Synthesis and anticancer activity evaluation of 7-oxygen-substituted and 8,17-epoxydized 1,2-didehydro-3-ox-14-deoxyandrographolide derivatives.

Two novel series of 1,2-didehydro-7-hydroxy-3-ox-14-deoxyandrographolide and 1,2-didehydro-8,17-epoxy-3-ox-14-deoxyandrographolide derivatives were designed, synthesized and evaluated for their cytotoxic activity in vitro against two human cancer cell lines HCT-116 (human colon cancer) and MCF-7 (human breast cancer). Most tested compounds, especially those of the first series, displayed better inhibitory activity on both HCT-116 and MCF-7 cells than andrographolide. HCT-116 cells were found to be more sensitive to tested compounds than MCF-7, and compound 13b exhibited the most potent activity against HCT-116, with an IC value of 7.32 μM. Further anti-cancer mechanistic investigation demonstrated that compound 13b effectively suppressed the growth of HCT-116 cells by triggering early and late cellular apoptosis in a concentration-dependent manner and arresting cell cycle in S phase.