The expanding frontiers of gallic acid: From dual chemistry and pharmacology to innovative technological applications

Gallic acid (3,4,5-trihydroxybenzoic acid), a phenolic compound of botanical origin, exhibits a historically significant role within the annals of traditional pharmacopeia and is currently garnering substantial academic attention for its multifaceted utility in contemporary scientific and technological spheres. In this treatise, a comprehensive synthesis of multidisciplinary insights is presented, wherein the dual redox behavior of gallic acid—characterized by its function as an antioxidant through radical scavenging and metal coordination, or alternatively as a pro-oxidant via Fenton-type reactions and the depletion of intracellular glutathione (GSH)—is established as the primary conceptual framework for its functional versatility. The pharmacological dimensions investigated herein comprise anti-inflammatory activities mediated by the inhibition of NF-κB and mitogen-activated protein kinase (MAPK) pathways; selective antineoplastic cytotoxicity facilitated by the generation of reactive oxygen species (ROS) and subsequent induction of apoptosis; metabolic regulation attained through the activation of AMPK and PPAR-γ; and neuroprotection enabled via the modulation of GSK3β–Nrf2 signaling. Notwithstanding its extensive therapeutic potential, the clinical translation of gallic acid is currently impeded by its classification as a Biopharmaceutics Classification System (BCS) Class III compound, reflecting a sub-optimal pharmacokinetic profile. Strategic interventions, including molecular derivatization and nanotechnology-based delivery architectures, are evaluated as means to circumvent these physiological barriers. Furthermore, this review delineates innovative applications in active packaging, environmental remediation, and the nascent frontier of metal–phenolic networks (MPNs). Through the integration of these disparate research trajectories, an AI-driven and sustainable roadmap is proposed to fully harness the redox duality of gallic acid in both biomedical and industrial implementations.