Design, Synthesis, and Biological Evaluation of Artemisinin-Indoloquinoline Hybrids as Potent Antiproliferative Agents

A series of artemisinin-indoloquinoline hybrids were designed and synthesized in an attempt to develop potent and selective anti-tumor agents. Compounds 7a–7f, 8 and 9 were prepared and characterized. Their antiproliferative activities against MV4-11, HCT-116, A549, and BALB/3T3 cell lines in vitro were tested. Nearly all of the tested compounds (7–9, except for compounds 7d and 7e against HCT-116) showed an increased antitumor activity against HCT-116 and A549 cell lines when compared to the dihydroartemisinin control. Especially for the artemisinin-indoloquinoline hybrid 8, with an 11-aminopropylamino-10H-indolo[3,2-b]quinoline substituent, the antiproliferative activity against the A549 cell line had improved more than ten times. The IC(50) value of hybrid 8 against A549 cell lines was decreased to 1.328 ± 0.586 μM, while dihydroartemisin showed IC(50) value of >20 µM in the same cell line. Thus, these results have proven that the strategy of introducing a planar basic fused aromatic moiety, such as the indoloquinoline skeleton, could improve the antiproliferative activity and selectivity towards cancer cell lines.