Identification of the Cat Attractants Isodihydronepetalactone and Isoiridomyrmecin from Acalypha indica

Abstract

Acalypha indica is a herb that grows throughout the tropical regions of the world. As well as being exploited for medicinal use, the roots of this plant are known to elicit a drug-like effect in cats. Recent research into feral cat control on Christmas Island has investigated whether a preparation of the roots of A. indica might be effective in traps to attract feral cats. However, the volatile nature of the attractants made it unviable for use in traps for more than a few days. In this study, we investigated the volatile components emitted by the plant roots and identified two iridoid compounds, (4R,4aR,7S,7aR)-isodihydronepetalactone and (4R,4aS,7S,7aR)-isoiridomyrmecin, which are known to affect behavioural activity in cats. Synthesis of standards confirmed the stereochemistry of both compounds emitted by the plant. Potential application of these compounds in feral cat control is discussed.