绿茶中茶多酚的复合酶-微波法提取工艺研究

目的 采用复合酶-微波法从绿茶中提取茶多酚.方法 通过单因素试验法和正交试验法确定复合酶-微波法提取茶多酚的最佳工艺,同时比较复合酶-微波法、复合酶法、索氏法和微波法对提取效果的影响.结果 优化得到提取茶多酚的最佳工艺为:在50℃条件下用纤维素酶和果胶酶前处理40 min,微波辐射8 min,微波功率500 W,料液比1∶30,25%乙醇溶液作为萃取剂.结论 验证试验表明,最佳工艺可行;从提取时间和提取效率来看,复合酶-微波法提取茶多酚比复合酶法、索氏法和微波法耗时少、提取效率高.     

重叠率在绿茶和茶多酚指纹谱研究中的应用

目的:探讨重叠率在植物以及植物提取物指纹谱研究中的地位和应用。方法:以绿茶和茶多酚的HPLC指纹谱为例来进行说明。结果:重叠率可为绿茶和茶多酚的特征指纹谱选择有代表性的样品,并可依之推断茶多酚样品的提取原料、工艺以及生产厂家等。结论:重叠率可作为建立特征指纹谱样品筛选的有力依据,并可为产品与原料、工艺间相互关系的探究提供参考。     

Modification of gamma-radiation response in mice by green tea polyphenols

In this study we evaluated the effect of water extracts of green tea (GT) and mixtures of green tea polyphenols (GTPs), epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC) and epicatechin (EC) on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of mice irradiated with gamma-ray. The radioprotective effect of green tea was compared with the effect of diethyldithiocarbamate (DDC). Jejunal crypts were protected by pretreatment of GT and ECG. Administration of GT, GTPs and EC prior to irradiation resulted in an increase in the formation of endogenous spleen colonies. The frequency of apoptosis in crypt cells was also reduced by pretreatment of GT, GTPs, EGCG, ECG and EGC. In the experiment on the effect of catechins, the effects were partly contradicted in irradiated mice. The rank order of activity was ECG > EGC > EGCG > EC on intestinal crypt survival assay, EC > EGC > ECG > EGCG on the spleen colony formation assay, EGCG > EGC > EC > ECG on inhibiting the death of cells caused by apoptosis. The results indicate that GT and GTPs may have a major radioprotective effect. Each one of the catechins was a much less effective radioprotector, suggesting that total extract or a mixture of GTPs may be more effective than individual catechins.     

Synergistic effect of green tea polyphenols on their protection against FK506-induced cytotoxicity in renal cells

FK506 (tacrolimus) is a widely used immunosuppressant first employed in the management of rejection in organ transplantation, but now used for autoimmune disease. However, the nephrotoxicity induced by FK506 remains a serious clinical problem. We previously demonstrated that FK506 caused a significant increase in apoptosis of LLC-PK1 cells, a porcine proximal tubule cell line, but the addition of green tea extract and its polyphenolic components suppressed the cell death. Here, we examined the synergistic effect of tea polyphenols on the protection of FK506-induced cell death. The combined treatment with 5 microM (-)-epigallocatechin-gallate (EGCG) and 5 microM of (+)-catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC) or (-)-epicatechin-gallate (ECG) reduced FK506-induced cytotoxicity in LLC-PK1. Similarly, the combined treatment with 5 microM EGC and 5 microM of C, EC, EGCG or ECG also reduced the cytotoxicity. These results showed that the co-treatments with EGCG and EGC, EGCG or ECG, and EGC and ECG have stronger synergistic effects on the protection of FK506-induced cell death. Furthermore, the combined treatment of EGCG (5 microM) and EGC (5 microM) showed a significant time-dependent suppression of the increased intracellular ROS levels 15 min after the addition of FK506, as well as on caspase activation. The results of these synergistic effects of the constituents of green tea extract suggest that its protective effects may reside in more than just one of its constituent.     

Anti-diabetic activity of medicinal plants and its relationship with their antioxidant property

Methanolic extract (75%) of Terminalia chebula, Terminalia belerica, Emblica officinalis and their combination named 'Triphala' (equal proportion of above three plant extracts) are being used extensively in Indian system of medicine. They were found to inhibit lipid peroxide formation and to scavenge hydroxyl and superoxide radicals in vitro. The concentration of plant extracts that inhibited 50% of lipid peroxidation induced with Fe(2+)/ascorbate were food to be 85.5, 27, 74 and 69 micro g/ml, respectively. The concentration needed for the inhibition of hydoxyl radical scavenging were 165, 71, 155.5 and 151 micro g/ml, and that for superoxide scavenging activity were found to be 20.5, 40.5, 6.5 and 12.5 micro g/ml, respectively. Oral administration of the extracts (100 mg/kg body weight) reduced the blood sugar level in normal and in alloxan (120 mg/kg) diabetic rats significantly within 4 h. Continued, daily administration of the drug produced a sustained effect.     

