title: New triterpenoids from the stem bark of Hypodaphnis zenkeri.
abstract: A new pentacyclic triterpenoid and three new derivatives based on the taraxer-14-ene skeleton with a C-28 attached a carboxylic acid group have been isolated from the stem bark of Hypodaphnis zenkeri, together with six known compounds. The new product was identified as 2α,3α-dihydroxytaraxer-14-en-28-oic acid (1). Its derivatives, 2α,3α-diacetyltaraxer-14-en-28-oic acid (2), 2α,3α-di-O-carbonyl-2α,3α-dihydroxytaraxer-14-en-28-oic acid (3) and 2α,3α-dipropionyltaraxer-14-en-28-oic acid (4) were obtained by semisynthesis. The known compounds were identified as 3β-hydroxytaraxer-14-en-28-oic acid or aleuritolic acid (5) (McPhail, A.T., McPhail, D.R., Wani, M.C., Wall, M.E. & A.W., Nicholas, A.W. (1989). Identity of maprounic acid with aleuritolic acid. Revision of the structure of maprounic acid: X-ray crystal structure of p-bromobenzyl acetylmaprounate. Journal Natural Products, 52, 212), 3α-hydroxytaraxer-14-en-28-oic acid or isoaleuritolic acid (6), 3α-acetyltaraxer-14-en-28-oic acid acetate or aleuritolic acid acetate (7) (Chaudhuri, S.K., Fullas, F., Brown, D.M., Wani, M.C., Wall, M.E., Cai, L., … Kinghorn, A.D. (1995). Isolation and structural elucidation of pentacyclic triterpenoids from Maprounea africana. Journal of Natural Products, 58, 1-9), 3-oxo-taraxer-14-ene or taraxerone (8) β-sitosterol (9) and stigmasterol (10) (Kamboj & Saluja, 2011), together with fatty acids. Their structures were established on the basis of spectroscopic studies and chemical transformations.
authors.affiliation: Faculté des Sciences Pharmaceutiques et Biologiques, Laboratoire de Pharmacognosie de l'Université Paris Descartes, UMR/CNRS 8638, 4 Avenue de l'Observatoire, 75006 Paris, France. mocarre@yahoo.fr
authors.forename: Itbert Joseph
authors.initials: IJ
authors.lastname: Momo
authors.forename: Thi-Hanh
authors.initials: TH
authors.lastname: Dufat
authors.forename: Jean
authors.initials: J
authors.lastname: Wandji
authors.forename: Sylvie
authors.initials: S
authors.lastname: Michel
authors.forename: David Dako
authors.initials: DD
authors.lastname: Chiozem
mesh_terms: D018360:Crystallography, X-Ray; D019770:Lauraceae / Q000737:chemistry*; D000432:Methanol; D015394:Molecular Structure; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000032:analysis* / Q000302:isolation & purification; D014315:Triterpenes / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D010936:Plant Extracts; D014315:Triterpenes; D000432:Methanol