The Synergistic Antidepressant Effect: Compatibility of Alkaloids with Saponins from Ziziphi Spinosae Semen

Context. Ziziphi Spinosae Semen (ZSS) is a well-known Chinese herbal medicine used in the treatment of depression and anxiety in China. ZSS contains several active components, such as alkaloids, saponins, and flavonoids. Objective. This study aimed to explore the synergistic effect of alkaloids and saponins from ZSS in alleviating depression in a mouse model. Materials and Methods. Modeling depression with chronic unpredictable stimuli. Pharmacodynamic methods (tail suspension test and forced swimming test) were used to evaluate the antidepressant effects of alkaloids, saponins, and combinations thereof from ZSS. The mechanisms underlying the effect were examined by measuring the levels of monoamine neurotransmitters in the hippocampus and frontal cortex of mice. Results. Compared with the model group, alkaloids therapy (AZSS), saponins therapy (SZSS), and combination therapy significantly reduced the immobility time in behavioral tests (P < 0.05). The contents of noradrenaline (NE), dopamine (DA), and serotonin (5-HT) in the hippocampus and frontal cortex of depressed mice were increased in the drug treatment groups, especially in the combination group, which increased by 14.65%, 87.72%, 33.44%, 25.64%, 25.39%, and 70.78%, respectively. Several groups showed better results (P < 0.05), especially the combination of alkaloids and saponins. Discussion and Conclusion. The saponins and alkaloids from ZSS exhibited a synergistic effect in improving the behavior of depressed mice. More importantly, the combination of alkaloids (15 mg·kg-1) and saponins (110 mg·kg-1) was effective in alleviating depression in mice, especially in terms of changing the level of DA in the hippocampus.