Inspired　by　the　significant　anti-cancer　activity　of　our　previously　screened　natural　ergosterol　peroxide　(EP,　1),　we　synthesized　and　characterized　a　series　of　novel　5　alpha,8　alpha-epidioxyandrost-3　beta-ol-17-(O-phenylacetamide)oxime　derivatives　(9a-o).　The　anti-proliferative　activity　of　the　synthesized　compounds　against　human　hepatocellular　carcinoma　cells　(HepG2,　Sk-Hep1)　and　human　breast　cancer　cells　(MCF-7,　MDA-MB231)　were　investigated.　Compounds　9d,　9f,　9h,　9j　and　9m　displayed　good　anti-proliferative　activity　(most　IC50　＜　20　mu　M)　in　vitro.　Furthermore,　fluorescence　imaging　showed　that　the　designed　coumarin-9d　conjugate　(12)　localized　mainly　in　mitochondria,　leading　to　enhanced　anticancer　activities　over　the　parent　structure.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.