Prenylated flavonoids of Erythrina lysistemon grown in Egypt

Three prenylated flavonoid derivatives; 5,7,4′-trihydroxy-8-(3‴-methylbut-2‴-enyl)-6- (2″-hydroxy-3″-methylbut-3″enyl) isoflavone (isoerysenegalensein E), 5,7,2′-trihydroxy-4′-methoxy-5′-(3″-methylbut-2 ″-enyl) isoflavanone (lysisteisoflavanone), 5, 4′-dihydroxy- 6-(3‴-methylbut-2‴-enyl)-2″-hydroxyisopropyl dihydrofurano [4″,5″:8,7] isoflavone (isosenegalensin), together with the four known flavonoids abyssinone V-4′-methylether, alpinumisoflavone, wighteone and burttinone were isolated from the stem bark of Erythrina lysistemon Hutch. (Leguminosae). Structures were elucidated by spectroscopic methods.