Reversal of LPS-induced immobility in mice by green tea polyphenols: possible COX-2 mechanism

An endotoxin (lipopolysaccharide, LPS) is known to activate the hypothalamo-pituitary adrenocortical axis, as well as norepinephrine and indolamine metabolism. Systemically administered LPS produces depression in the forced swimming-induced despair behaviour model in mice. The present study was designed to investigate the effect of green tea extract (GTE) on LPS-induced despair behaviour and to explore the mechanism involved in modulation of LPS-induced immobility by GTE. GTE (10-100 mg/kg) pretreatment reversed LPS-induced immobility in a dose-dependent manner. Rofecoxib (2 mg/kg) and nimesulide (2 mg/kg), COX-2 inhibitors, also reversed the LPS-induced immobility, which was significantly potentiated by concomitant administration of GTE. On the other hand, GTE did not show any potentiating effect on immobility with naproxen (10 mg/kg), which is a nonselective COX blocker. Interestingly the antioxidant, carvedilol (2 mg/kg) did not produce any effect on immobility either in normal or in LPS treated mice. The results of the study implicate the role of COX-2 inhibition by GTE in the reversal of LPS-induced immobility.     

Protective role of tea polyphenols in combination against radiation-induced haematopoietic and biochemical alterations in mice

The purpose of this study was to investigate the radioprotective effects of tea polyphenols (TPs) in various combinations against radiation‐induced damage in mice. Mice were divided into different groups: non‐irradiated control, irradiated control, amifostine (43.6 mg/kg, i.v. 30 min before irradiation; positive control) and various combinations of tea polyphenols in different doses. The radioprotective effect on the haematopoietic system, serum cytokines and endogenous antioxidant enzymes were studied. TP50, containing approximately 50% of (‐)‐epigallochatechin‐3‐gallate in addition to other catechins, showed the greatest radioprotective effect against radiation‐induced changes in haematological parameters (red blood cell count, white blood cell count and haemoglobin), and maintained the spleen and thymus indices unchanged (spleen or thymus weight/body weight × 1000). Tea polyphenols also significantly decreased radiation‐induced lipid peroxidation (malondialdehyde levels), elevated endogenous antioxidant enzymes (superoxide dismutase) and reduced the serum cytokines which were elevated in radiation‐induced toxicity. This evidence shows the potential of tea polyphenols, particularly in the combination found in TP50, as radioprotectors in mice, especially regarding recovery of the haematopoietic system, antioxidant potential activity and reduction of inflammatory cytokines. Copyright © 2011 John Wiley & Sons, Ltd.     

茶多酚中儿茶素类及咖啡因的含量测定

目的 :建立茶多酚中 6种儿茶素类成分 (EGC、DC、EGCG、EC、GCG、ECG)和咖啡因的HPLC一次进样检测方法 ,并对这 7种组分在 13个厂家 2 9个批号茶多酚样品中的含量进行测定。方法 :采用C18色谱柱 ,含量 0 .1%甲酸的甲醇和水梯度洗脱的反相HPLC法。结果 :混标分析时 ,7组分的色谱峰分离度Rs均 >2 ,样品分析时 ,除EGCG的色谱峰分离度>1外 ,其它各组分的均 >1.5 ;各组分的加样回收率在 98.5 6 %～ 10 0 .14 %之间。结论 :该检测方法准确、稳定、重复性好 ,可正确定量茶多酚中的 7种组分 ;不同厂家甚或同一厂家生产的茶多酚组成存在一定差异     

