Reactive oxygen species scavenging activities and inhibition on DNA oxidative damage of dimeric compounds from the oxidation of (−)-epigallocatechin-3-O-gallate

The dimeric catechins dehydrotheasinensin A (2) and theacitrin C (3) were prepared from the oxidation of (−)-epigallocatechin-3-O-gallate (EGCG, 1), and their antioxidant activity was investigated using a chemiluminescence (CL) method in vitro. Both compounds showed significant inhibitory effects on reactive oxygen species (O₂⁻, H₂O₂ and •OH) and DNA oxidative damage, with 2 being more potent than 3 and EGCG itself.     

绿茶和红茶多酚类化合物的抗病毒活性在新型冠状病毒肺炎预防和治疗中的应用

新型冠状病毒SARS-CoV-2或nCoV的迅速传播,已引起世界各国的高度重视并采取严格的预防和隔离措施。这个新的单链RNA冠状病毒通过唾液和鼻腔分泌物传播。鉴于新型冠状病毒感染病例数日益增多,美国食品药品监督管理局(FDA)已授权紧急使用瑞德西韦(Remdesivir)治疗,但至今仍然没有任何一种药物获批准用于治疗COVID-19。另一种替代的方法是用一些已知具有抗病毒特性的天然物质分子进行治疗。有报道证实,绿茶中的表没食子儿茶素没食子酸酯(EGCG)和红茶中的茶黄素对各种病毒,特别是对单链RNA病毒具有抗病毒活性。最近的研究揭示了在SARS-CoV-2病毒上存在可能的结合位点,并研究了它们与茶叶多酚类化合物之间的相互作用。这篇综述中也关注到EGCG和茶黄素,特别是茶黄素-3,3'-双没食子酸酯(TF3)和病毒上的受体有非常明显的相互作用。有些对接实验研究重点关注了这些多酚类化合物在抗COVID-19病毒方面的活性。文章对现有报道和支持使用茶多酚化合物作为预防和治疗COVID-19可能的候选药物的证据进行了综述。     

茶叶中EGCG泡腾片制备工艺研究

[目的]研究表没食子儿茶素没食子酸酯(EGCG)泡腾片的制备工艺.[方法]将各种原料在50℃条件下干燥不同时间,考察压片粘冲程度;采用正交试验确定茶叶中EGCG泡腾片最优配方.[结果]干燥150 min后,压片无粘冲,出片顺利.EGCG泡腾片的最佳配方为:EGCG 4％、柠檬酸和碳酸钠总量45％、柠檬酸:碳酸钠为1.6:1、乳糖20％、L-亮氨酸4％、甜蜜素4％、橙粉23％.[结论]用该配方制作的泡腾片,压片无粘冲,泡腾效果好,口感好.     

超声复合碱处理大豆蛋白与EGCG复合物功能特性研究

大豆分离蛋白(SPI)经超声复合碱处理后与表没食子儿茶素没食子酸酯(EGCG)进行复合形成复合物。采用傅里叶变换红外光谱和荧光光谱对超声复合碱处理及EGCG改性的SPI结构及构象进行解析,以粒径、Zeta电位、浊度及乳化特性为指标,分析该复合体系中SPI构象改变与功能特性之间的关系。结果表明:超声复合碱处理使SPI的粒径减小、溶液电位绝对值增加、乳化性显著提高。超声复合碱处理的SPI与EGCG复合后,SPI的Zeta电位绝对值进一步显著增加,其粒径明显减小,乳化特性显著提高。光谱分析显示,超声复合碱处理以及EGCG可以改变SPI的二级结构,使蛋白链解折叠,并且改变蛋白芳香族氨基酸残基所处的微环境,使蛋白的构象发生改变。通过荧光淬灭光谱分析发现,EGCG对SPI的荧光猝灭机制为静态猝灭,SPI与EGCG之间形成了结合位点数近似于1的复合物。     

Protective effects of EGCG on Bifenthrin-Induced Oxidative Stress in the Human Embryonic Lung Fibroblast Cell Line HFL-I

Bifenthrin （BF） is an important type I synthetic fluorinated pyrethroid insecticide and acaricide.Previous investigations have indicated that the metabolisms of BF in human cells were through oxidative processes,and cytotoxicity was induced by the oxidative stress.In this study,the protective effects of EGCG,which is a major individual of green tea polyphenols,on the human embryonic lung fibroblast cell line HFL-I exposed to BF were investigated.The results showed that BF could induce oxidative stress leading to cytotoxicity in HFL-I cells.The pretreatment of EGCG at low concentrations significantly recovered the cell viability and morphology,inhibited excess generation of ROS,enhanced antioxidant enzyme activities and avoided loss of mitochondrial membrane potential.The results suggested that EGCG might eliminate the BF-induced damage in HFL-I cells.     

