Characterization of Metabolites of Leonurine (SCM-198) in Rats after Oral Administration by Liquid Chromatography/Tandem Mass Spectrometry and NMR Spectrometry

Table 2

Mass spectra data and proposed structures of leonurine metabolites in rat.

Metabolites	Retention time (min)	Protonated molecule; [M + H]^+	MS^𝑛 product ion	Optimal MRM transitions	Description of metabolites
M0	8.1	312	295, 253, 181, 153, 132, 114, 97	312/181	Parent
M1	4.9	488	312, 295, 253, 181, 132, 114, 97	488/312	Glucuronidation
M2	6.9	392	312, 295, 253, 181, 153, 132, 114, 97	392/312	Sulfation
M3	7.2	298	281, 167, 132, 114, 97	298/167	O-demethylation