Preliminary studies on cowpea resistance to Aphis craccivora Koch (Hom., Aphididae)

Publication Type

Journal Article

Journal Name

Journal of Natural Products

Publication Date

1-1-1985

Abstract

Tephrosia elata Defiers (Leguminosae) is a short-lived, bushy perennial that occurs in Kenya on grassland, formerly cultivated land, and thicket margins in the highlands up to 6000 ft. (1). From a study of the seeds of T. elata, we have recently reported the isolation of isopongaflavone and tephrosin as feeding deterrents for Spodoptera exempta, Eldana saccharina, and Maruca testulalis larvae, and the identification of certain members of a community of insects associated with the seed pods of T. elata (2). Here we report the isolation and identification of six flavonoids from the roots of T. elata. They have been identified as the flavanones 8-(3, 3-dimethylallyl)-5, 7-dimethoxyflavanone and obovatin methyl ether, the flavone warangalone (scandenone), the pterocarpans (+)-pisatin and-()-maackiain, and the rotenoid tephrosin. Although isopongaflavone was found to occur in large quantities (1.2%) in the seeds of T. elata (2), we were unable to detect it in the roots. 8-(3, 3-Ditnethylallyl)-5, 7-dimethoxyflavanone has previously been isolated from Lonchocarpus costaricensis (3) while obovatin methyl ether has been isolated from Tephrosia obovata (4), Tephrosia praecans (5), and L. costaricensis (3). Warangalone has been isolated from Derris scandens (6). (+)-Pisatin is a major phytoalexin of Pisum sativum (7), while (—)-maackiain has been isolated as a phytoalexin from several species of Leguminosae (8). The isolation of pisatin and maackiain from apparently healthy roots of T. elata is interesting. Except for hildecarpin, an insect antifeedant 6a-hydroxypterocarpan that we recently isolated from Tephrosia hildebrandtii Vatke (9), pterocarpans have been isolated from Tephrosia only as phytoalexins, the formation of which has been induced by inoculation of the plants with microorganisms (10). © 1985, American Chemical Society. All rights reserved.

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