Optimization, identification and bioactivity of flavonoids extracted from Moringa oleifera leaves by deep eutectic solvent

Moringa oleifera leaves ( MO L) attract extensive attention in agriculture, pharmaceutical and food industry because of its rich biological activity. In this study, ChCl/LA as one of the deep eutectic solvents (DESs) was selected to extract flavonoids from Moringa oleifera leaves (F MO L). The extraction rate of F MO L reached 54.8 mg/g. After separation of F MO L, its biological activities were systematically studied. The IC50 values of F MO L for DPPH radical, ABTS radical scavenging activity, FRAP and ORAC were 27.3 μg/mL, 41.2 μg/mL, 18.7 mg TE/g and 6008.4 mg TE/g, respectively, indicating F MO L had excellent antioxidant activity . F MO L not only had better antibacterial activity than the positive controls, but also had inhibitory activity to tumor cells. The IC50 values of F MO L on B16 cells, HCT116 cells and Hep G-2 cells were 530.7, 328.0, and 533.7 μg/mL, respectively. Nine flavonoid compounds were identified by UPLC-Q-Orbitrap MS/MS, and four of them were confirmed from MO L for the first time. Therefore, F MO L extracted by ChCl/LA had rich bioactive components and is expected to be used in food and pharmaceutical industries.