IN-VIVO ANTITUMOR-ACTIVITY OF LARREA-DIVARICATA-C - COMPARISON OF 2 ROUTES OF ADMINISTRATION

We have previously demonstrated that an aqueous extract from Larrea di varicata has an antiproliferative activity on T lymphoma (BW 5147) cel ls in culture. Moreover the extract has in vivo antitumor activity whe n it was administered to a pregnant rat which had a spontaneous mammar y tumor. In this work, the effect of an extract of Larrea divaricata o n a mammary carcinoma chemically induced with N-nitrosomethylurea in f emales rats was studied. The extract was administered at a dose of 250 mg/kg three times each week by two different routes, subcutaneous (s. c.) and intratumoral (i.t.). The antitumor activity of the extract was evaluated by the survival time and the percentage of tumors that decr eased, remained static or increased. From tumors treated via i.t. with the extract, 7 decreased (58%), 4 remained static (33%), and 1 increa sed (8%); whereas from tumors treated via s.c. with the extract, 10 de creased (12%), 59 remained static (75%) and 9 increased (11%); The tot al number of control tumors was 80, none of them showed regression, 12 remained static (15%) and 68 increased (85%). The survival time of tr eated animals using both routes (s.c. and i.t.) was significantly grea ter (p < 0.05) than the saline-treated rats (control): extract 70 +/- 19 days, n: 32; saline (control) 38 +/- 22 days, n: 20. We conclude th at the aqueous extract of this plant has an in vivo antitumor activity with the intratumor route being most effective in induction of tumor regression.