Design, Synthesis and Anticancer Activity of Shikonin and Alkannin Derivatives with Different Substituents on the Naphthazarin Scaffold

Based on the asymmetric reduction of alkannin ketone derivative 4 by diisopinocampheylchloroborane(DIP-CI), a series of shikonin and alkannin derivatives was designed, synthesized and their anticancer activities against various kinds of cell lines were evaluated. The in vitro biological experiments demonstrated that compound S-10, a 5,8-O-dimethyl-1,4-dioxime alkannin derivative, not only displayed excellent antiproliferative activity against cancer cells, but also exhibited low toxicity towards normal cells. It could induce HCT-116 cell apoptosis, but had no impact on the cell cycle. The underlying anticancer mechanism of S-10 is most likely different from other shikonin and alkannin derivatives.