利用X—荧光光谱仪对14种茶叶及茶汤中不同元素进行定量分析

以14种市售的不同价格、不同产地、不同品级的茶叶为供试材料,利用X—荧光光谱仪对其所含元素成分进行定量分析,同时也对4种不同产地的茶叶浸泡,取不同时间段、不同层的茶水进行元素含量分析,此外还利用显微红外光谱仪对3种不同品种茶叶的有机官能团进行了测定。结果显示,不同品种茶叶中所含元素种类基本一致,但其含量存在一定差异,大多数元素在冲泡的前20 min便溶出到茶汤中、并大多集中在中上层。而3种茶叶中的有机官能团却基本相同。本实验结果为进一步研究茶叶的保健作用和冲泡方式等提供了较为科学的资料和数据。     

乌龙茶叶及茶汤中菊酯类农药和重金属的残留情况

目的探讨乌龙茶叶及茶汤中菊酯类农药和重金属的残留情况.方法于2004年采集3个茶叶生产基地的5种春季乌龙茶样品,进行常规的泡茶,测定干茶叶中的氯氰菊酯和氰戊菊酯农药以及Cu、Zn、As、Cd、Pb等重金属残留情况.干茶叶和茶汤中的菊酯类农药分别采用超声波萃取和振荡萃取,浓缩净化后用气相色谱-电子捕获检测器测定,干茶叶及茶汤分别经消解,用电感耦合等离子体-质谱及原子荧光光度法检测其中的重金属含量.结果干茶叶样品中氯氰菊酯和氰戊菊酯的含量分别为0.200～0.585和0.335～0.780 mg/kg,而其相应的茶汤样品中这2种菊酯类农药均未检出.各个干茶叶样品中均未检出Hg.故未做茶汤样品中Hg的残留分析,茶汤样品中Cu、Zn、As、Cd、Pb的含量分别为0.440～1.663μg/ml,1.590～3.509μg/ml,未检出～0.389μg/ml,未检出～14.220ng/ml,0.759～1.462 μg/ml.结论菊酯类农药残留不会因冲泡茶叶进入茶汤,冲泡过程能溶出茶叶中部分重金属,但其含量基本在国家标准范围内.     

三金茶质量标准研究

目的 建立三金茶（金樱根，菝葜，羊开口，金沙藤，积雪草，绿茶）的质量标准。方法 采用TLC法鉴别制剂中金樱根、积雪草；采用HPLC法对制剂中的积雪草苷进行定量分析，流动相：乙腈-水（23：77）；流速：1．0ml／min；检测波长：205nm。结果 积雪草苷在0．416～1.248μg范围内线性关系良好（r=0.9999）平均回收率为99．8％，RSD为1．1％。结论 本方法操作简便，结果准确、可靠，可有效控制制剂的质量。     

苦丁茶中28种元素含量分析及镉浸出率研究

采用不同消解方法对一种苦丁茶样品进行了预处理,并用电感耦合等离子体原子发射光谱法、电感耦合等离子体质谱法、原子吸收光谱法,原子荧光光谱法和冷蒸气原子吸收光谱法等仪器分析方法测定了其中Al、As、Ba、Ca、Cd、Ce、Co、Cr、Cs、Cu、Fe、Hg、K、La、Mg、Mn、Na、Ni、P、Pb、Rb、Sb、Se、Sr、Th、U、Y和Zn共28种元素的含量,同时还对其它苦丁茶样品及几类苦丁茶浸提液中Cd含量进行了分析。研究结果表明:苦丁茶含有较为丰富的对人体有益的宏、微量元素,但一些产地苦丁茶中Cd含量偏高,在冲泡时能部分被浸出,有可能对人体健康产生不利影响。     

乌玫茶中决明子质量控制方法的研究

【目的】通过对决明子的定性、定量分析来控制乌玫茶的质量。【方法】采用薄层层析法对决明子进行定性分析；应用高效液相色谱法，采用ODS-C18色谱柱，以甲醇：0．1％磷酸（80：20）为流动相，检测波长为365nm，测定决明子中大黄素的含量。【结果】在0．1—1．0mg/L浓度范围内，线性关系良好，回归方程为Y=7757．36X-89．64。r=0．9993，平均回收率为97．95％。【结论】本法简便可靠准确，可以作为质控方法。     

Modulation of MPP<Superscript>+</Superscript> uptake by tea and some of its components in Caco-2 cells

