Hepatotoxicity from green tea: a review of the literature and two unpublished cases

Purpose  To review the current literature on suspected green tea-related hepatic reactions and to describe two new cases reported within the framework of the Italian surveillance system of natural health products. Results  A literature search of publication between 1999 and October 2008 retrieved 34 cases of hepatitis. Histological examination of the liver revealed inflammatory reactions, cholestasis, occasional steatosis, and necrosis. A positive dechallenge was reported in 29 cases. There was one reported death. A positive rechallenge occurred in seven cases (20%). In the two new cases, the causality assessment was judged as “possible” according to the RUCAM score. Conclusions  Our analysis of the published case reports suggests a causal association between green tea and liver damage. The hepatotoxicity is probably due to (-)-epigallocatechin gallate or its metabolites which, under particular conditions related to the patient’s metabolism, can induce oxidative stress in the liver. In a few cases, toxicity related to concomitant medications could also be involved.     

Chemoprevention of liver cancer by plant polyphenols

Primary liver cancer or hepatocellular carcinoma (HCC) is one of the most frequent tumors representing the fifth commonest malignancy worldwide and the third cause of mortality from cancer. Currently, the treatments for HCC are not so effective and new strategies are needed for its fight. Chemoprevention, the use of natural or synthetic chemical agents to reverse, suppress or prevent carcinogenesis is considered an important way for confronting HCC. Many of the chemopreventive agents are phytochemicals, namely non-nutritive plant chemicals with protective or disease preventive properties. In this review, we focus on plant polyphenols, one of the most important classes of phytochemicals, their chemopreventive properties against HCC and discuss the molecular mechanisms accounting for this activity.     

EGCG在肿瘤防治中的作用

表没食子儿茶素没食子酸酯(EGCG)是绿茶的主要组成成分,国内外多年的研究表明其对多种肿瘤均有防治作用.本文将从EGCG在肿瘤的发生发展、肿瘤的转移浸润、肿瘤的血管生成及肿瘤的耐药等方面来阐述EGCG的肿瘤防治作用.     

C-PG血小板聚集试验在单采血小板捐献者筛查中的应用

本研究探讨以阳离子没食子酸丙酯（C-PG）为激活剂的血小板聚集试验用于单采血小板捐献者筛查的可行性,并调查血小板献血者血小板功能缺陷的发生率.测定不同浓度C-PG诱导的健康献血者的血小板聚集率,以确定C-PG的最适应用浓度;检测30名志愿者服用阿司匹林前和服药24小时后的血小板聚集率,以确定血小板功能不良的筛查界点值;检测483例血小板捐献者的C-PG诱导的血小板聚集率,并对聚集功能不良者进行活化血浆凝固时间（APCT）测定.结果表明：血小板聚集率随C-PG浓度的增加而升高,当C-PG浓度达200μmol/L时,血小板聚集率达最高;服用阿司匹林24小时后的血小板聚集率与服药前相比,均表现明显减低（P＜0.001）,但以C-PG诱导180秒时的血小板聚集率减低最显著.血小板功能不良的筛查界点值确定为C-PG诱导180秒时的血小板聚集率小于20%;在483例血小板捐献者中,检出25例有血小板聚集功能不良,其中有11例表现为血小板促凝血活性减低.结论：C-PG诱导的血小板聚集试验能有效的检出血小板功能不良者,适用于血小板捐献者血小板功能的筛选;在血小板献血者中,血小板功能缺陷者的检出率大约为5%.     

EGCG调节TLR4/MyD88/NF-κB信号通路对特应性皮炎大鼠Th1/Th2平衡的影响

目的 探讨表没食子儿茶素没食子酸酯(EGCG)对特应性皮炎(AD)大鼠的保护作用及潜在机制。方法 将SPF级SD大鼠分为对照(Control)组、AD模型(AD)组、AD+EGCG治疗(EGCG)组、AD+地塞米松阳性对照(DXM)组、AD+EGCG+TLR4激动剂(TLR4)组,每组18只。根据临床损伤严重程度计算皮肤损伤评分;ELISA检测炎症因子的表达;HE染色观察组织学变化;流式细胞仪分析Th1和Th2阳性细胞比例;Western blot检测TLR4/MyD88/NF-κB通路相关蛋白水平。结果 与Control组比较,AD组大鼠背部皮肤损伤程度较重,病理学损伤评分增加(P<0.05),白细胞介素-2(IL-2)、干扰素-γ(IFN-γ)水平及Th1细胞百分比降低,白细胞介素-4(IL-4)、白细胞介素-13(IL-13)水平及Th2细胞百分比升高(P<0.05),TLR4、MyD88、p-NF-κB蛋白水平升高(均P<0.05)。与AD组比较,EGCG组和DXM组大鼠皮肤损伤评分及皮肤损伤病理学评分降低,Th₁细胞百分比、IL-2、I...     

