The Modulating Effects of Alkaloids on Gut Microbiota: Insights andImplications for Parkinson's Disease Management

Parkinson's Disease (PD) is a neurodegenerative disorder characterized by the selective degeneration of dopaminergic neurons in the substantia nigra, leading to motor and non-motor symptoms. Recent research highlights the importance of the microbiome-Gut-Brain Axis (GBA) in PD pathogenesis, particularly the role of gut microbiota dysbiosis and inflammation. This review aims to explore the potential of alkaloids, a diverse group of naturally occurring compounds, in modulating gut microbiota and their implications for PD management. We evaluated studies that investigated the effects of various alkaloids on gut microbial composition, neuroinflammation, and dopaminergic neuron health using PubMed, Scopus, Web of Science, and Google Scholar databases. The search strategy combined Medical Subject Headings (MeSH) and free-text keywords. The primary search terms included: “Parkinson’s disease” OR “PD”, “gut-brain axis” OR “gut microbiota” OR “intestinal dysbiosis”, “alkaloids” OR specific compound names (e.g., “berberine,” “harmine,” “galantamine,” “nicotine,” etc.). Evidence suggests that alkaloids such as berberine, protopine, and palmatine, matrin, etc., can restore microbial balance, reduce inflammation, and enhance neuroprotective effects, potentially mitigating both gastrointestinal and neurological symptoms associated with PD. This review underscores the need for further research, particularly human clinical trials, to validate the therapeutic efficacy and safety of alkaloids in the context of PD. By elucidating the mechanisms through which alkaloids influence the GBA, we can pave the way for innovative treatment strategies that enhance the quality of life for PD patients.