Fourteen-Week Toxicity Study of Green Tea Extract in Rats and Mice

Abstract

The toxicity of green tea extract (GTE) was evaluated in 14-week gavage studies in male and female F344/NTac rats and B6C3F1 mice at doses up to 1,000 mg/kg. In the rats, no treatment-related mortality was noted. In the mice, treatment-related mortality occurred in male and female mice in the 1,000 mg/kg dose groups. The cause of early deaths was likely related to liver necrosis. Treatment-related histopathological changes were seen in both species in the liver, nose, mesenteric lymph nodes, and thymus. In addition, in mice, changes were seen in the Peyer’s patches, spleen, and mandibular lymph nodes. The no adverse effect level (NOAEL) for the liver in both species was 500 mg/kg. In the nose of rats, the NOAEL in males was 62.5 mg/kg, and in females no NOAEL was found. No NOAEL was found in the nose of female or male mice. The changes in the liver and nose were considered primary toxic effects of GTE, while the changes in other organs were considered to be secondary effects. The nose and liver are organs with high metabolic enzyme activity. The increased susceptibility of the nose and liver suggests a role for GTE metabolites in toxicity induction.

The Combination of Green Tea Extract and Eriodictyol Inhibited High-Fat/High-Sucrose Diet-Induced Cholesterol Upregulation Is Accompanied by Suppression of Cholesterol Synthesis Enzymes

“…Green tea is one of the most popular beverages worldwide, and many studies have reported the safety of green tea (40)(41)(42). A previous study reported that an extraordinarily high green tea concentration is demanded to induce hepatotoxicity in rats and mice (43). In addition, stability in the blood and safety of eriodictyol, which is abundantly present in citrus fruit peels, has also been shown (44).…”

Traditional Chinese Medicine (TCM) and Herbal Hepatotoxicity: RUCAM and the Role of Novel Diagnostic Biomarkers Such as MicroRNAs

“…Results of experimental hepatotoxicity in animals were equivocal [221,222,223]. Chinese green tea is a popular beverage prepared from the leaves of the plant Camellia sinensis , which has been cultivated in China and other Southeast Asian countries since thousands of years [224].…”

Adverse effects of concentrated green tea extracts

“…Interestingly, several studies reported hepatoprotective effects of green tea preparations [53][54][55][56][57][58][59][60], whereas others demonstrated hepatotoxic effects (usually at higher concentrations) of GTE [61][62][63][64]. These conflicting data are echoed in observations in humans.…”