Local anaesthetic activity of the essential oil of Lavandula angustifolia

In this work we studied the local anaesthetic activity of the essential oil obtained from Lavandula angustifolia Mill., a medicinal plant traditionall y used as an antispasmodic. We compared its activity to the essential oils obtained from two citrus fruits, Citrus reticulata Blanco and Citrus limon (L.) Burm. f., which have no medical uses, Biological tests were also perfo rmed on the major pure components of L. angustifolia Mill. essential oil: l inalol and linalyl acetate as determined by CC and confirmed by CC-MS. Anae sthetic activity was evaluated in vivo in the rabbit conjunctival reflex te st, and in vitro in a rat phrenic nerve-hemidiaphragm preparation, The esse ntial oil of L. angustifolia, linalyl acetate and linalol (0.01-10 mu g/ml) but not the oils of Citrus reticulata and Citrus limon were able to drasti cally reduce, in a dose-dependent manner, the electrically evoked contracti ons of rat phrenic-hemidiaphragm. In the rabbit conjunctival reflex test tr eatment with a solution of essential oil of L. angustifolia, as well as lin alyl acetate and linalol (30-2500 mu g/ml administered in the conjunctival sac) allow a dose-dependent increase in the number of stimuli necessary to provoke the reflex, thus confirming in vivo the local anaesthetic activity observed in vitro.