Extraction optimization and identification of anthocyanins from Nitraria tangutorun Bobr. seed meal and establishment of a green analytical method of anthocyanins

•Anthocyanins and polyphenols were ultrasound-assisted extracted from N. tangutorun seed meal.•Response surface methodology was used to optimize of extraction parameters.•Eight anthocyanins contained in N. tangutorun seed meal was identified by HPLC-MS.•A green HPLC method using ethanol-based mobile phase was developed to analysis anthocyanins from N. tangutorun seed meal.•The antioxidant capacity of extract of N. tangutorun seed meal was evaluated in vitro.

This study aimed to extract and identify anthocyanins from Nitraria tangutorun Bobr. seed meal and establish a green analytical method of anthocyanins. Ultrasound-assisted extraction of anthocyanins from N. tangutorun seed meal was optimized using response surface methodology. Extraction at 70 °C for 32.73 min using 51.15% ethanol rendered an extract with 65.04 mg/100 g of anthocyanins and 947.39 mg/100 g of polyphenols. An in vitro antioxidant assay showed that the extract exhibited a potent DPPH radical-scavenging capacity. Eight anthocyanins in N. tangutorun seed meal were identified by HPLC-MS, and the main anthocyanin was cyanidin-3-O-(trans-p-coumaroyl)-diglucoside (18.17 mg/100 g). A green HPLC-DAD method was developed to analyse anthocyanins. A mixtures of ethanol and a 5% (v/v) formic acid aqueous solution at a 20:80 (v/v) ratio was used as the optimized mobile phase. The method was accurate, stable and reliable and could be used to investigate anthocyanins from N. tangutorun seed meal.