Glycosides of tricetin methyl ethers as chemosystematic markers in Stachys subgenus Betonica

A flavonoid survey within the genus Stachys revealed that glycosides of methyl ethers of tricetin were restricted to species in subgenus Betonica. The new derivative tricetin 3 ′,4 ′,5 ′-trimethyl ether 7- O-β-glucopyranoside was obtained from Stachys scardica. Nine species from the genus Stachys L. representing subgenera Stachys and Betonica were surveyed for flavonoid glycosides by means of HPLC coupled to diode-array detection and LC-APCI-MS. Those species belonging to subgenus Betonica were characterised by the presence of glycosides of tricetin methyl ethers, including a new derivative, which was isolated from S. scardica Griseb. and identified as tricetin 3 ′,4 ′,5 ′-trimethyl ether 7- O-β-glucopyranoside by spectroscopic methods. This type of flavonoid was absent from species belonging to subgenus Stachys and can be considered as a chemosystematic marker for subgenus Betonica.