Chemical Variation in <i>Piper aduncum</i> and Biological Properties of Its Dillapiole‐Rich Essential Oil

The essential oils of the specimens of Piper aduncum that occur in deforested areas of Brazilian Amazon, North Brazil, are rich in dillapiole (35-90%), a derivative of phenylpropene, to which are attributed biological properties. On the other hand, the oils of the specimens with occurrence in the Atlantic Forest, and Northeastern and Southeastern Brazil, do not contain dillapiole, but only terpene compounds such as (E)-nerolidol and linalool. One specimen existing in the Amazon was hydrodistilled. The obtained oil was fractioned on a silica chromatographic column, resulting in fractions rich in dillapiole (95.0-98.9%) utilized for analyses by GC and GC/MS, structural characterization by NMR, confirmation of their biological properties, and to obtain the isomer isodillapiole. Dillapiole showed a fungicide action against the fungus Clinipellis perniciosa (witches' broom) by inhibition of its basidiospores, in concentrations ranging from 0.6 to 1.0 ppm. The larvicide and insecticide actions of dillapiole were tested against the larvae and the adult insects of Anopheles marajoara and Aedes aegypti (malaria and dengue mosquitoes), resulting in mortality of the larvae (48 h, 100%) at a concentration of 100 ppm, and mortality of the insects (30 min, 100%) at a concentration of 600 ppm. The isomeric isodillapiole showed no significant activity in the same biological tests.