UHPLC-MSn-assisted characterization of bioactive alkaloids extracted from Nitraria sibirica leaves and enriched using response surface method and adsorption on macroporous resin

In Xinjiang, China, Nitraria sibirica Pall. is traditionally used to treat hypertension, menstrual disorders, and gastroenteritis. Following process optimization by response surface modeling and Box-Behnken analysis, we extracted 3.83 mg/g of alkaloids from N. sibirica leaves in two cycles of extraction for 2.38 h in 89.45% ethanol at liquid-solid ratio 11.381 (mL/g). Subsequent adsorption on HPD-450 resin further enriched the total alkaloid content to 18.08%. Subsequently, 28 compounds, including 15 alkaloids and 13 flavonoids and phenolic compounds, were identified in the extract by UHPLC-Q-Orbitrap-MS. Strikingly, the extracts were strongly antimicrobial againstCandida albicans and Staphylococcus aureus, and significantly antiproliferative against A549, MCF7, and Hela tumor cells, probably due to induction of apoptosis. Finally, the extracts efficiently scavenged radicals with IC50 50.90 ± 6.45 μg/mL.