茶多酚抗氧化作用的应用研究进展

茶多酚的药理作用中以抗氧化作用最为突出,其抗氧化作用及其机制在早期的文献报道中已经探讨得相当清楚。近十年来,学术界对茶多酚的研究多聚焦在其应用方面。本文收集了近年来茶多酚抗氧化作用在治疗相关疾病方面的文献报道,拟从茶多酚抗氧化作用的最新应用及影响茶多酚含量的相关因素方面做一综述报道,旨在总结茶多酚抗氧化作用应用的研究成果,分析影响茶多酚含量的因素,同时也为今后的研究提供参考,为茶多酚的综合开发利用提供依据。     

茶多酚磷脂复合物的制备

目的研究茶多酚磷脂复合物的制备。方法对反应溶剂、药脂比、溶剂量、反应时间、反应温度进行单因素考察,筛选最优条件,进行正交试验,确立最优工艺。结果以30mL无水乙醇为反应溶剂,药物与磷脂比例为1∶1.5,30℃水浴回流搅拌0.5h,所得磷脂复合物的平均结合率为98.85%。结论采用工艺简单、成本较低的方法制备茶多酚磷脂复合物,可提高茶多酚提取物亲脂性,为进一步研究茶多酚磷脂复合物的体内药物动力学提供参考。     

茶叶中茶多酚提取分离技术的研究进展

简单介绍了茶叶中茶多酚和咖啡因的药理活性以及茶叶有效成分的组成和几种主要儿茶素类化合物的结构,分析探讨了提取分离废弃茶叶的原因和意义,并综述了近年来国内外有关茶叶中茶多酚提取分离技术的研究进展,包括溶剂提取法、离子沉淀法、超声波提取法、超临界流体萃取法、微波辅助萃取法、柱色谱法、大孔吸附树脂法和高速逆流色谱法,通过不同的实验过程对不同技术手段的应用及特点进行概述,并对这一研究领域的发展前景和发展方向做出展望。     

Chemical studies on plant polyphenols and formation of black tea polyphenols

Recent biological and pharmacological studies strongly suggested that plant polyphenols in foods, beverages and crude drugs have various health benefits. However, still there are chemically uncharacterized polyphenols, especially those with large molecular weights. The typical example is black tea polyphenols. Four tea catechins of fresh tea leaves are enzymatically oxidized in tea fermentation process of black tea manufacture to give a complex mixture of the oxidation products. Despite many efforts since 1950's, major part of the black tea polyphenols has not been clarified yet. We have investigated the oxidation mechanism of each catechin by employing a newly developed in vitro model fermentation system. The oxidation was initiated by enzymatic dehydrogenation of catechins, and subsequent intermolecular quinone-phenol coupling reactions followed by cascade-type degradation of the unstable products resulted in the formation of complex black tea polyphenols. Besides black tea polyphenols, this review introduces the chemistry of insolubilization of persimmon proanthocyanidins, wood polyphenols in connection with whisky polyphenols, and co-polymerization of cinnamaldehyde and proanthocyanidins in cinnamon bark.     

Antioxidative and anti-carcinogenic activities of tea polyphenols

Tea (Camellia sinensis, Theaceace), a popular beverage consumed world-wide, has been studied for its preventive effects against cancer as well as cardiovascular, neurodegenerative, and other diseases. Most of the proposed beneficial effects have been attributed to the polyphenolic compounds in tea, but the nature of these activities and the molecular mechanisms of their actions remain unclear. Tea polyphenols are known to be strong antioxidants. Prevention of oxidative stress, modulation of carcinogen metabolism, and prevention of DNA damage have been suggested as possible cancer preventive mechanisms for tea and tea polyphenols. In this chapter, we discuss these topics in the light of biotransformation and bioavailability of tea polyphenols. We also review the preventive effects of tea polyphenols in animal models of carcinogenesis and some of the possible post-initiation mechanisms of action. Finally, we discuss the effects of tea consumption on cancer risk in humans. It is our aim to raise some of the unanswered questions regarding cancer prevention by tea and to stimulate further research in this area.     

