The methanolic extract of the Rhizome of Curcuma zedoaria exhibited a significant prolongation of hexobarbital (HB)-induced hypnosis. Through liquid chromatography of an ether soluble fraction, monitoring by bioassay, three sesquiterpenes, germacrone(A), curzerenone(B) and germacrone epoxide(C) were isolated as active constituents. A single treatment (100-200mg/kg, i.p.) of each compound showed not only a significant prolongation of HB-induced sleeping time but also a significant inhibition of aminopyrine N-demethylase activity in mice, and further exhibited a typical type I binding spectra with oxidized rat hepatic cytochrome P-450 induced by phenobarbital. All of the compounds provoked a sleep episode at a subhypnotic dose of HB, implying that they possess CNS depressant properties.
|