表没食子儿茶素没食子酸酯抑制甲状腺癌细胞的端粒酶活性

目的　探讨表没食子儿茶素没食子酸酯 [(- )epigallocatechin - 3-gallate (EGCG) ]对甲状腺癌细胞端粒酶活性的抑制作用 ,为天然来源的端粒酶抑制剂治疗甲状腺癌提供理论依据。方法　不同浓度的EGCG处理甲状腺癌FRO细胞 ,MTT法测定EGCG对FRO细胞生长的影响 ,TRAP -PCR -ELISA法检测药物处理前后FRO细胞端粒酶的活性。结果　EGCG显著抑制FRO细胞的增殖 (P <0 .0 1) ;随着药物浓度的递增 ,FRO细胞的端粒酶活性逐渐降低。结论　EGCG显著抑制甲状腺癌FRO细胞的端粒酶活性 ,可考虑应用于甲状腺癌的临床治疗     

EGCG干预LMP1激活的AP-1信号转导通路

目的　探讨EGCG对鼻咽癌细胞激活蛋白 1(AP 1)信号转导通路的干预作用 ,阐明在鼻咽癌细胞中茶多酚干预EB病毒潜伏膜蛋白 1(LMP1)活化的AP 1信号转导通路中靶分子的机制。方法　采用EB病毒阴性及阳性的鼻咽癌细胞系CNE1和CNE1 LMP1细胞。利用四甲基偶氮唑蓝(MTT)法观察EGCG对CNE1和CNE1 LMP1细胞的生存率的影响。采用瞬间转染及报道基因法观察EGCG对AP 1活性的作用。利用间接免疫荧光法观察EGCG对JNK核移位的影响 ,再分别提取CNE1和CNE1 LMP1的胞浆及胞核蛋白 ,Westernblot分析EGCG抑制JNK的核移位后 ,胞浆及胞核蛋白中JNK的变化。采用Westernblot分析EGCG对c Jun的磷酸化水平的影响。采用瞬间转染及报道基因法观察EGCG对cyclinD1启动子活性的影响 ,并用Westernblot分析EGCG对cyclinD1蛋白表达的作用。结果　EGCG对鼻咽癌细胞的抑制作用有剂量依赖性 ,并可抑制AP 1的活性。EGCG能抑制JNK的核移位 ,并抑制c Jun的磷酸化。EGCG对AP 1信号通路下游的靶基因cyclinD1的启动子活性及其蛋白表达都有抑制作用。结论　EGCG对信号转导通路上的AP 1、JNK、c Jun、cyclinD1多个靶点分子具有干预作用。LMP1是EB病毒这种编码的蛋白 ,因此 ,EGCG抑制与病毒相联系的信号转导通路 ,可能是EGCG抑制与病毒相关的肿瘤的分子机     

茶多酚诱导膀胱癌EJ细胞株凋亡与细胞内钙离子变化的相关性

目的：探讨茶多酚对膀胱癌EJ细胞株抑制增殖的分子机理。方法：采用流式细胞术、噻唑蓝(MTT)比色法和激光共聚焦成像技术，分别测定膀胱癌EJ细胞株的凋亡状态、细胞的周期变化、线粒体功能及细胞内离子钙浓度水平变化。用茶多酚处理EJ肿瘤细胞。结果：细胞的周期依浓度的改变而变化，浓度增加至20μg／ml发生明显的凋亡，OD值与浓度呈负相关性。细胞内钙离子浓度与时间、浓度的增加呈量效正相关。钙离子浓度逐渐升高亦呈现为时效、量效正相关性。结论：茶多酚能影响肿瘤细胞的增殖、凋亡过程。茶多酚诱导所致线粒体变化、细胞内钙离子超载可能在肿瘤凋亡中起着重要作用。     

