A pair of new isoquinoline alkaloid enantiomers with cardioprotective effect from Corydalis yanhusuo

A new isoquinoline alkaloid derivative, yanhusanine M (1), featuring a rare C-8 hydroxymethyl substituent, was isolated from the tubers of Corydalis yanhusuo. The structure was elucidated by comprehensive spectroscopic analyses, including HR-ESI-MS, IR, 1D and 2D NMR (COSY, HMBC, HSQC, NOESY) and 13C NMR chemical shifts calculations coupled with the DP4+ probability method. It was resolved into its enantiomers, (+)-1 and (−)-1, via chiral-phase HPLC, and their absolute configurations were determined by comparison of experimental and calculated ECD spectra. Both enantiomers exhibited significant cardioprotective effects at the concentrations of 10–500 nM.