Research progress on the biological activity and applications of gamma-aminobutyric acid.

Gamma-aminobutyric acid (GABA) is a four‑carbon, non-proteinogenic amino acid widely found in vertebrates, plants, and tiny critters. This compound acts as the primary inhibitory neurotransmitter in the nervous system. Recent studies have shown that the physiological functions of GABA extend beyond neural regulation, as it also exhibits multiple biological activities, including antioxidant, antihypertensive, and antidiabetic effects. GABA exerts multi-targeted effects through several mechanisms, including regulating enzyme activity, modulating the expression of related signaling pathways, and controlling glycolysis and the tricarboxylic acid (TCA) cycle. Through these multi-targeted mechanisms, GABA demonstrates potential as a strategic functional molecule with cross-system and cross-disease applications. Safe microbial strains, including lactic acid bacteria (LAB) and Corynebacterium glutamicum, can efficiently produce GABA under mild, environmentally friendly conditions. These strains may help establish a biomanufacturing paradigm for the scalable and sustainable supply of raw materials for functional foods, pharmaceuticals, and cosmetics. This review systematically examines the multidimensional biological activities of GABA and their underlying mechanisms and summarizes its potential as a strategic functional food resource. The use of carefully selected, non-pathogenic microbial strains for biosynthesis reveals the significant potential of GABA across both the food and pharmaceutical sectors. However, current human studies on the clinical translation of GABA remain insufficient, and evidence of its antidiabetic and anticancer effects is derived primarily from animal models and in vitro studies. In addition, the safety and potential risks of long-term high-dose intake have not been fully elucidated. To advance industrial applications, future research should prioritize therapeutic calibration, extended risk evaluation, and regulatory considerations to establish a scientific foundation for the development of related products.