没食子儿茶素没食子酸酯对小鼠Lewis肺癌增殖以及A549与Calu-3肺癌增殖的抑制作用

 目的 观察没食子儿茶素没食子酸酯（epigallocatechin gallate,EGCG）对小鼠Lewis肺癌增殖的抑制作用,并在细胞水平比较没食子儿茶素没食子酸酯对A549与Calu-3两种肺癌细胞增殖和凋亡的影响,初步分析可能的机制。方法 利用C57BL/6J Lewis肺癌自发转移模型研究没食子儿茶素没食子酸酯 （12.5、25、50 mg·kg^-1口服给药,21 d）对Lewis肺癌增殖的抑制作用。采用WST-8方法检测5、10、50、100 μmol·L^-1的没食子儿茶素没食子酸酯对人源非小细胞肺癌Calu-3细胞及A549细胞增殖的抑制作用。利用TUNEL细胞凋亡检测试剂盒以及PI染色方法观察没食子儿茶素没食子酸酯对Calu-3细胞和A549细胞（Ki-Ras突变）的促凋亡作用。结果 没食子儿茶素没食子酸酯剂量依赖性地抑制皮下移植Lewis肺癌的增殖;采用WST-8检测法观察到没食子儿茶素没食子酸酯对Calu-3细胞增殖呈剂量依赖性的抑制,而对A549细胞抑制作用较弱;TUNEL方法研究结果显示,没食子儿茶素没食子酸酯通过促凋亡作用抑制Calu-3细胞增殖;细胞计数结果表明,给予不同剂量的没食子儿茶素没食子酸酯之后,Calu-3细胞数呈剂量依赖性减少,A549细胞数目无显著性变化。结论 没食子儿茶素没食子酸酯能够抑制Lewis 肺癌增殖,并剂量依赖性的抑制Calu-3细胞的增殖,而对A549细胞增殖无明显抑制作用。
     

表没食子儿茶素没食子酸酯对脊髓损伤大鼠炎症因子释放及神经营养因子表达的影响

目的 :研究表没食子儿茶素没食子酸酯(epigaloctechin-3-gallit,EGCG)对脊髓损伤(spinal cord injury, SCI)大鼠炎症因子的释放及神经营养因子表达的影响。 方法 :建立大鼠脊髓半切SCI模型。SCI大鼠给予EGCG治疗24 h后取血清和受损伤脊髓局部组织。ELISA法测定血清白介素-6(IL-6)、白介素-8(IL-8)含量;Western blot法测定脊髓组织neurotrophin-3(NT-3)、brain-derived neurotrophic factor(BDNF)蛋白表达。 结果 :与模型组比较,EGCG能显著降低SCI大鼠血清炎性因子IL-6、IL-8的浓度,促进脊髓组织内源性NT-3、BDNF表达。 结论 :EGCG可抑制炎症因子释放,增加内源性神经营养因子表达。     

Epigallocatechin gallate ameliorates tetrahydrochloride-induced liver toxicity in rats via inhibition of TGFβ / p-ERK/p-Smad1/2 signaling,antioxidant, anti-inflammatory activity

Chronic liver disease is a worldwide health problem. Carbon tetra hydrochloride is an environmental toxin which is regarded as highly toxic and a potential human carcinogen. It can cause liver damage through the generation of metabolites and production of free radicals. Green tea contains catechins such as Epigallocatechin gallate which has been found to reduce the inflammation, oxidative stress, and fibrosis in experimental animal models. Hence, it represents a good source to prevent or ameliorate several chronic diseases. Silymarin is extracted from milk thistle seeds and has been found to be an effective agent to reduce the oxidative stress and free radical production and thereby exert protective effects in chronic liver conditions. The present study was planned to keep in view the above-mentioned facts. We included thirty rats in our study and divided them into five groups, each having six rats and the study continued for 8 weeks. Group I received normal saline; Group 2 received i.p. CCl4 injections; Group 3 received CCl4 i.p. injection and Epigallocatechin gallate (EGCG) oral gavage, Group 4 received CCl4 i.p. injection and silymarin by oral gavage; and Group 5 received CCl4 i.p. injection and combined EGCG + silymarin by oral gavage. The study found that in group 2, CCl4 induced significant elevation of ALT and MDA and reduced GSH thereby signifying increased oxidative stress. CCl4 also significantly increased inflammatory (TNFα, NFκB, IL1β, and TGFβ) as well as fibrotic markers (p-ERK and p-Smad1/2 protein expression). EGCG and silymarin significantly reversed the previously mentioned parameters either alone or in combination; however, the effect was more pronounced in case of EGCG. We conclude that EGCG and silymarin possess liver protective effects through their antioxidant, anti-inflammatory, and antifibrotic action.     

