How Anti-Juvenile Hormones Work

Abstract

Synopsis. Two compounds which possess anti-juvenile hormone activity in insects have been isolated and identified from the plant Ageratum houstonianum. These compounds, called precocenes, have been shown to inhibit the development ofthe insect corpus allatum (CA) and/or destroy the CA in sensitive species. The action of the precocenes can be seen to affect only those CA which are actively synthesizing and secreting the juvenile hormone. Structure-optimization studies of the precocenes reveal that the 3,4-double bond must be present and unsubstituted for biological activity to occur. In vivo and in vitro studies reveal that the precocenes are very probably converted into reactive epoxides which undergo facile reaction with nucleophiles since histological examination of precocene-inactivated CAs indicate a direct cytotoxic action of the precocenes on the parenchymal cells of the CA. The most likely mode of action would appear to involve the alkylation of macromolecular cellular elements by a reactive epoxide or similar activated precocene inter? mediate.