HPLC-DAD/ESI-MS analyses of aqueous preparations from Stachys thirkei K. Koch and quantification of major phenolic components

The purpose of the study was to screen phenolic constituents present in aqueous and ethanolic extracts prepared from the aerial parts of Stachys thirkei K. Koch, one of the 83 species growing wild in Turkey and which are used with similar purposes as sage in traditional medicines. A previously developed and validated RP-HPLC method for Stachys species has been used for decoction, infusion and ethanolic extract of S. thirkei. Qualitative analyses showed the presence of three different classes of phenolic constituents: caffeoylquinic acids (mainly chlorogenic acid), phenylethyl glycosides (acteoside and lavandulifolioside) and flavone glycosides (isoscutellarein derivatives). HPLC-ESI-MS analyses of the ethanolic extract led to the identification of 19 components. Their structure identification was realised by comparing their retention times, UV and MS spectra with those of previously isolated compounds from S. cretica and/or literature data. Phenylethyl glycosides are expressed as acteoside, whereas flavonoids as isoscutellarein-7-O-[6'''-O-acetyl-β-allopyranosyl-(1→2)]-β-glucopyranoside. The most abundant component in all three extracts have been found to be acteoside constituting 7.08 percent of the infusion.