Physangulidines A, B, and C: Three New Antiproliferative Withanolides from <i>Physalis angulata</i> L.

Bioassay-directed fractionation of the whole plant of <i>Physalis angulata</i> L. afforded three new antiproliferative withanolides with an unusual carbon framework: physangulidines A (<b>1</b>), B (<b>2</b>), and C (<b>3</b>). Structures of the three isomeric withanolides were determined by a combination of HRMS, NMR spectroscopic, and X-ray crystallographic methods. Each has shown significant antiproliferative activity against DU145 prostate cancer cells. Physangulidine A (<b>1</b>) was further tested against a wide range of additional cancer cell lines and found to exhibit significant antiproliferative activity