C-methylated and C-prenylated isoflavonoids from root extract of Desmodium uncinatum

Abstract

A pterocarpan, 1,9-dihydroxy-3-methoxy-2-methylpterocarpan (named uncinacarpan) and two isoflavanones, 5,7-dihydroxy-2′,3′,4′-trimethoxy-6-(3-methylbut-2-enyl)isoflavanone (named uncinanone D) and 5,4′-dihydroxy-7,2′-dimethoxy-6-methylisoflavanone (named uncinanone E), were isolated from the CH2Cl2 root extract of Desmodium uncinatum (Jacq.) DC and characterised by spectroscopic methods. In addition, a rare pterocarpan edudiol and two known abietane diterpenes, 7-oxo-15-hydroxydehydroabietic acid and 7-hydroxycallitrisic acid were identified. The fraction of the root extract that was analysed induced germination of Striga hermonthica seeds, but none of the isolated compounds showed this activity. Graphical abstract

Three isoflavonoids, uncinacarpan (1), uncinanone D (3) and uncinanone E (4), along with three known compounds were isolated from the roots of Desmodium uncinatum, which induced germination of Striga hermonthica seeds. The isolated compounds were characterised by spectroscopic methods.