Valeric acid functions as a short-chain fatty acid (SCFA) metabolite derived from gut microbiota fermentation. It exhibits histone deacetylase (HDAC) inhibitory activity and acts as a G protein-coupled receptor (GPCR) agonist, contributing to the maintenance of intestinal barrier integrity and the modulation of systemic inflammatory responses.

Chemical Properties

Valeric acid (C₄H₉COOH), also known as pentanoic acid (molecular weight: 102.13 g/mol), is a colorless liquid characterized by a rancid odor. It has a density of 0.939 g/cm³, a boiling point of 185°C, and a melting point of -34.5°C. As a carboxylic acid (pKa 4.82), it displays typical acid reactivity. Its linear structure CH₃(CH₂)₃COOH undergoes metabolic β-oxidation to propionyl-CoA and participates in esterification reactions. It is moderately soluble in water (4.97 g/100 mL at 20°C) and is steam volatile, enabling detection by GC-MS.

Biochemical Applications

In microbiome research, valeric acid at concentrations ranging from 1 to 5 mM has been shown to restore radiation-induced intestinal epithelial damage in murine models, improving survival rates (60% to 90%) and significantly reducing intestinal permeability (up to 70%). These effects are associated with modulation of the intestinal proteome and microbiota composition through activation of GPR41 and GPR43 receptors.

In neuroinflammation studies, its HDAC inhibitory activity (IC₅₀ ≈ 1 mM) promotes the upregulation of neuroprotective genes. Additionally, in metabolic research, valeric acid is used to activate FFAR2 and FFAR3 receptors, enhancing glucagon-like peptide-1 (GLP-1) secretion and improving insulin sensitivity in 3T3-L1 adipocyte models.