Three new isoflavonoids from Erythrina caffra

Abstract

Three new isoflavonoids, 5,7-dihydroxy-2′,4′-dimethoxy- 5′-(3-methylbut-2-enyl) isoflavanone (erycaffra A) (1), 5,7-dihydroxy-2′,4′-dimethoxy-5′-(2-hydroxy-3-methylbut-3- enyl)isoflavanone (erycaffra B) (2), and 5,7-dihydroxy-6,8-di-(2-hydroxy-3- methylbut-3-enyl)isoflavone (erycaffra C) (3), were isolated from the stem bark of E. caffra Thunb., along with eight known compounds, namely, alpinumisoflavone (4), isoerysenegalensein E (5), β-amyrin (6), oleanolic acid (7), octacosyl-E-ferulate (8), triacontyl-4-hydroxycinnamate (9), n -tetracosyl p-coumarate (10 ) and octacosan-1-ol (11 ). The structures were determined on the basis of spectroscopic (1D, 2D-NMR) and MS data and by comparison with literature values.