Design, synthesis, and biological evaluation of novel 5-bromo derivatives of indole phytoalexins

The increasing diversity of small molecule libraries is a major source for the discovery of new drug candidates. In terms of this trend, we report the synthesis of five series 5-bromosubstituted derivatives of indole phytoalexins Types A–E using a straightforward synthetic approach. Novel compounds were screened in vitro for antiproliferative/cytotoxic activity against seven human cancer cell lines by MTT assay. Evaluation of their antiproliferative potency showed that the activity of some analogues was better or comparable to that of cisplatin and at the same time the toxicity of these compounds on 3T3 cells was lower than that of cisplatin. We found that all 5-bromosubstituted analogues of indole phytoalexins Types A–E exhibited lower or approximately the same activities as previously studied corrensponding non-brominated compounds. Graphic abstract: