Antitumoral activity of dipyrido [4,3-b] [3,4-f] indoles on L 1210 leukemia.

Newly synthesized dipyrido [4,3-b] [3,4-f] indole compounds have a structural similarity with the DNA intercalating agents ellipticines (pyrido-carbazoles). The procedure of synthesis of these compounds allows the addition of a lateral chain in position 1 of the nucleus. Comparison is made between different substitutions and the resulting cytotoxic and antitumoral effects. The most active compound of the serie (1-gamma-diethyl amino propyl amino)-5-methyl-dipyrido [4,3-b] [3,4-f] indole (called here BD40) protects mice against L1210 leukemia. At the non-toxic dose of 20 mg/kg, particularly, a single infection of this compound given one day after inoculation of 10(5) L1210 cells resulted in an increased life span of 69 per cent with one survivor at 60 days. A combination of cyclophosphamide and BD40 had a synergic effect on the life span of L1210 inoculated mice. The antitumoral action of these drugs may be linked to their intercalative action upon biding to DNA.