- AN ACYLATED FLAVONE APIGENIN 7-O-β-D-(4''-CIS-p-COUMAROYL)GLUCOSIDE FROM ECHINOPS ECHINATUS
-
Besides apigenin 7-O-glucoside, a new acylated flavone has been identified in Echinops echinatus as apigenin 7-O-β-D-(4''-cis-p-coumaroyl)glucoside from spectral and chemical analysis. Key Word Index - Echinops echinatus; Compositae; glycosylflavones; apigenin 7-O-glucoside; apigenin 7-O-β-D-(4''-cis-p-coumaroyl)glucopyranoside; FD-MS; 13C NMR.
- Chaudhuri, Prabir K.,Thakur, Raghunath S.
-
-
Read Online
- Chamaemeloside, a new flavonoid glycoside from Chamaemelum Nobile
-
From dried flowers of Chamaemelum nobile: a new flavonoid, apigenin 7-glucoside-6″-(3?-hydroxy-3?-methyl-glutarate), has been isolated. The structure has been elucidated by interpretation of its spectroscopic data: one- and two-dimensional NMR, mass spectrometry, IR and UV. Copyright
- Tschan, Gabriela M.,Koenig, Gabriele M.,Wright, Anthony D.,Sticher, Otto
-
-
Read Online
- Identification of a flavonoid 7-O-glucosyltransferase from Andrographis paniculata
-
Andrographis paniculata is an important traditional medicinal herb in which flavonoids are part of the primary specialized metabolites. A flavonoid glucosyltransferase with broad substrate spectrum (named ApUGT3) was successfully identified by screening homologous glycosyltransferase genes from A. paniculata. The enzyme displayed glycosylation activity toward multiple flavonoids in?vitro, and the major products were identified as 7-O-glucosides. Phylogenetic analysis revealed that ApUGT3 is the first reported glycosyltransferase from the Acanthaceae family that belongs to cluster I, suggesting that ApUGT3 is a new flavonoid glycosyltransferase of this subcluster. This enzyme is potentially useful as powerful glycosylation catalysts to modify flavonoid-like compounds and improve their biological activities. (Figure presented.).
- Li, Yuan,Gao, Wei,Huang, Lu-Qi
-
p. 279 - 286
(2019/11/21)
-
- Regioselective O-glycosylation of flavonoids by fungi Beauveria bassiana, Absidia coerulea and Absidia glauca
-
In the present study, the species: Beauveria bassiana, Absidia coerulea and Absidia glauca were used in biotransformation of flavones (chrysin, apigenin, luteolin, diosmetin) and flavanones (pinocembrin, naringenin, eriodictyol, hesperetin). The Beauveria bassiana AM 278 strain catalyzed the methylglucose attachment reactions to the flavonoid molecule at positions C7 and C3′. The application of the Absidia genus (A. coerulea AM 93, A. glauca AM 177) as the biocatalyst resulted in the formation of glucosides with a sugar molecule present at C7 and C3′ positions of flavonoids skeleton. Nine of obtained products have not been previously reported in the literature.
- Sordon, Sandra,Pop?oński, Jaros?aw,Tronina, Tomasz,Huszcza, Ewa
-
-
- Highly regioselective dehexanoylation in fully hexanoylated flavonoids
-
Highly selective removal of the 7-O-hexanoyl group in fully hexanoylated flavones, isoflavones, flavanone, and flavonol was achieved under mild conditions using K2CO3 in a 1:1 mixture of CH3OH–CH2Cl2. The resulting 7-OH flavonoids are valuable intermediates for the synthesis of flavonoid 7-O-glycosides via phase-transfer-catalyzed (PTC) glycosylation.
