生物活性

(-)-Epigallocatechin Gallate (EGCG) is a strong polyphenol catechin antioxidant found in green tea, reported to have broad efficacy against many conditions generated from oxidative damage. Also a DNMT1 inhibitor. Extensive oxidation of low density lipoproteins is correlated to cardiovascular diseases, and EGCG is reported to strongly inhibit Cu(2+)-mediated oxidative modification of LDLs. The antiapoptotic proteins Bcl-2 and Bcl-x(L) are observed to suppress apoptosis and convey survival to heavily damaged and mutated cells in vitro, and EGCG (along with the other catechins) is shown to directly inhibit these proteins, reestablishing the normal apoptotic pathway in the cell. EGCG also inhibits NOS2. Reduces Aβ42-induced cell death in three different cell types. Also inhibits β-secretase (IC50 = 1.6 μM) and glutamate dehydrogenase GDH. Inhibits cell growth and selectively induces apoptosis in A431 and human pancreatic cancer cells.

体外研究

体内研究

激酶实验

细胞实验

Cells[1]

The SW780 cells were cultured in Dulbecco’smodified Eagle’s medium (DMEM) containing 10% (v/v) fetal bovine serum and 1%penicillin–streptomycin at 37°C in 5% CO2 humidified incubator.

Cellviability assay

Cells (1×10⁴/well) were seededin 96-well plates and incubated with different concentrations of EGCG for 24and 48 h. Following incubation, 30μl of MTT solution [5 mg/ml inphosphate-buffered saline (PBS)] was added to each well, and the plate was incubatedat 37°C for another 4 h. Then, the medium was discarded and150μl of DMSO wasadded to dissolve the formazan crystals. The absorbance of each sample was readat 540 nm using a microplate reader.

动物实验

Animal experiments[2]

Male Wistar rats (six weeks old), with anaverage weight of 160 g, were housed at a constant temperature (23 ± 1 ^oC)with a12 h light-dark cycle in stainless steel wire-bottomed cages, and fed acommercial rodent chow (CE-2) and tap water ad libitum. The rats were fastedovernight and assigned to treatment groups (4–6 rats per group). (-)-EpigallocatechinGallate (EGCg) dissolved in distilled water or vehicle was administered orallyto rats at a dose of 500 mg/kg. The plasma EGCg concentration peaked at 60–120min after administration, therefore the rats were anesthetized withpentobarbital90 min after administration and exsanguinated from the abdominalaorta with a heparinized syringe to obtain the blood. In a separate experiment,rats were orally administered 100, 250, 500 mg/kg EGCg, or vehicle, and werethen anesthetized and exsanguinated as described above to analyze the ascorbicacid concentrations in plasma, lymphocytes, and adrenal glands.

Assayof antioxidant activity

The ORAC assay was carried out. In brief,50μL of sample was mixed with 150μL of 19.6nmol/L fluorescein solutions in a 96-well microplate and incubated at 37^oCfor 10 min, and then 50μL of 20mM AAPH solution was added to initiate the reaction. Trolox wasused as a control standard. The fluorescence intensity at 490nm (excitation)/530nm(emission) was measured every 2 min for 2 h at 37^oC using amicroplate fluorescence reader. The FRAP assay was performed. In brief, 40μLof sample was mixed with 1.2 mL of working FRAP solution in a test tube. At 4min after sample-reagent mixing, the absorbance at 593nm was measured against areagent blank at 37 ^oC using a UV-1600 spectrophotometer.

不同实验动物依据体表面积的等效剂量转换表（数据来源于FDA指南）

例如，已知某工具药用于小鼠的剂量为88 mg/kg , 则用于大鼠的剂量换算方法：将88 mg/kg 乘以小鼠的Km系数（3），再除以大鼠的Km系数（6），得到该药物用于大鼠的等效剂量44 mg/kg。

参考文献

[1] Luo KW, Wei C, Lung WY, et al. EGCG inhibited bladder cancer SW780 cell proliferation and migration both in vitro and in vivo via down-regulation of NF-kappaB and MMP-9. J Nutr Biochem. 2017;41:56-64.
[2] Yokotani K, Umegaki K. Evaluation of plasma antioxidant activity in rats given excess EGCg with reference to endogenous antioxidants concentrations and assay methods. Free Radic Res. 2017;51(2):193-199.
[3] Shankar et al (2008) EGCG inhibits growth, invasion, angiogenesis and metastastasis of pancreatic cancer. Front.Biosci. 13 440.
[4] Lee et al (2005) Mechanisms for the inhibition of DNA methyltransferases by tea catechins and bioflavonoids. Mol.Pharmacol. 68 1018.
[5] Ahmad et al (2000) Green tea polyphenol epigallocatechin-3-gallate differentially modulates nuclear factor κB in cancer cells versus normal cells. Ach.Biochem.Biophys. 376 338.

体内溶解度

Clinical Trial Information ( data from http://clinicaltrials.gov )

注：以上所有数据均来自公开文献，并不保证对所有实验均有效，数据仅供参考。

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