Ghelardini C, Galeotti N, Mazzanti G
Planta Medica, 2001
The local anaesthetic activity of a number of compounds with different structures, contained in essential oils, was studied. Anaesthetic activity was evaluated in vivo in the rabbit conjunctival reflex test and in vitro in a rat phrenic nerve-hemidiaphragm technique. Among the substances tested terpineol and trans-anethole (10(-3) – 1 microg/ml) were able to drastically reduce the electrically evoked contractions of rat phrenic nerve-hemidiaphragm in a concentration-dependent manner, but not eugenol, (-)- and (+)-citronellal, (-)- and (+)-carvone, trans cinnamaldehyde and alpha-terpinene. In the rabbit conjunctival reflex test, the treatment with a solution of terpineol and trans-anethole (10 – 100 microg/ml) effected a concentration-dependent increase in the number of stimuli required to evoke the reflex, thus confirming in vivo the local anaesthetic activity observed in vitro. Eugenol, (-)- and (+)-citronellal, trans-cinnamaldehyde, (-)- and (+)-carvone and alpha-terpinene were as ineffective in the in vivo test as they were in the in vitro results.
Ghelardini C, Galeotti N, Mazzanti G. Local anaesthetic activity of monoterpenes and phenylpropanes of essential oils. Planta Med. 2001;67(6):564-566.