- Total synthesis of scutellarin and apigenin 7-O-β-d-glucuronide
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A general protocol for direct glucuronic linkages formation featuring Au(I)-catalyzed appropriately protected glucuronyl o-alkynylbenzoate-involved glycosylation reaction, as well as a concise approach for easy access of scutellarein prominent for the mild and efficient hydroxyl group installation via borylation-oxidation sequence from flavanone derivative, has been established, based on which a novel route for scutellarin derivatives preparation has been devised. The developed strategies, among which the stepwise deprotection process was also included, guarantee the high whole synthetic efficiency, and definitely will find broad application in diversity-oriented synthesis of bioactive flavonoid glycosides.
- Liu, Xin,Wen, Guo-En,Liu, Jian-Chao,Liao, Jin-Xi,Sun, Jian-Song
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supporting information
p. 69 - 73
(2019/03/17)
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- METHOD FOR PREPARING 5,6,4'-TRIHYDROXYFLAVONE-7-0-D-GLUCURONIC ACID
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The present invention relates to the field of drug synthesis. Disclosed is a method for preparing 5,6,4'-trihydroxyflavone-7-O-D-glucuronic acid. The method for preparing 5,6,4'-trihydroxyflavone-7-O-D-glucuronic acid of the present invention uses 5,6,7,4'-tetrahydroxyflavone as a raw material and adopts a new synthetic route to obtain high-purity 5,6,4'-trihydroxyflavone-7-O-D-glucuronic acid through an acylation reaction, a glycosylation reaction, and two-step hydrolysis. The preparing method of the present invention has a short synthetic route, low cost, and high reaction yield, the product is easy for purification, and the method is applicable to industrial production of 5,6,4'-trihydroxyflavone-7-O-D-glucuronic acid.
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- Synthesis and physiochemical property evaluation of carbamate derivatives of scutellarin methyl ester
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A series of carbamate prodrugs of scutellarin methyl ester (4a-4e) were prepared in the presence of bis(trichloromethyl) carbonate (BTC) with scutellarin methyl esters and l-amino acid tert-butyl ester hydrochloride as starting materials. In vitro stability and aqueous solubility of target compounds were evaluated. The results indicated that compounds 4d and 4e have higher solubility and in vitro stability than scutellarin respectively.
- Jiang, Feng-Jie,Fu, Xiao-Zhong,Wang, Shan-Wu,Huang, Yong,Zhou, Wen,Wang, Ai-Min,Wang, Yong-Lin
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p. 338 - 340
(2013/06/26)
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- Co-pigmentation and flavonoid glycosyltransferases in blue Veronica persica flowers
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Glycosylation is one of the key modification steps for plants to produce a broad spectrum of flavonoids with various structures and colors. A survey of flavonoids in the blue flowers of Veronica persica Poiret (Lamiales, Scrophulariaceae), which is native of Eurasia and now widespread worldwide, led to the identification of highly glycosylated flavonoids, namely delphinidin 3-O-(2-O-(6-O-p-coumaroyl-glucosyl)-6-O-p-coumaroyl-glucoside)-5-O-glucoside (1) and apigenin 7-O-(2-O-glucuronosyl)-glucuronide (2), as two of its main flavonoids. Interestingly, the latter flavone glucuronide (2) caused a bathochromic shift on the anthocyanin (1) toward a blue hue in a dose-dependent manner, showing an intermolecular co-pigment effect. In order to understand the molecular basis for the biosynthesis of this glucuronide, we isolated a cDNA encoding a UDP-dependent glycosyltransferase (UGT88D8), based on the structural similarity to flavonoid 7-O-glucuronosyltransferases (F7GAT) from Lamiales plants. Enzyme assays showed that the recombinant UGT88D8 protein catalyzes the 7-O-glucuronosylation of apigenin and its related flavonoids with preference to UDP-glucuronic acid as a sugar donor. Furthermore, we identified and functionally characterized a cDNA encoding another UGT, UGT94F1, as the anthocyanin 3-O-glucoside-2″-O-glucosyltransferase (A3Glc2″GlcT), according to the structural similarity to sugar-sugar glycosyltransferases classified to the cluster IV of flavonoid UGTs. Preferential expression of UGT88D8 and UGT94F1 genes in the petals supports the idea that these UGTs play an important role in the biosynthesis of key flavonoids responsible for the development of the blue color of V. persica flowers.
- Ono, Eiichiro,Ruike, Miho,Iwashita, Takashi,Nomoto, Kyosuke,Fukui, Yuko
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experimental part
p. 726 - 735
(2010/07/02)
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- Purification and characterization of UDP-glucuronate: Baicalein 7-O- glucuronosyltransferase from Scutellaria baicalensis Georgi. cell suspension cultures
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UDP-glucuronate: baicalein 7-O-glucuronosyltransferase (UBGAT) catalyzes the transfer of glucuronic acid from UDP-glucuronic acid to the 7-OH of baicalein. UBGAT was purified from cultured cells of Scutellaria baicalensis Georgi (Lamiaceae). It was purified 95-fold using various chromatography and chromatofocusing procedures to apparent homogeneity. The M(r) was estimated to be 110 kDa by gel filtration chromatography with a 52 kDa subunit by SDS- PAGE. The isoelectric point was pH 4.8. UBGAT was specific to UDP-glucuronic acid as a sugar donor and flavones with substitution ortho- to the 7-OH group such as baicalein (6-OH), scutellarein (6-OH) and wogonin (8-OMe). (C) 2000 Elsevier Science Ltd.
- Nagashima, Shigeyuki,Hirotani, Masao,Yoshikawa, Takafumi
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p. 533 - 538
(2007/10/03)
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