Isoflavanones from the allelopathic aqueous root exudate of Desmodium uncinatum

• Published in: Phytochemistry (Oxford) Vol. 64; no. 1; pp. 265 - 273
• Main Authors: Tsanuo, M.K, Hassanali, A, Hooper, A.M, Khan, Z, Kaberia, F, Pickett, J.A, Wadhams, L.J
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier 01.09.2003
• Subjects: Agronomy. Soil science and plant productions; allelochemicals; allelopathy; biochemical pathways; Biochemistry; Biochemistry & Molecular Biology; Biochemistry and biology; Biological and medical sciences; Biological Assay - methods; chemical constituents of plants; chemical structure; Chemical, physicochemical, biochemical and biological properties; Desmodium uncinatum; dose response; Fabaceae - chemistry; flavones; Fundamental and applied biological sciences. Psychology; Germination - drug effects; host plants; hydroponics; Hydroponics - methods; isoflavanones; Isoflavones - chemistry; Isoflavones - isolation & purification; Isoflavones - pharmacology; isolation; legumes; Life Sciences & Biomedicine; Magnetic Resonance Spectroscopy; parasitic plants; Parasitism; Parasitism and symbiosis; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Plant physiology and development; Plant Roots - chemistry; Plant Sciences; root exudates; Science & Technology; seed germination; seedlings; Seeds - drug effects; Seeds - growth & development; Soil science; spectral analysis; Striga - drug effects; Striga - growth & development; Striga hermonthica; uncinanones; weeds; STRIGA-HERMONTHICA; ASIATICA; Striga hermonthica; SESQUITERPENE LACTONES; allelopathy; WITCHWEED GERMINATION; Leguminosae; uncinanone A, B and C; SORGHUM; Scrophulariaceae; radical growth inhibitor; PLANTS; GERMINATION STIMULANT; seed germination stimulant; Desmodium uncinatum; Growth inhibitor; Exudate; Root; Molecular structure; Allelopathy; Isoflavone derivatives; Allelochemicals; Flavanone derivatives; Structure activity relation; Dicotyledones; Angiospermae; Striga hermonthica; Scrophulariaceae; Desmodium uncinatum; Leguminosae; Allelopathy; Seed germination stimulant; Radical growth inhibitor; Uncinanone A; Spermatophyta; B and C; Parasitic plant
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/S0031-9422(03)00324-8

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. (C) 2003 Elsevier Ltd. All rights reserved.