绿茶及茶多酚药理作用研究进展

茶消费量占全球饮料消费量第2位,普及性仅次于水.绿茶的化学成分主要包括多酚、咖啡因和氨基酸,绿茶中含有丰富的儿荼素,其中茶多酚是最丰富的.绿茶及其中的多酚在治疗多种疾病方面发挥积极作用,如癌症、糖尿病、心血管疾病、肥胖症等.对茶和茶多酚相关的药理特征进行了重点讨论,希望能开拓新的研究领域,并鼓励对公众健康问题进行研究.     

HPLC-DAD测定大茶树和小茶树的西湖龙井茶中EGCG的含量

[目的]采用HPLC-DAD对西湖龙井茶中的表没食子儿茶素没食子酸酯（EGCG）的含量变化进行分析.[方法]采用AgilentC18色谱柱（4.6 mm×150 mm,5μm）,流动相：甲醇：水（2％乙酸）15∶85;流速：1.0 ml/min;检测波长：276 nm;柱温：35℃.[结果]EGCG线性范围为0.152～3.040 μg,相关系数r为1,平均回收率97.61％,RSD为6.61％.[结论]该方法精密度、准确度良好,稳定性高,能简便、快速地测定大小茶树的西湖龙井茶中的EGCG含量.     

EGCG对线粒体PT孔开放及Ca~(2+)转运的影响

对线粒体膨胀及线粒体膜电位的研究发现,EGCG对Ca2+和H2O2导致的线粒体通透性改变有抑制其膨胀的作用。EGCG对Ca2+诱导的线粒体Ca2+释放随加入时间有抑制和加速释放的作用;与Ca2+同时加入,它们可以抑制线粒体对Ca2+的吸收和线粒体Ca2+的释放;在线粒体吸收Ca2+达到最大时加入EGCG,则促进线粒体Ca2+的释放,EGCG还可抑制Ca2+引起的线粒体膜电位的降低。     

EGCG抑制PC12凋亡的细胞生物学研究

以神经毒素 6_OHDA诱导PC12细胞凋亡长期被用作帕金森氏病 (PD)研究模型。由于氧应激在PD发病中起重要作用 ,在 6_OHDA处理前提前 3 0min加入不同剂量的保护剂EGCG ,对 6_OHDA造成的PC12细胞损伤有一定的保护作用 ;流式细胞术检测细胞凋亡率 ,结果表明EGCG表现出剂量依赖的保护作用 ,且在 2 0 0 - 4 0 0 μM时保护作用最佳 ;荧光结果也表明EGCG保护效果明显     

A Novel Liquid Multi-Phytonutrient Supplement Demonstrates DNA-Protective Effects

This study explored the DNA protective (anti-mutagenic) effects of an oral, liquid, multi-phytonutrient dietary supplement containing a proprietary blend of fruits, vegetables and aloe vera concentrated components in addition to a proprietary catechin complex from green tea (VIBE Cardiac & Life, Eniva Nutraceuticals, Anoka, MN; herein described as “VIBE”). This study tested the hypothesis that VIBE would reduce DNA damage in skin cells exposed to UVR. Human epidermal cells, from the cell line A431NS, were treated with 0% (control), 0.125%, 0.5%, 1% and 2% VIBE, and then exposed to 240 J/m² UVR. The amount of DNA damage was assessed using the COMET assay. At each concentration tested, a significantly smaller amount of DNA damage was measured by the COMET assay for the VIBE treated cells compared to the control cells exposed to UVR without VIBE. The dose response curves showed a maximal response at 0.5% VIBE with a threefold reduction in COMET tail density compared to the control samples without VIBE (p < 0.001). Additional research is warranted in human clinical trials to further explore the results of this study which demonstrated the DNA protective and anti-mutagenic effects of VIBE for human skin cells exposed to UVR-induced DNA damage.