Neuroprotective Properties of Plant Extracts: An Evaluation of In vitro Evidence and Future Directions for Clinical Translation

Introduction/Objective:: The prevalence of neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, is increasing due to global population aging and the limited efficacy of current treatments. Oxidative stress and mitochondrial dysfunction are key contributors to neuronal damage, highlighting the urgent need for alternative therapeutic strategies. Plant extracts, rich in bioactive compounds with antioxidants and anti-inflammatory properties, have been extensively studied for their potential neuroprotective effects. Methods:: This review analyzes the preparation of plant extracts for in vitro neuroprotection studies, with a focus on efficacy and cytotoxicity. Results:: Among the studies reviewed, ethanol and methanol were the most commonly used solvents, employed in extraction techniques such as maceration, Soxhlet extraction, and ultrasound-assisted methods. Most studies utilized SH-SY5Y and PC12 neuroblastoma cell lines to evaluate the cytotoxic and neuroprotective properties of the extracts using MTT assays and oxidative stress models. The findings indicate that plant extracts obtained using ethanol and methanol exhibit varying degrees of neuroprotection, with several showing significant protection against oxidative stress-induced cytotoxicity. Notably, methanolic extracts from Alternanthera sessilis, Withania somnifera, and Rotheca serrata, as well as ethanolic extracts from Myrtus communis and Anemarrhena asphodeloides, demonstrated high efficacy in preventing neuronal apoptosis and oxidative damage. Discussion:: Plant extracts show strong antioxidant, anti-inflammatory, and cytoprotective activities, making them promising candidates for neuroprotection. They act through modulation of oxidative stress, reduction of neuroinflammation, and reinforcement of cellular defenses. Despite this potential, issues such as variability, limited bioavailability, and lack of clinical validation remain major challenges. Advances in nanotechnology, omics, and high-throughput screening offer strategies to improve delivery, standardization, and characterization. Multidisciplinary approaches are essential to optimize extraction, formulation, and reproducibility. Conclusion:: Continued research is needed to bridge experimental findings with clinical applications in neurodegenerative diseases, ultimately fostering the development of safe and effective plant-based therapeutic strategies.