Motherwort (Leonurus cardiaca)
The herb contains the alkaloid leonurine, which is a mild vasodilator and has a relaxing effect on smooth muscles. For this reason, it has long been used as a cardiac tonic, nervine, and an emmenagogue. Among other biochemical constituents, it also contains bitter iridoid glycosides, diterpinoids, flavonoids (including rutin and quercetin), tannins, volatile oils, and vitamin A.