Epigallocatechin Gallate: A Review of Its Beneficial Properties to Prevent Metabolic Syndrome

Obesity and being overweight are linked with a cluster of metabolic and vascular disorders that have been termed the metabolic syndrome. This syndrome promotes the incidence of cardiovascular diseases that are an important public health problem because they represent a major cause of death worldwide. Whereas there is not a universally-accepted set of diagnostic criteria, most expert groups agree that this syndrome is defined by an endothelial dysfunction, an impaired insulin sensitivity and hyperglycemia, dyslipidemia, abdominal obesity and hypertension. Epidemiological studies suggest that the beneficial cardiovascular health effects of diets rich in green tea are, in part, mediated by their flavonoid content, with particular benefits provided by members of this family such as epigallocatechin gallate (EGCG). Although their bioavailability is discussed, various studies suggest that EGCG modulates cellular and molecular mechanisms of various symptoms leading to metabolic syndrome. Therefore, according to in vitro and in vivo model data, this review attempts to increase our understanding about the beneficial properties of EGCG to prevent metabolic syndrome.     

表没食子儿茶素没食子酸酯预防正畸固定矫治者的牙釉质白斑

文题释义： 龋白斑：很多接受正畸固定矫治的患者其牙面上会呈现白垩色的点或斑块，临床上表现为龋白斑(white spot lesions，WSL)，即釉质脱矿，如病变进一步发展甚至会形成龋洞。 表没食子儿茶素没食子酸酯(Epigallocatechin gallate，EGCG)：是茶多酚中最有效的活性成分，属于儿茶素。EGCG具有抗菌、抗病毒、抗氧化、抗动脉硬化、抗血栓形成、抗血管增生、抗炎以及抗肿瘤作用。绿茶里有EGCG，但红茶里没有，因为红茶里的EGCG被转化成了茶玉红精。EGCG在医药保健上具有防治癌症等多种疾病和增强免疫力等功能。 背景：目前已有大量研究证实表没食子儿茶素没食子酸酯(Epigallocatechin gallate，EGCG)可应用于牙科治疗中，但目前尚未有临床研究讨论EGCG用于托槽的釉质粘接是否可以减少临床上正畸术后白斑的发生率。目的：探讨EGCG应用于预防正畸固定矫治患者牙釉质白斑发生的价值。方法：选择接受正畸固定矫治治疗的50例符合纳入排除标准的患者，采用自身对照法，右侧使用添加有1 g/L EGCG的粘接剂(EGCG组)，左侧使用不含EGCG的粘接剂(对照组)，其余治疗步骤和材料均相同。于治疗开始后3，6和12个月检测目标牙位(16，11，46，26，31，36)牙釉质脱矿指数(EDI)和釉质白斑的发生率，并统计托槽脱落情况。研究方案的实施符合柳州市人民医院对研究的相关伦理要求，患者及监护人对试验过程完全知情同意。结果与结论：①EGCG组和对照组在试验期间托槽脱落率差异无显著性意义(P > 0.05)；②在治疗开始后3个月，2组白斑发生率和牙釉质脱矿指数值差异无显著性意义(P > 0.05)，治疗6，12个月，EGCG组白斑发生率和牙釉质脱矿指数值均较对照组显著降低(P < 0.05)；③结果说明，添加有1 g/L EGCG的粘接剂可以在不影响托槽粘接强度的情况下，起到预防正畸固定矫治患者牙釉质脱矿和白斑发生作用，且能长期维持。 ORCID: 0000-0002-5325-5037(杨柳青) 中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程     

表没食子儿茶素没食子酸酯的抗感染作用研究进展

表没食子儿茶素没食子酸酯（epigallocatechin gallate，EGCG）是茶多酚的主要组成成分。EGCG具有多种生物学功能，包括抗细菌、抗真菌、抗病毒、抗肿瘤、抗炎症、抗衰老、抗肥胖、抗糖尿病、心血管疾病的预防和保护、免疫调节、神经保护等生物学功能。本文主要归纳了EGCG在治疗新型冠状病毒（SARS-CoV-2）感染中的潜在作用，在耐药细菌感染中的预防和治疗作用，以期为EGCG在抗感染药物开发方面提供一定的理论依据。     

