480-18-2Relevant academic research and scientific papers
Acidic hydrolysis of astilbin and its application for the preparation of taxifolin from Rhizoma Smilacis Glabrae
Qiu, Xiao-Lin,Zhang, Qing-Feng
, p. 290 - 294 (2020/12/01)
The acidic hydrolysis of astilbin to produce its aglycone, taxifolin, was investigated in this study. The effects of aq. HCl concentration and temperature on the reaction were studied, and the kinetic parameters were calculated. The results showed that with higher aq. HCl concentration and temperature, the hydrolysis of astilbin became faster. The activation energy of the hydrolysis reaction under 1 mol L?1 aq. HCl was calculated with a value of 148.6 kJ mol?1. The reaction was successfully applied to produce taxifolin from a sample of Rhizoma Smilacis Glabrae. A simple method for the purification of taxifolin from Rhizoma Smilacis Glabrae was developed with purity of 97.5%.
Optimization of the biosynthesis of b-ring ortho-hydroxy lated flavonoids using the 4-hydroxyphenylacetate 3-hydroxylase complex (Hpabc) of escherichia coli
Chen, Yang,Gao, Liping,Gui, Lin,Guo, Lina,Lei, Ting,Li, Yan,Ma, Xiubing,Ruan, Haixiang,Wang, Longji,Wang, Yunsheng,Xia, Tao
, (2021/05/31)
Flavonoids are important plant metabolites that exhibit a wide range of physiological and pharmaceutical functions. Because of their wide biological activities, such as anti-inflammatory, antioxidant, antiaging and anticancer, they have been widely used in foods, nutraceutical and pharmaceuticals industries. Here, the hydroxylase complex HpaBC was selected for the efficient in vivo production of ortho-hydroxylated flavonoids. Several HpaBC expression vectors were constructed, and the corresponding products were successfully detected by feeding naringenin to vector-carrying strains. However, when HpaC was linked with an S-Tag on the C terminus, the enzyme activity was significantly affected. The optimal culture conditions were determined, including a substrate concentration of 80 mg·L?1, an induction temperature of 28?C, an M9 medium, and a substrate delay time of 6 h after IPTG induction. Finally, the efficiency of eriodictyol conversion from P2&3-carrying strains fed naringin was up to 57.67 ± 3.36%. The same strategy was used to produce catechin and caf-feic acid, and the highest conversion efficiencies were 35.2 ± 3.14 and 32.93 ± 2.01%, respectively. In this paper, the catalytic activity of HpaBC on dihydrokaempferol and kaempferol was demonstrated for the first time. This study demonstrates a feasible method for efficiently synthesizing in vivo B-ring dihydroxylated flavonoids, such as catechins, flavanols, dihydroflavonols and flavonols, in a bacterial expression system.
Total Synthesis of the Natural Products Ulmoside A and (2 R,3 R)-Taxifolin-6- C -β- d -glucopyranoside
Batchu, Venkateswara Rao,Dorigundla, Aravind Reddy,Gurrapu, Raju,Macha, Lingamurthy,Vanka, Umamaheswara Sarma
, p. 1097 - 1101 (2020/07/03)
An efficient first total synthesis of highly polar ulmoside A and (2 R,3 R)-taxifolin-6- C -β- d -glucopyranoside, useful for the prevention of metabolic disorders, has been described. Key elements of the synthesis include a Sc(OTf) 3-catalyzed regio- and stereoselective C -glycosidation on taxifolin in 35percent yield with d -glucose and chiral semipreparative reverse-phase high-performance liquid chromatography (HPLC) for the separation of both taxifolins and the diastereomeric mixture of taxifolin-6- C -β- d -glucopyranosides. Correlation of the analytical data of synthetic ulmoside A and its diastereomer with a natural ulmoside A sample confirmed the assigned absolute stereochemistry of the natural products.
Oxidative Transformation of Leucocyanidin by Anthocyanidin Synthase from Vitis vinifera Leads only to Quercetin
Zhang, Jia-Rong,Trossat-Magnin, Claudine,Bathany, Katell,Delrot, Serge,Chaudière, Jean
, p. 3595 - 3604 (2019/03/29)
Anthocyanidin synthase from Vitis vinifera (VvANS) catalyzes the in vitro transformation of the natural isomer of leucocyanidin, 2R,3S,4S-cis-leucocyanidin, into 2R,4S-flavan-3,3,4-triol ([M + H]+, m/z 323) and quercetin. The C3-hydroxylation product 2R,4S-flavan-3,3,4-triol is first produced and its C3,C4-dehydration product is in tautomeric equilibrium with (+)-dihydroquercetin. The latter undergoes a second VvANS-catalyzed C3-hydroxylation leading to a 4-keto-2R-flavan-3,3-gem-diol which upon dehydration gives quercetin. The unnatural isomer of leucocyanidin, 2R,3S,4R-trans-leucocyanidin, is similarly transformed into quercetin upon C3,C4-dehydration, but unlike 3,4-cis-leucocyanidin, it also undergoes some C2,C3-dehydration followed by an acid-catalyzed hydroxyl group extrusion at C4 to give traces of cyanidin. Overall, the C3,C4-trans isomer of leucocyanidin is transformed into 2R,4R-flavan-3,3,4-triol (M + 1, m/z 323), (+)-DHQ, (-)-epiDHQ, quercetin, and traces of cyanidin. Our data bring the first direct observation of 3,4-cis-leucocyanidin- and 3,4-trans-leucocyanidin-derived 3,3-gem-diols, supporting the idea that the generic function of ANS is to catalyze the C3-hydroxylation of its substrates. No cyanidin is produced with the natural cis isomer of leucocyanidin, and only traces with the unnatural trans isomer, which suggests that anthocyanidin synthase requires other substrate(s) for the in vivo formation of anthocyanidins.
