Green Tea

Effect of green tea extracts on liver functions in Wistar rats
S.S. Buna, H.Bunb, D. Guédonc, C. Rosierc and E. Olliviera

aLaboratory of Pharmacognosy, Faculty of Pharmacy, 27 Boulevard Jean Moulin, F-13385 Marseille Cedex 5, France
bLaboratory of Pharmacokinetics and Toxicokinetics, Faculty of Pharmacy, 27 Boulevard Jean Moulin, F-13385 Marseille Cedex 5, France
cArkopharma Laboratories, BP 28, F-06511 Carros Cedex, France

Abstract

An herbal medicinal product (Exolise®) containing as active ingredient an hydro-alcoholic extract of green tea named AR25® (standardized to 25% catechins) has been implicated in hepatic failures, leading to the withdrawal of the marketing authorization. The active ingredient of Exolise® being manufactured with 80% ethanol, the question to know whether the extraction solvent could introduce some toxic components was hypothesized. Two investigations were conducted in Wistar rats to determine if repeated oral administration of different green tea extracts could corroborate the reported hepatotoxicity in humans. In a preliminary 6 week-study, experimental groups (n = 9/group) received either the vehicle or a methylene chloride extract (2500 mg/kg body weight) where potential non-polar hepatotoxin(s) could be concentrated. In a second experiment (12 week-study), rats were divided in three groups (n = 10/group) and treated with either the vehicle, or an aqueous extract (1400 mg/kg) or AR25® green tea extract (2000 mg/kg). Rat liver functions were assessed by serum biochemistry of hepatotoxicity markers. No sign of evidence of characteristic hepatotoxicity was found in rats treated with very high amount of different green tea extracts in these two experiments (respectively a daily dosage, which was about 900 and 80 times higher to the therapeutic daily dosage of Exolise®).

SOURCE : Science Diet

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