Xanthones induce cell-cycle arrest and apoptosis in human colon cancer DLD-1 cells

We investigated the antiproliferative effects of four structurally similar prenylated xanthones, α-mangostin, β-mangostin, γ-mangostin, and methoxy-β-mangostin, in human colon cancer DLD-1 cells. We investigated the antiproliferative effects of four structurally similar prenylated xanthones, α-mangostin, β-mangostin, γ-mangostin, and methoxy-β-mangostin, in human colon cancer DLD-1 cells. These xanthones differ in the number of hydroxyl and methoxy groups. Except for methoxy-β-mangostin, the other three xanthones strongly inhibited cell growth at 20 μM and their antitumor efficacy was correlated with the number of hydroxyl groups. Hoechst 33342 nuclear staining and nucleosomal DNA-gel electrophoresis revealed that the antiproliferative effects of α- and γ-mangostin, but not that of β-mangostin, were associated with apoptosis. It was also shown that their antiproliferative effects were associated with cell-cycle arrest by affecting the expression of cyclins, cdc2, and p27; G1 arrest was by α-mangostin and β-mangostin, and S arrest by γ-mangostin. These findings provide a relevant basis for the development of xanthones as an agent for cancer prevention and combination therapy with anti-cancer drugs.