Abstract
This study investigated the anxiolytic-like effects of 4-O-methylhonokiol, a neolignan compound of Magnolia officinalis, by using the experimental paradigms of anxiety and compared the results with those of a known anxiolytic, diazepam. A single treatment with 4-O-methylhonokiol (0.1, 0.2, and 0.5 mg/kg, p.o.) or treatment for 7 days (0.5 mg/kg in drinking water) increased the percentage of time spent in the open arms and the number of open arms entries in the elevated plus-maze test. However, the 4-O-methylhonokiol-increased percentage of time spent in the open arm was abolished by treatment with flumazenil, a benzodiazepine receptor antagonist (10 mg/kg). 4-O-Methylhonokiol also increased the number of head dips in the hole-board test, but decreased locomotor activity. Molecular experiments revealed that the α1-subunit of γ-aminobutyric acid (GABA) type A receptors was overexpressed in the cortex of brains of mice after treatment with 4-O-methylhonokiol for 7 days. In addition, 4-O-methylhonokiol also increased chloride influx in cultured cortical cells. It is concluded that 4-O-methylhonokiol may have anxiolytic-like effects and that these effects may be mediated by GABAergic transmission with the increase of Cl– channel opening.
Get full access to this article
View all access options for this article.
