Insights & Discussion
Bioactive components in green tea have demonstrated potential neuroprotective effects and might play a role in preventing Alzheimer’s disease.
In this study, the researchers focused on the potential preventative effects of bioactive compounds, specifically (-)-epigallocatechin-3-gallate, present in tea, on Alzheimer's disease (AD). This interest was based on recognition of the importance of lifestyle-related factors, including diet, in the primary prevention of AD. They compiled and analyzed the findings from various preclinical studies which pointed towards the neuroprotective qualities of these compounds.
The results reveal an association between the consumption of green tea and a reduction in the risk of age-related cognitive decline and AD. However, these results do not establish a causal relationship. That is, while people who drink green tea appear to have lower rates of AD, the study cannot confirm that green tea consumption is the reason for this reduced prevalence. The researchers also emphasized that while the preventative effects of green tea were deduced from preclinical (animal) studies, human-based clinical trials yielded unsatisfactory evidence regarding tea's preventive or therapeutic effect on AD.
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Green tea's catechins demonstrate therapeutic effects against neurodegenerative diseases via anti-inflammatory, antioxidant actions, and activating diverse brain cellular pathways.
2022 Molecules Green Tea Catechins Attenuate Neurodegenerative Diseases and Cognitive Deficits Afzal O, Dalhat MH, Altamimi ASA, Rasool R, Alzarea SI, Almalki WH, et al.
Review Article Alzheimer's Disease Cognitive Function Green Tea
The research primarily evaluates the effect of polyphenolic compounds found in green tea, known as catechins, on neurodegenerative diseases. By conducting several interventional and observational studies on humans, the research explores the anti-cancer, anti-obesity, antidiabetic, anti-inflammatory, and neuroprotective properties of these compounds. The biological, pharmacological, antioxidant, and metal chelating abilities of catechins, particularly their influence on different cellular pathways within the brain, are intensively studied.
The results elucidate that catechins exhibit multiple neuroprotective effects. Their anti-inflammatory and antioxidant properties help to inhibit excessive production of cytokines, and inflammatory pathways, while also controlling metal ions and free radicals. Researchers have further established that catechins may curb the phosphorylation of the tau protein and aggregation of amyloid beta, both key markers in neurodegenerative diseases. Additionally, these compounds show potential in reducing alpha-synuclein levels and augmenting dopamine levels. Hence, they significantly contribute to the prevention and treatment of neurodegenerative diseases, including Alzheimer's, Parkinson's, multiple sclerosis, and cognitive deficits.
Green tea polyphenolic compounds, (-)-epigallocatechin (EGC) and (-)-epicatechin-3-gallate (ECG), can diminish harmful Alzheimer's disease linked Aβ aggregates and ameliorate symptoms.
2020 Bioorganic Chemistry Inhibition of Aβ aggregates in Alzheimer’s disease by epigallocatechin and epicatechin-3-gallate from green tea Chen T, Yang Y, Zhu S, Lu Y, Zhu L, Wang Y, et al.
Experimental Study Alzheimer's Disease EGCG Green Tea
Green tea compounds EGC and ECG were tested for their effects on Cu/Zn-induced or self-assembled Aβ aggregation involved in Alzheimer's disease. To do so, a combination of thioflavine T fluorescent spectrometry, inductively coupled plasma mass spectrometry, UV-Vis spectroscopy, transmission electron microscopy, silver staining, immunohistochemistry, and immunofluorescence assays were utilized. Findings indicate that these compounds bind mildly to Cu and Zn and reduce their caused or self-assembled Aβ aggregates. Moreover, these compounds were shown to manage neurotoxicity in mouse neuroblastoma Neuro-2a cells by decreasing the production of reactive oxygen species (ROS).
From the findings, the EGC and ECG in green tea showed potential in reducing the toxicity of Aβ oligomers and fibrils which are heavily linked to Alzheimer's disease. Notably, ECG has the ability to traverse the blood-brain barrier and reduce Aβ plaques within the mouse brain, showcasing its potential for neuron protection. This study highlights the potential of green tea - specifically, its polyphenolic compounds - in the prevention or reduction of Alzheimer's disease symptoms.
Regular coffee consumption, due to its bioactive compounds, may have protective effects against chronic disorders and certain neurodegenerative conditions.
2020 International Journal of Molecular Sciences Neuroprotective Effects of Coffee Bioactive Compounds: A Review Socała K, Szopa A, Serefko A, Poleszak E, Wlaź P
Review Article Alzheimer's Disease Cardiovascular Disease Coffee
The paper evaluates the neuroprotective potential of the main bioactive elements in coffee: caffeine, chlorogenic acid, caffeic acid, trigonelline, kahweol, and cafestol. The analysis is focused on the coffee beverage as a complex mixture of these bioactive compounds. The comprehensive study includes in vitro and in vivo preclinical tests to determine the specific health benefits each of these compounds can offer.
The results indicate that regular coffee intake may have defensive effects against a variety of enduring disorders; including cardiovascular disease, type 2 diabetes, obesity, and some forms of cancer. Additionally, an interesting correlation is found between coffee consumption and a lower risk of developing certain neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease, and dementia. The study also highlights that regular coffee intake could possibly lower the risk of stroke. However, the study mentions that the mechanisms enabling these effects are yet to be fully understood.