Nanocarrier-Based Delivery Systems for Natural Compounds Across Research Stages.

Natural compounds such as polyphenols, flavonoids, and terpenoids have long been explored for their therapeutic potential. They can act as antioxidants, limit inflammation, and influence cancer or neurodegenerative pathways. However, these benefits rarely translate directly into medical practice, as their solubility is poor, chemical stability is fragile, and metabolism is too fast. In recent years, nanotechnology has offered an alternative route. A wide range of materials, polymeric, inorganic, hybrid, or responsive to external stimuli, were designed to protect and deliver such molecules. Each platform features different preparation methods and release behaviors; all intended to extend circulation and increase tissue selectivity. Considerable attention was paid to targeting strategies, both passive and ligand-mediated, that enhance accumulation in diseased tissues. Preclinical studies have confirmed that encapsulation can raise the therapeutic index of phytochemicals against various conditions, including cancer, inflammation, microbial infections, and neurodegeneration. Still, translation to the clinic is far from resolved, limited by uncertainties over safety, manufacturing scale, and regulation. A parallel line of research now investigates biomimetic carriers, including vesicles derived from red blood cells and whole erythrocytes, which offer immune evasion and versatile loading capacity. The convergence of nanotechnology and natural product pharmacology, enriched by such biologically inspired designs, may open the way to more precise, multifunctional, and patient-tailored therapies.