Secondary metabolites from Stachys palustris L.

In this work we report the first total analysis of the secondary metabolites from a sample of Stachys palustris L., an herbaceous perennial plant belonging to Lamiaceae, collected in Hungary. The phytochemical analysis, performed by means of classical column chromatography and NMR spectroscopy and Mass spectrometry (MS), allowed us to isolate and identify eight compounds such as verbascoside (1), echinacoside (2), two isoscutellarein derivatives (3, 4), chlorogenic acid (5), harpagide (6), 8-O-acetyl-harpagide (7) and monomelittoside (8). These compounds belong to four different classes of chemical compounds namely phenyl-ethanoid glycosides (PhGs) (compounds 1, 2), flavonoids (compounds 3,4), caffeoyl-quinic acids (compound 5) and iridoids (compounds 6,7 and 8). From a chemosystematic point of view, these compounds are all important: compounds (6) and (7) are considered as the major chemotaxonomic markers of the genus; compound (1) and (8) resulted new constituents in this species and compound (2) is even new in the genus. In addition to this, the co-occurrence of iridoids and PhGs has a chemosystematic importance since it is widely demonstrated their presence in Asterids. Lastly, compounds (3) and (4) such as compounds (5),(6) and (7) have already been found in Stachys species, giving, this way, evidence of a phytochemical pattern perfectly in accordance with those reported in literature for other members of this genus. Nevertheless, it’s worth to underline the fact that compounds (3) and (4), like all isoscutellarein derivatives containing allose, seem to have a restricted distribution in only some genera of Lamiaceae.