Design, synthesis and biological evaluation of homoerythrina alkaloid derivatives bearing a triazole moiety as PARP-1 inhibitors and as potential antitumor drugs

A series of homoerythrina alkaloid derivatives containing a 1,2,3-triazole moiety as PARP-1 inhibitors were designed and synthesized. And their anti-proliferative activity was further evaluated. Compound 10n had excellent activity to inhibit proliferation of A549 cells (IC50, = 1.89 mu M), which was higher than harringtonine (IC50 = 10.55 mu M), pemetrexed (IC50, = 3.39 mu M), and rucaparib (IC50, = 4.91 mu M). Furthermore, the selectivity index of compound 10n was higher than rucaparib and pemetrexed for lung cancer cells. Flow cytometry analysis showed that compound 10n significantly arrested the cell cycle in the S phase, then induced apoptosis of A549 cells (apoptosis rate is 46%), which effectively inhibited cell proliferation. Simultaneously, western blot analysis revealed that compound 10n could prevent the biosynthesis of PAR. Further analysis results revealed that compound 10n could inhibit the expression of cyclin A, down-regulate the expression of bcl-2/bax, activate caspase-3, and ultimately induce apoptosis of A549 cells. All the results indicated that compound 10n had potential research value as a novel PARP-1 inhibitor in antitumor, and it provided a new reference for further development of PARP-1 inhibitors.