theanine and Carcinoma--Ehrlich-Tumor

Considering of novel biochemical modulation by some foods and beverages, we have performed screening for green tea components that have enhancing effects on doxorubicin (DOX) induced antitumor activity. Components, such as caffeine, theanine, (-)-epigallocatechin gallate (EGCG) and flavonoids have inhibitory effects on the DOX efflux from Ehrlich ascites carcinoma cells. Thus, it is suggested that EGCG and flavonoids may enhance DOX induced antitumor activity and increase the DOX concentrations in tumors through the inhibition of DOX efflux. It is expected that these components in green tea exhibit low toxicity and that there are few side effects of drinking green tea in combination with an antitumor agent. We think that the intake of a favorite beverage favors a positive mental attitude of a patient and increases the efficacy of the chemotherapeutic index, and that this efficacy is useful for improving the quality of life on cancer chemotherapy. In DOX resistant P388 leukemia cell bearing mice theanine increased the DOX induced efficacy through an increase in the DOX concentrations in the tumors. Theanine attacked the same transport process for DOX in both types of cells, elevated the DOX concentration and increased the DOX induced antitumor activity.

Topics: Animals; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Caffeine; Calcium Channel Blockers; Carcinoma, Ehrlich Tumor; Catechin; Doxorubicin; Drug Resistance, Multiple; Drug Screening Assays, Antitumor; Drug Synergism; Flavonoids; Glutamates; Intracellular Fluid; Leukemia P388; Male; Mice; Neoplasm Transplantation; Phytotherapy; Tea; Theobromine; Verapamil

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

Topics: Animals; Antibiotics, Antineoplastic; Caffeine; Carcinoma, Ehrlich Tumor; Doxorubicin; Glutamates; Glutathione Peroxidase; In Vitro Techniques; Kidney; Lipid Peroxides; Liver; Male; Mice; Myocardium