Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science & Technology, 13 Hangkong Road, Wuhan 430030, PR China.
J Ethnopharmacol. 2011 Mar 8;134(1):156-64. doi: 10.1016/j.jep.2010.11.068. Epub 2010 Dec 4.
Pu-erh black tea, which is obtained by first parching crude green tea leaves and then undergoes secondary fermentation with microorganisms, has been believed to be beneficial beverages for health for nearly 2000 years in China, Japan and Taiwan area. But its potential toxicity when administered at a high dose as concentrated extracts has not been completely investigated.
The present study was aimed at evaluating potential toxicity of Pu-erh black tea extracts (BTE) from acute and sub-chronic administration to male and female Sprague-Dawley (SD) rats.
A single BTE dose of 10,000 mg/kg of body weight was administered by oral gavage for acute toxicity in SD rats. Four groups (10 males and 10 females per group) of dose levels of 1250, 2500, and 5,000 mg/kg/day of the test article, as well as controls (distilled water) were tested as the subchronic toxicity study.
No deaths and signs of toxicity occurred during the 14 days of the study. There were no test article related mortalities, body weight gain, feed consumption, clinical observation, organ weight changes, gross finding, clinical or histopathological alterations during the 91-day administration.
The LD(50) of BTE can be defined as more than 10,000 mg/kg, and a dose of 5,000 mg/kg/day was identified as the no-observed-adverse-effect-level (NOAEL) in this study.
普洱茶是一种通过先烘焙粗制绿茶叶，然后用微生物进行二次发酵制成的茶，在中国、日本和台湾地区，人们近 2000 年来一直认为它是有益于健康的饮品。但作为浓缩提取物高剂量给药时的潜在毒性尚未得到全面研究。
本研究旨在评估普洱茶提取物（BTE）经急性和亚慢性给药对雄性和雌性 Sprague-Dawley（SD）大鼠的潜在毒性。
SD 大鼠经口服灌胃给予 10,000 mg/kg 体重的单次 BTE 剂量进行急性毒性试验。将 4 组（每组 10 只雄性和 10 只雌性）的受试物剂量水平为 1250、2500 和 5,000 mg/kg/天以及对照组（蒸馏水）进行亚慢性毒性研究。
在研究的 14 天内，没有死亡和毒性迹象发生。在 91 天给药期间，没有与试验药物相关的死亡率、体重增加、饲料消耗、临床观察、器官重量变化、大体发现、临床或组织病理学改变。
BTE 的 LD50 可定义为大于 10,000 mg/kg，本研究中 5,000 mg/kg/天的剂量被确定为无观察到不良效应水平（NOAEL）。
