A novel triazole derivative of betulinic acid induces extrinsic and intrinsic apoptosis in human leukemia HL-60 cells

•Synthesis of 32 betulinic acid derivatives.•Several derivatives were active against human cancer cell lines.•The active molecule induces apoptosis through both extrinsic and intrinsic pathway.

In an attempt to arrive at more potent cytotoxic agent than the bioactive natural product betulinic acid, influence of small structural modifications of its 1, 2, 3 triazole derivatives tethered at C-28 and both C3, C-28 using click chemistry approach has been studied. The chemically characterized triazoles have been screened for in vitro cytotoxicity against four human cancer cell lines HL-60, MiaPaCa-2, PC-3 and A549 which has allowed to identify triazole derivative 28{1N (4-fluoro phenyl)-1H-1, 2, 3-triazol-4-yl} methyloxy betulinic ester having better potency profile than the parent compound with IC50 values in the range of 5–7 μM. It caused disruption of mitochondrial membrane potential, rendered Bcl-2 cleavage, Bax translocation and decrease Bcl-2/Bax ratio. These events are accompanied by activation of caspases −9, -3, which cleave the PARP-1. It also induces caspase-8, which is involved in extrinsic apoptotic pathway. Therefore, it induces apoptosis through both intrinsic and extrinsic pathways in human leukemia HL-60 cells.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideCytotoxic study of new betulinic acid analogs showed the anti-leukemic potential of C28-aryl substituted 1,2,3 triazoles derivatives of betulinic acid that induce G1 arrest and apoptosis.