茶属植物及茶多酚类成分对抗原诱导RBL-2H3细胞过敏反应的抑制作用

目的:研究茶属植物及茶多酚类和嘌呤碱类成分对抗原刺激RBL-2H3细胞脱颗粒及肿瘤坏死因子α(TNF-α)和白细胞介素4(IL-4)释放的抑制作用。方法:测定β-hexosaminidase的释放以评价脱颗粒反应的指标,酶联免疫吸附法测定TNF-α和IL-4的释放,评价茶中主要成分的抗过敏活性。结果:茶属植物均有抑制RBL-2H3细胞脱颗粒作用,其中花类表现出较叶类更强的抗过敏活性;EGCG对抗原刺激的RBL-2H3细胞即刻相(IC50:234μmol·L-1)和延缓相反应(IL4,IC50:158μmol·L-1),及钙离子载体A23187诱导的脱颗粒反应均有抑制作用(IC50:126μmol·L-1)。结论:茶属植物和EGCG具有明显的抗过敏作用。     

Herbal medicines for the prevention of alcoholic liver disease: A review

Ethnopharmacological relevance

Long-term excess alcohol exposure leads to alcoholic liver disease (ALD)—a global health problem without effective therapeutic approach. ALD is increasingly considered as a complex and multifaceted pathological process, involving oxidative stress, inflammation and excessive fatty acid synthesis. Over the past decade, herbal medicines have attracted much attention as potential therapeutic agents in the prevention and treatment of ALD, due to their multiple targets and less toxic side effects. Several herbs, such as Cnidium monnieri (L.) Cusson (Apiaceae), Curcuma longa L. (Zingiberaceae) and Pueraria lobata (Willd.) Ohwi (Leguminosae), etc., have been shown to be quite effective and are being widely used in China today for the treatment of ALD when used alone or in combination.

Aim of the review

To review current available knowledge on herbal medicines used to prevent or treat ALD and their underlying mechanisms.

Materials and methods

We used the pre-set searching syntax and inclusion criteria to retrieve available published literature from PUBMED and Web of Science databases, all herbal medicines and their active compounds tested on ALD induced by both acute and chronic alcohol ingestion were included.

Results

A total of 40 experimental studies involving 34 herbal medicines and (or) active compounds were retrieved and reviewed. We found that all reported extracts and individual compounds from herbal medicines/natural plants could be beneficial to ALD, which might be attributed to regulate multiple critical targets involved in the pathways of oxidation, inflammation and lipid metabolism.

Conclusions

Screening chemical candidate from herbal medicine might be a promising approach to drug discovery for the prevention or treatment of ALD. However, further studies remain to be done on the systematic assessment of herbal medicines against ALD and the underlying mechanisms, as well as their quality control studies.     

EGCG调控miR-133a/b-3p和TGF-β1/Smad3抗慢性阻塞性肺疾病的作用研究

目的:探讨表没食子儿茶素没食子酸酯(EGCG)对慢性阻塞性肺疾病(COPD)大鼠的保护作用和机制。方法:通过烟熏和脂多糖滴注建立大鼠COPD模型。每日灌胃给予100或200 mg/kg EGCG,4 w后观察肺部形态学改变。检测肺促炎细胞因子、MDA、GSH、SOD水平。免疫组化法评价纤维连接蛋白(fibronectin)和波形蛋白(vimentin)表达情况,Western blot检测TGF-β_1、p-Smad3表达水平,q PCR检测fibronectin、vimentin、TGF-β_1mRNA和微小RNA(miR)-133a/b-3p水平。结果:与正常对照组比较,模型组肺泡壁破损明显,肺组织促炎细胞因子、MDA及Smad3磷酸化水平显著升高,GSH、SOD、miR-133a/b-3p水平显著降低,fibronectin、vimentin、TGF-β_1蛋白表达显著升高。与模型组比较,EGCG能改善COPD大鼠的肺损伤,显著降低促炎细胞因子、MDA和Smad3的磷酸化水平,升高GSH、SOD、miR-133a/b-3p水平,并减少fibronectin、vimentin、TGF-β_1蛋白表达。结论:EGCG能改善COPD大鼠的肺损伤,其作用机制与调控肺TGF-β_1/Smad3和miR-133a/b-3p水平,抑制氧化应激和炎症有关。