茶多酚影响同型半胱氨酸对内皮细胞的作用

目的:探讨茶多酚能否减弱同型半胱氨酸(HCY)对内皮细胞(EC)的损伤作用。方法:体外培养牛主动脉内皮细胞,随机分为5组,正常对照组,用含20%小牛血清DMEM培养液培养;0.25 mmol/L HCY组,培养液中加入HCY使其终浓度为0.25 mmol/L;1 mg/L茶多酚 +0.25 mmol/L HCY组;2 mg/L茶多酚 +0.25 mmol/L HCY组;4 mg/L茶多酚 +0.25 mmol/L HCY组。培养72h后,用流式细胞仪检测细胞周期,观察细胞生长情况,同时检测培养液中的一氧化氮(NO)、 一氧化氮合酶(NOS)、内皮素(ET)、谷胱甘肽过氧化酶(GSH-Px)、丙二醛(MDA)浓度或活性。结果:浓度为1、2、4、8 mg/L茶多酚组与HCY组相比,(1)细胞形态规则性增强,立体感增加,细胞内颗粒减少;(2)细胞周期检测提示茶多酚组细胞S期比例增多;(3)功能实验提示,茶多酚组EC释放的血管舒张因子NO浓度较HCY组高;而血管收缩因子ET低;(4)MDA含量和GS H-Px活性无明显改变。结论:茶多酚有抑制HCY对EC的损伤作用。     

茶多酚对大鼠主动脉微血管样结构影响的研究

目的:开展茶多酚对大鼠主动脉微血管样结构影响,为其抗肿瘤血管生成分子机制研究提供实验资料.方法:大鼠主动脉无血清培养,加入茶多酚大、中、小剂量及bFGF(碱性成纤维母细胞生长因子),观察对微血管结构影响.结果:茶多酚大、中、小剂量均可抑制新生血管形成.结论:茶多酚能抗血管生成.     

Antioxidant properties of black tea in alcohol intoxication

Food ingredients such as alcohol may modify cellular redox state. Ethanol metabolism is accompanied by generation of free radicals that can damage cell components especially when antioxidant mechanisms are no able to neutralize them. However black tea is a source of polyphenol antioxidants that may enhance cellular antioxidant abilities. The aim of this study was to investigate the effect of black tea on antioxidant abilities of the liver, blood serum and brain of 12-months old rats sub-chronically (for 28 days) intoxicated with ethanol. Administration of black tea alone caused increase in the activity and concentration of antioxidant parameters more extensively in the liver and serum than in the brain. Alcohol caused decrease in the liver glutathione peroxidase and reductase and catalase activity but increase in activity of superoxide dismutase. Moreover, decrease in the level of non-enzymatic antioxidants, such as reduced glutathione, vitamin C, A and E and β-carotene was observed. The activity of serum glutathione peroxidase and reductase decreased while superoxide dismutase activity was not changed. The level of non-enzymatic antioxidants in serum was also decreased. However brain activity/level of all examined antioxidants enzymatic as well as non-enzymatic was decreased after ethanol intoxication. Black tea considerably prevented antioxidant parameters against changes caused by ethanol. These results indicate beneficial antioxidant effect of black tea regarding all examined tissues, but especially the liver.     

清咽袋泡剂的制备及质量控制

目的 :制备清咽袋泡剂并建立其质量控制方法。方法 :用薄层色谱法对金银花、甘草进行鉴别 ,并测定主药材金银花中绿原酸的含量。结果 :绿原酸线性范围为1 2μg～4 8μg(r=0 9993) ,平均回收率为99 50 % ,RSD=2 39 %。结论 :本方法操作简便、结果可靠 ,适用于清咽袋泡剂的质量控制。     

Potentiating effects of honey on antioxidant properties of lemon-flavoured black tea

Health benefits including antioxidant potential of black tea (Camellia sinensis), lemon (Citrus limon) and honey bees (Apis mellifera) have been extensively reported. Nevertheless, nothing is reported about the effects of their concomitant use. Herein, those effects were evaluated in infusions of lemon-flavoured black tea with three different kinds of honey (light amber, amber and dark amber) from Lavandula stoechas, Erica sp. pl. and other indigenous floral species from north-east Portugal, a region with high amounts of this food product. Data obtained showed that the use of honey (dark amber>amber>light amber) potentiates the antioxidant activity of lemon-flavoured black tea, increasing the reducing power and lipid peroxidation inhibition properties, as also the antioxidant contents such as phenolics, flavonoids and organic acids including ascorbic acid.     

