Natural flavonoid in green tea

(-)-表没食子儿茶素 (EGC) 是淀粉样蛋白半胱氨酸蛋白酶抑制剂 I66Q 淀粉样原纤维发育的强体外抑制剂。根据计算研究，(-)-表没食子儿茶素可将分子稳定在其原始状态，而不是导致聚集重新形成无序、无定形聚集体，从而防止淀粉样半胱氨酸蛋白酶原纤维的产生[1]。姜黄素和 EGCG 联合治疗可减少癌症干细胞样分化簇 44 (CD44) 阳性细胞的数量。蛋白质印迹和免疫沉淀研究表明，姜黄素和 (-)-表没食子儿茶素 (EGC) 显着抑制 STAT3 磷酸化并保留 STAT3-NFkB 连接 [2]。 (-)-表没食子儿茶素 (EGC) 可有效去除粪肠球菌生物膜，MIC 和 MBC 值分别为 5 μg/mL 和 20 μg/mL。粪肠球菌接触 (-)-表没食子儿茶素时会产生羟基自由基。 DIP 保护的 E 添加。通过 EGCG 的抗菌作用来消灭粪杆菌。 (-)-表没食子儿茶素在亚 MIC 水平上显着下调粪肠球菌毒力基因 [3]。

ThT荧光分析[1]
为了确定淀粉样纤维的形成，使用磷酸盐缓冲液（50 mM Na2HPO4，50 mM NaH2PO4，pH 7.0）制备1 mM的ThT储备溶液。在不同时间采集的cC I66Q样品的等分试样用磷酸盐缓冲液稀释，然后加入30μL的ThT储备溶液。通过在440nm激发样品并使用Cary Eclipse荧光分光光度计在120秒内记录485nm的发射信号来进行ThT荧光测量。

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ANS结合试验[1]
通过将ANS溶解在PBS（pH 7.0）中制备0.4mM ANS储备溶液。ANS储备溶液在4°C下储存。将不同时间取的含或不含EGCG的cC I66Q溶液等分试样与ANS溶液等分试样混合，然后加入PBS（pH 7.0）至最终体积为3 mL。在室温下在黑暗中孵育30分钟后，使用380 nm的激发波长和400至600 nm的发射波长对样品进行荧光分析。记录ANS荧光强度和平均发射波长，以解释强度和光谱的变化。

PC12细胞购自美国典型培养物保藏中心。PC12细胞在含有10%马血清、5%胎牛血清和1%青霉素/链霉素抗生素的DMEM中维持。细胞在37°C的5%CO2气氛中培养，然后收获并以104个细胞/孔的密度接种在96孔中。将平板在37°C下孵育24小时。随后，将含有和不含EGCG的cC I66Q在65°C下孵化35天，在6000g离心1小时后收集样品的等分试样。将浓缩的cC I 66Q样品溶解在PBS缓冲液（pH 7.0，50 mM）中，通过BCA测定每个样品中的蛋白质浓度。将含有和不含有ECGC的cC 166Q样品分别加入细胞中，使细胞中的cC 166 Q最终浓度在0至500 ng/mL之间。每个孔中cC I66Q样品（含有和不含EGCG）的最终浓度分别为0、1、5、50和500 ng/mL。然后将平板与蛋白质样品在37°C下孵育48小时，并通过向每个孔中加入10μL 5 mg/mL MTT（北京鼎国昌盛生物技术有限公司）试剂，使用MTT毒性测定法测定细胞活力，然后进一步孵育3小时。之后，取出培养基并更换为100μL二甲基亚砜。在室温下摇动10分钟后，使用iMarkMicroplate Reader在490nm处测量板的吸光度。[1]
为了抑制CSC表型，用姜黄素（10μM）加或不加EGCG（10μM）处理两种癌症细胞系（MDA-MB-231细胞和用HER2转染的MCF7细胞）48小时。我们使用肿瘤球形成和伤口愈合试验来确定CSC表型。为了量化CSC群体，监测了荧光激活细胞分选分析。通过蛋白质印迹和免疫沉淀分析STAT3磷酸化和与核因子-kB（NFkB）的相互作用。 [2]
测定了EGCG对粪肠球菌的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）。通过将7天大的粪肠球菌生物膜暴露于EGCG，测试了EGCG对粪肠杆菌生物膜的疗效。羟基苯基荧光素（HPF）标记的粪肠球菌的流式细胞术分析用于确定EGCG是否诱导细胞内羟基自由基的形成。将EGCG与铁螯合剂2,2-二吡啶基（DIP）共处理，以确定Fenton反应产生的羟基自由基是否在EGCG介导的杀粪肠球菌中发挥作用。此外，通过定量聚合酶链反应评估了EGCG对粪肠球菌毒力基因表达的影响。
结果：EGCG的MIC和MBC分别为5μg/mL和20μg/mL，能有效根除粪肠球菌生物膜。EGCG诱导粪肠球菌中羟基自由基的形成。添加DIP可以保护粪肠球菌免受EGCG介导的抗菌作用。在MIC以下，EGCG诱导粪肠球菌毒力基因显著下调。
结论：EGCG是一种有效的抗菌剂，可对抗粪肠球菌的浮游和生物膜形式，抑制细菌生长，抑制与毒力和生物膜形成相关的特定基因的表达。EGCG对粪肠球菌的抗菌作用是通过羟基自由基的产生实现的[3]。

