title: Tricalysiosides A-G: rearranged ent-kauranoid glycosides from the leaves of Tricalysia dubia.
abstract: Seven rearranged ent-kaurane glycosides, named tricalysiosides A-G (1-7), were isolated from the leaves of Tricalysia dubia collected on Okinawa Island. Their C-18 and 19 methyls were found to have rearranged to form an alpha,beta-unsaturated gamma-lactone ring, with other functional groups remotely located only on C-15, -16, and -17 of the five-membered ring. Information available from various kinds of two-dimensional NMR spectra was limited and insufficient to allow total characterization of the structures. Finally, using X-ray crystallographic analysis, the structure of tricalysioside A (1) was determined to be 4-nor-18-homo-ent-kauran-4(18)-en-15beta,16beta,17-triol-3beta,19-olide 16-O-beta-D-glucopyranoside (1). On the basis of the crystal structure of 1, the structures of the other tricalysiosides (2-7) were also established.
authors.affiliation: Institute of Pharmaceutical Sciences, Hiroshima University Faculty of Medicine, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Dong-Hui
authors.initials: DH
authors.lastname: He
authors.forename: Hideaki
authors.initials: H
authors.lastname: Otsuka
authors.forename: Eiji
authors.initials: E
authors.lastname: Hirata
authors.forename: Takakazu
authors.initials: T
authors.lastname: Shinzato
authors.forename: Masahiko
authors.initials: M
authors.lastname: Bando
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Takeda
mesh_terms: D002845:Chromatography; D018360:Crystallography, X-Ray; D006027:Glycosides / Q000737:chemistry* / Q000302:isolation & purification*; D006868:Hydrolysis; D007564:Japan; D007783:Lactones / Q000737:chemistry* / Q000302:isolation & purification*; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D019666:Rubiaceae / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D006027:Glycosides; D007783:Lactones