Design, synthesis, and in vitro cytotoxicity evaluation of novel dihydroartemisinin-isatin hybrids tethered via different length of esters as potential anti-breast cancer agents

In the present work, we reported the design, synthesis, and in vitro cytotoxicity evaluation of novel dihydroartemisinin-isatin hybrids tethered via different length of esters against MCF-7, MDA-MB-231, MCF-7/ADR and MDA-MB-231/ADR breast cancer cell lines. The preliminary results showed that the majority of the hybrids exhibited good anti-breast cancer cell activity. In particular, hybrids 7 g and 7n not only were more potent than ART, DHA and ADR against the four tested breast cancer cell lines, but also were non-toxic towards normal MCF-10A breast cells. The selectivity index values of hybrids 7 g and 7n were > 12.83 and > 25.97 respectively, revealing their excellent safety and selectivity profiles. The drug-resistant index values of hybrids 7 g and 7n were in a range of 0.33 to 1.12, implying that these hybrids had the potential to overcome drug resistance. Accordingly, hybrids 7 g and 7n could be considered as potential lead molecules for the development of novel anti-breast cancer agents with minimal untoward events to normal human cells. The structure-activity relationships indicated that the length of ester likner between DHA and isatin as well as substituents at C-3 and C-5 positions of isatin moiety had great impact on the activity.