茶叶中微量锰的新催化光度法测定

利用于氨三乙酸存在下，锰（Ⅱ）对高碘酸钾氧化二甲苯蓝ＦＦ的催化效应，建立了一个新的测定微量锰的动力学分光光度法。该法检出限为６×１０￣（－２）ｎｇ·ｍｌ￣（－１），线性范围为０．２～８．０ｎｇ·２．５ｍｌ￣（－１），常见离子基本不干扰测定。用于直接测定健齿茶和茉莉花茶中的锰含量，结果发现，锰含量分别为２２１４μｇ·ｇ￣（－１）及６４８μｇ·ｇ￣（－１）。此法简便易行，灵敏度高。     

绿茶对交链孢霉代谢物致突变性的抑制作用

观察绿茶对交链孢酚单甲醚(AME)和B_(2-a6)提取物诱导人胚肺2BS细胞SCE的影响。结果表明:不同浓度的绿茶,均不能增加SCE的频率,但在绿茶存在的情况下,由AME(10μg/ml)和B_(2-a6)(0.1mg/ml)所诱导的SCE频率比没有绿茶时低(P<0.01),并呈剂量—效应关系。结果提示:绿茶对某些霉菌毒素的致突变性有抑制作用。     

绿茶及绿茶多酚抗羟自由基诱导的大鼠肝脂质过氧化作用

本研究采用Ｆｅ２＋，Ｈ２Ｏ２反应生成ＯＨ·诱导大鼠离体肝脏脂质过氧化反应体系，用ＧＴ和ＧＴＰ作为抗氧化剂观察对肝脂质过氧化的阻抑作用。随ＧＴ和ＧＴＰ浓度的升高对ＭＤＡ的抑制率分别为０．７７４～０．８９２，０．８１４～０．９７６，浓度与ＭＤＡ之间存在剂量效应关系。     

苏乐康等抑制细胞转化能力及其机制的探讨

研究了苏乐康、绿茶提取物对~(60)钴γ射线和雌性激素联合诱发叙利亚金黄地鼠胚胎细胞恶性转化的抑制能力,并用脉冲辐解技术,对其抑制机制进行初步探讨。实验结果表明,苏乐康、绿茶提取物对γ射线和雌性激素联合诱发的金黄地鼠胚胎细胞恶性转化的抑制率分别为70.15％(P<0.05)和81.59％(P<0.05),它们的这种抑制能力与其清除超氧阴离子的能力有关,     

茶多酚口含片中总儿茶素的含量测定

在酸性介质中对香英兰素与儿茶素的显色反应进行了研究，改进了反应条件，以５０６ｎｍ为测定波长，测定ＴＰ口含片中儿茶素的含量，线性范围７．５８μｇ～５３．０５μｇ（ｒ＝０．９９９８），回收率９７．９７％，ＲＳＤ１．８５％，认为改良法简便，灵敏，口含片辅料无干扰，可用于原料的药和制剂的含量分析。     

Effects of Daily Matcha and Caffeine Intake on Mild Acute Psychological Stress-Related Cognitive Function in Middle-Aged and Older Adults: A Randomized Placebo-Controlled Study

Matcha, a type of green tea, has a higher amino acid content than other types of tea. We previously examined the ability of matcha to improve cognitive function in older adults and determined that continuous matcha intake improves attention and executive function. This study aimed to compare the effects of matcha and caffeine and clarify the differences between these effects. The study was registered at the University Hospital Medical Information Network (UMIN000036578). The effect of single and continuous intake was compared, and the usefulness of continuous intake was evaluated under the stress condition. The Uchida–Kraepelin test (UKT) was used to induce mild acute stress, and the Cognitrax was used to evaluate cognitive function. A single dose of caffeine improved attentional function during or after stress loading. The reduced reaction time in the Cognitrax, observed following a single dose of matcha, was likely due to caffeine. The matcha group showed an increase in the amount of work after continuous intake, whereas the caffeine group only showed an increase in the amount of work for the UKT after a single dose. Ingesting matcha with caffeine improves both attention and work performance when suffering from psychological stress compared with caffeine alone.     