Cavernous antioxidant effect of green tea,epigallocatechin‐3‐gallate with/without sildenafil citrate intake in aged diabetic rats

This study aimed to assess the cavernous antioxidant effect of green tea (GT), epigallocatechin‐3‐gallate (EGCG) with/without sildenafil citrate intake in aged diabetic rats. One hundred and four aged male white albino rat were divided into controls that received ordinary chow, streptozotocin (STZ)‐induced aged diabetic rats, STZ‐induced diabetic rats on infused green tea, induced diabetic rats on epigallocatechin‐3‐gallate and STZ‐induced diabetic rats on sildenafil citrate added to EGCG. After 8 weeks, dissected cavernous tissues were assessed for gene expression of eNOS, cavernous malondialdehyde (MDA), glutathione peroxidase (GPx), cyclic guanosine monophosphate (cGMP), and serum testosterone (T). STZ‐induced diabetic rats on GT demonstrated significant increase in cavernous eNOS, cGMP, GPx and significant decrease in cavernous MDA compared with diabetic rats. Diabetic rats on EGCG demonstrated significant increase in cavernous eNOS, cGMP, GPx and significant decrease in cavernous MDA compared with diabetic rats or diabetic rats on GT. Diabetic rats on EGCG added to sildenafil showed significant increase in cavernous eNOS, cGMP and significant decrease in cavernous MDA compared with other groups. Serum T demonstrated nonsignificant difference between the investigated groups. It is concluded that GT and EGCG have significant cavernous antioxidant effects that are increased if sildenafil is added.     

表没食子儿茶素没食子酸酯对雨蛙素导致的小鼠急性胰腺炎肺损伤的作用

目的研究表没食子儿茶素没食子酸酯(EGCG)对急性胰腺炎相关性肺损伤的作用及机制。方法用随机数表法将balb/c小鼠分为3组:空白对照组腹腔注射0.9%NaC l(10 mL·kg^-1);模型组腹腔注射雨蛙素50μg·kg^-1建立小鼠急性胰腺炎肺损伤模型,这2组均每小时注射1次,共7次;实验组在造模后1,3,6 h,分别腹腔给予EGCG 25 mg·kg^-1。于造模后24 h,用脱颈法处死小鼠。眼球取血,切取肺,取胰腺,进行病理学检查;用全自动生化分析仪测定血清中淀粉酶,以硫代巴比妥酸法检测丙二醛(MDA)水平,以酶联免疫吸附法(ELISA)测定肿瘤坏死因子(TNF-α)的含量,以免疫组化SP法检测肺组织核因子(NF-κB)水平,用苏木精-尹红(HE)染色法进行肺组织学观察及组织病理学评分。结果实验组、模型组与对照组的血清淀粉酶分别为(3613.21±351.87),(4720.43±672.24),(895.41±107.18)U·L^-1;这3组的MDA分别为(13.06±0.11),(15.49±0.40),(4.26±0.69)mmol·mL^-1;这3组的TNF-ɑ分别为(59.83±14.74),(83.29±24.10),(24.76±10.24)pg·L^-1;这3组的肺组织NF-κB表达分别为0.38±0.14,0.55±0.12,0.14±0.09;这3组的肺组织病理学评分分别为(3.47±1.20),(6.54±0.51),(0.21±0.07)分;模型组与对照组比较,以上指标差异均有统计学意义(均P<0.05);实验组与模型组比较,以上指标差异均有统计学意义(均P<0.05)。结论 EGCG可通过抑制NF-κB的表达和提高对氧自由基的清除,从而减轻实验小鼠胰腺炎症相关肺组织损伤。     

Oolong tea prevents cardiomyocyte loss against hypoxia by attenuating p‐JNK mediated hypertrophy and enhancing P‐IGF1R,p‐akt,and p‐Badser136 activity and by fortifying NRF2 antioxidation system

Tea, the most widely consumed natural beverage has been associated with reduced mortality risk from cardiovascular disease. Oolong tea is a partially fermented tea containing high levels of catechins, their degree of oxidation varies between 20%‐80% causing differences in their active metabolites. In this study we examined the effect of oolong tea extract (OTE) obtained by oxidation at low‐temperature for short‐time against hypoxic injury and found that oolong tea provides cyto‐protective effects by suppressing the JNK mediated hypertrophic effects and by enhancing the innate antioxidant mechanisms in neonatal cardiomyocytes and in H9c2 cells. OTE effectively attenuates 24 h hypoxia‐triggered cardiomyocyte loss by suppressing caspase‐3‐cleavage and apoptosis in a dose‐dependent manner. OTE also enhances the IGFIR/p‐Akt associated survival‐mechanism involving the elevation of p‐Bad^ser136 in a dose‐dependent manner to aid cellular adaptations against hypoxic challenge. The results show the effects and mechanism of Oolong tea to provide cardio‐protective benefits during hypoxic conditions.     

