Immunomodulatory Effect of Flavonoids of Blueberry (Vaccinium corymbosum L.) Leaves via the NF-κB Signal Pathway in LPS-Stimulated RAW 264.7 Cells

OBJECTIVE: This study aimed to explore the immunoregulatory effect of flavonoids of blueberry (Vaccinium corymbosum L.) leaves (FBL). METHODS: The flavonoids of blueberry leaves were prepared with 70% ethanol and were identified by ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-Tof-MS). The immunoregulatory effect and possible regulatory mechanisms of FBL were investigated in lipopolysaccharide- (LPS-) induced RAW 264.7 cells. RESULTS: According to the results of UPLC/Q-Tof-MS, nine flavonoids of blueberry leaves were identified. FBL showed a significant reduction in the production of TNF-α in LPS-stimulated RAW 264.7 cells. FBL significantly decreased the expression of NF-κB p65 and P-NF-κB p65 in LPS-induced RAW 264.7 cells in a dose-dependent manner. CONCLUSION: Our study showed the immunoregulatory effect of FBL through the suppression of TNF-α via the NF-κB signal pathway.