5127-64-0Relevant articles and documents
Study on in Vitro Preparation and Taste Properties of N-Ethyl-2-Pyrrolidinone-Substituted Flavan-3-Ols
Han, Zisheng,Ho, Chi-Tang,Jiang, Zongde,Lai, Guoping,Qin, Chunyin,Wan, Xiaochun,Wen, Mingchun,Zhai, Xiaoting,Zhang, Hui,Zhang, Liang
, (2022/04/07)
N-ethyl-2-pyrrolidinone-substituted flavan-3-ols (EPSFs) were prepared by an in vitro model reaction, and the taste thresholds of EPSFs and their dose-over-threshold factors in large-leaf yellow tea (LYT) were investigated. The effects of initial reactant
The oxidation of (-)-epigallocatechin-3-gallate inhibits T-cell acute lymphoblastic leukemia cell line HPB-ALL: Via the regulation of Notch1 expression
Wang, Yu-Na,Wang, Jing,Yang, Hao-Nan,Zhang, Bang-Lei,Zhang, Pan,Sun, Pei-Yuan,Zhang, Nin,Wang, Ya,Sheng, Jun,Wang, Xuan-Jun,Zi, Cheng-Ting
, p. 1679 - 1684 (2020/01/28)
T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy, and commonly associated with activating mutations in the Notch1 pathway. (-)-Epigallocatechin-3-gallate (EGCG) is the most abundant and active catechin and has been shown to regulate Notch signaling. Taking into account the highly oxidizable and unstable of EGCG, we proposed that EGCG oxides may have greater potential to regulate Notch signaling than EGCG. In this study, we isolated and identified EGCG oxides (compound 2-4), using a chemical oxidation strategy, and evaluated for cytotoxicity against T-cell acute lymphoblastic leukemia cell line (HPB-ALL) by using the MTS assay. We found compound 3 significantly induced cell proliferation inhibition (38.3858 ± 1.67106 μM), cell apoptosis and cell cycle arrest in a dose-dependent manner. Remarkably, compound 3 inhibited expression of Notch1 compared with EGCG in HPB-ALL cells. Meanwhile, we found that compound 3 significantly inhibited c-Myc and Hes1, which are downstream target genes of Notch1. The findings demonstrate for the first time that an oxidation product of EGCG (compound 3) inhibits T-cell acute lymphoblastic leukemia cell line (HPB-ALL) and is a promising agent for cancer therapy deserving further research.
Oligomerization mechanism of tea catechins during tea roasting
Morikawa, Hitomi,Okuda, Keita,Kunihira, Yuji,Inada, Aoi,Miyagi, Chika,Matsuo, Yosuke,Saito, Yoshinori,Tanaka, Takashi
, p. 252 - 259 (2019/02/14)
Roasting of green tea causes oligomerization of tea catechins, which decreases the astringency. The aim of this study was to elucidate the oligomerization mechanism. The 13C NMR spectrum of the oligomer fraction showed signals arising from catechin and sugar residues. Heating of epigallocatechin-3-O-gallate with 13C-labeled glucose (150 °C for 2 h) suggested that condensation of sugars with catechin A-rings caused the oligomerization. The dimeric product obtained by heating for a shorter period (30 min) suggested cross-linking occurred between sugars and catechin A-rings. Furthermore, heating of phloroglucinol, a catechin A-ring mimic, with glucose, methylglyoxal, and dihydroxyacetone, confirmed that the basic mechanism included reaction of the catechin A-ring methine carbons with carbonyl carbons of glucose and their pyrolysis products.
Molecular Mechanism by Which Tea Catechins Decrease the Micellar Solubility of Cholesterol
Sakakibara, Takumi,Sawada, Yoshiharu,Wang, Jilite,Nagaoka, Satoshi,Yanase, Emiko
, (2019/07/03)
Tea polyphenols lower the levels of cholesterol in the blood by decreasing the cholesterol micellar solubility. To clarify this mechanism, the interactions between taurocholic acid and (-)-epigallocatechin gallate (EGCg) and its derivatives were investigated. 13C NMR studies revealed remarkable chemical-shift changes for the carbonyl carbon atom and the 1″- and 4″-positions in the galloyl moiety. Furthermore, 1H NMR studies using (-)-EGCg derivatives showed that the number of hydroxyl groups on the B ring did not affect these interactions, whereas the carbonyl carbon atom and the aromatic ring of the galloyl moiety had remarkable effects. The configuration at the 2- and 3-positions of the catechin also influenced these interactions, with the trans-configuration resulting in stronger inhibition activity than the cis-configuration. Additionally, a 1:1 component ratio for the catechin-taurocholic acid complex was determined by electrospray ionization-mass spectrometry. These molecular mechanisms contribute to the development of cholesterol-absorption inhibitors.
