Abstract

We evaluated the anti-depressive activity of ethanolic extracts of Gardenia jasminoides Ellis. (GJ _EtOH), Gardenia jasminoides Ellis. var. grandiflora Nakai. (GJG _EtOH) and geniposide with mouse forced swimming test (FST) and tail suspension test (TST). In addition, we investigated the possible mechanisms of action of anti-depressive effect of geniposide (GPO). The results showed that GJ_EtOH (0.1, 1.0 g/kg, p.o.) and GJG _EtOH (0.1, 1.0 g/kg, p.o.) significantly reduced the immobility time of mice in both FST and TST, but they did not affect the locomotor activity of mice. Geniposide (10 mg/kg, i.p.) augmented the anti-depressive effect of desipramine (5 mg/kg, i.p.) and fluoxetine (5 mg/kg, i.p.) in the FST, but it did not affect the anti-depressive effect of clorgyline and maprotiline. Geniposide (10 mg/kg, i.p.) increased the levels of serotonin and 5-HIAA in striatum and serotonin in hippocampus. These results suggested that anti-depressive mechanism of GPO may be related to the increasing serotonin level in striatum and hippocampus in mice.

Key words: Gardenia jasminoides Ellis., Gardenia jasminoides Ellis. var. grandiflora Nakai., geniposide, forced swimming test, anti-depressive effect, monoamines.