Isoliquiritin suppressed LPS/CuSO₄-induced pro-inflammatory response on RAW264.7 cell and zebrafish

Isoliquiritin (ISL) as one of bioactive flavonoid from licorice was reported to have bioactivities. This study aims to evaluate the anti-inflammatory properties of ISL on RAW264.7 cells and zebrafish and reveal its possible anti-inflammatory mechanism.

The anti-inflammatory activity of ISL was measured by LPS-induced RAW264.7 cells and CuSO₄-induced zebrafish models. The accumulation of reactive oxygen species (ROS) and nitric oxide (NO) in RAW264.7 cells and zebrafish were detected by H2DCFDA fluorescent probe and nitric oxide detection kit, respectively. The nuclear translocation of NF-κB p65 in LPS-induced RAW264.7 cells was detected by immunofluorescence assay. The protein levels of IL-1β, IL-6 and TNF-α in LPS-induced RAW264.7 cells were detected by ELISA assay. The recruitment of neutrophils and macrophages was observed using fluorescence microscope and quantified by ImageJ in the zebrafish inflammatory model. The expression level of inflammation-related cytokines was analyzed by quantitative real-time PCR (qRT-PCR).

ISL reduced the accumulation of ROS and NO in LPS-induced RAW264.7 cells and CuSO₄-induced zebrafish inflammatory models, inhibited the nuclear translocation of NF-κB p65 and reduced the release of IL-1β, IL-6 and TNF-α in LPS-induced RAW264.7 cells. Furthermore, the decrease in inflammatory cell infiltration and neutrophil migration suggests the occurrence of inflammatory reactions and the anti-inflammatory effect of ISL in vivo. ISL reduced the expressions of inflammation-related cytokines in LPS-induced RAW264.7 cells and zebrafish inflammatory models.

ISL exerts significant anti-inflammatory effects by reducing the production of ROS and NO, inhibiting the nuclear translocation of NF-κB p65, and inhibiting the expression of inflammatory-related factors. And it is a potential treatment option for inflammatory-related diseases.