Chemical profiling of six Stachys taxa from Balkan Peninsula

Abstract

Aim of this work was the chemical profiling of six Stachys taxa from Balkan Peninsula: S. recta subsp. nitens, S. atherocalyx, S. beckeana, S. zepcensis (all four belonging to S. recta group), S. alpina subsp. dinarica and S. plumosa. Dry ethanol extracts of aerial flowering plant parts were qualitatively and quantitatively characterized for their phenolic composition using the HPLC-DAD-ESI-MS technique. In total, 44 phenolic compounds were detected, belonging to three main classes of constituents: phenolic acids, phenylethanol glycosides (PhGs) and flavonoids. Chlorogenic acid was the main phenolic acid in all samples. Regarding PhGs, in all investigated extracts acteoside and lavandulifolioside were present. In S. recta group, extracts of S. atherocalyx, S. recta subsp. nitens and S. beckeana showed similar pattern considering phenylethanol glycosides, while S. zepcensis contained only the two aforementioned compounds. PhGs profile of S. plumosa extract comprised the same compounds from S. recta group, but it was also characterized by the presence of few high-molecular compounds. PhGs composition of S. alpina subsp. dinarica extract was somewhat similar with those of S. recta group and also with S. plumosa, but still specific by the presence of echinacoside and leucosceptoside A. The main flavonoids in extracts of Stachys recta group as well as in S. alpina subsp. dinarica extract were 8-hydroxyflavone glycosides (7-O-allosylglucosides of isoscutellarein and hypolaetin and their 4′-methyl derivatives). In addition, in the extract of S. alpina subsp. dinarica two luteolin-7-O-hexosides were also present. On the other hand, S. plumosa extract differed considerably containing mainly derivatives of chrysoeriol and apigenin, while 8-hydroxyflavones (isoscutellarein derivatives) were detected in traces. The results confirmed the importance of flavone 7-O-allosylglucosides at the sectional level of Stachys genus.