Cytotoxic activity of withanolides isolated from Tunisian Datura metel L.

► Bioassay guided isolation of withanolide-type steroids from Tunisian Datura metel. ► The withanolide, 12α-hydroxydaturametelin B, inhibited the growth of cancer cell lines. ► Withanolides from Datura block colon cancer cells in S-phase and induced apoptosis.