Anti-proliferative and anti-malarial activities of spiroisoxazoline analogues of artemisinin.

A series of spiroisoxazoline analogues of artemisinin was synthesized by employing 1,3-dipolar cycloaddition between various in situ generated nitrile oxides and artemisitene. All the synthesized compounds were tested for their anti-proliferative and anti-malarial activities. Among the compounds tested, compound 11a was found to be potent against the HCT-15 cancer cell line with IC50  = 4.04 μM when compared to 5-fluorouracil (IC50  = 35.53 μM). DNA cell cycle analysis shows that 11a was inhibiting cell proliferation at the G2/M phase. Compound 11b was found to be most active against Plasmodium falciparum with IC50  = 0.1 μM and also blocked host hemoglobin hydrolysis by the falcipain-3 receptor. It was demonstrated to have better dynamics of parasite killing efficiency than artemisinin. Molecular docking studies revealed that these compounds interacted with falcipain-3 receptor sites.