Department of Tea Science, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029, Zhejiang, China.
J Ethnopharmacol. 2011 Jan 27;133(2):583-90. doi: 10.1016/j.jep.2010.02.030. Epub 2010 Oct 27.
Tea (Camellia sinensis (L.) O. Kuntze, Theaceae) flowers possess many physiological functions and have been used in traditional medicines for deodorization, skin care, cough suppressant and expectorant in China. However, there is a little information about its possible toxicity.
The present investigation was carried out to evaluate the safety of tea flower extract by mutagenicity and acute and subchronic toxicity studies.
Mutagenicity of tea flower extract was evaluated by the Ames test in Salmonella typhimurium strains TA97, TA98, TA100 and TA102 at concentrations of 0.008, 0.04, 0.2, 1.0, 5.0 mg/plate. In the acute toxicity study, Sprague-Dawley rats were administered a single dose of 12.0 g/kg of body weight by gavage, and were monitored for 14 days. In the subchronic toxicity study, tea flower extract was administered by gavage at doses of 1.0, 2.0 and 4.0 g/kg body weight daily for 13 weeks to Sprague-Dawley rats.
In the Ames test, there was no mutagenic effect of tea flower extract (up to 5.0 mg/plate) towards four tested strains (TA97, TA98, TA100, TA102), with or without metabolic activation (S9). In the acute toxicity study, all animals gained weight and appeared active and normal, so the LD(50) value must be >12.0 g/kg body weight. In the subchronic toxicity study, no dose-related effects on survival, growth, hematology, blood chemistry, organ weights, or pathologic lesions were observed.
These results indicate that tea flower extract does not possess mutagenic potential, and that both acute and subchronic toxicity towards animals is very low. A no-observed adverse-effect level (NOAEL) for tea flower extract is 4.0 g/kg bw/day for rats under the conditions of this study.
茶（山茶属植物（L.）O. 库恩茨，山茶科）花具有许多生理功能，并在中国传统医学中被用于除臭、护肤、镇咳和祛痰。然而，关于其潜在毒性的信息却很少。
本研究旨在通过致突变性和急性及亚慢性毒性研究评估茶花提取物的安全性。
采用鼠伤寒沙门氏菌 TA97、TA98、TA100 和 TA102 菌株，在 0.008、0.04、0.2、1.0、5.0mg/平板浓度下，用 Ames 试验评价茶花提取物的致突变性。在急性毒性研究中，SD 大鼠经灌胃给予 12.0g/kg 体重的单次剂量，观察 14 天。在亚慢性毒性研究中，SD 大鼠经灌胃给予 1.0、2.0 和 4.0g/kg 体重/天的茶花提取物，连续 13 周。
在 Ames 试验中，茶花提取物（高达 5.0mg/平板）对 4 株受试菌株（TA97、TA98、TA100、TA102）均无致突变作用，无论是否有代谢活化（S9）。在急性毒性研究中，所有动物体重增加，表现活跃正常，因此 LD50 值必须>12.0g/kg 体重。在亚慢性毒性研究中，未见生存、生长、血液学、血液化学、器官重量或病理损伤与剂量相关的影响。
这些结果表明，茶花提取物不具有致突变潜能，对动物的急性和亚慢性毒性均很低。在本研究条件下，茶花提取物对大鼠的无观察不良效应水平（NOAEL）为 4.0g/kg bw/day。
