Abstract: In this study,high performance liquid chromatography coupled with photo-diode array detector and electrospray ionization mass spectrometry(HPLC-ESI-MS) was used to screen and identify isoflavonoids with lactate dehydrogenase inhibitory activity from Belamcanda chinensis extracts.Lactate dehydrogenase was used as biotargeting molecule,six major compounds in B.chinensis was identified as lactate dehydrogenase inhibitors using ultrafiltration methods,namely tectoridin,iristectorin A,iridin,tectorigenin,irigenin,and irisflorentin.Following this,semi-preparative high performance liquid chromatography(semiprep·HPLC) was applied to separate and isolate the active constituents.These compounds were then isolated by semi-prep HPLC with purity higher than 90%.Our results demonstrated that systematic isolation of bioactive components from B.chinensis guided by ultrafiltration HPLC-ESI-MS was a feasible and efficient technique.It can be extended for the identification and isolation of other enzyme inhibitors.

Key words: Belamcanda chinensis, ultrafiltration, liquid chromatography/mass spectrometry, semi-preparative high performance liquid chromatography, lactate dehydrogenase