Phytochemicals self-assemblies: Bridging biomedicine and agriculture for next-generation crop protection

Conventional pesticides face persistent challenges of instability, rapid wash-off, and resistance, while synthetic nanocarriers often suffer from poor degradability, scalability barriers, and regulatory uncertainty. Phytochemical self-assemblies (Phyto-SANs), defined in this review as carrier-free nanoassemblies constructed entirely from plant-derived metabolites, provide a carrier-free and eco-compatible alternative, spontaneously organized from natural metabolites such as polyphenols, alkaloids, and saponins through hydrogen bonding, π-π stacking, hydrophobic, and dynamic covalent interactions. These nanoscale architectures integrate intrinsic bioactivity with structural robustness, achieving enhanced rainfastness, UV resistance, and multi-stimuli-responsive release while potentially contributing to plant defense modulation. Drawing on biomedical precedents, this review establishes a mechanism-centered framework linking supramolecular interactions with agricultural functionality, encompassing stability, interfacial transport, responsive release, and defense co-activation. It further outlines translational priorities in green manufacturing, biosafety evaluation, and regulatory readiness to guide large-scale adoption. Collectively, Phyto-SANs represent an emerging conceptual framework of phyto-mediated protection-where plant-derived molecules are re-engineered through supramolecular chemistry to achieve intelligent, sustainable, and field-ready crop protection.