Biodistribution and pharmacokinetics of theaflavin-3,3'-digallate, the major antioxidant of black tea, in mice

Abstract

The present study was conducted to investigate the absorption, distribution and pharmacokinetics of TFDG in mice for which it was labeled with ¹²⁵I. For comparison, the radiolabeled polyphenol was given either along with Black Tea Extract (BTE) or as pure TFDG. Following intravenous (5 mg kg^-1) or intragastric (500 mg kg^-1) administration, plasma and tissue levels were quantified by radioactive counting and the results were analysed by the SPSS program. Although lower than intravenous dosing, maximum plasma concentration (C_max) for TFDG was achieved at 6 h post-oral dosing with an AUC_0-α of 504.92 g min L^-1, which was 20 fold higher than that for i.v. dosing. Maximum radioactivity (42%) was recovered in kidney following i.v., administration, whereas for oral administration maximum radioactivity (0.07%) was recovered in liver as revealed by tissue distribution studies. Uptake of TFDG was > 4-fold more efficient in hepatocytes than in non parenchymal cells. However, TFDG showed better absorption by various organs as well as by liver cells when given along with BTE. Moreover, a second equal administration of TFDG after 6 h interval enhanced tissue levels of radioactivity above those after a single administration. These results point towards a wide distribution of ¹²⁵I-TFDG in mouse organs and suggest that frequent consumption of black tea may be better for increased systemic availability of polyphenols.