Anthraquinones, Cdc25B phosphatase inhibitors, isolated from the roots of Polygonum multiflorum Thunb.

Three anthraquinones, Cdc25B phosphatase inhibitors, were isolated from the methanolic extract of the roots of Polygonum multiflorum Thunb. (Polygonaceae). Anthraquinones, physcion (1), emodin (2), and questin (3), inhibited the enzymatic activity of Cdc25B phosphatase with IC50 values of 62.5, 30, and 34 µg mL−1, respectively. Emodin (2) and questin (3) strongly inhibited the growth of human colon cancer cells, SW620 with GI50 values of 6.1 and 0.9 µg mL−1, respectively. Commercially available anthraquinones, chrysophanol (4), and rhein (5) also inhibited Cdc25B phosphatase with IC50 values of 10.7 and 22.1 µg mL−1, respectively.