Synthesis and cytotoxic activity of novel 1-((indol-3-yl)methyl)-1H-imidazolium salts.

A series of novel 1-((indol-3-yl)methyl)-1H-imidazolium salts were prepared and evaluated in vitro against a panel of human tumor cell lines. The results suggest that the 5,6-dimethyl-benzimidazole ring, and substitution of the imidazolyl-3-position with a naphthylacyl or 4-bromophenacyl group, were vital for modulating inhibitory activity of cell growth. In particular, 1-((N-Boc-indol-3-yl)methyl)-3-(2-naphthylacyl)-1H-5,6-dimethyl-benzimidazolium bromide was found to be the most potent derivative and more selective against myeloid liver carcinoma (SMMC-7721), lung carcinoma (A549) and breast carcinoma (MCF-7), with IC50 values 1.9-fold, 1.7-fold and 4.8-fold lower than DDP. This compound can induce significant cell apoptosis in SMMC-7721 cells.