Oxidation derivative of (-)-epigallocatechin-3-gallate (EGCG) inhibits RANKL-induced osteoclastogenesis by suppressing RANK signaling pathways in RAW 264.7 cells
Xu, Huanhuan,Liu, Titi,Li, Jin,Xu, Jing,Chen, Fei,Hu, Lihong,Zhang, Banglei,Zi, Chengting,Wang, Xuanjun,Sheng, Jun
, (2019/08/02)
Tea consumption has positive effects on the skeletal system and prevents postmenopausal osteoporosis, mainly by inhibiting osteoclastogenesis. In green tea, (-)-epigallocatechin-3-gallate (EGCG) is the most abundant and active compound and has been shown to inhibit RANKL-induced osteoclast formation. Taking into account the highly oxidizable and unstable nature of EGCG, we hypothesized that EGCG oxidation product exhibits greater anti-osteoclastogenesis potential than EGCG. In this study, we successfully isolated and identified an EGCG oxidation derivative, (-)-gallocatechin gallate (compound 2), using a chemical oxidation strategy. We then compared the ability of compound 2 and EGCG to inhibit RANKL-induced osteoclastogenesis in RAW 264.7 cells. The results of TRAP staining and F-actin ring immunofluorescent staining showed that compound 2 exhibits stronger inhibition of RANKL-induced osteoclast differentiation and F-actin ring formation, respectively, than EGCG. Additionally, quantitative real-time PCR (qRT-PCR) and western blotting analyses showed that compound 2 significantly and more strongly inhibited the expression of osteoclastogenesis-related marker genes and proteins, including c-Src, TRAP, cathepsin K, β3-Integrin, and MMP-9, compared with EGCG. Furthermore, compound 2 significantly suppressed RANKL-induced expression of NFATc1 and c-Fos, the master transcriptional regulators of osteoclastogenesis, more strongly than EGCG. Mechanistically, molecular interaction assays showed that compound 2 binds to RANK with high affinity (KD = 189 nM) and blocks RANKL–RANK interactions, thereby suppressing RANKL-induced early RANK signaling pathways including p65, JNK, ERK, and p38 in osteoclast precursors. Taken together, this study demonstrates for the first time that an oxidation derivative of EGCG (compound 2) inhibits RANKL-induced osteoclastogenesis by suppressing RANK signaling pathways in RAW 264.7 cells.
METHODS OF TREATING COGNITIVE AND BEHAVIORAL IMPAIRMENT IN DOWN SYNDROME AND ALZHEIMERS DISEASE PATIENTS
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, (2018/09/24)
The present invention relates to methods of treating cognitive and behavioral impairment in Down syndrome and/or Alzheimer's disease patients, Alzheimer's disease, neurodegenerative disease, cancer, DYRK1A-mediated disorders and methods of modulating and inhibiting DYRK1-A comprising use of catechins.
Semisynthesis of fluoro-substituted benzoates of Epi-gallocatechin
Qin, Xu Long,Li, Xue Min,Yuan, Jian,Chen, Di,Jiang, Tao,Dou, Q. Ping,Chan, Tak Hang,Wan, Sheng Biao
experimental part, p. 3524 - 3531 (2012/09/25)
In the present study, four fluoro-substituted benzoates of epi-gallocatechin (EGC) were prepared through a semisynthetic strategy, and the yield of benzylation of epi-gallocatechin gallate (-)-EGCG was improved by using freshly purified (-)-EGCG as starting material and a mild base of K 2CO3. All structures of new compounds were characterized by 1H NMR, 13C NMR, high-resolution mass spectrometry, and optical rotation.
Reagent-controlled stereoselective synthesis of (±)-gallo- and (±)-epigallo-catechin gallates
Tanaka, Hiroshi,Chino, Ayaka,Takahashi, Takashi
supporting information; experimental part, p. 2493 - 2495 (2012/06/16)
Synthesis of (±)-gallocatechin and (±)-epigallocatechin gallates by electrophilic cycloarylation is reported. The precursors for cyclization were prepared by reagent-controlled stereo-selective opening of epoxide with phenol. Activation of the S-oxidized S,O-acetal enabled electrophilic cycloarylation to stereoselectively provide the acylated catechins.
Isolation of two new bioactive proanthocyanidins from Cistus salvifolius herb extract
Qa'dan, Fadi,Nahrstedt,Schmidt
experimental part, p. 454 - 457 (2012/01/12)
Two new proanthocyanidins, epigallocatechin-3-O-p-hydroxybenzoate- (4β→8)-epigallocatechin (1) and epigallocatechin-3-O-p- hydroxybenzoate-(4β→8)-epigallocatechin-3-O-gallate (2) in addition to the known compound epigallocatechin-(4β→6)-epigallocatechin-3-O- gallate (3), were isolated from the air-dried herb of Cistus salvifolius. The chemical structures were determined on the basis of 1D-and 2D-NMR-spectra (HSQC, HMBC) of their peracetylated derivatives, MALDI-TOF-mass spectra, and by acid-catalysed degradation with phloroglucinol. The isolated compounds 1-3 and the water extract of C. salvifolius herb were tested for their inhibitory activities against COX-1 and COX-2. Compound 2 showed the strongest inhibitory effect on COX-2 followed by compound 3, compound 1 and the water extract, while compounds 1-3 exhibited moderate in vitro inhibition against COX-1.
New oligomeric proanthocyanidins from Alhagi pseudalhagi
Alimova,Nishanbaev,Vdovin,Abdullaev,Aripova
experimental part, p. 352 - 356 (2010/10/03)
Two new oligomeric proanthocyanidin glucosides were isolated from the aerial part and roots of Alhagi pseudalhagi. Their structures and relative configurations were elucidated as 7-O-β-D-Glc p→6 galloyl-(+)catechin-(4α-8)-(+)-catechin-(4α-8)-(-
