Synthesis, anti-inflammatory activities and docking studies of amide derivatives of meclofenamic acid

NSAIDs constitute a heterogeneous class of pharmacological agents widely prescribed for the treatment of inflammation, pain and edema, as well as osteoarthritis, rheumatoid arthritis and musculoskeletal disorders. This class of drugs has proved efficacious on account of their analgesic, anti-pyretic and anti-inflammatory activities, but gastrointestinal toxicity exists as the biggest problem associated with their chronic use. Many attempts have been made to structurally modify conventional NSAIDs as selective COX-2 inhibitors based on the old and still prevalent common belief that selective inhibition of COX-2 would provide safer NSAIDs. The present work thus focused on the synthesis of amide derivatives of one of the conventional non-selective NSAID, meclofenamic acid utilizing the one pot procedure involving a selective agent, bis (2-oxo-3-oxazolidinyl) phosphonic chloride. The synthesized compounds were tested for their in vivo inflammatory activity using carrageenan rat paw edema assay, and were subsequently docked on COX-2 PDB code 4COX to have better insights into their mechanism of action. The amide derivative with N-4-methoxybenzyl moiety (TSN4) proved to have anti-inflammatory potential (72.8%) better than meclofenamic acid (56.75%). This compound also docked with the highest dock score among the synthesized compounds and was found to have both hydrogen bonding with Arg120 and Tyr355 and hydrophobic interactions with Val349, Leu352, Ser353, Tyr385, Trp387, Met522, Val523, Ala527 and Ser530. N-4-methoxybenzyl amide derivative (TSN4) followed by benzyl amide derivative (TSN1) of meclofenamic acid were identified as potential anti-inflammatory compounds in both in vivo and in silico studies.