491-67-8Relevant articles and documents
Enzyme-polysaccharide interaction and its influence on enzyme activity and stability
Li, Jian,Jiang, Zhongyi,Wu, Hong,Liang, Yanpeng,Zhang, Yufei,Liu, Jiaxian
, p. 160 - 166 (2010)
An attempt was made to probe and elucidate the influence of three kinds of polysaccharides including the negatively charged sodium carboxymethyl cellulose (CMC), the uncharged methyl cellulose (MC) and the positively charged sodium carboxymethyl chitosan (CMCS), on the catalytic activity and stability of the model enzyme, β-d-glucuronidase (GUS). DSC analysis showed that the denaturing temperature of GUS was increased by 7 °C in the presence of CMC, but decreased in the presence of MC or CMCS by 5 and 3 °C, respectively. This variation was in good accordance with changes in the enzyme's catalytic activity. Circular dichroism was employed to characterize the conformational changes of GUS before and after the addition of the polysaccharide. It suggested that charged polysaccharides, CMC and CMCS, were favorable for improving the pH stability and the storage stability of GUS, whereas uncharged MC did not show such a stabilizing effect. At an elevated temperature up to 70 °C, GUS in CMC solution remained 78% activity and displayed the highest thermal stability among the three enzyme-polysaccharide pairs. The electrostatic interaction between enzyme and polysaccharides was closely relevant to the enzyme conformation, activity and stability.
ADDITIONAL FLAVONOIDS FROM ELICITOR-TREATED CELL CULTURES OF CEPHALOCEREUS SENILIS
Liu, Qin,Dixon, Richard A.,Mabry, Tom J.
, p. 167 - 170 (1993)
Five major flavonoids induced by chitin in Cephalocereus senilis cell suspension cultures have been reported previously.We describe here five minor induced flavonoids including two new and three known ones.The two new compounds are (2S)-5,6,7-trihydroxyflavanone 7-glycoside and baicalein 7-(6''-malonylglucoside).
Investigation on the inclusion behaviour of baicalein with β-cyclodextrin and derivatives and their antioxidant ability study
Chao, Jianbin,Su, Jian,Li, Jinxia,Zhao, Wei,Huang, Shuping,Du, Rui
, p. 644 - 653 (2011)
The formation of the complexes of baicalein (Ba) with β-cyclodextrin (β-CD) and β-CD derivatives (HP-β-CD and Me-β- CD) was studied by UV-vis absorption spectroscopy, fluorescence method, nuclear magnetic resonance spectroscopy and phase-solubility measurement. The solid-inclusion complexes of Ba with CDs were synthesised by the co-precipitation method. The characterisations of the solid-inclusion complexes have been proved by infrared spectra and differential scanning calorimetry. Experimental conditions including the concentration of various CDs and media acidity were investigated in detail. The results suggested that the inclusion ratio of HP-β-CD with Ba was the highest among the three kinds of CDs. The binding constants (Ks) of the inclusion complexes were determined by fluorescence method and phasesolubility measurement. Kinetic studies of DPPHz with Ba and CDs complexes were also done. The results indicated that the Ba/HP-β-CD complex was the most reactive form.
Biotransformation of Chrysin to Baicalein: Selective C6-Hydroxylation of 5,7-Dihydroxyflavone Using Whole Yeast Cells Stably Expressing Human CYP1A1 Enzyme
Williams, Ibidapo S.,Chib, Shifali,Nuthakki, Vijay K.,Gatchie, Linda,Joshi, Prashant,Narkhede, Niteen A.,Vishwakarma, Ram A.,Bharate, Sandip B.,Saran, Saurabh,Chaudhuri, Bhabatosh
, p. 7440 - 7446 (2017)
Naturally occurring polyphenolic compounds are of medicinal importance because of their unique antioxidant, anticancer, and chemopreventive properties. Baicalein, a naturally occurring polyhydroxy flavonoid possessing a diverse range of pharmacological activities, has been used in traditional medicines for treatment of various ailments. Apart from its isolation from natural sources, its synthesis has been reported via multistep chemical approaches. Here, we report a preparative-scale biotransformation, using whole yeast cells stably expressing human cytochrome P450 1A1 (CYP1A1) enzyme that allows regioselective C6-hydroxylation of 5,7-dihydroxyflavone (chrysin) to form 5,6,7-trihydroxyflavone (baicalein). Molecular modeling reveals why chrysin undergoes such specific hydroxylation mediated by CYP1A1. More than 92% reaction completion was obtained using a shake-flask based process that mimics fed-batch fermentation. Such highly efficient selective hydroxylation, using recombinant yeast cells, has not been reported earlier. Similar CYP-expressing yeast cell based systems are likely to have wider applications in the syntheses of medicinally important polyphenolic compounds.
Flavonoid derivative as well as preparation method and identification method thereof
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Paragraph 0078; 0079; 0080; 0088; 0100; 0110; 0120; 0129, (2019/02/17)
The invention discloses a flavonoid derivative, which has structure formulas shown as a general formula (I) and a general formula (II) as in the description, wherein R1 is alkyl or cyclo alkane; R2 isalkyl or cyclo alkane; R1, R2 and nitrogen atoms form cycloaliphatic ring or heterocycle; R3 is alkyl or aryl or aralkyl; the value of n is 1 to 10. The invention also discloses a preparation methodand an identification method of the flavonoid derivative.
