Alkylphosphonium salts as a new class of antitumor agents.

A series of twenty-four alkylphosphonium salts were prepared and evaluated as potential antitumor agents in vivo against Ehrlich ascites carcinoma (EAC). Eleven compounds were screened in vivo against lymphoid leukemia L1210 and one against lymphocytic leukemia P388. Out of these, three compounds exhibited mild antitumor activity against EAC. Twenty compounds were tested for their cytotoxic activity against the growth of tissue culture cells originated from human epidermoid carcinoma of the nasopharynx (KB). All compounds but one exhibited significant cytotoxicity in this cell line. 2-Bromoethyltriphenylphosphonium bromide, chosen as a standard compound, was earlier reported [4] to have borderline activity against P388, but it failed to show any activity against EAC though it has exhibited significant in vitro cytotoxicity in KB cell culture. In the course of this study, seven new alkylphosphonium salts were synthesized.