Bioactive nutrients - Time for tolerable upper intake levels to address safety

There is increasing interest by consumers, researchers, and regulators into the roles that certain bioactive compounds, derived from plants and other natural sources, can play in health maintenance and promotion, and even prolonging a productive quality of life. Research has rapidly emerged suggesting that a wide range of compounds and mixtures in and from plants (such as fruits and vegetables, tea and cocoa) and animals (such as fish and probiotics) may exert substantial health benefits. There is interest in exploring the possibility of establishing recommended intakes or dietary guidance for certain bioactive substances to help educate consumers. A key aspect of establishing dietary guidance is the assessment of safety/toxicity of these substances. Toxicologists need to be involved in both the development of the safety framework and in the evaluation of the science to establish maximum intake/upper limits.     

Targeting events in melanoma carcinogenesis for the prevention of melanoma

Melanoma is one of the few tumors that have increased in incidence over the last few decades. Strategies devoted solely to protecting against ultraviolet radiation have, at best, had a modest impact on the development of melanoma. Chemoprevention is an under-explored approach that could significantly decrease the morbidity and mortality from this deadly cancer. However, the scientific and logistical challenges of performing clinical studies in chemoprevention require innovative approaches to prove the effectiveness of putative preventive agents. There are several pharmacological and nutriceutical agents that are mechanistically linked to events in melanoma carcinogenesis that are candidates for advanced human studies. We will review the data for several promising agents, including statins, curcumin, resveratrol, silymarin and green tea, and discuss some importance issues and concepts that should be considered in any melanoma chemoprevention strategy.     

四城市成年居民夏季不同时间段饮水行为的分析

目的分析北京、成都、上海、广州居民的夏季一天不同时间段的饮水行为。方法采用多阶段随机抽样方法从四城市抽取18～60岁成年人1483名,使用连续7天的饮水记录表,由调查对象利用定量用具详细记录每天8个时间段内每次饮水的种类及饮水量。结果调查对象早、中、晚餐后的饮水率(97%～99%)及饮水量(290～471ml)较其他5个时间段高(饮水率:49%～88%;饮水量:54～166ml,F=972.55,P<0.01);白水、茶水、饮料的饮水人数与饮水量的分布情况同总水趋势一致。调查对象上午(719ml/d)的饮水量最高,其次是下午(539ml/d),晚上(417ml/d)的最低(F=265.49,P<0.01)。白水和饮料的饮用量均是上午最高;茶水上午和下午的接近,同时高于晚上(t=-52.13,P<0.01)。非就餐时(1436ml/d)的饮水量高于就餐时(240ml/d)的饮水量。就餐时饮料的饮用量最高;非就餐时白水的饮用量最高(P<0.05)。结论我国四城市居民在上午、下午、晚上均以饮用白水为主;就餐时以饮用饮料为主,非就餐时以白水为主。     

Acute drug toxicity related to drinking herbal tea in a kidney transplant recipient

Calcineurin and mTOR inhibitors are commonly used immunosuppressive agents with narrow therapeutic range. As the drugs are mainly metabolized by the P450 cytochrome system, the interaction between food and herbs are also commonly seen and affect the drug levels. We present a case of a kidney transplant recipient with toxic therapeutic levels of cyclosporine A and sirolimus due to interaction between the immunosuppressive agents and Chinese herbal tea. Ingredients within the herbal tea were reported to have inhibitory effect on cytochrome CYP3A4 in-vitro studies. Transplant recipients should be alert that there may be potent interaction between the immunosuppressive drugs and herbs resulting in adverse effect on allograft function.