[Effect of madecassoside on depression behavior of mice and activities of MAO in different brain regions of rats].

Objective: To evaluate the effects of madecassoside (MC) on the depression behavior of mice and the activities of monoamine oxidase (MAO) in different rat brain regions.

Methods: Imipramine as the positive contrast medicine, effects of MC on the depression behavior of mice were observed by forced swimming test and reserpine antagonist test. Moclobemide and pargyline as the positive controlled medicines, the activities of monoamine oxidase-A (MAO-A) and monoamine oxidase-B (MAO-B) in different rat brain regions were determined after intragastric administration of MC in 3 different dosages for 3 days or 21 days.

Results: (1) The low, middle and high dosages of MC (i.g.) significantly reduced the immobility time of mice in forced swimming test (P<0.05). (2) MC in dosages of 10 mg/kg and 20 mg/kg prevented the lowering of temperature induced by reserpine (P<0.05), while 40 mg/kg had no significant effects on it (P>0.05). (3) With acute administration (3 days), the low, middle and high dosagey of MC (i.g.) significantly inhibited the activity of MAO-A in hippocampus (P<0.01), and the high dosage significantly inhibited the activity of MAO-A in hypothalamus (P<0.01), while the 3 dosages had no significant effects on the activity of MAO-A in cortex (P>0.05). With chronic administration (21 days), MC in 3 dosages had no significant effects on the activities of MAO-A in cortex and hypothalamus (P>0.05), and the high dosage (40 mg/kg) significantly enhanced the activity of MAO-A in hippocampus (P<0.01). (4) With acute administration, MC in dosages of 10 mg/kg and 20 mg/kg significantly inhibited the activity of MAO-B in cortex (P>0.05), and MC in dosage of 10 mg/kg significantly inhibited the activity of MAO-B in hypothalamus (P<0.05), and MC in dosage of 20 mg/kg significantly enhanced the activity of MAO-B in hippocampus (P<0.01). With chronic administration, MC of 3 dosages produced no significant effects on the activities of MAO-B in 3 different rat brain regions (P>0.05).

Conclusion: These results support the idea that MC produces antidepressant effects through MAO inhibition in rat brain, which seems stronger with acute administration than chronic administration, while its mechanism remains to be further studied.