The effects of green tea polyphenols on drug metabolism

INTRODUCTION: Tea, made from the dried leaves of the plant Camellia sinensis Theaceae, is a very popular beverage consumed worldwide. Recently, green tea extract-based dietary supplements have also been widely consumed for the acclaimed beneficial health effects, such as weight reduction. Although tea consumption is considered to be innocuous, the potential interactions between tea polyphenols and drugs have been demonstrated in studies in vitro and in vivo. AREAS COVERED: This article reviews the current literature on the chemistry and biotransformation of tea constituents, mainly catechins from green tea. The article also provides a review of their effects on the absorption, efflux, metabolism and elimination of different drugs. EXPERT OPINION: Tea catechins may bind to certain drugs to affect their absorption and bioactivities. Tea catechins may inhibit the activities of drug-metabolizing enzymes and drug transporters or affect the expression of these proteins, either upregulation or downregulation. Although these effects have been demonstrated in studies in vitro and in animal models, such effects have only been observed in limited cases in humans at common doses of human tea consumption. The ingestion of tea catechins from dietary supplements, which could be in large bullet doses, may produce more profound effects on drug metabolism, and such effects with drugs need to be further investigated.     

茶多酚对早期龋进展的影响

目的　探讨茶多酚对牙齿早期龋进展的影响。方法　采用体外脱矿的方法建立牛牙牙釉质和牙本质早期龋模型。将釉质龋及牙本质龋标本随机分为4组（n=6）：空白对照组（DW组）、氟化钠组（NaF组）、茶多酚组（TP组）、茶多酚与氟化钠联合应用组（TP+NaF组）,pH循环实验模拟早期龋的进程。检测pH循环后的脱矿液中钙、磷离子浓度,通过显微硬度计检测牙体硬组织表面显微硬度值,X线能谱分析样本表面钙磷比,并测定再矿化液中羟脯氨酸水平。结果　在牙釉质及牙本质的脱矿液中,TP组钙、磷离子相对释放量与DW组差异无统计学意义,明显高于NaF组和TP+NaF组（P＜0.05）。TP组牙釉质表面显微硬度值与DW组差异无统计学意义,牙本质表面显微硬度值高于DW组;DW组、TP组牙釉质及牙本质表面显微硬度值均低于NaF组和TP+NaF组（P＜0.05）。TP组牙釉质及牙本质表面钙磷比均高于DW组（P＜0.05）,牙釉质表面钙磷比与NaF组和TP+NaF组差异无统计学意义,牙本质表面钙磷比低于NaF组和TP+NaF组（P＜0.05）。NaF组和TP+NaF组牙本质再矿化液中羟脯氨酸水平均低于DW组和TP组（P＜0.05）,TP组与DW组以及TP+NaF组与NaF组间差异均无统计学意义。结论　在早期龋的进展过程中,茶多酚无明显抑制牙釉质及牙本质脱矿的作用,但可通过促进钙磷离子的再沉积促进再矿化的发生。     

两种茶多酚化学改性制备的脂溶性茶多酚抗氧化性能研究

目的对茶多酚不同改性方法制备的脂溶性茶多酚（LTP）的抗氧化性能研究并与其他抗氧化剂比较。方法以紫外分析、薄层层析、化学发光、氧化还原滴定等方法分别考察了两种改性方法制备的LTP及其他抗氧化剂的紫外表征、脂溶性、抗自由基、抗超氧负离子及抗油脂脂质过氧化性能。结果两种改性方法制备的LTP具有不同的紫外表征及抗氧化特性,且碳酰化LTP性能更优于氧酰化LTP。这两种LTP都具有与TBHQ相近的抗氧化能力,都优于除TBHQ外的其他抗氧化剂。结论两种改性方法制备的LTP都可作为脂相系统抗氧化剂。     

茶多酚口腔凝胶的制备及质量控制

目的 研制茶多酚口腔用凝胶,对其进行质量控制.方法 以卡波姆940、甘油为基质,制备茶多酚口腔凝胶,并用分光光度法测定其含量,建立质量标准.同时25 ℃留样观察其稳定性.结果 该凝胶剂性质稳定,含量准确.平均加样回收率为101.2%,RSD=0.97%(n=6).结论 该凝胶处方简单,质量可靠,可供临床使用.     

