Analysis of Multiple Constituents in Cong‐Ming‐Tang, a Chinese Herbal Formula for the Treatment of Amnesia, by High‐performance Liquid Chromatography with Quadrupole Time‐of‐flight Mass Spectrometry

Abstract

Cong-Ming-Tang (CMT), named smart-soup in English, is a well-known traditional Chinese medicine formula for the treatment of amnesia in China. However, the isolation, purification and identification procedures of the major bioactive constituents in CMT are difficult and time consuming. To establish a rapid and sensitive high-performance liquid chromatography/electrospray ionisation with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF/MS/MS) method that could be applied to rapidly separate and identify the major bioactive constituents in CMT. Methanolic extract of CMT was used for HPLC-QTOF/MS/MS analysis. Separation was performed on an Agilent Poroshell 120 EC- C18 column (2.7 ×100 mm .i.d., 2.7 µm) with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase under gradient conditions. Both positive and negative ion modes were employed. This analytical tool allowed the identification of 55 compounds from CMT formulae by comparing their retention times and MS spectra with those of authentic compounds or literature data in both positive and negative ion modes, including 4 xanthone C-glycosides, 4 sucrose esters, 11 oligosaccharide multi-esters,15 triterpene saponins, 15 triterpene acids, 2 lignans and 4 phenylpropanoids. Onjisaponin MF was tentatively elucidated as a new triterpene saponin based on the summarised fragmentation rules. HPLC-QTOF/MS/MS provides a new powerful approach to identify the major chemical constituents in CMT rapidly and accurately. This study proposed a series of potential bioactive components without preparative isolation from the crude extract of CMT and indicated that the HPLC-QTOF/MS/MS method also can be a promising tool for the analysis of other traditional Chinese medicines.