Chemometric analysis based on high-performance liquid chromatographic data in the fingerprint construction of selected Achillea species

Fourteen Achillea species were collected, extracted using Soxhlet apparatus with dichloromethane and methanol as solvents. The obtained methanolic extracts were analyzed using the reversed-phase high-performance liquid chromatography–diode array detector (RP-HPLC-DAD) with the Kinetex C18 column and the mobile phase consisting of methanol–water–0.1% formic acid mixture (gradient 5–85% (v/v)) at 30°C with the run time of 45?min and the detection wavelength 320?nm. Next, the chromatograms were preliminarily processed with smoothing, noise reduction, background subtraction, and alignment in the SpecAlign program (version 2.4.1) to construct the fingerprints of studied extracts. Selected standards (phenolic acids and flavonoids) were analyzed in the same chromatographic conditions and its presence in extracts was confirmed based on their spectra and the retention time values. The chemical similarity between the samples was evaluated using the Pearson correlation coefficient as similarity parameter, Euclidean distance index, the principal component analysis, and cluster analysis (CA).