Multi-component HPLC fingerprinting of Radix Salviae Miltiorrhizae and its LC-MS-MS identification

The multi-component fingerprinting method of Radix Salviae Miltiorrhizae (Root of Salvia miltiorrhiza BGE.), an important and popular medicinal herb in traditional Chinese medicine, was studied using reverse-phase HPLC and LC-MS-MS. Extract containing both the water-soluble phenolic compounds and nonpolar diterpenoid compounds known to be the herb's main bioactive components was prepared by a two-step extractive procedure. An HPLC fingerprinting method which can simultaneously separate these two types of compounds was established with gradient elution mode and photodiode array detection at 280 nm. Eighteen peaks in this HPLC fingerprint were structurally identified by employing LC-MS-MS techniques. The electrospray ionization (ESI) MS-MS spectra of most salvianolic acids displayed a characteristic behavior of loss of danshensu and caffeic acid moieties, while those of tanshinones showed a particular behavior of loss of H₂O which is quite different from the fragmentation pattern in electron ionization mass spectrometry (EI-MS). The HPLC fingerprints of 7 batches of crude drugs showed similar separation pattern and provided much chemical information of the pharmacologically-active compounds in the crude drugs, which is useful for the authentication and quality evaluation of this medicinal herb.