The entry of most xeno/endobiotics into the organism is limited by their intestinal absorption. The interference of certain foods with the therapeutic efficacy of drugs or with chemical toxicity is becoming evident and growing attention is being given to these subjects. The aim of this work was to study the effect of green tea (GT) and black tea (BT), as well as some of their components, on the transport of organic cation molecules. For this purpose, ³H-MPP⁺ (radiolabeled 1-methyl-4-phenylpyridinium) was used as a model organic cation and Caco-2 cells were used as an intestinal epithelial model. Our results showed that both GT and BT significantly increased ³H-MPP⁺ absorption in these cells. Additionally, we studied the effect of epigallocatechin-3-gallate (EGCG), myricetin, caffeine, and theophylline. Whereas EGCG (2 mM) increased, myricetin (50 μM) and caffeine (1 mM) decreased, and theophylline (1 mM) had no effect on the uptake of ³H-MPP⁺ into Caco-2 cells. When GT was supplemented with caffeine or theophylline, we observed a partial loss of its effect. When BT was supplemented with EGCG, its ability to increase ³H-MPP⁺ uptake was much more pronounced than that observed with BT alone. In conclusion, this study showed that GT and BT might interfere with the absorption of the model organic cation MPP⁺ by the intestinal epithelium. Since important compounds are organic cations, the consequences of this interference may have an impact on human health. Although this constitutes only preliminary work and further studies are needed, tea should be included in the growing list of foodstuffs that have the potential to be involved in food–drug interactions.     

茶多酚对顺铂所致肾损伤的作用及其可能机制探讨

目的 研究茶多酚（TP）对顺铂（DDP）所致肾毒性作用的保护作用及其可能机制。方法 小鼠随机分为4组：对照组、DDP组、DDP＋高剂量TP组、DDP＋低剂量TP组,分别给药处理后,观察血清中尿素氮（BUN）、肌酐（Cr)变化情况,测定肾组织均浆中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH－Px)的活性。结果 DDP组的血清中BUN及Cr值上升与对照组比较差异有显著性（P＜0．05）,加入高剂量TP以后血清中BUN及Cr值低于DDP组（P＜0．05）。给予DDP后SOD、GSH－Px活性降低与对照组比较差异有显著性;DDP＋高剂量TP组SOD及GSH－Px值高于DDP组（P＜0．05）。结论 TP在一定程度上缓解DDP所致的肾损伤,其可能机制可能与抗氧化功能有关。     

市售几种茶叶及其汤汁中咖啡因和铅、铜的检测

目的:对收集到的六安市售的十个茶叶品种样品,分别进行咖啡因、铅和铜含量的检测,以了解其质量状况。方法:1 g茶叶 100 ml 100℃纯净水浸泡20 min所得茶汤中咖啡因的含量,采用HPLC法检测;利用FAA法检测铅、铜的含量。结果:被检茶样中铅含量在2.5952~4.6785 mg/kg之间、铜含量在7.3784~25.7182 mg/kg之间;茶汤中铅、铜溶出量均未检出;一泡茶汤中咖啡因含量在66.226~278.880 mg/L之间。结论:十个茶叶样品中铅铜含量均未超标,其一泡茶汤中咖啡因含量符合国标限量。     

茶多酚对硝酸羟胺染毒小鼠血常规和血清生化值的影响

目的　观察绿茶提取物茶多酚对硝酸羟胺染毒小鼠血常规、血清生化值的影响。方法　采用腹腔注射硝酸羟胺建立中毒模型。雄性ICR小鼠随机分为正常组、硝酸羟胺染毒组、茶多酚预防组、茶多酚治疗组 ,常规测量各组外周血细胞和生化指标。结果　经过统计学分析 ,茶多酚可明显促进硝酸羟胺中毒导致的小鼠血常规的WBC、RBC、HGB、PLT计数改变的恢复 ,部分血清生化值AST/ALT、ChE、ALB、LDH、UA、Fe病理性改变的恢复。结论　茶多酚灌胃给药对硝酸羟胺中毒引起的氧化损伤具有一定的保护作用     

Dietary Factors and Risk of Pancreatic Cancer: a Multi-Centre Case-Control Study in China

Background: Pancreatic cancer is the sixth leading cause of cancer death with an increasing trend in China.Dietary intake is believed to play an important role in pancreatic cancer carcinogenesis. The aim of this paper wasto evaluate associations between some dietary factors and risk of pancreatic cancer in a multi-centre case-controlstudy conducted in China. Materials and Methods: Cases (n=323) were ascertained from four provincial cancerhospitals. Controls (n=323) were randomly selected from the family members of patients without pancreaticcancer in the same hospitals, 1:1 matched to cases by gender, age and study center. Data were collected with aquestionnaire by personal interview. Odds ratios (OR) and 95% confidence intervals (95%CI) were estimatedusing conditional logistic regression. Results: Tea intake (OR =0.49; 95%CI: 0.30-0.80) was associated with a halfreduction in risk of pancreatic cancer. Reduced vegetable consumption (P trend: 0.04) was significant related topancreatic cancer. Although no significant association was found for meat and fruit, ORs were all above or belowthe reference group. A protective effect was found for fruit (OR=1.73 for consumption of 1-2 times/week vs morethan 3 times/week; 95%CI: 1.05-2.86). A high intake of meat was associated to a higher risk of pancreatic cancer(OR=0.59 for consumption of 1-2 times /week vs. more than 3 times /week; 95%CI: 0.35-0.97). Conclusions: Thepresent study supports fruit consumption to reduce pancreatic cancer risk and indicates that high consumptionof meat is related to an elevated risk. Direct inverse relations with tea and vegetable intake were also confirmed.