Abstract: To investigate the anticancer effects of ring C in 18β-glycyrrhetinic acid (GA), a series of GA derivatives featured with 9(11)-ene moiety in ring C were designed and synthesized. The structures were confirmed by IR, LC-MS and ¹H NMR. Their inhibitory effects towards human prostate cancer PC-3 and leukemia HL-60 cell lines were determined. Most of the derivatives displayed stronger antiproliferative activities than GA. Particularly, compound 14 showed promising anticancer activity with the GI₅₀ values of 4.48 μmol·L^-1 and 1.2 μmol·L^-1 against PC-3 and HL-60 cells respectively, which is worth further study.