In this study we evaluate the in vivo antidepressant effect of a natural phenolic compound, trans-resveratrol, and a synthetic derivative from Menispermum dauricum DC (Menispermaceae) 5-methoxy-7H-dibenzo[de,h]quinolin-7- one known as 5-methoxyoxoisoaporphine (OXO 4). The antidepressant-like effect of trans-resveratrol and OXO 4 were evaluated through a Forced Swimming Test (FST), and they were compared with reference antidepressants: imipramine, desipramine, nomifensine, bupropion, nisoxetine, citalopram and moclobemide. Trans-resveratrol (10 mg/kg, intraperitoneally i.p. significantly decreased the immobility time in mouse model of despair test (69.03 ± 8.74 sec) p<0.05, as well as OXO 4 (1mg/kg, i.p. (60.92 ± 11.37 sec); p<0.05. We also evaluate the OXO 4 at 15, 30 and 45 min. affording the mayor reduction at 30 minutes after the administration. Thus, our results suggest that OXO 4 has a great antidepressant effect non-reported for this type of isoquinoline alkaloids. The pharmaceutical use of OXO 4 in the treatment of depressive disorders is a therapeutic alternative to be studied.