茶叶中多糖的分离及降血糖活性的研究

目的对茶叶中的水溶性中性多糖(NTPS)和酸性多糖(ATPS)进行分离,以探讨不同结构的茶多糖的降血糖活性。方法采用弱碱性的大孔阴离子交换树脂D 315分离出两种带不同电荷的茶多糖NTPS和ATPS,采用气相色谱和离子色谱分析其单糖组成,并采用DEAE-Sepharose FF对其作进一步分离,通过HPGPC法分析其分离产物主要级分的相对分子质量。通过四氧嘧啶ip造成高血糖模型,连续ig茶多糖12 d,对比研究两种茶多糖的降血糖活性。结果NTPS和ATPS都是杂聚糖。NTPS以中性糖为主,含质量分数为6.82%半乳糖醛酸,中性糖部分主要由半乳糖组成;ATPS以酸性糖为主,含质量分数为33.02%半乳糖醛酸,中性糖部分主要由鼠李糖、阿拉伯糖和半乳糖组成。两种茶多糖相对分子质量均小于3×104。NTPS、ATPS按照200和400 m g/kg.d的剂量连续给四氧嘧啶糖尿病小鼠ig 12 d,发现都能抑制四氧嘧啶糖尿病小鼠血糖的升高。结论首次采用D 315阴离子交换树脂从茶叶中分离出了不同结构的多糖NTPS和ATPS,两种多糖都有很好的降血糖效果。     

The effects of rooibos (Aspalathus linearis), green tea (Camellia sinensis) and commercial rooibos and green tea supplements on epididymal sperm in oxidative stress-induced rats

Reactive oxygen species (ROS) are involved in many physiological functions of mammalian sperm. Numerous endogenous antioxidants belonging to both enzymatic and non‐enzymatic groups can remove excess ROS and prevent oxidative stress (OS). This study compares the modulation of OS by rooibos, Chinese green tea and commercial rooibos and green tea supplements in rat sperm. Male Wistar rats (n = 60) were supplemented with fermented rooibos, ‘green’ rooibos, Chinese green tea, rooibos supplement, green tea supplement or water for 10 weeks while OS was induced during the last 2 weeks. Sperm count and motility were significantly higher for rats consuming fermented rooibos and ‘green’ rooibos when compared with the other groups. Catalase activity was significantly higher in the sperm of rats consuming fermented rooibos, ‘green’ rooibos and both the rooibos and green tea supplements. Superoxide dismutase concentration in the sperm of rats supplemented with fermented rooibos, ‘green’ rooibos and green tea was higher. Sperm glutathione levels of rats consuming the fermented and ‘green’ rooibos were also significantly higher. Rooibos fermented and ‘green’ rooibos showed a tendency to lower the levels of ROS and lipid peroxidation when compared with the control group. In conclusion, both rooibos extracts could offer a measure of protection against induced oxidative damage by increasing the antioxidant defence mechanisms and thereby improving the sperm quality and function. Copyright © 2012 John Wiley & Sons, Ltd.     

茶多酚的药动学研究进展

大量的国内外研究表明,自绿茶中得到的儿茶素类成分,即茶多酚具有极强的抗氧化、抗自由基活性和多种有益的药理作用,对多种疾病具有预防和治疗价值,从而受到医药界广泛的重视.近20年来.其药动学研究亦取得很大进展.综合国内外文献并结合多年的研究,综述了茶多酚吸收、分布、代谢和排泄等体内过程,非临床和临床药动学特点以及用于药动学研究的儿茶素类的生物分析方法,为其进一步研究提供参考.     

Physiological activity of irradiated green tea polyphenol on the human skin

Physiological activity of irradiated green tea polyphenol on the human skin was investigated for further industrial application. The green tea polyphenol was separated and irradiated at 40 kGy by y-ray. For an anti-wrinkle effect, the collagenase inhibition effect was higher in the irradiated sample (65.3%) than that of the non-irradiated control (56.8%) at 200 ppm of the concentration (p < 0.05). Collagen biosynthesis rates using a human fibroblast were 19.4% and 16.3% in the irradiated and the non-irradiated polyphenols, respectively. The tyrosinase inhibition effect, which is related to the skin-whitening effect, showed a 45.2% and 42.9% in the irradiated and the non-irradiated polyphenols, respectively, at a 100 ppm level. A higher than 90% growth inhibition on skin cancer cells (SK-MEL-2 and G361) was demonstrated in both the irradiated and the non-irradiated polyphenols. Thus, the irradiation of green tea polyphenol did not change and even increased its anti-wrinkle, skin-whitening and anticancer effects on the human skin. The results indicated that irradiated green tea polyphenol can be used as a natural ingredient with excellent physiological functions for the human skin through cosmetic or food composition.     

