title: Withanolides Q and R, two new 23-hydroxy-steroidal lactones.
mesh_terms: D002775:Cholestadienols / Q000302:isolation & purification*; D004852:Epoxy Compounds; D007783:Lactones / Q000302:isolation & purification; D010944:Plants / Q000378:metabolism
chemical_list: D002775:Cholestadienols; D004852:Epoxy Compounds; D007783:Lactones