THE EFFECTS OF THEANINE, AS A NOVEL BIOCHEMICAL MODULATOR, ON THE ANTITUMOR-ACTIVITY OF ADRIAMYCIN

We studied the effects of theanine, a component of green tea leaves, o n the antitumor activity of adriamycin (ADR) from the biochemical modu lation view point. In vitro, theanine inhibited the ADR efflux from Eh rlich ascites carcinoma cells and maintained the ADR concentration in tumor cells. Theanine enhanced the inhibitory effect of ADR on tumor g rowth by 2.1-fold in vivo, and increased 2.9-fold the ADR concentratio n in the tumor, compared to the ADR alone group. An increase in ADR co ncentration was not observed in normal tissues, such as the heart and liver. Theanine did not enhance, rather tended to normalize the increa se of lipid peroxide level and reduction of glutathione peroxidase act ivity as indicators of the ADR-induced side toxicity.