- Zheng, Zhiwei,Han, Ziyi,Cai, Li,Zhou, Dandan,Chavis, Bryson R.,Li, Changsheng,Sui, Qiang,Jiang, Kaiyuan,Gao, Qi
-
supporting information
p. 4442 - 4447
(2018/11/23)
-
- Differentially evolved glucosyltransferases determine natural variation of rice flavone accumulation and UV-tolerance
-
Decoration of phytochemicals contributes to the majority of metabolic diversity in nature, whereas how this process alters the biological functions of their precursor molecules remains to be investigated. Flavones, an important yet overlooked subclass of flavonoids, are most commonly conjugated with sugar moieties by UDP-dependent glycosyltransferases (UGTs). Here, we report that the natural variation of rice flavones is mainly determined by OsUGT706D1 (flavone 7-O-glucosyltransferase) and OsUGT707A2 (flavone 5-O-glucosyltransferase). UV-B exposure and transgenic evaluation demonstrate that their allelic variation contributes to UV-B tolerance in nature. Biochemical characterization of over 40 flavonoid UGTs reveals their differential evolution in angiosperms. These combined data provide biochemical insight and genetic regulation into flavone biosynthesis and additionally suggest that adoption of the positive alleles of these genes into breeding programs will likely represent a potential strategy aimed at producing stress-tolerant plants.
- Peng, Meng,Shahzad, Raheel,Gul, Ambreen,Subthain, Hizar,Shen, Shuangqian,Lei, Long,Zheng, Zhigang,Zhou, Junjie,Lu, Dandan,Wang, Shouchuang,Nishawy, Elsayed,Liu, Xianqing,Tohge, Takayuki,Fernie, Alisdair R.,Luo, Jie
-
-
- Preparation method of flavone aglycone or monoglycoside from aluminum-salt-flavonoid-glycoside complex through hydrolysis
-
Disclosed is a preparation method of flavone aglycone or monoglycoside from aluminum-salt-flavonoid-glycoside complex through hydrolysis. The problems that flavonoid glycosides neither dissolve in water nor are hard to dissolve in a common organic alcohol solution, and flavone aglycone prepared from hydrolysis has slow hydrolysis speed, needs a large amount of an organic solvent, and cannot be totally hydrolyzed are solved. A complex product from complexation of aluminum salt and flavonoid glycosides is easy to dissolve in alcohol, hydrogen chloride generated by the complex product is utilized with addition of hydrochloric acid or sulfuric acid, and hydrolysis is carried out at a certain temperature to prepare aglycone or a mixture of aglycone and monoglycoside. After the reaction is over, phosphoric acid or phosphate is added to break complexation of aluminum ions and flavone to obtain flavone aglycone, or the mixture of flavone aglycone and flavone monoglycoside, or a mixture of flavone aglycone, flavone monoglycoside, and flavonoid glycoside. The method is simple and easy to operate, relatively high in yield and purity, and extremely low in cost, and is suitable for massive industrial production of flavone aglycone or the mixture of flavone aglycone and flavone monoglycoside.
- -
-
Paragraph 0018
(2016/10/31)
-
- Semisynthesis of apigenin and acacetin-7-O-β-d-glycosides from naringin and their cytotoxic activities
-
Apigenin-7-O-β-d-glycosides 1-8 and acacetin-7-O-β-d-glycosides 9-16 were semisynthesized from 4′-O-benzyl apigenin 17 and acacetin 18 by glycosidation and deprotection with the corresponding α-acetylglycosyl bromide, respectively. Compounds 17 and 18 were prepared by iodination followed by base-induced elimination, 4′-O-benzylation, or 4′-O-methylation and acid hydrolysis using naringin as starting material which is readily available and cheap. Their cytotoxic potential against five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW480) was evaluated by standard MTT method. The results show that compounds 2, 9, and 19 exhibit moderate cytotoxicity against HL-60, SMMC-7721, A-549, MCF-7, and SW480, while compound 3 exhibits potent cytotoxicity against MCF-7 selectively. Among the synthesized target compounds, 3, 4, 7, 11, 12, 15, and 16 were new compounds, the natural product 8 was the first synthesized and the synthesis of natural products 5, 6, 13, and 14 was efficiently improved by the new synthetic routes.
