Characterization of tanshinones with quinone reductase induction activity from Radix Salvia miltiorrhiza by liquid chromatography/tandem mass spectrometry

Quinone reductase (QR) induction is a reliable biomarker of phase 11 enzyme induction. In this study, glutathione (GSH) was employed and a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was introduced to reveal the chemical constituents with QR activity from the ethyl acetate extract of roots Salvia miltiorrhiza ('Danshen') and nine tanshinones (9, 13, 17-19, 21, 2426), which could conjugate with GSH, were characterized by LC/MS/MS and considered to have QR activities. Then, thirteen tanshinones, including six compounds (17, 18, 21, 24-26) of the above nine tanshinones, were isolated to conduct QR induction evaluation, and it was found that miltirone and its derivatives (18, 20, 24, 26) exhibited significant activities. The GSH conjugate abilities of the isolated tanshinones were also examined; this showed that compounds 18, 20, 24 and 26 had good conjugating abilities with GSH. Compared with the in vitro bioactivity screening results, this proved that conjugate ability is related with QR activity, so an LC/MS/MS method can be applied to find more active compounds. Copyright (C) 2009 John Wiley & Sons, Ltd.