The inhibitory activity of nutmeg essential oil on GABAA α1β2γ2s receptors

The inhibitory effects of nutmeg essential oil and three components of this oil at different concentrations were tested by GABA-induced chloride current (I GABA) stimulation through gamma-aminobutyric acid type A (GABAA) receptors comprising of α1β2γ2s subtype using the two-microelectrode voltage clamp technique on Xenopus laevis oocytes. The essential oil of the kernels of Myristica fragrans was extracted by steam distillation and was analysed by gas chromatography-mass spectrometer (GC-MS) technique. A total of 16 compounds were isolated from the essential oil. The essential oil showed promising activity by enhanced I GABA up to 100% of stimulation when tested at 100 nL/mL. For dose dependent activity, α-terpineol and myristicin showed statistical significant potentiation of I GABA. α-Terpineol was found to induce an enhancement of I GABA modulation (EC5-10) by 229.6±23.8% and 326.3±43.8%, at 100 μM and 500 μM, respectively. Myristicin induced an enhancement up to 237.6±35.1% at 500 μM. In contrast, limonene exhibited weak modulation compared to GABA controls at the same concentration. The essential oil and its two components exhibited promising inhibitory activity by enhancement of I GABA that provides scientific evidence for its traditional use in the treatment of epilepsy.