Screening and analyzing potential hepatotoxic compounds in the ethanol extract of Asteris Radix by HPLC/DAD/ESI-MS(n) technique.

A refined toxic fraction, Fr-2, from the ethanol extract of Aster tataricus roots was obtained by a toxic tracing isolation. The hepatotoxic effects of Fr-2 were proved by the level elevation of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in mice serum and further confirmed by the histopathological examination on mice liver. A simple method was developed for qualitative analysis of constituents in Fr-2 fraction by high-performance liquid chromatography with diode array detection (HPLC-DAD) and electrospray ionization tandem mass spectrometry (ESI-MS(n)). As a result, 35 compounds were detected and identified in Fr-2. Among them, 28 compounds are pentapeptides, including 18 cyclic and 10 linear ones, and the sum of their peak area occupied about 87% (71.2% for cyclic and 15.8% for linear) of total area of chromatographic peak. Other 7 compounds are phenols, occupied about 5.9% of total area of chromatographic peak. Moreover, the structures of 10 cyclic and 2 linear peptides were reported for the first time. The results suggested that the peptides, especially the cyclic ones, are probably the principal toxic substances in Fr-2 also in A. tataricus roots.