Retention behavior of silica-bonded and novel polymeric reversed-phase sorbents in studies on flavones as chemotaxonomic markers of Scutellaria L. genus

In this study, the effectiveness of both classical and novel polymeric sorbents used in solid-phase extraction (SPE) for isolation of pharmacologically active flavones (baicalin, luteolin, apigenin, wogonin and chrysin) from aerial parts of 13 species of Scutellaria L. (Skullcap) genus was assessed. The highest recoveries of hydrophilic (baicalin, luteolin) flavones for Oasis® HLB were obtained, whereas for medium hydrophobic (apigenin) and hydrophobic (wogonin, chrysin) flavones better quantitative results for BakerBond phenyl cartridges were stated. Eluates were analysed using reversed-phase high-performance liquid chromatography with diode array detection (RP-HPLC–DAD). For the five target compounds the determined concentrations ranged from ∼4 to ∼15,500 μg/g dry wt. Very good linearities (r2 > 0.9995) of calibration curves were achieved for each flavone. The accuracy was below 5% for most compounds examined. This is the first method reported that enabled simultaneous qualification and quantitation of five flavones (being chemotaxonomic markers) in 13 species of Scutellaria L. genus.