Liquid chromatography fingerprint analysis and antioxidant activity of selected lavender species with chemometric calculations

The extracts of seven Lavandulae species (Lavandula stoechas, Lavandula lanata, Lavandula viridis, Lavandula angustifolia „Rosea”, Lavandula angustifolia „Afropurpurea”, Lavandula angustifolia and one unknown) were analyzed using the reversed-phase-high performance liquid chromatography–diode array detection (RP-HPLC–DAD) with gradient elution technique to obtain the chromatographic fingerprint profiles. The HPLC analysis was performed using the Kinetex RP18 chromatographic column and eluent consisting of methanol-water-0.1% formic acid (5–100% (v/v)) at 30 °C with the run time of 60 min. and the detection wavelength 280 nm. The chromatograms were preliminary processed with the smoothing, noise reduction, background subtraction and alignment using the SpecAlign program (version 2.4.1). The presence of selected standards (apigenin, myricetin, luteolin, luteolin 7-glucoside, chlorogenic acid, caffeic acid, ferulic acid) in the extracts was confirmed. The chemical similarity between studied plants was evaluated using the Cluster Analysis (Pearson correlation coefficient, r, and Euclidean) and PCA. The preliminary antioxidant activity of studied extracts was evaluated based on the total phenolic content (Folin-Ciocalteu method), ferric ion reducing antioxidant parameter (FRAP) and α,α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method using the spectrophotometric technique.