title: Phyteumosides A and B: new saponins with unique triterpenoid aglycons from Phyteuma orbiculare L.
abstract: Phyteumosides A (1) and B (2), two saponins with unprecedented triterpenoid aglycons, were isolated from the aerial parts of Phyteuma orbiculare (Campanulaceae). Their structures were elucidated by spectroscopic and chemical methods and corroborated by X-ray diffraction analyses of the aglycons obtained through enzymatic hydrolysis. The aglycon of 1 can be considered as an incompletely cyclized onoceroid or gammaceroid triterpene with two additional tetrahydropyran rings arising from oxygen bridges. Compound 2 possesses a new 17-polypodene aglycon.
authors.affiliation: Division of Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, CH-4056 Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Abbet
authors.forename: Markus
authors.initials: M
authors.lastname: Neuburger
authors.forename: Trixie
authors.initials: T
authors.lastname: Wagner
authors.forename: Melanie
authors.initials: M
authors.lastname: Quitschau
authors.forename: Matthias
authors.initials: M
authors.lastname: Hamburger
authors.forename: Olivier
authors.initials: O
authors.lastname: Potterat
mesh_terms: D029422:Campanulaceae / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008968:Molecular Conformation; D015394:Molecular Structure; D012503:Saponins / Q000737:chemistry / Q000302:isolation & purification*; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D012503:Saponins; D014315:Triterpenes; C558616:phyteumoside A; C558617:phyteumoside B