Autoimmune/Inflammatory Syndrome Induced by Adjuvants (ASIA) after Silicone Breast Implants.

UNLABELLED: Neurodegenerative diseases (NDDs), including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, are characterized by progressive neuronal loss involving multiple pathological mechanisms, including protein aggregation, oxidative stress, neuroinflammation, and mitochondrial dysfunction. Although conventional therapies provide symptomatic relief, they fail to halt disease progression and are limited by poor blood-brain barrier (BBB) penetration, off-target effects, and systemic toxicity. Likewise, several herbal bioactives, such as curcumin, resveratrol, quercetin, and epigallocatechin gallate, exhibit promising neuroprotective properties but suffer from poor aqueous solubility, low oral bioavailability, rapid metabolism, and inadequate brain delivery. Nanotechnology-based delivery systems have emerged as a promising approach to overcome these pharmacokinetic limitations by enhancing stability, controlled release, BBB transport, and brain accumulation of herbal therapeutics. This review critically summarizes recent advances in herbal nanoformulations, emphasizing disease-specific molecular targets, BBB-targeting strategies, comparative nanocarrier systems, pharmacokinetic optimization, intracellular trafficking, and translational challenges. Unlike previous reviews, it integrates recent evidence on nanotoxicology, manufacturing scalability, quality control, regulatory considerations, and emerging technologies, including biomimetic nanoparticles and extracellular vesicles. Despite encouraging preclinical outcomes, clinical evidence remains limited, and no herbal nanoformulation has yet demonstrated definitive efficacy or received regulatory approval for neurodegenerative diseases. Future clinical translation will require standardized formulations, rigorous safety evaluation, and well-designed clinical trials. Unlike previous reviews that primarily summarize individual nanocarrier systems or herbal therapeutics, the present review provides a comprehensive and critical synthesis of the current evidence by integrating disease-specific molecular mechanisms, herbal bioactives, nanocarrier design strategies, blood-brain barrier transport mechanisms, intracellular trafficking, pharmacokinetic considerations, translational barriers, regulatory challenges, clinical evidence, and emerging technologies. Furthermore, the review identifies major knowledge gaps and future research priorities to facilitate the successful clinical translation of herbal nanoformulations for neurodegenerative disorders.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s13205-026-05048-8.