The challenge of developing green tea polyphenols as therapeutic agents

The health benefits of green tea and its main constituent (-)-epigallocatechin gallate [(-)-EGCG] have been widely supported by results from epidemiological, cell culture, animal and clinical studies. On the other hand, there are a number of issues, such as stability, bioavailability and metabolic transformations under physiological conditions, facing the development of green tea polyphenols into therapeutic agents. We previously reported that the synthetic peracetate of (-)-EGCG has improved stability and better bioavailability than (-)-EGCG itself and can act as pro-drug under both in vitro and in vivo conditions. Analogs of catechins have been synthesized and their structure activity relationship provides an understanding to the mechanism of proteasome inhibition. Metabolic methylation of catechins leading to methylated (-)-EGCG may alter the biological activities of these compounds.     

绿茶中茶多酚的分析方法研究进展

茶多酚是茶叶中一类具有强抗氧化作用的多酚类化合物的总称,具有抗氧化、抗炎、抗肿瘤、抗辐射、抗病毒等多种药理作用,其含量对茶叶的品质有非常重要的影响。但是,茶多酚结构复杂,不易准确测定,制约着对茶多酚的深入研究。综述近年来国内外对茶多酚的分析测定方法,重点阐述滴定法、红外光谱法、分光光度法、高效液相色谱法、气相色谱法等研究方法的应用和进展,为进一步研究提供参考。     

茶多酚脂质体的制备研究

目的优化制备茶多酚-维生素E脂质体的配方。方法采用逆相蒸发法制备。以包封率作为考察指标,经正交优化选择,确定制备脂质体的最佳配方。结果最佳配方为:卵磷脂/胆固醇(摩尔比)为2∶1;茶多酚浓度为10 mg/mL;维生素E/卵磷脂(质量比)为1∶8;有机相/水相(体积比)为3∶1,此时包封率可达(50.81±1.92)%。显微镜下观察到了脂质体结构。平均粒径为327 nm。结论此法操作简便可靠,所需设备简单,重现性较好,可适用于包埋水溶性药物。     

茶多酚对家犬的长期毒性作用

目的观察用药90d及停药2kw后 ,茶多酚(TP)对家犬的长期毒性反应。方法家犬以650、65、6.5mg·kg-1·d-1 3个剂量分别连续饲服TP90d及停药2kw后 ,观察动物的一般情况、检查动物的心电图、血尿常规、血脂、血糖、凝血时间、肝肾功能等生化指标。结果用药组体重增加情况与对照组无显著性差异 (P>0.05) ;用药前、服药中、停药后家犬的活动情况、毛发、粪便、心电图、血尿常规、各项生化指标均未见异常 ,用药前后比较无显著性差异 (P>0.05) ;大、中、小剂量组血清胆固醇水平进行性降低。结论TP按650mg·kg-1·d-1 饲服90d对家犬未见明显毒性作用     

Prevention of carcinogenesis by tea polyphenols.

Tea, an extract of the leaves of the plant Camellia sinensis, has been considered a medicine and healthful beverage for ages. The beneficial effects of tea are thought to be due to its polyphenolic components. Herein, we discuss the present status of tea as a possible cancer chemopreventive agent, covering basic chemistry and biochemical activity of tea, pharmacokinetics of major tea components, studies in animal and cell lines, epidemiological investigations, and future challenges. Tea is one of the few chemopreventive agents known to have protective effects at different stages of the carcinogenic process. Tea constituents may inhibit this process by modulating signal transduction pathways leading to the inhibition of cell proliferation and transformation and enhancement of apoptosis. These activities may or may not be due to the antioxidative activity of tea polyphenols. The bioavailability and tissue levels of tea polyphenols is a key topic to be studied in order to understand the mechanisms of action of tea and its possible protection against cancer in humans.     

