Dihydromagnolol - A potent anxiolytic-like agent in mice

Oral administration of a single 1 mg/kg dose of dihydromagnolol [DHM; 5′-(2-propenyl)-5-propyl-(1,1′-biphenyl)-2,2′-diol] produced a significant anxiolytic-like effect in mice, as assessed in an elevated plus-maze test. This dose did not cause any marked change in ambulatory activity. The anxiolytic-like effect peaked at 1 h and persisted for more than 3 h after administration. Significant anxiolytic-like activity at a dose of 1 mg/kg of dihydromagnolol was also indicated by use of Vogel's conflict test. Although dihydromagnolol enhanced ³⁶Cl^- uptake into mouse cortical synaptoneurosomes in the absence of muscimol in in vitro experiments, it did not alter the activities of diazepam, flumazenil or bicuculline in vivo. The results of these studies suggest that the anxiolytic-like activity of DHM occurs through action at a site(s) in the nervous system other than the GABA_A/benzodiazepine receptor complex which is the site of action of the traditional benzodiazepine anxiolytics.