Identification, structural properties and chelating capacity of miltipolone as a broad-spectrum inhibitor to cancer cells

Miltipolone ( 1) was discovered as a good and broad-spectrum inhibitor against the growth of cancer cells from “Danshen” based on the activity-driven screening of TCMs. The structural features make 1 easily tautomerize between different forms and 1 is linked and stabilized by intermolecular O–H⋯O hydrogen bonds in the crystal structure. The interaction of 1 in ddH 2O solution with Co 2+, Mn 2+, Zn 2+, Fe 2+ or Fe 3+ changed UV absorption values; the chelation of 1 with Fe 2+ or Fe 3+ also altered the characteristic UV absorption peaks. However, only did Fe 2+ reverse 1’s inhibition against the growth of cancer cells; therefore, we concluded that 1 possibly acts as a Fe 2+ chelator to conduct its inhibitory activity. Miltipolone ( 1), a good and broad-spectrum growth inhibitor to cancer cells, can complex with Co 2+, Fe 2+, Fe 3+, Mn 2+ and Zn 2+ but its inhibition can only be reversed by Fe 2+. [Display omitted] ► Miltipolone ( 1) was discovered as a good and broad-spectrum inhibitor against the growth of cancer cells. ► The chelation of 1 with Fe 2+ or Fe 3+ altered the characteristic UV absorption peaks. ► Only did Fe 2+ reverse 1’s inhibition against the growth of cancer cells and it is concluded that 1 possibly acts as a Fe 2+ chelator to conduct its inhibitory activity.