title: Nine new isoxuxuarine-type triterpene dimers from Maytenus chuchuhuasca.
abstract: Nine new isoxuxuarine-type triterpene dimers, named isoxuxuarines B alpha (1), B beta (2), 7,8-dihydro-B alpha (3), C alpha (4), C beta (5), 7,8-dihydro-C alpha (6), D alpha (7), D beta (8), and 7,8-dihydro-D alpha (9), were isolated from the South American medicinal plant 'xuxuá' (Maytenus chuchuhuasca). The structures were elucidated on the basis of several spectroscopic analyses, including 2D-NMR experiments, MS spectra, and CD spectral studies. The isolations and structure elucidations of the new triterpene dimers are presented, and a rationale for the divergent formation of the regiochemical and stereochemical isomers of triterpene dimers is discussed.
authors.affiliation: Division of Pharmacognosy and Phytochemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan. shirota@kph.bunri-u.ac.jp
authors.forename: Osamu
authors.initials: O
authors.lastname: Shirota
authors.forename: Setsuko
authors.initials: S
authors.lastname: Sekita
authors.forename: Motoyoshi
authors.initials: M
authors.lastname: Satake
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morita
authors.forename: Koichi
authors.initials: K
authors.lastname: Takeya
authors.forename: Hideji
authors.initials: H
authors.lastname: Itokawa
mesh_terms: D019281:Dimerization; D029755:Maytenus; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification; D014315:Triterpenes / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D010936:Plant Extracts; D014315:Triterpenes