title: Isoschaftoside, a C-glycosylflavonoid from Desmodium uncinatum root exudate, is an allelochemical against the development of Striga.
abstract: In East African small-holder farming of maize, the cattle forage legume, Desmodium uncinatum is used as an intercrop due to its allelopathic inhibition of parasitism by Striga hermonthica, an obligate parasitic weed that can devastate the maize crop. Bioassay-guided fractionation of the root extract of D. uncinatum revealed isoschaftoside to be the main compound in the most potent fraction inhibiting growth of germinated S. hermonthica radicles. Bioassays repeated with isoschaftoside isolated from a different plant source, Passiflora incarnata, proved it to be a biologically active component. Analysis of the root exudates produced by hydroponically grown D. uncinatum showed isoschaftoside to be present in the hydroponic media at biologically active concentrations of 10-100 nM.
authors.affiliation: Biological Chemistry Department, Centre for Sustainable Pest and Disease Management, Rothamsted Research, Harpenden, Herts, UK. tony.hooper@bbsrc.ac.uk
authors.forename: Antony M
authors.initials: AM
authors.lastname: Hooper
authors.forename: Muniru K
authors.initials: MK
authors.lastname: Tsanuo
authors.forename: Keith
authors.initials: K
authors.lastname: Chamberlain
authors.forename: Kay
authors.initials: K
authors.lastname: Tittcomb
authors.forename: Julie
authors.initials: J
authors.lastname: Scholes
authors.forename: Ahmed
authors.initials: A
authors.lastname: Hassanali
authors.forename: Zeyaur R
authors.initials: ZR
authors.lastname: Khan
authors.forename: John A
authors.initials: JA
authors.lastname: Pickett
mesh_terms: D000351:Africa, Eastern; D000818:Animals; D002417:Cattle; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D015394:Molecular Structure; D010675:Pheromones / Q000494:pharmacology; D010935:Plant Diseases / Q000469:parasitology; D053147:Plant Exudates / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism; D034362:Striga / Q000187:drug effects / Q000378:metabolism*; D003313:Zea mays / Q000254:growth & development
chemical_list: D005419:Flavonoids; D006027:Glycosides; D010675:Pheromones; D053147:Plant Exudates; C515113:isoschaftoside