Linalool and
linalyl acetate are the principal components of many
essential oils known to possess several biological activities, attributable to these
monoterpene compounds. In this work, we evaluated individually the anti-inflammatory properties of (-)
linalool, that is, the natural occurring enantiomer, and its racemate form, present in various amounts in distilled or extracted
essential oils. Because in the
linalool-containing
essential oils,
linalyl acetate, is frequently present, we also examined the anti-inflammatory action of this
monoterpene ester.
Carrageenin-induced
edema in rats was used as a model of
inflammation. The experimental data indicate that both the pure enantiomer and its racemate induced, after systemic administration, a reduction of
edema. Moreover, the pure enantiomer, at a dose of 25 mg/kg, elicited a delayed and more prolonged effect, while the racemate form induced a significant reduction of the
edema only one hour after
carrageenin administration. At higher doses, no differences were observed between the (-) enantiomer and the racemate; a further increase in the dose of both forms did not result in an increased effect at any time of observation. The effects of equi-molar doses of
linalyl acetate on local
edema were less relevant and more delayed than that of the corresponding alcohol. These finding suggest a typical
pro-drug behavior of
linalyl acetate. The results obtained indicate that
linalool and the corresponding
acetate play a major role in the anti-inflammatory activity displayed by the
essential oils containing them, and provide further evidence suggesting that
linalool and
linalyl acetate-producing species are potentially
anti-inflammatory agents.