Studies On The Antidepressant Effect And Mechanisms Of Total Flavonoids Extracted From Xiao Bu Xin Tang

Objects In order to develop new antidepressant from the traditional Chinese medicine(TCM), some prescriptions of TCM was screened and evaluated, and the antidepressant mechanisms, as well as the substantial basis of the selected prescription, Xiao Bu Xin Tang ,were studied.Methods (1) Using the forced swimming test and suspension test in mice, seven prescriptions of TCM were screened and evaluated; (2) In order to further evaluate the antitdepressant effect of Xiao Bu Xin Tang and its total flavonoids(code name: BX-2), the forced swimming test, suspension test, 5-HTP induced head-twitches in mice and the forced swimming test in rats were used; (3) The effect of BX-2 on the monoamine level in the brain of chronically stressed mice was detected by HLPC-ECD. Using immunohistochemistry, the effects BX-2 on hippocampal neurogenesis and neurotrophy in chronically stressed mice were detected. (4) The viability of PC 12 cells was measured with MTT assay.Results (1) Xiao Ding Zhi Wan, Xiao Bu Xin Tang and Bai He Di Huang Tang all exerted antidepressant effect in forced swimming test and tail suspension test in mice.(2) Xiao Bu Xin Tang and BX-2 show antidepressant effect in forced swimming test in mice and rats, as well as in the suspension test and 5-HTP induced head-twitches in mice.(3) BX-2 could increase 5-HT and its metabolite 5-HIAA in the brain of chronically stressed mice. And BX-2 up-regulated hippocampal nurogenesis in chronically stressed mice. It was also found that BX-2 had neuroprotective effect on the impaired neurocyte of CA3 subfield. Meanwhile, BX-2 could increase BDNF (brain-derived neurotrophic factor) and pERK (phosphorylate extracellular signal-regulated kinase) levels in hippocampus of chronically stressed mice. (4) BX-2 could antagonize the corticosterone induced lesion in PC 12 cells.Conclusion (1) Xiao Bu Xin Tang and BX-2 have antidepressant effect. (2) The antidepressant mechanisms of BX-2 may be related to the followings: â‘  BX-2 can up-regulate the function of 5-HT transmission system. â‘¡BX-2 can increase hippocampal neurogenesis in chronically stressed mice and antagonize the chronic stress-induced hipocampal impairement. And also, increasing of hippocampal BDNF and pERK levels may be underlying the neurotrophy and neuroplasticity effects of BX-2.