title: Isoflavanones from the allelopathic aqueous root exudate of Desmodium uncinatum.
abstract: Three isoflavanones, 5,7,2',4'-tetrahydroxy-6-(3-methylbut-2-enyl)isoflavanone (1), 4",5"-dihydro-5,2',4'-trihydroxy-5"-isopropenylfurano-(2",3";7,6)-isoflavanone (2) and 4",5"-dihydro-2'-methoxy-5,4'-dihydroxy-5"-isopropenylfurano-(2",3";7,6)-isoflavanone (3) and a previously known isoflavone 5,7,4'-trihydroxyisoflavone [genistein (4)] were isolated and characterised spectroscopically from the root exudate of the legume Desmodium uncinatum (Jacq.) DC. We propose the names uncinanone A, B, and C for compounds 1, 2 and 3, respectively. Isolated fractions containing uncinanone B (2) induced germination of seeds from the parasitic weed Striga hermonthica (Del.) Benth. and fractions containing uncinanone C (3) moderately inhibited radical growth, the first example of a newly identified potential allelopathic mechanism to prevent S. hermonthica parasitism.
authors.affiliation: Chemistry Department, Jomo Kenyatta University of Agriculture and Technology, PO Box 62000, Nairobi, Kenya.
authors.forename: Muniru K
authors.initials: MK
authors.lastname: Tsanuo
authors.forename: Ahmed
authors.initials: A
authors.lastname: Hassanali
authors.forename: Antony M
authors.initials: AM
authors.lastname: Hooper
authors.forename: Zeyaur
authors.initials: Z
authors.lastname: Khan
authors.forename: Festus
authors.initials: F
authors.lastname: Kaberia
authors.forename: John A
authors.initials: JA
authors.lastname: Pickett
authors.forename: Lester J
authors.initials: LJ
authors.lastname: Wadhams
mesh_terms: D001681:Biological Assay / Q000379:methods; D007887:Fabaceae / Q000737:chemistry*; D018525:Germination / Q000187:drug effects; D018527:Hydroponics / Q000379:methods; D007529:Isoflavones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D018517:Plant Roots / Q000737:chemistry*; D012639:Seeds / Q000187:drug effects / Q000254:growth & development; D034362:Striga / Q000187:drug effects / Q000254:growth & development
chemical_list: D007529:Isoflavones; C065753:isoflavanone