- Liu, Jidan,Chen, Ling,Cai, Shuanglian,Wang, Qiuan
-
-
- Total synthesis of apigenin 7,4′-di-O-β-glucopyranoside, a component of blue flower pigment of Salvia patens, and seven chiral analogues
-
We have succeeded in the first total synthesis of apigenin 7,4′-di-O-β-D-glucopyranoside (1a), a component of blue pigment, protodelphin, from naringenin (2). Glycosylation of 2 according to Koenigs-Knorr reaction provided a monoglucoside 4a in 80% yield, and this was followed by DDQ oxidation to give apigenin 7-O-glucoside (12a). Further glycosylation of 4′-OH of 12a with 2,3,4,6-tetra-O-acetyl-α-D- glucopyranosyl fluoride (5a) was achieved using a Lewis acid-and-base promotion system (BF3·Et2O, 2,6-di-tert-butyl-4- methylpyridine, and 1,1,3,3-tetramethylguanidine) in 70% yield, and subsequent deprotection produced 1a. Synthesis of three other chiral isomers of 1a, with replacement of D-glucose at 7 and/or 4′-OH by L-glucose (1b-d), and four chiral isomers of apigenin 7-O-β-glucosides (6a,b) and 4′-O-β- glucosides (7a,b) also proved possible.
- Oyama, Kin-Ichi,Kondo, Tadao
-
p. 2025 - 2034
(2007/10/03)
-
- Thermal Degradation of Glycosides, VI - Hydrothermolysis of Cardenolide and Flavonoid Glycosides
-
The hydrothermolysis of cardenolide and flavonoid glycosides is described.On heating with water or water/dioxane, cardenolide (1, 5, 11) and flavonoid glycosides (16, 20, 23, 27) are converted into their genuine aglycones and partially hydrolyzed products, together with saccharide components.Meanwhile, the glycosidic linkage of 2-deoxy sugar moieties in cardenolide glycosides is more readily cleaved than that of the common sugar moieties by means of hydrothermolysis.Therefore, hydrothermolysis of the uzarigenin triglycoside (13), bearing a 2-deoxy sugar moiety whichis directly attached to the aglycone, leads to selective cleavage of the sugar-aglycone linkage.The hydrothermolyzed products have been isolated by chromatography and their structures elucidated by spectroscopic methods. Key Words: Thermolysis / Degradation, thermal / Carbohydrates / Glycosides / Cardenolides / Steroids / Flavonoids
- Kim, Youn Chul,Higuchi, Ryuichi,Komori, Tetsuya
-
p. 575 - 580
(2007/10/02)
-
- FLAVONOIDS OF Thermopsis alterniflora. CROTONOYLTHERMOPSOSIDE AND CROTONOYLCOSMOSIIN - NEW ACYLATED FLAVONE GLYCOSIDES
-
From the epigeal part of Thermopsis alterniflora Rgl. et Schmalh. (Fabaceae), in addition to formononetin, ononin, cynaroside, and rothindin, two new acylated flavone glycosides have been isolated and, on the basis of chemical transformations and spectral characteristics, their structures have been established as 4',5,7-trihydroxy-3'-methoxyflavone 7-O-(6"-O-crotonoyl-β-D-glucopyranoside) and 4',5,7-trihydroxyflavone 7-O-(6"-O-crotonoyl-β-D-glucopyranoside).
- Yuldashev, M. P.,Batirov, E. Kh.,Vdovin, A. D.,Malikov, V. M.,Yagudaev, M. R.
-
p. 303 - 308
(2007/10/02)
-
- ANISOFOLIN-A, A NEW ACYLATED FLAVONE GLUCOSIDE FROM ANISOMELES OVATA R. Br.
-
Aerial parts of Anisomeles ovata R.Br. contain a new acylated apigenin glucoside (0.002percent).It was identified as apigenin-7-0-β-D-(3",6"-di-O-p-coumaroyl)-glucoside (anisofolin-A) by 13C nmr, 1H nmr and chemical degradative methods of anisofolin-A and its acetate.
- Rao, Iagan L. Mohan,Kumari, G. N. Krishna,Rao, N. S. Prakasa
-
p. 1655 - 1662
(2007/10/02)
-
