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.