Synthesis and Cytotoxic Effects of 3,6‐Bis‐indolyl 2,5‐Dihydroxybenzoquinone Acetates

The synthesis of a novel series of indolyl‐2,5‐dihydroxybenzoquinone derivatives, analogues of asterriquinones, is reported together with their antiproliferative activity against various carcinoma cell lines, such as A549, MCF7, Hcc827 and PC3. For the synthesis, acid catalyzed reactions of 2,5‐diacetoxybenzoquinone with 2‐methyl and 1,2‐dimethyl indole have been employed. Ten compounds have been tested and exhibited differential activity across the various cell lines. Derivative 7 b was the most cytotoxic with an IC50 value of 25±2.0 μΜ against A549 cancer cells and was more active than cisplatin in PC3 cells (IC50 value of 38±1.5 μΜ). The activity and selectivity of the tested compounds depends both on the number of indole units, the presence of protected hydroxyl groups on 1,4‐benzoquinone and N−Me groups on indole. The synthesis of a novel series of indolyl‐2,5‐dihydroxybenzoquinone derivatives, analogues of asterriquinones, is reported together with their antiproliferative activity against various carcinoma cell lines, such as A549, MCF7, Hcc827 and PC3.