Abstract: The water eluate of total flavonoids extracted from Allium mongolicum Regel (wAMF) was evaluated for its inhibitory effect on lipopolysaccharide (LPS)-induced inflammation in mouse peritoneal macrophages. The CCK-8 method was used to examine the effect of the purified flavonoids at different concentrations (0, 50, 100, 200, 400 and 800 μg/mL) on the proliferation of mouse peritoneal macrophages. The following groups were created: blank control, LPS-induced model and wAMF pretreatment at different concentrations. The Griess method and enzyme-linked immunosorbent assay (ELISA) were used to determine the concentrations of NO, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and IL-10 in the macrophage culture supernatants, and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) was applied to detect the mRNA expression levels of inducible nitric oxide synthase (iNOS), TNF-α, IL-1β, IL-6, IL-10, myeloid differential protein 88 (MyD88) and nuclear factor κB (NF-κB). The results obtained were as follows: 1) Compared with the control group, wAMF at concentrations of 50–800 μg/mL had no toxicity on macrophages (P > 0.05). 2) Compared with the LPS-induced model, wAMF significantly inhibited the concentrations and mRNA expression of proinflammatory mediators including NO, TNF-α, IL-6 and IL-1β (P < 0.01 or P < 0.001), significantly increased the concentration of the anti-inflammatory factor IL-10 and its mRNA expression (P < 0.001) in a dose-dependent manner, and significantly decreased the mRNA expression of MyD88 and NF-κB (P < 0.01 or P < 0.001). To sum up, wAMF has an anti-inflammatory effect on LPS-stressed mouse peritoneal macrophages, probably by inhibiting the secretion of NO, TNF-α, IL-6 and IL-1β and increasing IL-10 concentration; and the mechanism is possibly associated with the NF-κB signaling pathway.

Key words: Allium mongolicum Regel, flavonoids, mouse peritoneal macrophage, cytokines, myeloid differential protein 88, nuclear factor κB