Gallic Acid Monohydrate (3,4,5-Trihydroxybenzoic acid Monohydrate) is a hydrate of Gallic Acid, a natural polyhydroxyphenol, which inhibits the free radical scavenging effect of COX-2, and possesses a variety of physiological activities such as antioxidant, anti-inflammatory, anti-tumor, and antibacterial.

In RAW264.7 macrophages, Gallic Acid Monohydrate (0–100 μM) inhibited LPS-induced NF-κB activation and significantly reduced the production of proinflammatory mediators including nitric oxide (NO), IL-6, and TNF-α.[1] In human corneal epithelial cells (HCECs), Gallic Acid Monohydrate (0–100 μM) suppressed hyperosmotic stress-induced reactive oxygen species (ROS) generation and upregulated antioxidant enzymes such as Nrf2, HO-1, and NQO1. [1] In peripheral blood mononuclear cells (PBMCs) from psoriasis patients, gallic acid (0–100 μM) significantly decreased the frequency of IFN-γ– and IL-17–producing T cell subsets. [1]

In TMT- and ICV-STZ–induced Alzheimer's disease (AD) rat models, Gallic Acid Monohydrate was orally administered at doses of 30, 50, or 100 mg/kg. Treatment increased hippocampal BDNF and TNF-α levels, improved passive avoidance and memory performance, enhanced antioxidant enzyme activities including SOD, CAT, and GPx, and reduced TBARS levels in the hippocampus, indicating neuroprotective and cognitive-enhancing effects. [2]