Taxifolin preparation method
-
Paragraph 0039-0044; 0049-0054; 0059-0064; 0065; 0069-0074, (2019/03/08)
The invention relates to a method for synthesizing a raw material medicine, in particular to a taxifolin preparation method, aiming to solve the technical problems that waste of plant resources and solvents is great during separation and purification of taxifolin from plants, complete synthesis methods of the taxifolin have long synthetic routes, many complicated raw ingredients are involved, theoverall yield is low and the methods are not suitable for industrial production in the prior art. The taxifolin preparation method has the advantages that dihydromyricetin is selected as a starting material, a crude taxifolin product is obtained by hydrolysis and catalysis closed-loop two-step reactions, and a qualified refined taxifolin product is obtained through purification and refining; the raw material is easy to obtain, the operation is simple, the cost is low, environment friendliness and small pollution are realized, and the taxifolin preparation method is suitable for industrial production.
A through pot synthesis of dihydro flavonoid compound and its preparation method (by machine translation)
-
, (2017/10/31)
The invention discloses a through a pot synthesis of dihydro flavonoid compound and its preparation method, the method comprises the following steps: (1) first of all, in order to 2 - hydroxy phenyl ketone compounds and benzaldehyde compound as a starting raw material, in the chloromethyl methyl ether, sodium hydride, sodium hydroxide aqueous solution to produce an intermediate common under the action of the 3; (2) then adding 30% hydrogen peroxide solution, to obtain the intermediate 4; (3) filling the hydrogen chloride gas in the final reaction solution, the reaction is finished adding water and ethyl acetate extraction, the organic phase dried, concentrated, over silica gel column purification, states the dihydro flavonoid compound is obtained. The invention the synthetic mild condition, reagent, solvent is single, simple operation, thereby avoiding the various reaction steps of processing and purification, reducing solvent loss, reducing the labor, time and cost. (by machine translation)
Enzymatic activity of cell-free extracts from Burkholderia oxyphila OX-01 bio-converts (+)-catechin and (-)-epicatechin to (+)-taxifolin
Otsuka, Yuichiro,Matsuda, Motoki,Sonoki, Tomonori,Sato-Izawa, Kanna,Goodell, Barry,Jelison, Jody,Navarro, Ronald R.,Murata, Hitoshi,Nakamura, Masaya
, p. 2473 - 2479 (2016/11/22)
This study characterized the enzymatic ability of a cell-free extract from an acidophilic (+)-catechin degrader Burkholderia oxyphila (OX-01). The crude OX-01 extracts were able to transform (+)-catechin and (-)-epicatechin into (+)-taxifolin via a leucocyanidin intermediate in a two-step oxidation. Enzymatic oxidation at the C-4 position was carried out anaerobically using H2O as an oxygen donor. The C-4 oxidation occurred only in the presence of the 2R-catechin stereoisomer, with the C-3 stereoisomer not affecting the reaction. These results suggest that the OX-01 may have evolved to target both (+)-catechin and (-)-epicatechin, which are major structural units in plants.
A natural active product process for synthesis of dihydro-quercetin (by machine translation)
-
Paragraph 0023; 0024, (2017/02/24)
The invention discloses a process for synthesizing (2R,3R)-dihydroquercetin. The process comprises the specific steps of carrying out Friedel-Crafts acylation on caffeic acyl chloride and phloroglucin which serve as raw materials, forming epoxy bonds through peroxidizing double bonds, opening cycles under acidic conditions, forming ether with phenolic hydroxyl, and carrying out separation, purification and crystallization after reaction is ended, thereby obtaining the product with high content and high purity. In the aspects of reagents and raw and auxiliary materials used during the reaction, both environment-friendliness and efficiency are taken into account. The process disclosed by the invention has the advantages of high atom economical efficiency, simple equipment and environment-friendly production procedure and has very large economic and social benefits.
Stereospecific inhibition of nitric oxide production in macrophage cells by flavanonols: Synthesis and the structure-activity relationship
Jiang, Wen-Jun,Ishiuchi, Kan'Ichiro,Furukawa, Megumi,Takamiya, Tomoko,Kitanaka, Susumu,Iijima, Hiroshi
, p. 6922 - 6929 (2015/11/11)
To explore the structure-activity relationships on the inhibitory activity of flavanonols against nitric oxide (NO) production in inflammatory cells, we synthesized 19 flavanonols which shared a common 3,5,7-trihydroxychroman scaffold. A range of substitutions was included in the B ring in order to investigate the structure-activity relationship. We also succeeded in isolating stereoisomers from 16 of the flavanonols using chiral column chromatography. The inhibitory effects of these compounds on NO production were examined in RAW 264.7 cells (a murine macrophage-like cell line), which were activated by lipopolysaccharide (LPS). We only observed inhibitory activity against NO production in (2R,3R) stereoisomers, while the inhibitory activities of (2S,3S) stereoisomers were significantly weaker. We also evaluated the free radical scavenging potential of the flavanonols using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Each stereoisomer indicated the equivalent DPPH scavenging potential as expected. The radical scavenging activity was not correlated with the inhibitory activity against NO. The inhibition of NO production by flavanonols is stereospecific and cannot simply be explained by their radical scavenging activity. We propose the possible existence of a 'target' molecule for flavanonols which is involved in the production and/or regulation of NO in RAW 264.7 cells.
