title: Oleanane-type triterpenes of Embelia schimperi leaves.
abstract: An investigation of an ethyl acetate extract of Embelia schimperi leaves has led to the isolation of 10 oleanane-type triterpenes characterized as 3beta,16alpha-di-O-acetyl-13beta, 28-epoxyoleanane (1), 3beta-acetyl-16-oxo-13beta, 28-epoxyoleanane (2), 3beta-acetyl-16alpha-hydroxy-13beta, 28-epoxyoleanane (3), 3beta-acetyl-16alpha-hydroxyoleanane-13beta, 28-olide (4), 3beta-acetyl-28-hydroxy-16-oxo-12-oleanene (5), 3beta, 28-di-O-acetyl-16alpha-hydroxy-12-oleanene (6), 3beta-acetyl-11alpha, 28-dihydroxy-16-oxo-12-oleanene (7), 3beta, 11alpha, 16alpha, 28-tetrahydroxy-12-oleanene (8), 3beta-acetyl-16alpha, 28alpha-dihydroxy-13beta, 28-oxydooleanane (9) and 3beta, 28alpha-dihydroxy-16-oxo-13beta, 28-oxydooleanane (10). The known compounds isolated from the same extract included 3beta, 16alpha-dihydroxy-13beta, 28-epoxyoleanane (protoprimulagenin A) (11), 3beta-hydroxy-16-oxo-13beta, 28-epoxyoxyoleanane (aegicerin) (12), 3, 16-dioxo-13beta, 28-epoxyoleanane (embilionone) (13), 3beta, 28-dihydroxy-16-oxo-12-oleanene (schimperinone) (14), taraxerone (15), taraxerol (16) and stigmasterol (17). Structure elucidations were carried out spectroscopically.
authors.affiliation: Department of Chemistry, Maseno University, Private Bag, Maseno, Kenya. kamanguro@yahoo.com
authors.forename: Lawrence Onyango Arot
authors.initials: LO
authors.lastname: Manguro
authors.forename: Steve Onyango
authors.initials: SO
authors.lastname: Okwiri
authors.forename: Peter
authors.initials: P
authors.lastname: Lemmen
mesh_terms: D031645:Embelia / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009828:Oleanolic Acid / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification; D018515:Plant Leaves / Q000737:chemistry*; D014315:Triterpenes / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D014315:Triterpenes; C413246:oleanane; D009828:Oleanolic Acid