EGCG改善油酸诱导的SW872脂肪细胞胰岛素抵抗作用及机制

目的观察植物化学物表没食子儿茶素没食子酸酯(EGCG)对胰岛素抵抗SW872脂肪细胞葡萄糖转运、胰岛素敏感性及炎症因子表达作用。方法利用油酸处理脂肪细胞诱导胰岛素抵抗模型,给予不同剂量EGCG(25、50、100μmol/L)处理24 h,利用激光共聚焦显微镜检测2–脱氧葡萄糖标记的葡萄糖摄取、Western–blot检测葡萄糖转运因子4(GLUT4)蛋白表达、实时荧光定量逆转录多聚酶联反应(RT–q PCR)检测肿瘤坏死因子α(TNF–α)、白细胞介素6(IL–6)、C反应蛋白(CRP)mRNA表达,酶标记免疫吸附测定法(ELISA)检测培养液中TNF–α、IL–6、CRP蛋白含量。结果与对照组比较,模型组脂肪细胞葡萄糖摄取和GLUT4蛋白表达明显降低(P<0.05),TNF–α、IL–6、CRP mRNA明显升高(P<0.01),TNF–α、IL–6、CRP蛋白分泌量[分别为(161.3±14.2)、(121.6±13.6)、(1.82±0.17)]明显升高(P<0.01);与模型组比较,EGCG组脂肪细胞葡萄糖摄取和GLUT4蛋白表达明显增加(P<0.05),TNF–α、IL–6、CRP mRNA明显下降(P<0.01),低、中、高剂量EGCG组脂肪细胞TNF–α、IL–6、CRP蛋白分泌量[分别为(148.8±13.3)、(93.3±10.4)、(1.74±0.12)pg/m L,(131.4±11.3)、(85.5±14.1)、(1.53±0.15)pg/m L和(119.5±12.1)、(73.9±11.3)、(1.36±0.12)pg/m L]明显降低(P<0.01),呈剂量效应关系。结论 EGCG可促进脂肪细胞葡萄糖摄取和增强胰岛素敏感性,进而改善胰岛素抵抗,其机制可能与降低脂肪细胞炎症因子表达有关。     

The effects of green tea on acne vulgaris: A systematic review and meta‐analysis of randomized clinical trials

Green tea extract (GTE) has been studied for the treatment of acne based on its anti‐inflammatory/antioxidant properties. This systematic review and meta‐analysis aimed to examine the effects of GTE on acne. Electronic databases, including PubMed, Embase, and the Cochrane Library were systematically searched up to August 2019. The effect size of acne lesion counts is presented as mean differences and 95% confidence intervals (CIs). Five randomized‐controlled studies were included in the meta‐analysis (N; experimental = 125, control = 122). GTE significantly reduced the number of inflammatory lesions (?9.38; 95% CI: ?14.13 to ?4.63). In subgroup analysis, topical GTE application significantly reduced the inflammatory lesion counts (?11.39; 95% CI: ?15.91 to ?6.86) whereas oral GTE intake showed minimal effect (?1.40; 95% CI: ?2.50 to ?0.30). Although GTE did not significantly reduce the number of non‐inflammatory lesions (?21.65; 95% CI: ?47.52 to 4.22), when stratified by the route of admission, non‐inflammatory acne lesions were significantly reduced by topical GTE application (?32.44; 95% CI: ?39.27 to ?25.62) but not with oral GTE administration (0.20; 95% CI: 0.00 to 0.40). This systematic review and meta‐analysis suggest that topical GTE application is beneficial for the treatment of acne without causing significant adverse events while oral GTE intake has limited effects. Further high‐quality clinical trials are warranted.