Biological Function of Solanaceous Withanolides and Their Effects on Herbivorous Insects

Abstract

Naturally occurring withanolides are secondary metabolites with interesting biological activities in vivo and in vitro. The role of withanolide production in plants is still conjectural though numerous studies strongly indicate a potent feeding deterrent effect against insects and other herbivores. In contrast to the potential medical applications of withanolides, the ecological effects on herbivores have not been studied intensively. In this article, we collect and summarise present studies on herbivore–plant interactions in the light of potential insecticidal functions of withanolides. Moreover, taking the case of the specialist noctuid moth Chloridea ( Heliothis ) subflexa , we not only illustrate the known negative effects of these compounds seem to have on herbivorous insect species but also discuss how C. subflexa larvae might benefit from adaptation to their host plants in the genus Physalis . Further, we describe potential activation and detoxification mechanisms based on the current state of knowledge.