组蛋白脱乙酰酶2介导的组蛋白乙酰化失衡在压力过载性心肌重构中的作用

目的探讨组蛋白脱乙酰酶2（histonedeacetylase2,HDAC2）介导的组蛋白乙酰化修饰失衡在压力过载性心肌重构中的调控作用。方法选取SPF级成年昆明小鼠,通过部分结扎胸主动脉（transverseaorticconstriction,TAC）建立小鼠压力过载性心肌重构模型,应用表没食子儿茶素没食子酸酯（epigallocatechingallate,EGCG）腹腔注射干预模型小鼠。根据随机数字表法将小鼠分为正常组、TAC组、溶剂组、假手术组和EGCG+TAC组,每组6只小鼠。收集各组小鼠心脏组织进行如下检测：Westernblot检测HDAC2、第27位赖氨酸乙酰化的组蛋白H3（acetylatedhistoneH3atlysine27,H3K27ac）、心肌细胞增强因子2A（myocyteenhancerfactor2A,MEF2A）和脑钠肽（brainnatriureticpeptide,BNP）蛋白表达水平;超声心动图检测小鼠心功能;ES420生物系统检测小鼠左室收缩末期压力（leftventricularend-systolicpressure,LVESP）。结果Westernblot结果显示,TAC组小鼠心肌H3K27ac水平及心脏发育相关蛋白MEF2A和BNP表达水平较假手术组显著降低（P<0.05）,而EGCG+TAC组小鼠心肌H3K27ac水平及MEF2A和BNP表达水平较TAC组显著升高（P<0.05）。HDAC2表达水平在TAC组较假手术组显著升高,而EGCG+TAC组HDAC2表达水平较TAC组显著降低（P<0.05）;超声心动图及LVESP结果显示,TAC组小鼠心功能及LVESP较假手术组显著降低（P<0.05）,而EGCG+TAC组小鼠心功能及LVESP与TAC组相比显著升高（P<0.05）。结论EGCG能够抑制小鼠压力过载性心肌重构。HDAC2介导的H3K27乙酰化修饰可能是EGCG抑制压力过载性心肌重构的调控靶点之一。     

表没食子儿茶素没食子酸酯促进2型糖尿病伤口愈合的实验研究

目的系统评价表没食子儿茶素没食子酸酯( EGCG)对于 2型糖尿病 db/db小鼠伤口愈合的治疗效果。方法 3月龄雄性无特定病原体( SPF)级 db/db小鼠共 32只以及同背景的野生型雄性小鼠共 16只用于本实验,共等分为野生小鼠组( Control)、 db/db小鼠组( db/db)和 db/db小鼠 EGCG治疗组( db/db+EGCG),每组 16只。所有小鼠均构建背部圆形创口(直径 1 cm),db/ db+EGCG组小鼠在伤口模型构建后立即施以每日的 EGCG(10 mg/kg)灌胃处理。术后第 5、12、19天处死每组 4只小鼠,分析伤口愈合速率、抗张强度、局部皮肤血流速率、细胞因子表达情况。结果 db/db+EGCG组小鼠在伤口模型建立的第 5、12、19天伤口愈合率分别为( 19.4±3.2)%、(55.2±4.8)%和( 79.7±5.2)%,db/db组小鼠各时间点伤口愈合率分别为( 10.1±2.0)%、(39.1±5.2)%和( 59.2±6.2)%,db/db+EGCG组均显著高于 db/db组( P＜0.05)同时 EGCG也显著降低了 db/db小鼠伤口愈合时间( P＜0.05);并且 EGCG在术后第 5、12、19天均显著增加了 db/db小鼠伤织的生物力学抗张强度( P＜0.05)改善了伤口位置局部血流速率( P＜0.05)并显著抑制了炎性因子白细胞介素 1β(IL-1β)、白细胞介素 6(IL-6)和肿瘤坏死α(TNF-α)表达(P＜0.05),促进了血皮生长因子( VEGF)表达( P＜0.05)。结论 EGCG能够显著改善 2型糖尿病 db/db小鼠的伤口愈合口组,因子,管内,能力,具有可观的临床应用前景。