Researchers from Zhejiang University reported that a preventative effect may also be exerted via the metabolism of tryptophan and the increase in blood-brain barrier (BBB) permeability following butyrate production.
“The molecular mechanisms of the intricate interaction of anthocyanins and different kinds of gut microbes on the beneficial or pathogenic effects of neurological diseases should be more deeply elaborated,” wrote the researchers in Nutrients.
Powerful prevalence
There has been a substantial rise in life expectancy across the globe, increasing those suffering from age-related conditions such as neurodegenerative diseases (NDs) including Alzheimer’s and Parkinson’s disease. Despite such growth in ND prevalence, treatment methods remain conservative, highlighting a greater need for research into this area.
The potential of polyphenols in ND prevention and treatment has been previously demonstrated; an observation resulting from their potent antioxidant capabilities. Specifically, anthocyanins have been found to exhibit regulatory effects on the central nervous system (CMS) through the gut-brain axis.
The sub-class of flavonoids, which exist as natural colour pigments within berry fruits and vegetables, have been found to exert anti-inflammatory, antioxidant, and anti-aging properties in this way.
Consequently, researchers conducted the present literature review to assess the current evidence regarding the potential therapeutic properties of anthocyanins for treating NDs via the gut-brain axis.
Anthocyanin action
“Anthocyanins have been shown to subside NDs by reducing oxidative stress and the viability of microglia. In addition, it can also prevent lipid peroxidation and inflammation caused by neurotoxins, thereby exerting its effects on the nervous system.”, the report highlights.
The neuroprotective effects are achieved as “anthocyanins can restrain the production of pro-inflammatory mediators in microglia and avoid inflammatory cell damage”, the researchers state.
In addition to these mechanisms of action, anthocyanins have been reported to influence the gut microbiota, which can then directly or indirectly influence neuronal and cognitive functions through the gut brain axis. This is achieved through the production of short-chain fatty acids (SCFAs), bile acid metabolism influence, as well as neurotransmitter production, such as glutamate and dopamine.
The scientists explain their influence via the gut-brain axis may be due to their polarity, which “allows molecules to penetrate the BBB.”, as shown in some previous studies.
Future research
The present literature review provides an important summary highlighting the potential for the use of anthocyanins in future prevention and treatment interventions for NDs.
“It has been increasingly demonstrated that anthocyanins regulate the CNS through the gastrointestinal tract or through the immune, neurological, and endocrine systems.
“It is also worth exploring the mechanism by which anthocyanins pass through the BBB to regulate the microbial-intestinal-brain axis.”, the researchers stress with regards to future study.
“The underlying mechanism of anthocyanins of different structures for NDs under the microbial-intestinal-brain axis system needs further study, and other structures of anthocyanins may have different targeting molecules and initial mechanisms.”, they conclude.
Source: Nutrients
2023, 15(3), 496; doi: 10.3390/nu15030496
“Protective Effect of Anthocyanins against Neurodegenerative Diseases through the Microbial-Intestinal-Brain Axis: A Critical Review”
Authors: H. Zhong, et al.