Polar constituents, essential oil and antioxidant activity of marsh woundwort (Stachys palustris L.)

Stachys palustris, well-known as marsh woundwort, is a perennial herb growing in wet environments of Europe. Its tubers, leaves and seeds are eaten raw or cooked. Alike other Stachys species, the plant is also used as a traditional remedy. Despite S. palustris has been consumed for centuries, little is known about its chemical constituents. In this work the main secondary metabolites of S. palustris from Hungary and France have been analysed. From the plant ethanolic extracts, ethanoid glucosides, isoscutellarein derivatives, caffeoyl-quinic acids and iridoids have been isolated and structurally characterized by NMR. The essential oils were analysed by GC/MS and showed (E)-phytol, fatty acids and carbonylic compounds as the most abundant compounds. The radical scavenging capacity of plant ethanolic extracts, as evaluated by the DPPH assay, was noteworthy, with IC50 values of 92.08 – 105.42 lg/ml.