17654-26-1Relevant articles and documents
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)
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.
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 (2021)
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%.
Taxifolin 3-arabinoside from Fragaria x ananassa
Ishimaru, Kanji,Omoto, Toshio,Asai, Iwao,Ezaki, Katsushi,Shimomura, Koichiro
, p. 345 - 348 (1995)
From the roots of Fragaria x ananassa, a new flavanoid, (+)-taxifolin 3-O-α-L-arabinofuranoside was isolated and its structure was established on the basis of chemical and spectroscopic evidence.A hydrolysable tannin, pedunculagin, and condensed tannins, (+)-catechin, (+)-afzelechin-(4α-8)-(+)-catechin, procyanidin B-3 and procyanidin B-6 were also isolated.
Structural and mechanistic studies on anthocyanidin synthase catalysed oxidation of flavanone substrates: The effect of C-2 stereochemistry on product selectivity and mechanism
Welford, Richard W.D.,Clifton, Ian J.,Turnbull, Jonathan J.,Wilson, Stuart C.,Schofield, Christopher J.
, p. 3117 - 3126 (2005)
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.
Estrogenic and anti-estrogenic compounds from the Thai medicinal plant, Smilax corbularia (Smilacaceae)
Wungsintaweekul, Boonsong,Umehara, Kaoru,Miyase, Toshio,Noguchi, Hiroshi
, p. 495 - 502 (2011)
From the rhizomes of Smilax corbularia Kunth. (Smilacaceae), 11 compounds, (2R,3R)-2″-acetyl astilbin, (2R,3R)-3″-acetyl astilbin, (2R,3R)-4″-acetyl astilbin, (2R,3R)-3″-acetyl engeletin, (2R,3S)-4″-acetyl isoastilbin, 2-(4-hydroxyphenyl)-3,4,9,10-tetrahydro-3, 5-dihydroxy-10-(3,4-dihydroxyphenyl)-(2R,3R,10R)-2H,8H-benzo [1,2-b:3,4-b′] dipyran-8-one, 2-(4-hydroxyphenyl)-3,4,9,10-tetrahydro-3,5- dihydroxy-10-(3,4-dihydroxyphenyl)-(2R,3R,10S)-2H, 8H-benzo [1,2-b:3,4-b′] dipyran-8-one, 3,4-dihydro-7-hydroxy-4-(3,4-dihydroxyphenyl)-5-[(1E)-2-(4- hydroxyphenyl) ethenyl]-2H-1-benzopyran-2-one, 3,4-dihydro-7-hydroxy-4-(3,4- dihydroxy-phenyl)-5-[(1E)-2-(3,4-dihydroxyphenyl) ethenyl]-2H-1-benzopyran-2- one, 3,4-dihydro-7-hydroxy-4-(4-hydroxy-3-methoxyphenyl)-5-[(1E)-2-(4- hydroxyphenyl) ethenyl]-2H-1-benzopyran-2-one, and 5,7,3′,4′- tetrahydroxy-3-phenylcoumarin along with 34 known compounds were isolated and characterized as 19 flavonoids, 14 catechin derivatives, 6 stilbene derivatives, and 6 miscellaneous substances. All isolates had their estrogenic and anti-estrogenic activities determined using the estrogen-responsive human breast cancer cell lines MCF-7 and T47D. The major constituents were recognized as flavanonol rhamnosides by the suppressive effect on estradiol induced cell proliferation at a concentration of 1 μM. Meanwhile, flavanonol rhamnoside acetates demonstrated estrogenic activity in both MCF-7 and T47D cells at a concentration of 100 μM, and they enhanced the effects of co-treated E2 on T47D cell proliferation at concentrations of more than 0.1 μM.
TAXIFOLIN APIOSIDE AND DAVURICIIN M1, A HYDROLYSABLE TANNIN FROM ROSA DAVURICA
Yoshida, Takashi,Jin, Zhe Xiong,Okuda, Takuo
, p. 2177 - 2182 (1989)
Key Word Index - Rosa davurica; Rosaceae; (+)-taxifolin-3-O-β-D-apio-D-furanoside; dihydroflavonol apioside; tannin; davuriciin M1; ellagitannin.Abstract - The structure of a dihydroflavonol glycoside from the roots of Rosa davurica has been characterized as (+)-taxifolin-3-O-β-D-apio-D-furanoside. A new hydrolysable tannin, davuriciin M1, together with three known hydrolysable tannins, have also been isolated.The structure of new tannin was elucidated by spectroscopic and chemical methods.
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.
Synthesis, biological evaluation, and molecular docking of dihydroflavonol derivatives as anti-inflammatory agents
Xiang, Yuanhang,Hu, Chunling,Zhang, Yuejie,Ye, Xiaochuan
, p. 863 - 872 (2019/04/17)
A series of dihydroflavonol derivatives (4a–4l) were synthesized from chalcones via classical Algar–Flynn–Oyamada (AFO) reaction and characterized on the basis of spectroscopic analyses. All synthesized compounds were evaluated for their inhibitory activity against the pro-inflammatory-inducible TNF-alpha, IL-1beta, and IL-6 in lipopolysaccharide (LPS)-stimulated RAW 264.7 cell lines and showed various efficiency. Furthermore, compounds 4d and 4k were selected to examine their in vivo anti-inflammatory activity by using two classical models. Herein compound 4k showed maximum anti-inflammatory activity of 32.98% inhibition in mice ear-swelling model and 40.06% inhibition at the 2 h intervals in rat paw edema model in comparison to the two references: aspirin and meloxicam. Similar effect was observed at a lower dose. In addition, the compound 4k was docked against cyclooxygenases-2 to validate the attained pharmacological data and provide understandable evidence for the observed anti-inflammatory activity.
