Isoflavanones from the allelopathic aqueous root exudate of Desmodium uncinatum.
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.
Tsanuo
Muniru K
MK
Chemistry Department, Jomo Kenyatta University of Agriculture and Technology, PO Box 62000, Nairobi, Kenya.
Hassanali
Ahmed
A
Hooper
Antony M
AM
Khan
Zeyaur
Z
Kaberia
Festus
F
Pickett
John A
JA
Wadhams
Lester J
LJ
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
D007529:Isoflavones; C065753:isoflavanone