Ultrasound-assisted extraction and (U)HPLC-DAD-ESI-MSn analysis of phenolic compounds from black chokeberries cultivated in Turkey

Abstract

Phenolic compounds from two black chokeberry cultivars 'Viking' and 'Nero' grown in Turkey were analyzed by high performance liquid chromatography-diode array detection-electrospray ionization-multistage mass spectrometry (HPLC-DAD-ESI-MSn). In the first step, five different solvents were compared to efficiently isolate phenolic compounds by ultrasound-assisted extraction. Three sequential extraction cycles using methanol/formic acid (95:5, v/v) sufficed for exhaustive extraction of anthocyanins, hydroxycinnamic acid derivatives, and flavonol glycosides from black chokeberry within merely 60 sec. A total of four cyanidin glycosides, two hydroxycinnamic acids, and five quercetin mono- and diglycosides were detected in both cultivars. Total anthocyanins (425-438 mg/100 g of fresh weight, FW), hydroxycinnamic acids (173-179 mg/100 g of FW), and flavonols (37 mg/100 g of FW) were determined in a similar range for both cultivars. Complementary, a rapid ultra-high performance liquid chromatography (UHPLC)-DAD method was developed, permitting a high throughput screening of chokeberry phenolics. The established methods were validated considering extraction recoveries, intra- and inter-day repeatability, calibration linearity, limit of detection (LOD), and limit of quantitation (LOQ). UHPLC provided a 2.3 times faster compound separation (30 min) and less solvent consumption than HPLC (68 min).