Search

Some essential oils obtained from the branches of four Pinus species (P. pinea L., P. halepensis Mill., P. pinaster Soil in Ait., and P. nigra Arnold) have been evaluated for their acaricidal activity by aerial diffusion against the stored food mite Tyrophagus putrescentiae (L.). All the essential oils showed a good efficacy, but P. pinea oil and its two constituents 1,8-cineole and limonene were the most effective compounds, showing 100% acaricidal activity at 8 microL; 1,8-cineole showed the same activity at 6 microL.

The pharmacological activity of many essential oils on a large number of human and animal pathogens, as used in folk medicine, has been confirmed world-wide by several laboratory investigations. Unfortunately, the biological properties of essential oils can be extremely inconsistent because of the variability of their chemical composition. The acaricidal activities of some natural terpenoids, which are the main constitutents of several essential oils, were evaluated in vitro against the mange mite (Psoroptes cuniculi) of the rabbit, by direct contact and by inhalation. Because the test components represent different chemical classes (hydrocarbons, alcohols, and phenols, with free and esterified or etherified functional groups), it was also possible to discern in a preliminary fashion a correlation between chemical structure and acaricidal activity. The results obtained suggest that molecules possessing free alcoholic or phenolic groups showed the most potent acaricidal activity.

Lavandula angustifolia Miller essential oil and some of its main constituents, i.e. linalool, linalyl acetate, and camphor were tested in vitro for their bioactivities against Psoroptes cuniculi (Delafond, 1859), mite of the rabbit. The essential oil and linalool were found to have very powerful miticidal activities.