Julibroside C1 is a saponin-containing compound isolated from Albizzia julibrissin Durazz. In this study, we investigated the putative anxiolytic effects of Julibroside C1 using the elevated plus maze (EPM) in mice. Julibroside C1 at doses of 0.5 and 1 mg/kg significantly increased the time spent in the open arms and the number of entries into the open arms of the EPM compared to the control group. Moreover, the anxiolytic-like effects of Julibroside C1 (0.5 mg/kg) were blocked by WAY-100635 (5-HT1A receptor antagonist), bicuculline (GABAA receptor antagonist), and flumazenil (antagonist of the GABAA receptor benzodiazepine site). However, Julibroside C1 did not change locomotor activity or induce myorelaxant effects. We used quantitative receptor autoradiography to investigate the effects of Julibroside C1 on alterations in mouse brain receptors. After acute treatment with Julibroside C1 (0.5 mg/kg), [3H]-8-OH-DPAT binding was significantly decreased in the CA1 region of the hippocampus and [3H]-flunitrazepam binding was decreased remarkably in the cingulate cortex region. However, [3H]-muscimol binding did not show a significant change in any brain region. Taken together, our findings suggest that Julibroside C1 shows anxiolytic-like effects, which might be mediated by the 5-HT1A and GABAA–benzodiazepine receptor systems.Highlights
▪ Julibroside C1 showed anxiolytic-like effects in the EPM test. ▪ Julibroside C1 effects were blocked by WAY-100635, bicuculline, and flumazenil. ▪ Julibroside C1 induced alterations in 5-HT1A and GABAA receptors in the mouse brain.