Determination of cardiac glycosides and phenolic compunds in the extract of Digitalis ferruginea ssp. schischkinii and some endemic species of digitalis by chromatographic methods

In this study, davisiana, cariensis, trojana ve lamarckii species of Digitalis from Scrophulariaceae family which are endemic in Turkey, (Turkish: Yüksük otu) and two subspecies of ferruginea (ferruginea and schischkinii) were investigated for their phenolic compunds of their leaves, collected at different seasons. The compounds were extracted in optimized conditions and analyzed by HPLC-UV. Three different procedure were carried out for optimization of the extraction; direct metanol, hydrolyzed and at pH=2 extraction. The phenolics could not be determined by HPLC-UV were characterized by HPLC-MS. Total phenolic constituents were determined using a spectrophotometric method assaying as gallic acid and catechin equivalent and the results were compared with chromatographic results. The analysis results of phenolic compouds were compared according to species, location and collection period of the plant. The cardiac glycosides were determined in the leaves, flowers and petiole of Digitalis ferruginea ssp. schischkinii by HPLC-DAD.Digitalis species were found quite rich for caffeic, ferulic and p-coumaric acids by HPLC-UV analysis. Apigenin, kaempferid, luteolin, fisetin, rhamnazin and their dihexose, hexose, glucuronide, acetylglycoside and deoxyhexose attached derivatives were mainly characterized by HPLC-MS. Lanatoside C, digoxine and digitoxine were found major cardiac glycosides in the leaves of Digitalis ferruginea ssp. schischkinii, 86,14; 20,8; and 15,43 mg/L respectively by HPLC-DAD analysis. Total phenolic constituent of Digitalis davisiana (September) (34,105 mg GAE/g sample) in metanolic extracts, Digitalis cariensis (September) (35,010 mg GAE/g sample) in the hydrolyzed extracts and Digitalis ferruginea ssp. schischkinii (September) were the highest (7,198 mg GAE/g sample) in the pH=2 extracts.Key Words: Digitalis ferruginea ssp. schischkinii, phenolic compounds, cardiac glycosides, HPLC-UV, HPLC-UV-MS