title: New flavonoids from the stem bark of Erythrina caffra Thunb.
abstract: Three new flavonoids 5,7-dihydroxy-2',4'-dimethoxy-5'-formylisoflavanone (erycaffra E) (1), 5,7-dihydroxy-3'-(2″-hydroxy-3″-methylbut-3-enyl)-5'-(3‴-hydroxy-3‴-methyl-trans-but-1-enyl)-4'-methoxyflavanone (erycaffra D) (2) and 5,7-dihydroxy-4'-methoxy-3',5'-di-(3″-hydroxy-3″-methyl-trans-but-1-enyl)flavanone (erycaffra F) (3) were isolated from the stem bark of Erythrina caffra along with four known compounds, namely 5,4'-dihydroxy-6-(3″-methylbut-2″-enyl)-5‴-hydroxyisopropyldihydrofurano[2‴,3‴:7,8]isoflavone (isosenegalensein) (4), 5,7-dihydroxy-4'-methoxy-3'-(3″-methylbut-2-enyl)-5'-(3‴-hydroxy-3‴-methylbut-1-enyl)flavanone (burttinone) (5), 5,4'-dihydroxy-5″-hydroxyisopropyldihydrofurano[2‴,3‴:7,6]isoflavone (erythrinin C) (6) and 5,4'-dihydroxy-6″-hydroxymethyl-6″-methylpyrano[2″,3″:6,7]isoflavone (erysubin B) (7). The structures were determined on the basis of spectroscopic data (1D, 2D NMR and MS) and by comparison with literature values.
authors.affiliation: a Department of Chemistry , University of Botswana , Private Bag 0022, Gaborone , Botswana.
authors.forename: Zelalem Yibralign
authors.initials: ZY
authors.lastname: Desta
authors.forename: Norbert
authors.initials: N
authors.lastname: Sewald
authors.forename: Runner R T
authors.initials: RR
authors.lastname: Majinda
mesh_terms: D001902:Botswana; D004895:Erythrina / Q000737:chemistry*; D007529:Isoflavones / Q000737:chemistry / Q000302:isolation & purification*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D024301:Plant Bark / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: C000591773:5,7-dihydroxy-2',4'-dimethoxy-5'-formylisoflavanone; C000591774:5,7-dihydroxy-3'-(2'-hydroxy-3'-methylbut-3-enyl)-5'-(3''-hydroxy-3'-methyl-trans-but-1-enyl)-4'-methoxyflavanone; D007529:Isoflavones
keywords: Erythrina caffra; fabaceae; flavanone; isoflavanone; isolation