,Labib,Barakat,Singab,Linscheid,Nawwar
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- On the difference in decomposition of taxifolin and luteolin vs. fisetin and quercetin in aqueous media
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Abstract: The decomposition of flavonols quercetin and fisetin, flavone luteolin and flavanone taxifolin was studied in slightly alkaline solution under ambient conditions. The study was based on spectrophotometry and high-pressure liquid chromatography. Products formed by atmospheric oxygen oxidation and hydrolysis were identified by HPLC–DAD and HPLC–ESI-MS/MS. Only small differences in the chemical structure of flavonoids resulted in extremely variable oxidation pathways and products. Oxidation of flavonols led to the formation of both a benzofuranone derivative and several open structures. On the contrary, the benzofuranone derivative was not found as a product of taxifolin and luteolin oxidative decomposition. These compounds were oxidized to their hydroxylated derivatives and typical open structures. Quercetin was not identified as a possible oxidation product of taxifolin. Graphical Abstract: [Figure not available: see fulltext.]
- Sokolová, Romana,Rame?ová, ?árka,Kocábová, Jana,Kolivo?ka, Viliam,Degano, Ilaria,Pitzalis, Emanuela
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p. 1375 - 1383
(2016/08/12)
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- Inhibitory effects of constituents from Euphorbia lunulata on differentiation of 3T3-L1 cells and nitric oxide production in RAW264.7 cells
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A new flavonol galactopyranoside, myricetin 3-O-(2″,3″- digalloyl)-β-D-galactopyranoide (1), and 23 known constituents, including myricetin 3-O-(2″-galloyl)-β-D-galactopyranoide (2), myricitrin (3), myricetin (4), quercetin 3-O-(2″, 3″-digalloyl)-β-D- galactopyranoide (5), quercetin 3-O-(2″-galloyl)-β-D-galactopyranoide (6), hyperin (7), isoquercetrin (8), quercetin (9), kaempferol (10), apigenin (11), luteolin (12), 3-O-methylquercetin (13), 5,7,2',5'-tetrahydroxyflavone (14), 1,3,4,6-tetra-O-galloyl-β-D-glucose (15), 1,2,6-tri-O-galloyl-β- D-glucose (16), 1,3,6-tri-O-galloyl-β-D-glucose (17), gallic acid (18), protocatechuic acid (19), 3,4,5-trimethoxybenzoic acid (20), 2,6-dihydroxyacetophenone (21), 3,3'-di-O-methylellagic acid (22), ellagic acid (23) and esculetin (24) were isolated from Euphorbia lunulata Bge. Their structures were determined by spectroscopic analysis. Isolated hydrolysable tannins, flavonoids, and flavonol galactopyranoside gallates showed significant inhibition of the differentiation of 3T3-L1 preadipocytes and triglyceride accumulation in maturing adipocytes, and nitric oxide production in RAW 264.7 cells.
