Synthesis and anti‐inflammatory activity evaluation of benzoxazole derivatives as new myeloid differentiation protein 2 inhibitors

Myeloid differentiation protein 2 (MD2), a key TLR4 adaptor protein for sensing LPS, plays an important role in inflammatory process and has been identified as a promising target for the treatment of a variety of inflammatory diseases. In our study, a series of benzoxazolone derivatives were synthesized, characterized and tested for anti-inflammatory activity in vitro. The compounds 3c, 3d and 3g demonstrated the greatest anti-inflammatory activity against IL-6 with IC50 values of 10.14 ± 0.08, 5.43 ± 0.51 and 5.09 ± 0.88 µM, respectively. Furthermore, the bis-ANS displacement assay revealed that these compounds competitively inhibited the binding between the probe bis-ANS and the MD2 protein. The most active compound 3g, revealed a directly bind with MD2 protein via Arg90 binding and a dissociation constant value of 1.52×10-6 mol·L-1 as determined by the biological layer interference (BLI) assay. Our finding suggested that compounds 3g could be a promising lead compound as MD2 inhibitor for further anti-inflammatory agent development.