Structure-activity relationships of saframycins.

In vitro antitumor activities of 13 saframycins, including the potent antitumor component, saframycin A, were determined with the highly sensitive established cell line of L1210 mouse leukemia to investigate structure-activity relationships. Saframycins which lack the alpha-cyanoamine group or the alpha-carbinolamine group exhibited much lower cytotoxic activity than saframycin A. The modification of active saframycins either at the C-14 position on the basic skeleton or at the C-25 position on the side chain with bulky substituents resulted in a decrease in cytotoxic activity. These structure-activity relationships corroborated the proposed major mechanism of action for the antitumor activity of saframycin A and supported our proposed model for the saframycin A-DNA adduct.