Coixol (6-methoxybenzoxazolone) contained in Coix Lachryma-Jobi L. var. ma-yuen Stapf was compared with
chlorzoxazone with respect to behavioral and EEG effects in mice and rats.
Coixol 50-100 mg/kg, i.p. decreased locomotor activities of both species and produced
hypothermia in rats. These effects of
coixol were the same in potency as
chlorzoxazone given in the same dose.
Coixol was approximately twice as potent as
chlorzoxazone in potentiating
thiopental-induced sleep. This compound attenuated the writhing syndrome induced by 1%
acetic acid and increased the threshold to jumping response induced by foot
shock, to the same degree as seen with
chlorzoxazone.
Coixol was equipotent to
chlorzoxazone in preventing convulsions induced by maximal electro-
shock, while it was about 1.5 times more potent than
chlorzoxazone in suppressing
pentylenetetrazol-induced convulsion.
Coixol 20-100 mg/kg inhibited the lever pressing response of hypothalamic self-stimulation in rats. In rats with chronically
implanted electrodes,
coixol 50-100 mg/kg induced drowsy patterns on the spontaneous EEG. The EEG arousal response to the external auditory stimulation was inhibited by the same doses of
coixol, whereas it failed to suppress the arousal response to the midbrain reticular stimulation. These results indicate that
coixol has pharmacological properties qualitatively similar to
chlorzoxazone and acts as a central muscle relaxant with an anti-
convulsant effect.