Ancient plants meet modern science in Parkinson's research

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by aggregates of α-synuclein and the degeneration of dopaminergic neurons in the substantia nigra. Current pharmaceutical therapies mainly alleviate symptoms without halting disease progression. Evidence suggests that traditional plant-based interventions may serve as supplementary therapies by targeting oxidative stress, mitochondrial dysfunction, neuroinflammation, and apoptosis. This review explores the neuroprotective properties of ten medicinal plants commonly used in traditional medicine: Bacopa monnieri, Curcuma longa, Mimosa pudica, Zingiber officinale, Ocimum sanctum, Emblica officinalis, Camellia sinensis, Cannabis sativa, Panax ginseng, and Withania somnifera. A systematic and comprehensive search of PubMed, Scopus, and Web of Science identified relevant in vitro, in vivo, and clinical studies. This study highlights the mechanisms by which plant-derived chemicals influence cellular pathways associated with PD, emphasising their therapeutic potential despite limited clinical validation. Studies have shown that bioactive compounds such as curcumin, bacoside, Epigallocatechin-3-gallate (EGCG), cannabidiol, ginsenosides, and withanolides exhibit antioxidant, anti-inflammatory, anti-apoptotic, and neuroprotective effects in PD models. Nanotechnology offers promising strategy to enhance the efficacy of herbal compounds, addressing challenges of poor solubility, rapid metabolism, low bioavailability, and restricted blood-brain barrier penetration. Nano-delivery systems including liposomes, polymeric nanoparticles, nanoemulsions, and metal nanoparticles can improve stability, brain targeting, controlled release, and cellular uptake of these bioactives, thereby enhancing therapeutic efficiency while reducing systemic toxicity. Green-synthesized plant-based nanoparticles further provide synergistic neuroprotective benefits, positioning phyto-nanomedicine as a multi-target approach for PD therapy. However, extensive clinical studies are required to confirm safety and effectiveness.