title: Withanolides from Physalis coztomatl.
abstract: Six withanolides (1-6), as well as two known withanolides (physachenolide D 7 and withanoside VI 8), were isolated from the aerial parts of Physalis coztomatl (Solanaceae). Structural elucidations of 1-6 were achieved through 2D NMR and other spectroscopic techniques, while the structure of 1 was confirmed by X-ray crystallographic analysis. In addition, the stereochemical orientation of the 17-hydroxy group in withanolides was discussed in relation to (13)C NMR shifts of C-12, 13, 14 and 16. Such analysis established that coagulansin A contains a 17α-hydroxy moiety rather than the reported 17β-hydroxy functionality, and has been revised accordingly.
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66045, USA.
authors.forename: Huaping
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66045, USA.
authors.forename: Cong-Mei
authors.initials: CM
authors.lastname: Cao
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66045, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gallagher
authors.affiliation: The Small-Molecule X-ray Crystallography Laboratory, University of Kansas, Lawrence, KS 66047, USA.
authors.forename: Victor W
authors.initials: VW
authors.lastname: Day
authors.affiliation: Kansas Biological Survey, University of Kansas, Lawrence, KS 66047, USA.
authors.forename: Kelly
authors.initials: K
authors.lastname: Kindscher
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66045, USA. Electronic address: btimmer@ku.edu.
authors.forename: Barbara N
authors.initials: BN
authors.lastname: Timmermann
mesh_terms: D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D032321:Physalis / Q000737:chemistry*; D054358:Withanolides / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D054358:Withanolides
keywords: Coagulansin A; Physacoztolide; Physalis coztomatl; Solanaceae; Structure revision; Withanolide