New 6a-hydroxypterocarpan with insect antifeedant and antifungal properties from the roots of Tephrosia hildebrandtii vatke
Njoroge, P. W.
Bentley, M. D.
Monache, F. D.
Jondiko, J. I.
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A new 6a-hydroxylated pterocarpan, named hildecarpin, has been isolated from the healthy roots of Tephrosia hildebrandtii. It has been assigned the structure (−)-3, 6a-dihydroxy-2-methoxy-8, 9-methylenedioxypterocarpan on the basis of its spectroscopie data, optical rotation and chemical transformations. Hildecarpin has exhibited insect antifeedant activity against the legume pod-borer Maruca testulalis, an important pest of the cowpea (Vigna unguiculata), and antifungal activity against Cladosporium cucumerinum. This finding suggests that the pterocarpan phytoalexins formed as a result of microbial infection of the cowpea plant may constitute a basis for induced resistance in the plant against M. testulalis.