Separation and identification of multiple constituents in Xiao Chai Hu Decoction (Sho-saiko-to) by bioactivity-guided fractionation combined with LC-ESI-QTOFMS/MS.

Xiao Chai Hu Decoction (XCHD), named Sho-saiko-to in Japanese, is a well-known traditional Chinese medicine formula used in Asia. However, the characterization methods used in the past have lacked sensitivity and the nature of the active constituents of XCHD remains unclear. This study was carried out to establish the hyphenated method of bioactivity-guided fractionation and liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOFMS/MS) in order to identify the major bioactive constituents of XCHD. D101 macroporous resin was used to separate and enrich the material base into four fractions, XCHD-1, XCHD-2, XCHD-3 and XCHD-4. Each fraction was then evaluated for its antidepressant effect using depression-related parameters. An LC-ESI-QTOFMS/MS method in both positive and negative ion mode was also applied for separation and identification of the biological active fractions of XCHD. As a result, 79 compounds including polysaccharides, flavonoids, saikosaponins, ginsenosides, licoricesaponins and gingerols were detected, 69 of them were identified or tentatively characterized. Based on our preliminary characterization investigations, polysaccharides, gingerols and flavonoids in XCHD may contribute to the antidepressant effect of XCHD. In conclusion, the hyphenated method of bioactivity-guided fractionation and LC-ESI-QTOFMS/MS was meaningful for the isolation and preliminary identification of the biological active components in complex matrices of traditional Chinese medicine.