- Electrochemical investigations into host-guest interactions of a natural antioxidant compound with β-cyclodextrin
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The electrochemical behavior of mangiferin (MGN), a natural antioxidant compound, is examined using cyclic and differential pulse voltammetry in a protic medium on a glassy carbon electrode. The voltammograms exhibit a single irreversible pH-dependent anodic wave with current controlled by adsorption. Complexes of MGN with β-cyclodextrin (β-CD) were prepared and their formation was confirmed by UV-vis spectroscopy and electrochemical experiments, using a self-assembled monolayer of cyclodextrin on a gold electrode. The association constant of MGN:β-CD complexes was estimated by the Benesi-Hildebrand method, based on the spectrophotometric quantification of free β-CD and by the direct method using cyclic voltammetry and the Langmuir isotherm. PM IRRAS experiments corroborated the inclusion process based on the observation of the corresponding peaks in the spectra of the samples. MGN was quantified using a simple electrochemical method based on a β-CD incorporated carbon nanotube (CNT)-modified electrode (β-CDCNT). The presence of β-CD led to a 10-fold lower detection limit than that obtained with a CNT-modified electrode.
- Ferreira, Fabricia Da Rocha,Da Silva, Emanuella Gomes,De Leo, Lucila P. Méndez,Calvo, Ernesto J.,Bento, Edson De Souza,Goulart, Marília Oliveira Fonseca,De Abreu, Fabiane Caxico
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- Total synthesis of mangiferin, homomangiferin, and neomangiferin
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Total synthesis of mangiferin, homomangiferin, and neomangiferin, three C-glycosyl xanthone natural products with a wide spectrum of pharmacological effects, has been achieved starting from 2,3,4,6-tetra-O-benzyl-α/β-d-glucopyranose. The key steps involve a stereoselective Lewis acid promoted C-glycosylation of protected phloroglucinol with tetrabenzylglucopyranosyl acetate and a highly regioselective base-induced cyclization for the construction of the core xanthone skeleton.
- Wei, Xiong,Liang, Danlin,Wang, Qing,Meng, Xiangbao,Li, Zhongjun
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p. 8821 - 8831
(2016/10/03)
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- Probing the catalytic promiscuity of a regio- and stereospecific C-glycosyltransferase from Mangifera indica
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The catalytic promiscuity of the novel benzophenone C-glycosyltransferase, MiCGT, which is involved in the biosynthesis of mangiferin from Mangifera indica, was explored. MiCGT exhibited a robust capability to regio- and stereospecific C-glycosylation of 35 structurally diverse druglike scaffolds and simple phenolics with UDP-glucose, and also formed O- and N-glycosides. Moreover, MiCGT was able to generate C-xylosides with UDP-xylose. The OGT-reversibility of MiCGT was also exploited to generate C-glucosides with simple sugar donor. Three aryl-C-glycosides exhibited potent SGLT2 inhibitory activities with IC50 values of 2.6×, 7.6×, and 7.6×10-7-M, respectively. These findings demonstrate for the first time the significant potential of an enzymatic approach to diversification through C-glycosidation of bioactive natural and unnatural products in drug discovery. C-glycodiversification: MiCGT, as the first benzophenone C-glycosyltransferase (CGT) from Mangifera indica, showed robust regio- and stereospecific C-glycosylation activity for 35 structurally diverse acceptors with UDP-glucose or xylose. The aryl-C-glycoside 1 exhibited potent antidiabetic activity toward SGLT2.
- Chen, Dawei,Chen, Ridao,Wang, Ruishan,Li, Jianhua,Xie, Kebo,Bian, Chuancai,Sun, Lili,Zhang, Xiaolin,Liu, Jimei,Yang, Lin,Ye, Fei,Yu, Xiaoming,Dai, Jungui
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p. 12678 - 12682
(2015/10/28)
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- Synthesis of mangiferin, isomangiferin, and homomangiferin
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Mangiferin, isomangiferin, and homomangiferin, the xanthone C-glycosides with a wide spectrum of pharmacological effects, were synthesized concisely, featuring a C-glycosylation of a xanthene derivative with perbenzylglucopyranosyl N-phenyltrifluoroacetimidate.
- Wu, Zhongtao,Wei, Guo,Lian, Gaoyan,Yu, Biao
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supporting information; experimental part
p. 5725 - 5728
(2010/10/03)
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- Process for preparing mangiferin
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A process for preparing mangiferin from plants of the genus of Hedysarum (Hedysarum alpinum L., Hedysarum flavescens Rgl. et Schmalh) comprising extraction of xanthone glycosides from the aerial portion of the plants by means of a mixture acetone-water at a volume ratio of the mixture components of 1:0.5-2 respectively; the resulting extract is evaporated, the evaporated extract is filtered. To the filtered evaporated extract sulphuric acid is added to a pH of from 2 to 4, heated at reflux and filtered. The thus-prepared extract is treated with a non-polar organic solvent with the formation of two layers, wherefrom the upper aqueous layer contains xanthone glycosides. This upper layer is treated with butanol with the formation of two layers, wherefrom the upper layer comprises a solution of xanthone glycosides in butanol. This upper butanolic layer is evaporated. The precipitated mangiferin is separated and recrystallized.
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- Tannins and Related Compounds. XXI. Isolation and Characterization of Galloyl and p-Hydroxybenzoyl Esters of Benzophenone and Xanthone C-glucosides from Mangifera indica L.
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Six new galloyl and p-hydroxybenzoyl esters (2-7) of benzophenone C-glucosides have been isolated, together with a new benzophenone C-glucoside (1), from the leaves of Mangifera indica L. (Anacardiaceae).On the basis of chemical and spectroscopic evidence, the structures of these compounds have been established as maclurin 3-C-β-D-glucoside (1), maclurin 3-C-(6''-O-p-hydroxybenzoyl)-β-D-glucoside (2), maclurin 3-C-(2''-O-galloyl-6''-O-p-hydroxybenzoyl)-β-D-glucoside (3), maclurin 3-C-(2''-O-p-hydroxybenzoyl-6''-O-galloyl)-β-D-glucoside (4), maclurin 3-C-(2'',3'',6''-tri-O-galloyl)-β-D-glucoside (5), iriflophenone 3-C(2'',6''-di-O-galloyl)-β-D-glucoside (6) and iriflophenone 3-C-(2'',3'',6''-tri-O-galloyl)-β-D-glucoside (7). (-)-Epicatechin 3-O-gallate (9), mangiferin (10), isomangiferin (11) and a new xanthone C-glucoside gallate, mangiferin 6'-O-gallate (8), have also been isolated and their structures have been similarly characterized.Furthermore, the above plant source contained polygalloylglucoses which were characterized on the basis of chemical and high performance liquid chromatographic analyses as a mixture of penta- to undecagalloylglucoses based on a 1,2,3,4,6-penta-O-galloyl-β-D-glucose core.Maclurin 3-C-glucoside (1) has been transformed enzymatically to mangiferin (10) and isomangiferin (11), and it has become clear that 1 is a key intermediate in the biosynthesis of 10 and 11. Keywords - Mangifera indica; Anacardiaceae; galloyl maclurin 3-C-glucoside p-hydroxybenzoate; galloyl iriflopenone 3-C-glucoside; galloyl mangiferin; benzophenone C-glucoside; biosynthesys; mangiferin; isomangiferin; galloylglucose
- Tanaka, Takashi,Sueyasu, Tokiko,Nonaka, Gen-ichiro,Nishioka, Itsuo
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p. 2676 - 2686
(2007/10/02)
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