Oxidation of Flavone, 5-Hydroxyflavone, and 5,7-Dihydroxyflavone to Mono-, Di-, and Tri-Hydroxyflavones by Human Cytochrome P450 Enzymes
Nagayoshi, Haruna,Murayama, Norie,Kakimoto, Kensaku,Tsujino, Masaki,Takenaka, Shigeo,Katahira, Jun,Lim, Young-Ran,Kim, Donghak,Yamazaki, Hiroshi,Komori, Masayuki,Guengerich, F. Peter,Shimada, Tsutomu
, p. 1268 - 1280 (2019/05/07)
Biologically active plant flavonoids, including 5,7-dihydroxyflavone (57diOHF, chrysin), 4′,5,7-trihydroxyflavone (4′57triOHF, apigenin), and 5,6,7-trihydroxyflavone (567triOHF, baicalein), have important pharmacological and toxicological significance, e.g., antiallergic, anti-inflammatory, antioxidative, antimicrobial, and antitumorgenic properties. In order to better understand the metabolism of these flavonoids in humans, we examined the oxidation of flavone, 5-hydroxyflavone (5OHF), and 57diOHF to various products by human cytochrome P450 (P450 or CYP) and liver microsomal enzymes. Individual human P450s and liver microsomes oxidized flavone to 6-hydroxyflavone, small amounts of 5OHF, and 11 other monohydroxylated products at different rates and also produced several dihydroxylated products (including 57diOHF and 7,8-dihydroxyflavone) from flavone. We also found that 5OHF was oxidized by several P450 enzymes and human liver microsomes to 57diOHF and further to 567triOHF, but the turnover rates in these reactions were low. Interestingly, both CYP1B1.1 and 1B1.3 converted 57diOHF to 567triOHF at turnover rates (on the basis of P450 contents) of >3.0 min-1, and CYP1A1 and 1A2 produced 567triOHF at rates of 0.51 and 0.72 min-1, respectively. CYP2A13 and 2A6 catalyzed the oxidation of 57diOHF to 4′57triOHF at rates of 0.7 and 0.1 min-1, respectively. Our present results show that different P450s have individual roles in oxidizing these phytochemical flavonoids and that these reactions may cause changes in their biological and toxicological properties in mammals.
Anti-angiogenic and anticancer effects of baicalein derivatives based on transgenic zebrafish model
Jiang, Xueyang,Zhou, Junting,Lin, Qinghua,Gong, Guiyi,Sun, Haopeng,Liu, Wenyuan,Guo, Qinglong,Feng, Feng,Qu, Wei
supporting information, p. 4481 - 4492 (2018/08/11)
Angiogenesis leads to tumor neovascularization by promoting tumor growth and metastatic spread, therefore, angiogenesis is considered as an attractive target for potential small molecule anticancer drug discovery. Herein, we report the structural modification and biological evaluation of baicalein derivatives, among which compound 42 had potent in vivo anti-angiogenic activity and wide security treatment window in transgenic zebrafish model. Further, 42 exhibited the most potent inhibitory activity on HUVEC proliferation, migration and tube formation in vitro. Moreover, 42 significantly inhibited growth of human lung cancer A549 cells and weak influence on human normal fibroblast L929 cells. The present research demonstrated that the significant anti-angiogenic and anticancer effects, which provided the supportive evidence for 42 could be used as a potential compound of cancer therapy.
Synthesis of oroxylin A starting from naturally abundant baicalin
Fujita, Rie,Hanaya, Kengo,Higashibayashi, Shuhei,Sugai, Takeshi
, p. 1165 - 1174 (2019/07/31)
– A new approach to oroxylin A, a monomethylated trihydroxyflavone, is described. The starting material was baicalin, a representative naturally abundant flavonoid glucuronide. First, conditions for the cleavage of the glycosidic bond were established, using a mixture of water and conc. sulfuric acid (5:2) at 121 °C for 40 min. The hydrolysis was performed in a high-pressure steam sterilizer so that the temperature and reaction time were precisely controlled. Subsequent acetylation of the crude material furnished baicalein 6,7-diacetate on a preparative scale and in a reproducible manner. Next, the C-7 position was protected site-selectively with a methoxymethyl (MOM) group, taking advantage of an unexpected sequential migration of the two acetyl groups among the C-5, C-6, and C-7 positions under basic conditions. The removal of the two remaining acetyl groups followed by site-selective methylation of the C-6 position furnished 5-hydroxy-6-methoxy-7-methoxymethoxyflavone (oroxylin A C-7 MOM ether). Finally, by the deprotection of the MOM ether, oroxylin A was obtained in 6 total steps and 62% overall yield from baicalin.
The invention relates to a raw material for preparing the glucuronic acid the glucoside is corresponding aglycone (by machine translation)
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Paragraph 0056; 0057; 0058; 0059, (2017/09/23)
The invention discloses a glucuronic acid the glucoside is raw material for preparing the corresponding aglycone method, comprises the following steps: (1), synthesis of methyl chlorine sulfurous acid; (2), glucuronic acid methyl ester glucoside synthesis; (3), the inorganic acid is added in the ethanol, into inorganic acid ethanol solution, and then the inorganic acid ethanol solution is added to step (2) is made in the product of the glucuronic acid methyl ester glucoside, acid hydrolysis; (4), after the reaction, the reaction is cooled down to the room temperature after the, in the reaction liquid is poured into the water, standing precipitate, precipitation after complete filtering, the resulting solid for recrystallization dilute alcohol, obtaining the corresponding aglycone pure product. The method of the invention essentially solves the problem of the glucuronic acid the glucoside is difficult hydrolysis, the process is simple, short reaction time, does not need to use a large amount of organic solvent, after treatment is simple, the resulting aglycone yield is as high as 90%, purity as high as 99%, low cost, can be used for large-scale industrial production. (by machine translation)
Macroporous resin auxiliary various glycoside hydrolysis to prepare their aglycon, secondary glucoside method
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Paragraph 0044; 0045, (2017/08/23)
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.
