Study On The Antidepressant Fraction From The Compound Prescription Of Xiao Bu Xin Tang And It's Chemical Components

The compound prescription of Xiao Bu Xin Tang is derived from the posthumous writings "Fuxingjue Zangfu Yongyao Fayao" of Tunhuang Mogaoku, and is constituted by four crude drugs which are ochre, inula flower, fermented soybean and bamboo leaf. In the investigation of new antidepressant agents from some compound prescription of traditional Chinese medicine (TCM), the water extract and the 70% alcohol extract of Xiao Bu Xin Tang recipe both showed remarkable antidepressant effect in the multi-models evaluation by mice forced swimming test, mice suspension test, rat forced swimming test and mice 5-HTP induced head-twitches.Further fractionation of the 70% alcohol extract under the guidance of bioassays led to the discovery of an active fraction BX-2 that contains about 76.03% flavonoids. BX-2 was isolated by using macroporous resin and its content of flavonoids was detected by colour comparimetry using lutin as standard.The chemical components in BX-2 was studied for the explaination of the major chemicals and the effective compounds. By this time, two new flavonols japonicins A and B, along with 19 flavonoids and an organic acid were isolated from BX-2. And the special structure of japonicins A and B having the substituent 1-phenylethyl at C-8 position of a flavonoid nuclus was discovered for the first time. And it was also revealed that the major constituents of BX-2 were flavones, flavonols, isoflavones and their glycosides.HPLC analysis revealed that the flavones and flavonols were primary derived from inula flower as well as the most isoflavones were derived from fermented soybean, and the rest of isoflavones came from bamboo leaf.All results mentioned above showed that the flavonoid fraction from the compound prescription of Xiao Bu Xin Tang had definitive antidepressant effect in animal experiments and was easy to be separated. Hence, the flavonoid fraction would be a potential antidepressant medicine. Moreover, this study will be a good experience for the secondary research and development on the compound prescriptions of TCM as well as the modernization of TCM.