普洱茶、红茶、绿茶中真菌毒素的检测

检测茶叶中黄曲霉毒素(B_1,B_2,G_1和G_2)、伏马霉素(FB_1,FB_2,FB_3)和脱氧雪腐镰刀菌烯醇,明确茶叶中的真菌毒素含量范围并为茶叶监管提供依据。采用有机溶剂(0.1%甲酸乙腈溶液)以及80℃热水2种方法提取茶叶中的真菌毒素,利用超高效液相色谱串联质谱(UPLC-MS/MS)法进行分析测定。黄曲霉毒素B1,G1的线性范围为39.1~5 000 ng·L~(-1),黄曲霉毒素B2,G2的线性范围为117~15 000 ng·L~(-1);伏马霉素(FB1,FB2,FB3)的线性范围为2.44~313 ng·L~(-1);脱氧雪腐镰刀菌烯醇的线性范围为3 125~5 000 ng·L~(-1)。所得8种真菌毒素的回归方程均有良好的线性关系(r≥0.999 0),回收率为85.7%~99.6%,相对标准偏差10%。对20种国际市售茶叶中的8种真菌毒素进行测定,结果显示采用有机溶剂提取法,包括普洱茶、红茶、绿茶在内的多种茶叶产品都不同程度含有微量的真菌毒素,其中黄曲霉毒素B2在6种茶叶产品中被检测到,黄曲霉毒素G_1在3种茶叶中被检测到,伏马霉素FB_1在2种茶叶中被检测到,伏马霉素FB2在一种茶叶中被检测到。而采用热水提取方法,只有一种茶叶产品的茶汤中检测到微量的伏马霉素B_1,B_2,其他各种茶叶的茶汤中均未检出毒素。以上2种方法检出的真菌毒素含量在0.15~7.31μg·kg~(-1),均未超过国际食品安全规定的真菌毒素限量。80℃热水提取模拟实际的饮茶方法,更能准确地检测茶叶中进入茶汤的真菌毒素,适用于茶叶(采用热水冲泡的)饮用产品,而有机溶剂萃取法适用于食用产品中霉菌毒素绝对含量的检测。     

茶多酚对阿霉素心脏毒性的保护作用及其机制的研究

 目的：探讨茶多酚(tea polyphenols,TP)减轻阿霉素心脏毒性的作用及其机制。方法：以病理记分法记录心肌损害程度;用TBA法测定大鼠心肌组织的脂质过氧化水平;用邻苯三酚自氧化法测定心肌组织、红细胞的SOD活力;用DTNB法测定心肌GSH-Px活力。结果：阿霉素两周累积用量16mg·kg^-1（第2天,第4天1mg·kg^-1;第6天,第8天2mg·kg^-1;第10天,第12天3mg·kg^-1;第14天4mg·kg^-1;ip可致大鼠心肌损害,心肌MDA水平升高,GSH-Px活性下降,心肌和红细胞SOD活性降低,TP28,56和84mg·kg^-1具有减轻阿霉素所致的大鼠心肌毒性作用。结论：茶多酚减轻阿霉素心肌毒性机制可能与其清除自由基作用、保护心肌SOD及GSH-Px活性有关,从而有效地对抗阿霉素引起的大鼠心肌脂质过氧化有关。     

Anti-diabetic activity of Bauhinia forficata decoction in streptozotocin-diabetic rats

The effects of using Bauhinia forficata leaf decoction (150 g leaf/l water; 35.2+/-7.8 ml/100 g body weight mean daily dose) as a drinking-water substitute for about 1 month on streptozotocin-diabetes (STZ-diabetes) in male Wistar rats were investigated. The physico-metabolic parameters measured were: body weight, food and liquid intake, urinary volume, hepatic glycogen, serum triglycerides and cholesterol, plasma glucose, urinary glucose and urea, and the weight of epididymal and retroperitoneal adipose tissue and soleus and extensor digitorum longus muscles. The STZ-diabetic rats treated with decoction showed a significant reduction in serum and urinary glucose and urinary urea as compared to the STZ-diabetic control, no difference being seen between decoction-treated and -untreated non-diabetic rats. The other physico-metabolic factors showed no changes in treated STZ-diabetic rats. The improvement in carbohydrate metabolism seen in the rats treated with Bauhinia forficata decoction does not appear to be linked to the inhibition of glycogenolysis or the stimulation of glycogenesis nor does it appear to act in a way similar to insulin or the sulfonylureas, although it may act by the inhibition of neoglycogenesis in a manner similar to that of the biguanides.     

