Isolation and identification of house fly,Musca domestica L., repellents from pepper tree,Schinus molle L.

Foliage from the pepper tree,Schinus molle L., is traditionally used in Ethiopia to "repel" house flies,Musca domestica L. The volatile extracts of pepper tree leaves were shown to have repellent and feeding-deterrent activity against house flies in a two-choice laboratory bioassay. High-performance liquid chromatographic fractionation of steam-distilled volatiles from leaves, monitored by laboratory bioassays, demonstrated that bioactivity is associated with two compounds,cis-menth-2-en-1-ol andtrans-piperitol. The absolute configuration of the latter was established as (1S,6S)-piperitol by comparison of acetyl lactate derivatives. Racemic compounds were synthesized from piperitone, and bioassays with house flies indicatedtrans-piperitol to be the most active house fly repellent.