Regioselective synthesis of methylated epigallocatechin gallate via nitrobenzenesulfonyl (Ns) protecting group

Aihara, Yoshiyuki; Yoshida, Atsusi; Furuta, Takumi; Wakimoto, Toshiyuki; Akizawa, Toshifumi; Konishi, Motomi; Kan, Toshiyuki

doi:10.1016/j.bmcl.2009.05.111

Cited by 30 publications

(21 citation statements)

References 22 publications

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“…Since the most reactive hydroxyl group is para position of carbonyl moiety among the eight phenols of EGCG, this methylation proceeded specifically at 4″-position. On the other hand, we previously compared MMP inhibitory activity of methylated EGCGs with EGCG and demonstrated that the activity of 4″-Me-EGCG was a little bit weakened in comparison with EGCG, but 4″-Me-EGCG sufficiently possessed the potentials in similar to EGCG [12]. As shown in Figure 2, the synthesis of positron-labeled EGCG was accomplished by similar procedure for the preparation of [ 12 C]Me-EGCG.…”

Section: Resultsmentioning

confidence: 99%

“…The synthesis of various methylated catechins including 4″-Me-EGCG by utilizing our original synthetic method and the investigation of their biological activities in comparison with EGCG have been reported by us [12]. Since the sample of [ 12 C]Me-EGCG could be in a gram scale as shown in Figure 1, HPLC profile has been determined by employment it as an authentic sample.…”

Section: Methodsmentioning

confidence: 99%

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Use of Positron Emission Tomography for Real-Time Imaging of Biodistribution of Green Tea Catechin

et al. 2014

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The aim of this study was to achieve real-time imaging of the in vivo behavior of a green tea polyphenol, catechin, by positron emission tomography (PET). Positron-labeled 4″ -[11C]methyl-epigallocatechin gallate ([11C]Me-EGCG) was orally administered to rats, and its biodistribution was imaged for 60 min by using a small animal PET system. As the result, images of [11C]Me-EGCG passing through the stomach into the small intestines were observed; and a portion of it was quantitatively detected in the liver. On the other hand, intravenous injection of [11C]Me-EGCG resulted in a temporal accumulation of the labeled catechin in the liver, after which almost all of it was transferred to the small intestines within 60 min. In the present study, we succeeded in obtaining real-time imaging of the absorption and biodistribution of [11C]Me-EGCG with a PET system.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Use of Positron Emission Tomography for Real-Time Imaging of Biodistribution of Green Tea Catechin

et al. 2014

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“…9 For the synthesis of theaflavin, we initially investigated the selective incorporation of Ns groups into the A-ring of catechin (CC) (9), epicatechin (EC) (10) and epigallocatechin (EGC) (11), as shown in Scheme 2.…”

Section: Figurementioning

confidence: 99%

Synthesis of Theaflavins via Biomimetic Oxidative Coupling Reactions

Kawabe

Aihara

Hirose

et al. 2013

Synlett

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“…11,12) Our previous studies also demonstrated that EGCG suppresses tumor angiogenesis through the inhibition of membrane-type1 matrix metalloproteinase (MT1-MMP). 13,14) These findings indicate that EGCG, as a functional component of green tea, will become useful for cancer therapy and chemoprevention.Previous study demonstrated that 5,7-deoxyepigallocatechin gallate (DOEGCG), a synthetic EGCG derivative, possesses more potent anti-influenza infection activity than the original EGCG, suggesting that the phenolic hydroxyl groups on the A-ring in the flavan structure are not involved in the biological activity and that modification of A-ring of the EGCG structure does not abolish but rather enhances the functional ability of EGCG.15) Based on this and other structure-relationship studies, 16,17) we synthesized (Ϯ)-6-(5-aminopentyl)-5,7-deoxyepigallocatechin gallate (cis-APDOEGCG) and (Ϯ)-6-(5-aminopentyl)-5,7-deoxygallocatechin gallate (trans-APDOEGCG) as EGCG derivatives containing linkers and reactive amino groups added to the EGCG structure, as shown in Fig. 1.…”

