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

Abstract 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 2 O 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.