17(13-18)abeo 5alphah pregna 2,13,15,17 tetraen 1,20 dione 2 1alpha hydroxy 17(13-18) abeo 5alphah pregna 2,13,15,17 tetraen 20 one 2 20 (tert butyldimethylsilyloxy) 17 (13-18) abeo 5alphah pregna 13,15,17 trien 3beta ol 2 20 acetoxy 17(13-18) abeo 5alphah pregna 2,13,15,17 tetraen 1alpha ol 2 20 acetoxy 17(13-18)abeo 5alphah pregna 13,15,17 trien 3 one 2 20 acetoxy 17(13-18)abeo5alphah pregna 1,13,15,17 tetraen 3 one 2 20 acetoxy 1alpha,2alpha epoxy 17(13-18)abeo 5alphah pregna 13,15,17 trien 3 one 2 3beta acetoxy 20 (tert butyldimethylsilyloxy) 17 (13-18)abeo 5alphah pregna 13,15,17 triene 2 Antiestrogenic activity 2 Antineoplastic Agents, Hormonal 2 Antiproliferative activity 2 Cell Proliferation 2 Dose-Response Relationship, Drug 2 Drug Screening Assays, Antitumor 2 Ergosterol 2 Estrogen Antagonists 2 Humans 2 MCF 7 cell line 2 MCF-7 Cells 2 Molecular Structure 2 Salpichrolides 2 Structure-Activity Relationship 2 Tumor Cells, Cultured 2 Withanolides 2 analogs and derivatives 2 antiestrogen 2 antiestrogenic activity 2 antineoplastic activity 2 antineoplastic hormone agonists and antagonists 2 antiproliferative activity 2