Inflammation plays an important role in acute lung injury (ALI). Hesperetin (HES), a natural flavanone and an aglycone of hesperidin, has established potent anti-inflammatory activity. The aim of this study was to evaluate the potential protective effect of HES on lipopolysaccharide (LPS)-induced ALI in mice and to illuminate its possible directly target. Results indicated that HES pretreatment significantly attenuated LPS-induced pulmonary pathological injury, total protein concentration, markedly decreased the number of neutrophils and the levels of inflammatory cytokines, TNF-α and IL-6, in ALI model in vivo and in vitro. Meanwhile, pretreatment with HES dramatically reduced myeloperoxidase (MPO) activity in LPS-induced ALI mice. Additionally, using molecular docking and co-immunoprecipitation assay, HES showed a directly bind with myeloid differentiation 2 (MD2), in which HES could inhibit MAPK activation, regulate IκB degradation, block the interaction MD2 and its co-receptor Toll-like receptor 4 (TLR4). Taken together, HES showed a significantly protective effect against LPS-induced ALI, which might be associated with MD2 protein. These results attested HES worthy of further progress into an adjunctive potential drug for the treatment for ALI. VSports手机版.