Lumbee traditional medicine: Neuroprotective activities of medicinal plants used to treat Parkinson's disease-related symptoms.

ETHNOPHARMACOLOGICAL RELEVANCE: Parkinson's disease (PD) is a neurodegenerative disorder characterized by a loss of dopaminergic neurons in the substantia nigra pars compacta and the presence in surviving neurons of Lewy body inclusions enriched with aggregated forms of the presynaptic protein α-synuclein (aSyn). Although current therapies provide temporary symptomatic relief, they do not slow the underlying neurodegeneration in the midbrain. In this study, we analyzed contemporary herbal medicinal practices used by members of the Lumbee tribe to treat PD-related symptoms, in an effort to identify safe and effective herbal medicines to treat PD. AIM OF THE STUDY: The aims of this study were to (i) document medicinal plants used by Lumbee Indians to treat PD and PD-related symptoms, and (ii) characterize a subset of plant candidates in terms of their ability to alleviate neurotoxicity elicited by PD-related insults and their potential mechanisms of neuroprotection. MATERIALS AND METHODS: Interviews of Lumbee healers and local people were carried out in Pembroke, North Carolina, and in surrounding towns. Plant samples were collected and prepared as water extracts for subsequent analysis. Extracts were characterized in terms of their ability to induce activation of the nuclear factor E2-related factor 2 (Nrf2) antioxidant response in cortical astrocytes. An extract prepared from Sambucus caerulea flowers (elderflower extract) was further examined for the ability to induce Nrf2-mediated transcription in induced pluripotent stem cell (iPSC)-derived astrocytes and primary midbrain cultures, to ameliorate mitochondrial dysfunction, and to alleviate rotenone- or aSyn-mediated neurotoxicity. RESULTS: The ethnopharmacological interviews resulted in the documentation of 32 medicinal plants used to treat PD-related symptoms and 40 plants used to treat other disorders. A polyphenol-rich extract prepared from elderflower activated the Nrf2-mediated antioxidant response in cortical astrocytes, iPSC-derived astrocytes, and primary midbrain cultures, apparently via the inhibition of Nrf2 degradation mediated by the ubiquitin proteasome system. Furthermore, the elderflower extract rescued mitochondrial functional deficits in a neuronal cell line and alleviated neurotoxicity elicited by rotenone and aSyn in primary midbrain cultures. CONCLUSIONS: These results highlight potential therapeutic benefits of botanical extracts used in traditional Lumbee medicine, and they provide insight into mechanisms by which an elderflower extract could suppress neurotoxicity elicited by environmental and genetic PD-related insults.

Pikuni-Blackfeet traditional medicine: Neuroprotective activities of medicinal plants used to treat Parkinson's disease-related symptoms.

ETHNOPHARMACOLOGICAL RELEVANCE: Parkinson's disease (PD) is a multifactorial neurodegenerative disorder affecting 5% of the population over the age of 85 years. Current treatments primarily involve dopamine replacement therapy, which leads to temporary relief of motor symptoms but fails to slow the underlying neurodegeneration. Thus, there is a need for safe PD therapies with neuroprotective activity. In this study, we analyzed contemporary herbal medicinal practices used by members of the Pikuni-Blackfeet tribe from Western Montana to treat PD-related symptoms, in an effort to identify medicinal plants that are affordable to traditional communities and accessible to larger populations. AIM OF THE STUDY: The aims of this study were to (i) identify medicinal plants used by the Pikuni-Blackfeet tribe to treat individuals with symptoms related to PD or other CNS disorders, and (ii) characterize a subset of the identified plants in terms of antioxidant and neuroprotective activities in cellular models of PD. MATERIALS AND METHODS: Interviews of healers and local people were carried out on the Blackfeet Indian reservation. Plant samples were collected, and water extracts were produced for subsequent analysis. A subset of botanical extracts was tested for the ability to induce activation of the Nrf2-mediated transcriptional response and to protect against neurotoxicity elicited by the PD-related toxins rotenone and paraquat. RESULTS: The ethnopharmacological interviews resulted in the documentation of 26 medicinal plants used to treat various ailments and diseases, including symptoms related to PD. Seven botanical extracts (out of a total of 10 extracts tested) showed activation of Nrf2-mediated transcriptional activity in primary cortical astrocytes. Extracts prepared from Allium sativum cloves, Trifolium pratense flowers, and Amelanchier arborea berries exhibited neuroprotective activity against toxicity elicited by rotenone, whereas only the extracts prepared from Allium sativum and Amelanchier arborea alleviated PQ-induced dopaminergic cell death. CONCLUSIONS: Our findings highlight the potential clinical utility of plants used for medicinal purposes over generations by the Pikuni-Blackfeet people, and they shed light on mechanisms by which the plant extracts could slow neurodegeneration in PD.