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confidence: 95%

“…15) Based on this and other structure-relationship studies, 16,17) we synthesized (Ϯ)-6-(5-aminopentyl)-5,7-deoxyepigallocatechin gallate (cis-APDOEGCG) and (Ϯ)-6-(5-aminopentyl)-5,7-deoxygallocatechin gallate (trans-APDOEGCG) as EGCG derivatives containing linkers and reactive amino groups added to the EGCG structure, as shown in Fig. 1.…”

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confidence: 99%

Anti-angiogenic Activity and Intracellular Distribution of Epigallocatechin-3-gallate Analogs

Piyaviriyakul

Shimizu

Asakawa

et al. 2011

Biological & Pharmaceutical Bulletin

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Tumor angiogenesis, a process of new blood vessel formation from pre-existing vessels, is crucial for the growth and development of tumors. It requires multiple interactions among endothelial cells, surrounding pericytes, and smooth muscle cells, extracellular matrix, and angiogenic cytokines/growth factors. [1][2][3] Since effective inhibition of tumor angiogenesis promises to provide crucial suppression of not only tumor growth but also tumor metastasis, the development of agents inhibiting angiogenic processes has become a matter of focus. (Ϫ)-Epigallocatechin-3-O-gallate (EGCG) is known as a major component of green tea extracts and to exhibit various biological activities including anti-viral, anti-microbial, and anti-oxidative ones. [4][5][6][7][8] Especially, the relationship between EGCG and anti-cancer activity is now the most notable, since cancer is the leading cause of human death in various countries. Previous studies demonstrated that EGCG suppresses tumor growth through the inhibition of tumor angiogenesis, and mechanistic studies on this anti-angiogenic effect of EGCG is now ongoing. Tang et al. demonstrated that EGCG inhibits vascular endothelial growth factor (VEGF)-induced Akt activation and VE-cadherin phosphorylation 9) ; and Rodriguez et al., that green tea catechin disrupts VEGF/VEGF receptor (VEGFR) complexes and subsequent signal transduction. 10) Also, Tachibana et al. directly identified the target molecule of EGCG as a 67-kDa laminin receptor by using surface plasmon resonance (SPR) assay, and they observed the suppression of tumor angiogenesis through the inhibition of the receptor-mediated signal transduction. 11,12) Our previous studies also demonstrated that EGCG suppresses tumor angiogenesis through the inhibition of membrane-type1 matrix metalloproteinase (MT1-MMP). 13,14) These findings indicate that EGCG, as a functional component of green tea, will become useful for cancer therapy and chemoprevention.Previous study demonstrated that 5,7-deoxyepigallocatechin gallate (DOEGCG), a synthetic EGCG derivative, possesses more potent anti-influenza infection activity than the original EGCG, suggesting that the phenolic hydroxyl groups on the A-ring in the flavan structure are not involved in the biological activity and that modification of A-ring of the EGCG structure does not abolish but rather enhances the functional ability of EGCG.15) Based on this and other structure-relationship studies, 16,17) we synthesized (Ϯ)-6-(5-aminopentyl)-5,7-deoxyepigallocatechin gallate (cis-APDOEGCG) and (Ϯ)-6-(5-aminopentyl)-5,7-deoxygallocatechin gallate (trans-APDOEGCG) as EGCG derivatives containing linkers and reactive amino groups added to the EGCG structure, as shown in Fig. 1. We compared their antiangiogenic activity with that of EGCG by examining the inhibitory effect on proliferation, migration, invasion, and tube formation by HUVECs. Then, we synthesized fluorescencelabeled EGCG by conjugating the fluorescent reagent TokyoGreen (TG) to (Ϯ)-cis-APDOEGCG (EGCG-TG) and examined the intracel...

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Regioselective synthesis of methylated epigallocatechin gallate via nitrobenzenesulfonyl (Ns) protecting group

Cited by 30 publications

References 22 publications

Use of Positron Emission Tomography for Real-Time Imaging of Biodistribution of Green Tea Catechin

Use of Positron Emission Tomography for Real-Time Imaging of Biodistribution of Green Tea Catechin

Synthesis of Theaflavins via Biomimetic Oxidative Coupling Reactions

Anti-angiogenic Activity and Intracellular Distribution of Epigallocatechin-3-gallate Analogs

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