Astragaloside IV Alleviates Fructose-Induced Intestinal Metabolic Senescence by Targeting Ketohexokinase Asn261/Ala226 to Preserve Intestinal Stem Cell Homeostasis.

Excessive fructose intake drives intestinal aging and impairs intestinal stem cell (ISC) function, yet effective therapeutic interventions remain elusive. Astragaloside IV (AS-IV), a natural saponin from Astragalus membranaceus, has been widely recognized for its antiaging, anti-inflammatory, and gut-protective properties. Here, we revealed that AS-IV alleviates fructose-induced intestinal metabolic senescence via direct inhibition of ketohexokinase (KHK), the key rate-limiting enzyme in fructose metabolism. Molecular docking and site-directed mutagenesis identified Asn261 and Ala226 as distinct binding sites for AS-IV on KHK, with Asn261 also serving as a critical catalytic residue that is essential for KHK activity. Mutation at Asn261 abolished KHK enzymatic function, reduced the accumulation of fructose-derived metabolites such as palmitic acid and ceramide, and thereby prevented fructose-induced ISC cycle arrest. AS-IV's therapeutic efficacy was validated across Drosophila, murine intestinal organoids, and mice, where treatment consistently reversed high-fructose-induced intestinal metabolic senescence phenotypes, restored ISC proliferation, and preserved ISC homeostasis. These findings indicate that KHK is a previously unrecognized molecular target of AS-IV and reveal a conserved mechanism by which AS-IV modulates fructose metabolism to interfere with gut aging. Our results highlight its therapeutic potential in treating fructose-driven intestinal aging and associated metabolic disorders.