Towards a Better Understanding of the Psychopharmacology of Nutmeg – Observed Activitiesin the Mouse Tetrad Assay

Nutmeg, the seed of Myristica fragrans (family Myristicacae), is a well known kitchen spice whose reputation as a psychoactive herb has been observed since ancient times. Nutmeg at high doses (5 gm or more) is considered a cheap substitute to marijuana. Earlier reports also attributed amphetamine-like activities to nutmeg [1]. However, no thorough investigation has been conducted to date to substantiate, or dispute, the reputed activity of nutmeg. In this preliminary study, different extracts of nutmeg (n -hexane, dichloromethane, methanol and a trimyristin-rich fraction) and myristicin were tested in the mouse tetrad model for locomotor activity, catalepsy, analgesia and hyper/hypothermia alongside of Δ⁹ -tetrahydrocannabinol (THC) (20 mg/kg, i.p.) and amphetamine (10 mg/kg, i.p.) as positive controls. The dichloromethane and n-hexane extracts caused significant reduction in locomotor activity (p < 0.01) and pronounced hypothermia (p < 0.01) at a dose of 100 mg/kg. In a time-course study, the hypothermic effect of the dichloromethane extract persisted for 120 min while the locomotor activity was lowest after 60 min. None of the tested samples displayed analgesic effects or catalepsy at the tested doses. The collective results suggest that the effects of nutmeg are more related, but not identical, to THC than to amphetamine and that the dichloromethane extract is a potential candidate for further investigation. Acknowledgements: The project was supported by Grant Number P20RR021929 from the National Center for Research Resources. References: [1] Braun U, Kalbhen D (1973) Pharmacology 9: 312–316.