Lack of chronic toxicity and carcinogenicity of dietary administrated catechin mixture in Wistar Hannover GALAS rats

Abstract

-Chronic toxicity and carcinogenicity of catechin mixture were examined in Wistar Hannover GALAS rats. Administration was in the diet at concentrations of 0, 0.02, 0.3, 1 or 3%. Slight increases in relative liver weight and centrilobular hypertrophy of hepatocytes associated with induction of CYP3A2 were found at the 3% in males of both studies. However, because there were no signs indicative of hepatotoxicity on serum biochemical and histopathological examinations, the changes observed in the liver were regarded as adaptation, and not adverse effects. The slight depressions of body weights at the 3% in females of the chronic toxicity study and in both sexes of the carcinogenicity study were observed. These decreases were because the diet at the highest concentration was frangible and nominal food consumption may not have reflected the actual food consumption resulting in decrease in caloric intake, rather than toxic effects. Thus it was concluded that catechin mixture had no toxicity. In addition, tumor incidences and types were comparable between treated and control groups. Based on the results, the no observed adverse effect levels estimated from the chronic toxicity study were 3% in both sexes equal to 1922.9 in males and 2525.7 mg/kg/day in females. Catechin mixture has no carcinogenic potential in male and female rats.

Effect of oral administration of green tea extract in various dosage schemes on oxidative stress status of mice in vivo

“…This indicates that green tea catechins, even at high doses, have no pro-oxidative eff ects in erythrocytes and plasma. In agreement with this fi nding, a lack of chronic toxicity of the catechin mixture up to 2.5 g kg -1 per day was documented in rats (23).…”

Green tea for ovarian cancer prevention and treatment: A systematic review of the in vitro, in vivo and epidemiological studies

“…One was an abstract [28], one was a review [13] and one was a meta-analysis [12]. Eleven in vitro/in vivo studies did not address EOC [29][30][31][32][33][34][35][36][37][38][39]. Three epidemiologic studies were excluded because there was no direct assessment of tea intake [41], there was no assessment of the relationship between tea intake and EOC [42] or no confidence intervals were provided [43].…”

Liver-related safety assessment of green tea extracts in humans: a systematic review of randomized controlled trials

“…Similarly, other animal experiments showed no evidence of liver cancer when high concentrations of green tea extracts were tested. 8 However, the results of animal experiments cannot be simply extrapolated to humans.…”