Green chemistry approach to insect repellents

Plant essential oils have provided an expanse of interesting chemistry, but for many of them the biological activity is yet to be explored. Following the trail of folklore about catnip and osage orange (hedgeapple) provided us with our entry into the world of natural insect repellents. Major terpenoids are isolated from the oils and evaluated for their bioactivity against mosquitoes. Our research on the monoterpenoids and sesquiterpenoids from plant essential oils has focused on distinguishing between spatial repellency and contact irritancy, as well as developing quantitative structure-activity relationships for their repellent activity against mosquitoes. The results of the QSAR studies are equations that help predict activity of new or unavailable terpenoids or of synthetic derivatives.