- Yang, Zhi-Gang,Jia, Liu-Nan,Shen, Yan,Ohmura, Atsuko,Kitanaka, Susumu
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experimental part
p. 8305 - 8318
(2011/12/15)
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- Triterpene saponins of Maesa lanceolata leaves
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Chemical investigation of Maesa lanceolata leaves aqueous MeOH extract has led to the isolation of eight new triterpene glycosides identified as 16-oxo-28-hydroxyolean-12-ene 3-O-β-glucopyranosyl-(1''→6')-β- glucopyranoside 1, 16α, 28-dihydroxyolean-12-ene 3-O-β-[(6"-O- galloylglucopyranosyl-(1"→2')][β-glucopyranosyl-(1'''→6')] -β-glucopyranoside 2, 16α, 22α, 28-trihydroxyolean-12-ene 3-O-[β-glucopyranosyl-(1"→2')] [α-rhamnopyranosyl- (1'''→6']-β-glucopyranoside 3, 22α-acetyl-16α- hydroxyolean-12-en-28-al 3-O-[α-rhamnopyranosyl- (1""→6"')-β-glucopyranosyl-(1"'→3')] [β-glucopyranosyl-(1"→2')]-β-arabinopyranoside 4, 22α-acetyl-16α,21 β-dihydroxyoleanane-13β:28-olide 3-O-[β-glucopyranosyl-(1'''→6')] [6''-O-coumaroylglucopyranosyl- (1''→2')]-β-glucopyranoside 5, 16α,22α-diacetyl-21β- angeloyloleanane-13β:28-olide 3 β-O-[β-glucopyranosyl- (1''→2')][β-glucopyranosyl-(1'''→4')]-β-glucopyranoside 6, 16α, 22α, 28-trihydroxy-21β-angeloyloleanan-12-ene 3 β-O-[α-rhamnopyranosyl-(1'''→6'')][β-glucopyranosyl- (1''→2')]-β-xylopyranoside 7, 16α, 28-dihydroxy-22α- acetyl-21β-angeloylolean-12-ene 3-O-[β-galactopyranosyl- (1"→2')] [α-rhamnopyranosyl-(1'"→4')]-α- arabinopyranoside 8. Together with these were known compounds quercetin, myricetin, quercetin 3-O-rhamnopyranoside, myricetin 3-O-β-glucopyranoside, gallic acid, sistosterol 3-O-β-glucopyranoside, rutin, myricetin 3-O-α-rhamnopyranosyl-(1"→3')-β-glucopyranoside and quercetin 3,7-O-β-diglucopyranoside. Their structures were determined using spectroscopic methods as well as comparison with data from known compounds. The in vitro antibacterial activity of aqueous MeOH extract of the leaves of M. lanceolata was also investigated and zones of inhibition ranging from 28±0.1 to 10±0.2 mm were observed. The minimum inhibitory concentration (MIC) for the extract ranged between 100 to 1000 μg/ml with the highest activity being observed with Vibro cholerae. Among the pure isolates, compound 6 was the most active and its highest recorded MIC value was 62.5 μg/ml against V. cholerae. ARKAT-USA, Inc.
- Manguro, Lawrence Onyango A.,Midiwo, Jacob O.,Tietze, Lutz F.,Hao, Pang
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experimental part
p. 172 - 198
(2011/06/09)
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- High molecular weight persimmon (Diospyros kaki L.) proanthocyanidin: A highly galloylated, a-linked tannin with an unusual flavonol terminal unit, myricetin
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MALDI-TOF MS suggested that the high molecular weight proanthocyanidin (condensed tannin) from persimmon (Diospyros kaki L.) pulp comprised a heteropolyflavanol series with flavan-3-O-galloylated extenders, flavan-3-ol and flavonol terminal units, and A-type interflavan linkages. Thiolysis-HPLC-ESI-MS with DAD, electrochemical, and ESI-MS detection confirmed a previously unreported terminal unit, the flavonol myricetin, in addition to the typical flavan-3-ols catechin and epigallocatechin gallate. The extender units were epicatechin, epigallocatechin, (epi)gallocatechin-3-O-gallate, and (epi)catechin-3-O-gallate. The crude tannin had a high prodelphinidin content (65%) and a high degree of 3-O-galloylation (72%). The material was fractionated on Toyopearl TSK-HW-50-F to yield fractions distinguished by degree of polymerization (DP). Thiolysis suggested that the persimmon tannin was composed of polymers ranging from 7 to 20 kDa (DP 19-47), but sizes estimated by GPC were 50-70% smaller. The crude material was chemically degraded with acid to yield products that were amenable to NMR and ESI-MS analysis, which were used to establish for the first time that persimmon tannin has a mixture of B-type and A-type linkages. 2010 American Chemical Society.
- Li, Chunmei,Leverence, Rachael,Trombley, John D.,Xu, Shufen,Yang, Jie,Tian, Yan,Reed, Jess D.,Hagerman, Ann E.
