Natural monomer compounds in neurodegenerative diseases: Targeting ferroptosis and neuroinflammation.

Neurodegenerative diseases (NDDs), including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, are characterized by progressive neuronal loss driven by oxidative stress, mitochondrial dysfunction, and chronic neuroinflammation. Ferroptosis, an iron-dependent and lipid peroxidation-associated form of regulated cell death, has recently been identified as a key contributor to neuronal vulnerability. Emerging evidence demonstrates that purified natural monomer compounds derived from medicinal plants exert potent neuroprotective effects by targeting ferroptosis and neuroinflammatory pathways. Representative agents such as curcumin, baicalin, resveratrol, and ginsenoside Rg1 activate nuclear factor E2-related factor-2 and glutathione peroxidase 4 signaling to preserve redox balance, while suppressing microglia-mediated inflammation through inhibition of toll-like receptor 4 pathways. This review highlights the interplay between ferroptosis and neuroinflammation in NDDs, summarizes the regulatory effects of bioactive herbal monomer compounds, and discusses recent advances in multi-omics profiling, nano-delivery strategies, and translational research. By modulating the ferroptosis-neuroinflammation axis, these compounds may represent promising therapeutic candidates for NDDs.