A novel series of 4- and 5-aroylindole derivatives was prepared and evaluated for antitumor activity. Several compounds showed excellent antiproliferative activity as inhibitors of tubulin polymerization. Compounds 13, 14, 15, and 18, with IC50 values of 1.9, 1.1, 1.2, and 1.8 mu M, respectively, exhibited more potent inhibition of tubulin polymerization than colchicine. They also displayed antiproliferative activity, with IC50 values ranging from 10 to 43 nM in a variety of human cell lines from different organs.