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experimental part
p. 9033 - 9042
(2011/05/05)
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- Flavonol glycosides with α-D-aldohexoses from Rhododendron irroratum
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Two new flavonol glycosides which contain rare α-D-galactose or α-D-glucose were obtained from the flowers of Rhododendron irroratum Franch., namely myricetin 3-O-β-D-galactoside-3′-O -α-D-glucoside (1) and myricetin 3-O-β-D-galactoside-3′-O- α-D-glucosid
- Yang, Ming Hua,Luo, Jian Guang,Huang, Xue Feng,Kong, Ling Yi
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experimental part
p. 920 - 925
(2010/08/19)
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- Identification and quantification of phenolic compounds from the forage legume sainfoin (Onobrychis viciifolia)
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Phenolic compounds of sainfoin (Onobrychis viciifolia) variety Cotswold Common are assumed to contribute to its nutritive value and bioactive properties. A purified acetone/water extract was separated by Sephadex LH-20 gel chromatography. Sixty-three phen
- Regos, Ionela,Urbanella, Andrea,Treutter, Dieter
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experimental part
p. 5843 - 5852
(2010/06/17)
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- Anti-complement activity of constituents from the stem-bark of Juglans mandshurica
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Four known flavonoids and two galloyl glucoses isolated from the stem-bark of Juglans mandshurica (Juglandaceae), namely taxifolin (1), afzelin (2), quercitrin (3), myricitrin (4), 1,2,6-trigalloylglucose (5), and 1,2,3,6-tetragalloylglucose (6), were evaluated for their anti-complement activity against complement system. Afzelin (2) and quercitrin (3) showed inhibitory activity against complement system with 50% inhibitory concentrations (IC50) values of 258 and 440 μM. 1,2,6-Trigalloylglucose (5) and 1,2,3,6-tetragalloylglucose (6) exhibited anti-complement activity with IC 50 values of 136 and 34 μM. In terms of the evaluation of the structure-activity relationship of 3,5,7-trihydroxyflavone, compounds 2, 3, and 4 were hydrolyzed with naringinase to give kaempferol (2a), quercetin (3a), and myricetin (4a) as their aglycones, and these were also tested for their anti-complement activity. Of the three aglycones, kaempferol (2a) exhibited weak anti-complement activity with an IC50 value of 730 μM, while quercetin (3a) and myricetin (4a) were inactive in this assay system. Among the compounds tested, 1,2,3,6-tetragalloylglucose (6) showed the most potent anticomplement activity (IC50, 34 μM).
- Min, Byung-Sun,Lee, Sun-Young,Kim, Jung-Hee,Lee, Joong-Ku,Kim, Tae-Jin,Kim, Dong-Hee,Kim, Young-Ho,Joung, Hyouk,Lee, Hyeong-Kyu,Nakamura, Norio,Miyashiro, Hirotsugu,Hattori, Masao
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p. 1042 - 1044
(2007/10/03)
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- Polyoxygenated flavonoids from Eugenia edulis
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Leaves of Eugenia edulis contain the new polyoxygenated flavonoid derivatives, gossypetin-3,8-dimethyl ether-5-O-β-glucoside; gossypetin-3,5-dimethyl ether, and myricetin-3,5,3′-trimethyl ether. In addition, ten known polyphenolics were also isolated and identified. All structures were established on the basis of chemical and spectral evidence, including ESI-MS and 13C NMR.
- Hussein, Sahar A.M.,Hashem, Amani N.M.,Seliemb, Mohammed A.,Lindequist, Ulrike,Nawwar, Mahmoud A.M.
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p. 883 - 889
(2007/10/03)
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- Methods and compositions for enhancing cellular function through protection of tissue components
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Methods and compositions for enhancing cellular function through protection of a tissue components such receptors, proteins, lipids, nucleic acids, carbohydrates, hormones, vitamins, and cofactors, by administering pyrophosphate analogs or related compounds.
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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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- A NEW FLAVONOL GLYCOSIDE FROM Azara microphylla
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The leaves of Azara microphylla Hook., introduced into the Sukhami Botanical Garden of the Academy of Sciences of the Georgian SSR, have yielded a new glycoside, which has been called azamicroside and its structure has been established as myricetin 3-O-L-dirhamnoside.
- Sagareishvili, T. G.,Alaniya, M. D.,Kemertelidze, E. P.
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p. 275 - 278
(2007/10/02)
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