<![CDATA[Background: Lactic Acid Bacteria (LAB), classified as Generally Recognized as Safe (GRAS) microorganisms, produce functional compounds such as Gamma-Aminobutyric Acid (GABA), a non-protein amino acid acting as the principal inhibitory neurotransmitter in the central nervous system and possessing antioxidant activity. Chao, a traditional fermented fish product from Pangkep, South Sulawesi, is a promising yet underexplored source of GABA-producing LAB. Objective: This study aimed to identify the ability of LAB isolated from Chao Pangkep to produce GABA as an antioxidant compound. Methods: LAB isolates C2 and C10 were rejuvenated, screened for hemolytic activity, cultivated in de Man Rogosa Sharpe Broth (MRSB) with and without 1% Monosodium Glutamate (MSG), extracted with ethyl acetate, and detected by Thin Layer Chromatography (TLC) using Pregabalin as the reference standard. Antioxidant activity was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay based on IC50 values. Results: Retention factor (Rf) values were 0.82 (C2 without MSG), 0.84 (C2 with MSG), 0.80 and 0.64 (C10 without MSG), and 0.86 and 0.68 (C10 with MSG), all close to the standard Rf of 0.88. IC50 values were 940.11, 1124.97, 884.73, and 939.17 ppm for C2 without MSG, C2 with MSG, C10 without MSG, and C10 with MSG, respectively, with coefficients of determination (R²) ranging 0.9916–0.9960. Conclusion: LAB isolates C2 and C10 from Chao Pangkep produced GABA, though their antioxidant activity was low, as IC50 values far exceeded the weak-activity threshold. These findings offer a preliminary basis for optimizing GABA production by LAB from local fermented products toward developing functional probiotics or supplements. ]]>