Metabolism / Metabolites
(-)-Epigallocatechin has known human metabolites that include (-)-Epigallocatechin, 3p-hydroxy-glucuronide.

[1]. (-)-Epigallocatechin-3-gallate Inhibits Fibrillogenesis of Chicken Cystatin. J Agric Food Chem. 2015 Jan 26.

[2]. Curcumin and Epigallocatechin Gallate Inhibit the Cancer Stem Cell Phenotype via Down-regulation of STAT3-NFκB Signaling. Anticancer Res. 2015 Jan;35(1):39-46.

[3]. Effects of Epigallocatechin gallate against Enterococcus faecalis biofilm and virulence. Arch Oral Biol. 2015 Mar;60(3):393-9.

(-)-epigallocatechin is a flavan-3,3',4',5,5',7-hexol having (2R,3R)-configuration. It has a role as an antioxidant, a plant metabolite and a food component. It is a flavan-3,3',4',5,5',7-hexol and a catechin. It is an enantiomer of a (+)-epigallocatechin.
Epigallocatechin has been reported in Camellia sinensis, Eschweilera coriacea, and other organisms with data available.
Epigallocatechin is a metabolite found in or produced by Saccharomyces cerevisiae.
See also: Crofelemer (monomer of).

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Previous studies have reported that (-)-epigallocatechin-3-gallate (EGCG), the most abundant flavonoid in green tea, can bind to unfolded native polypeptides and prevent conversion to amyloid fibrils. To elucidate whether this antifibril activity is specific to disease-related target proteins or is more generic, we investigated the ability of EGCG to inhibit amyloid fibril formation of amyloidogenic mutant chicken cystatin I66Q, a generic amyloid-forming model protein that undergoes fibril formation through a domain swapping mechanism. We demonstrated that EGCG was a potent inhibitor of amyloidogenic cystatin I66Q amyloid fibril formation in vitro. Computational analysis suggested that EGCG prevented amyloidogenic cystatin fibril formation by stabilizing the molecule in its native-like state as opposed to redirecting aggregation toward disordered and amorphous aggregates. Therefore, although EGCG appears to be a generic inhibitor of amyloid-fibril formation, the mechanism by which it achieves such inhibition may be specific to the target fibril-forming polypeptide.[1]