复方茶多酚膜剂的制备和质量控制

目的:制备复方茶多酚膜剂。方法:以茶多酚和木糖醇为主药制备复方茶多酚膜剂,采用高效液相色谱法测定主药的含量,对制备的膜剂进行质量控制。结果:该膜剂性质稳定,符合制剂要求,用HPLC法测定含量,茶多酚和木糖醇分别在0.024～0.144 mg.mL-1和0.012～0.072 mg.mL-1范围内线性关系良好,平均回收率分别为98.30%和99.75%,RSD分别为1.01%和0.76%。结论:该膜剂制备工艺简单,质量可靠,可供临床使用。     

Black tea polyphenols inhibit tumor proteasome activity

Tea is a widely consumed beverage and its constituent polyphenols have been associated with potential health benefits. Although black tea polyphenols have been reported to possess potent anticancer activities, the effect of its polyphenols, theaflavins on the tumor's cellular proteasome function, an important biological target in cancer prevention, has not been carefully studied. Here black tea extract (T5550) enriched in theaflavins inhibited the chymotrypsin-like (CT) activity of the proteasome and proliferation of human multiple myeloma cells in a dose-dependent manner. Also an isolated theaflavin (TF-1) can bind to, and inhibit the purified 20S proteasome, accompanied by suppression of tumor cell proliferation, suggesting that the tumor proteasome is an important target whose inhibition is at least partially responsible for the anticancer effects of black tea.     

应用基因芯片技术研究茶多酚对金葡菌基因表达的影响

目的 了解茶多酚对金葡菌的抗菌机制.方法 应用金葡菌全基因组表达谱芯片研究茶多酚对金葡菌的作用机制,观察茶多酚处理前后金葡菌基因组表达谱的变化,并以RT-PCR对部分差异表达基因进行验证.结果 共筛选出功能已明确的差异表达基因204个.与对照组比较,有160个基因表达上调,有44个表达下调.经RT-PCR验证,结果与全基因组表达谱芯片结果相符.结论 差异表达基因主要涉及金葡菌细胞生物合成、代谢和毒力因子合成等生物过程.     

Effect of tea polyphenols on alcoholic liver disease

AIM: To investigate the scavenging effects of tea polyphenols on aldehyde in vitro and searching for the preliminary mechanism of tea polyphenols (TP) on alcoholic liver disease.METHODS: The effect of aldehyde absorption is tested at gaseous and liquid phases. High performance liquid chromatography (HPLC, HPll00Series) and UV-visible Detector(Wavelength: 235 nm) are used to analyze the components of the outcome of solution reaction. RESULTS: In vitro study showed     

RP-HPLC法测定市售绿茶饮料中茶多酚和生物碱的含量

目的建立HPLC同时测定市售绿茶饮料中茶多酚和生物碱含量的方法并考察放置时间对其产生的影响。方法样品经SPE小柱萃取后进样分析。色谱柱为Phenomemex Synergi 4u FusionRP ODS(250 mm×4.6 mm,5μm),流动相为乙腈-水,梯度洗脱,流速为1.0 mL·min~(-1),检测波长为210 nm,柱温为25℃。结果在上述色谱条件下,6个待测成分在测定范围内线性关系良好(r≧0.999 1),平均加样回收率为97.3%~99.1%,RSD≦2.9%(n=9);随放置时间的延长,饮料中茶多酚的含量降低,生物碱含量无明显变化。结论随放置时间的延长,饮料中茶多酚的损失率增加,含量减少,其抗氧化活性有所降低。