Structure characterization and identification steroidal saponins from Ophiopogon japonicus Ker-Gawler (Liliaceae) by high-performance liquid chromatography with ion trap mass spectrometry.

Introduction: Steroidal saponins are the main active constituents in Ophiopogon japonicus Ker-Gawler (Liliaceae). However, because of their high polarity, non-chromophores and low content in plants, steroidal saponins are difficult to be isolated from O. japonicus by conventional phytochemical methods.

Objective: To develop a sensitive and rapid approach towards the structural analysis of steroidal saponins using HPLC/ESI-MS(n).

Methodology: The fragmentation behaviors of six known steroidal saponins in negative ESI-MS(n) were used to deduce their mass spectral fragmentation mechanisms. By using HPLC/ESI-MS(n) , the important structural information on aglycone types, sugar types and saccharide sequences can be obtained.

Results: According to the HPLC retention behaviour, the molecular structural characteristics provided by multistage mass spectrometry spectra and the literature, a total of 8 steroidal saponins were tentatively identified or characterized in O. japonicus rapidly.

Conclusion: This work has shown that HPLC-ESI-MS(n) may be used as an effective and rapid method for the characterization and identification of steroidal saponins from O. japonicus.