Neuroprotective Effects of the Flowers of Camellia japonica var. Hagoromo: A Potential Candidate for Neurodegenerative Disease Treatment

Neurodegenerative diseases such as Alzheimer's and Parkinson's are characterized by cholinergic dysfunction and oxidative stress, leading to progressive cognitive decline. The lack of effective treatments for these disorders makes the search for naturally derived neuroprotective agents increasingly important. Various Camellia species have demonstrated neuroprotective effects, primarily attributed to their rich phytochemical composition. However, no previous study has investigated the neuroprotective properties of Camellia japonica, particularly the Hagoromo cultivar. This study evaluates the neuroprotective potential of C. japonica var. Hagoromo flower extract by evaluating its inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes using previously established methods. The extract showed a dose-dependent increase in AChE inhibition, with 1 mg/mL achieving 7% inhibition and 2 mg/mL reaching 22%. For BuChE inhibition, the extract showed its highest activity at 1 mg/mL, reaching 37% inhibition. These findings indicate potential neuroprotective properties, although the observed inhibition levels were lower than the levels of well-known neuroprotective compounds such as fucoxanthin and polyphenols found in seaweeds (Pruccoli et al., 2024; Dhami et al., 2021). However, this study was conducted using unpurified extracts, which may limit the accuracy of the observed effects. Therefore, further studies should focus on purifying and isolating the bioactive compounds present in the sample to provide a more precise assessment of their neuroprotective potential. Previous studies suggest that catechins, quercetin, kaempferol, and their derivatives are the primary neuroprotective phytochemicals in Camellia. These compounds exert their effects by synergistically enhancing endogenous antioxidant defenses, regulating neurotrophic signaling pathways, and reducing neuroinflammation (An et al., 2020). Future research should optimize extraction parameters, identify key active compounds, and conduct in vivo evaluations to further validate the therapeutic potential of C. japonica in neurodegenerative disorders.