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The cancer stem cell (CSC) model postulates the existence of a small proportion of cancer cells capable of sustaining tumor formation, self-renewal and differentiation. Signal Transducer and Activator of Transcription 3 (STAT3) signaling is known to be selectively activated in breast CSC populations. However, it is yet to be determined which molecular mechanisms regulate STAT3 signaling in CSCs and what chemopreventive agents are effective for suppressing CSC growth. The aim of this study was to examine the potential efficacy of curcumin and epigallocatechin gallate (EGCG) against CSC and to uncover the molecular mechanisms of their anticancer effects. Results: Combined curcumin and EGCG treatment reduced the cancer stem-like Cluster of differentiation 44 (CD44)-positive cell population. Western blot and immunoprecipitation analyses revealed that curcumin and EGCG specifically inhibited STAT3 phosphorylation and STAT3-NFkB interaction was retained. Conclusion: This study suggests that curcumin and EGCG function as antitumor agents for suppressing breast CSCs. STAT3 and NFκB signaling pathways could serve as targets for reducing CSCs leading to novel targeted-therapy for treating breast cancer.[2]

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Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea (Camellia sinesis) has been shown to exert antimicrobial effects on numerous bacterial pathogens. However its efficacy against Enterococcus faecalis biofilm, which is associated with persistent root canal infection is unknown. The aims of this study were to investigate the effects of EGCG against E. faecalis biofilm and virulence.[3]

C15H14O7

306.27

306.073

C, 58.82; H, 4.61; O, 36.57

970-74-1

(-)-Epigallocatechin Gallate;989-51-5;(-)-Gallocatechin;3371-27-5;(+)-Gallocatechin;970-73-0

72277

White to off-white solid powder

1.7±0.1 g/cm3

685.6±55.0 °C at 760 mmHg

208-210°C

368.5±31.5 °C

0.0±2.2 mmHg at 25°C

1.776

-0.1

130.61

6

7

1

22

380

2

C1[C@H]([C@H](OC2=CC(=CC(=C21)O)O)C3=CC(=C(C(=C3)O)O)O)O

WMBWREPUVVBILR-WIYYLYMNSA-N

InChI=1S/C22H18O11/c23-10-5-12(24)11-7-18(33-22(31)9-3-15(27)20(30)16(28)4-9)21(32-17(11)6-10)8-1-13(25)19(29)14(26)2-8/h1-6,18,21,23-30H,7H2/t18-,21-/m1/s1

[(2R,3R)-5,7-dihydroxy-2-(3,4,5-trihydroxyphenyl)chroman-3-yl] 3,4,5-trihydroxybenzoate

EGC; NSC 674039; (-)-Epigallocatechin; Epigallocatechin; 970-74-1; Epigallocatechol; L-Epigallocatechin; epi-Gallocatechin; Antiscurvy factor C2; (-)-Epigallocatechol; epiGallocatechin

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~66.67 mg/mL (~217.68 mM)

配方 1 中的溶解度: ≥ 2.5 mg/mL (8.16 mM) (饱和度未知) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将100 μL 25.0 mg/mL澄清DMSO储备液加入到400 μL PEG300中，混匀；然后向上述溶液中加入50 μL Tween-80，混匀；加入450 μL生理盐水定容至1 mL。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 2 中的溶解度: ≥ 2.5 mg/mL (8.16 mM) (饱和度未知) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL澄清DMSO储备液加入900 μL 20% SBE-β-CD生理盐水溶液中，混匀。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 3 中的溶解度: ≥ 2.5 mg/mL (8.16 mM) (饱和度未知) in 10% DMSO + 90% Corn Oil (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL 澄清 DMSO 储备液加入到 900 μL 玉米油中并混合均匀。

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
4、 如产品在配制过程中出现沉淀/析出，可通过加热(≤50℃)或超声的方式助溶;
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6、如不确定怎么将母液配置成体内动物实验的工作液，请查看说明书或联系我们;
7、 以上所有助溶剂都可在 Invivochem.cn网站购买。