Kaempferol: advances in biosynthesis, molecular mechanisms, and therapeutic applications.

Kaempferol is a ubiquitous dietary flavonol found in fruits, vegetables, and medicinal plants, existing in both aglycone and glycosylated forms which contribute to its structural and functional diversity. This review provides a comprehensive overview of kaempferol, focusing on its biosynthesis, pharmacokinetic challenges, and the mechanistic basis for its diverse pharmacological properties. Its biosynthesis originates from phenylalanine, with subsequent enzymatic modifications yielding derivatives of varying bioactivity. The principal mechanism of kaempferol is rooted in its potent antioxidant capacity, acting through both direct radical scavenging and the upregulation of the cytoprotective Nrf2 pathway. This redox modulation is intricately linked to its anti-inflammatory effects, which are mediated by the suppression of key signaling cascades including NF-κB, MAPKs, and STATs. In preclinical models, kaempferol demonstrates significant antidiabetic activity by activating AMPK and enhancing insulin sensitivity. Its anticancer properties are equally notable, involving the induction of apoptosis, cell cycle arrest, and inhibition of metastasis through the disruption of pathways such as PI3K/AKT and Wnt/β-catenin. Furthermore, it exhibits antimicrobial effects and hepatoprotective actions by modulating SIRT1/AMPK signaling. Despite these promising bioactivities, therapeutic translation is severely hampered by its poor aqueous solubility and extensive first-pass metabolism, which critically limit oral bioavailability. Consequently, while kaempferol is a compelling polypharmacological agent with the potential to address complex diseases, its unfavorable pharmacokinetic profile remains the critical bottleneck for clinical advancement. A promising direction for future research is to prioritize the development of advanced drug delivery systems and the execution of rigorous clinical trials to translate its extensive preclinical promise into validated clinical applications.