Matcha Green Tea Alleviates Non-Alcoholic Fatty Liver Disease in High-Fat Diet-Induced Obese Mice by Regulating Lipid Metabolism and Inflammatory Responses

Lately, matcha green tea has gained popularity as a beverage and food additive. It has proved to be effective in preventing obesity and related metabolic syndromes. However, the underlying mechanisms of its control effects against non-alcoholic fatty liver disease (NAFLD) are complicated and remain elusive. In the present study, we performed an in vivo experiment using male C57BL/6 mice fed with a high-fat diet and simultaneously treated with matcha for six weeks. Serum biochemical parameters, histological changes, lipid accumulation, inflammatory cytokines, and relevant indicators were examined. Dietary supplementation of matcha effectively prevented excessive accumulation of visceral and hepatic lipid, elevated blood glucose, dyslipidemia, abnormal liver function, and steatosis hepatitis. RNA sequencing analyses of differentially expressed genes in liver samples indicated that matcha treatment decreased the activity of lipid droplet-associated proteins and increased the activity of cytochrome P450 enzymes, suggesting improved metabolic capacity and liver function. The current study provided evidence for new dietary strategies based on matcha supplementation to ameliorate lipotoxicity-induced obesity and NALFD.     

Dark Tea: A popular beverage with possible medicinal application

Tea is a famous beverage that is produced from leaves of Camellia sinensis. Amongst the six major tea categories in China, dark tea is the only one that involves microbial fermentation in the manufacturing process, which contributes unique flavors and functions for the tea. In the recent decade, the reports about the biofunctions of dark teas have increased rapidly. Therefore it may be the proper time to consider dark tea as one potential homology of medicine and food. In this viewpoint, our current understanding of the chemical constituents, biological activities and possible health beneficial effects of dark teas were introduced. Some future directions and challenges to the development perspectives of dark teas were also discussed.     

茶皂素为乳化剂制备黄芩苷纳米乳及其促小鼠毛发生长的药效学研究

目的 以茶皂素为天然乳化剂制备黄芩苷纳米乳（baicalin nanoemulsion,Bai-NE）,并探究其对C57BL/6小鼠毛发生长的促进作用。方法 采用超声乳化法制备Bai-NE,利用单因素实验法对Bai-NE的处方和制备工艺进行优化,并对最优处方和工艺制备的Bai-NE进行理化性质和稳定性考察。以C57BL/6小鼠为研究对象,评价Bai-NE对毛发生长的促进作用。结果 Bai-NE的最佳处方为茶皂素用量为0.5%,油相用量为5%,最佳制备工艺为超声功率180W,超声时间10min,超声次数1次。制得的Bai-NE为O/W型乳液,外观均一,平均粒径为（225.1±0.6）nm,多分散指数（polydispersity index,PDI）为0.082±0.031,载药量为1.10mg/g,pH值为7.25±0.20。稳定性结果显示,Bai-NE具有良好的离心稳定性和储存稳定性。Bai-NE能显著促进C57BL/6小鼠的毛发生长。结论 茶皂素可作为一种潜在的天然乳化剂用于Bai-NE的制备,制备的Bai-NE对C57BL/6小鼠的毛发生长有促进作用。     

分散固相萃取-气相色谱串联质谱法测定菊花茶中的56种农药残留

目的 建立菊花茶中56种农药残留的分散固相萃取（QuEChERS） - 气相色谱串联三重四级杆质谱（GC - MS/MS）测定方法。方法 样品用乙腈提取,PSA+C18+GCB混合型分散固相萃取剂净化,DB - 5MS色谱柱分离,多反应监测模式（MRM）检测,外标法定量。结果 在0.005～500 mg/L范围内,56种农药的线性相关系数均≥0.995,方法定量限为0.002～0.057 mg/kg,平均回收率为60.0%～118.0%,相对标准偏差（RSD）为0.53%～20.09%。结论 该方法简单快速灵敏,可以实现菊花茶中农药残留的快速高通量检测。