Identification and quantification of the major volatile constituents in antidepressant active fraction of xiaoyaosan by gas chromatography-mass spectrometry

Ethnopharmacological relevance

Xiaoyaosan (XYS), a well-known formula for relieving depression, was originated from the book of “Taiping Huimin Heji Jufang” in Song Dynasty (960–1127 AD), composed of Radix Bupleuri, Radix Angelicae Sinensis, Radix Paeoniae Alba, Rhizoma Atractylodis Macrocephalae, Poria, Herba Menthae, Rhizoma Zingiberis Recens and Radix Glycyrrhizae with dose proportion of 6:6:6:6:6:3:2:2. It is commonly used for the treatment of depression-related syndromes in China. In the formula, Radix Bupleuri usually serves as the principal drug, Radix Angelicae Sinensis and Radix Paeoniae Alba serve as the ministerial drugs, Rhizoma Atractylodis Macrocephalae, Poria, Herba Menthae and Rhizoma Zingiberis Recens serve as adjunctive drugs, Radix Glycyrrhizae serves as messenger drug, they coordinate with each other and enhance the effect of the formula. In our previous experiments, the antidepressant effect of XYS was revealed. However, the antidepressant part (or component) of this prescription was still obscure.

Materials and methods

An experimental despair animal model: the mice tail suspension test (TST) was used to evaluate the antidepressant activity of XYS and its fractions. GC–MS method was developed to identify the volatile components and determine 4 major volatile components in active fraction.

Results

In the TST test, the effect of a low polar fraction (XY-EA) was superior to other fractions of XYS. 13 volatile compounds in the XY-EA were identified on the basis of standards, isolation and structural determination in our laboratory, NIST 05 database and literature data. The content of 4 major volatile compounds in XY-EA which is 6.703%.

Conclusions

The petroleum ether fraction (XY-EA) appears to be the active fraction of XYS. 4 major components Z-ligustilide, palmitic acid, atractylenolide I, and atractylenolide II may be the antidepressant active compounds.