绿茶多酚对晚期氧化蛋白产物诱导大鼠血管平滑肌细胞增殖的影响

血管平滑肌细胞(vascular smooth muscle cells,VSMCs)增殖和表型改变是动脉粥样硬化的主要病理基础.研究表明,晚期氧化蛋白产物(advanced oxidation protein products,AOPP)参与了糖尿病及动脉粥样硬化等疾病的发生发展过程.本研究观察了绿茶多酚对AOPP诱导的大鼠血管平滑肌细胞增殖的影响.     

Rosa rugosa attenuates diabetic oxidative stress in rats with streptozotocin-induced diabetes

The effects of Rosa rugosa on diabetic oxidative stress were investigated using rats with streptozotocin (STZ)-induced diabetes. The diabetic rats showed less body weight gain and heavier kidney and liver weights than normal rats, while the oral administration of Rosa rugosa at a dose of 100 or 200 mg/kg body weight/day for 20 days attenuated the physiological changes induced by diabetes. In addition, administrating Rosa rugosa to diabetic rats resulted in significant and dose-dependent decreases in the serum glucose and glycosylated protein levels, implying that Rosa rugosa improves the abnormal glucose metabolism that leads to oxidative stress. Diabetic rats had higher serum levels of superoxide and nitrite/nitrate. However, the administration of Rosa rugosa dose-dependently reduced the over-production of radicals associated with diabetes, suggesting Rosa rugosa is a radical scavenger that would play a crucial role in protecting against diabetic oxidative stress. Rosa rugosa significantly and dose-dependently reduced thiobarbituric acid-reactive substance levels in serum, hepatic and renal mitochondria, implying that Rosa rugosa would alleviate the oxidative stress associated with diabetes by inhibiting lipid peroxidation. This study provides evidence that Rosa rugosa has potential as a treatment for diabetes through attenuating oxidative stress induced by the diabetic condition.     

异甘草酸镁对肝纤维化大鼠氧化应激反应的影响研究

目的观察异甘草酸镁(Mg IG)对肝纤维化大鼠氧化应激反应指标的影响,探讨异甘草酸镁治疗肝纤维化的机制。方法将24只雄性Wistar大鼠随机分为正常组、模型组和异甘草酸镁组,每组8只。正常组大鼠给予正常饲养,其余2组大鼠均采用四氯化碳(CCl4)建立大鼠肝纤维化模型。建模成功后,模型组与异甘草酸镁组继续给予CCl4皮下注射,每2周注射1次,共8周;异甘草酸镁组同时给予异甘草酸镁30 mg/kg腹腔注射,每日1次,共8周。末次注射24 h后断头取血检测肝功能指标和肝纤维化指标水平,采用实时定量PCR和免疫印迹技术检测肝组织中胶原(Collagen)Ⅰ、CollagenⅢ、基质金属蛋白酶13(MMP-13)和组织金属蛋白酶抑制因子1(TIMP-1)mRNA和蛋白表达情况,采用化学发光法检测肝组织中丙二醛(MDA)、超氧化物歧化酶(SOD)和还原型谷胱甘肽(GSH)含量。结果异甘草酸镁组肝功能指标及肝纤维化指标均较模型组明显改善(P均<0.05),CollagenⅠ、CollagenⅢ和TIMP-1 mRNA和蛋白表达水平及MDA含量均明显低于模型组(P均<0.05),MMP-13 mRNA和蛋白表达水平及SOD、GSH含量均明显高于模型组(P均<0.05)。结论异甘草酸镁可通过降低氧化应激水平起到抗肝纤维化的作用。     

茶多酚及其主要成分EGCG在辐射损伤小鼠模型中的保护作用

目的:评价不同含量茶多酚(TP)及其主要成分表没食子儿茶素没食子酸酯(EGCG)的抗辐射及抗氧化作用。方法:采用60Coγ射线照射小鼠造成亚急性损伤模型,给予不同剂量TP及EGCG后1,3,7,14,21,28 d检测对小鼠外周血指标和脏器系数的影响,同时检测血清中抗氧化酶(SOD)和脂质过氧化物(MDA)水平。结果:与非照射组相比,辐射组可明显降低脾腺指数,降低外周血白细胞(WBC)、红细胞(RBC)和血小板(PLT);同时降低过氧化物歧化酶并升高脂质过氧化物水平。给予TP(50 mg.kg-1)及EGCG(20 mg.kg-1)治疗后,可明显缓解由于辐射损伤所造成的全血象下降,且表现出较好的体内抗氧化活性。结论:含50%EGCG的茶多酚(TP50)具有明显缓解辐射所造成的造血功能损伤和抗氧化作用。