Elucidation of metabolite isomers of Leonurus japonicus and Leonurus cardiaca using discriminating metabolite isomerism strategy based on ultra-high performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry.

•A new discriminating metabolite isomerism strategy was developed.•Metabolome of L. japonicus and L. cardiaca were elucidated.•257 compounds and 67 pairs of isomers were characterized and identified.•56 characteristic markers were discovered to discriminate these two species.