4-Aminosalicylic acid

4-Aminosalicylic acid (CAS No.: 65-49-6) is a synthetic antimetabolite and antitubercular agent that functions as an analog of p-aminobenzoic acid, positioning it within antimicrobial and anti-inflammatory small molecules relevant to infectious disease and immunology research. It exerts its primary activity through interference with folate metabolism, acting as an alternative substrate for mycobacterial dihydropteroate synthase and contributing to downstream inhibition of folate-dependent pathways, as well as reported inhibition of dihydrofolate reductase, collectively leading to disruption of nucleotide biosynthesis and bacterial growth. The compound demonstrates activity against both drug-sensitive and drug-resistant strains of Mycobacterium tuberculosis, with efficacy observed in the sub-micromolar to low micromolar range in vitro, and its antibacterial effects can be modulated by competing folate pathway substrates. In addition to its antimicrobial properties, 4-aminosalicylic acid exhibits anti-inflammatory activity, including modulation of inflammasome-associated signaling pathways such as NLRP3 and downstream mediators, supporting its utility in studies of inflammatory conditions including inflammatory bowel disease. It is orally active and has historically been used in combination regimens, with improved tolerability observed for its salt forms relative to the free acid. In research settings, this compound is widely applied in cell-based assays of microbial metabolism, folate pathway inhibition, and inflammatory signaling, as well as in animal models of infection and inflammation, where dosing and concentration are tailored to specific experimental objectives.