title: Seven-membered vibsane-type diterpenes with a 5,10-cis relationship from Viburnum awabuki.
abstract: New five seven-membered vibsane-type diterpenes named 5-epi-vibsanin C, 5-epi-vibsanin H, 5-epi-vibsanin K, 18-O-methyl-5-epi-vibsanin K and 5-epi-vibsanin E have been isolated from the leaves of Viburnum awabuki (Caplifoliaceae). Their structures have been elucidated by analyses of spectroscopic data and comparison of their spectral data with those of the previously known seven-membered vibsane-type diterpenes. The occurrence of these seven-membered vibsane-type diterpenes with a cis relationship on the C-5 and C-10 positions in nature have been predicted by conformational analysis of vibsanin B, an eleven-membered vibsane-type diterpene. Vibsanin C, 5-epi-vibsanin C and 5-epi-vibsanin H exhibited moderate cytotoxic activities on KB cells.
authors.affiliation: Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Japan. fukuyama@ph.bunri-u.ac.jp
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Fukuyama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Minami
authors.forename: Asami
authors.initials: A
authors.lastname: Matsuo
authors.forename: Kanako
authors.initials: K
authors.lastname: Kitamura
authors.forename: Mie
authors.initials: M
authors.lastname: Akizuki
authors.forename: Miwa
authors.initials: M
authors.lastname: Kubo
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Kodama
mesh_terms: D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D019684:Magnoliopsida / Q000737:chemistry*; D015394:Molecular Structure; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013055:Spectrophotometry, Infrared
chemical_list: D004224:Diterpenes; C000598979:vibsanin B