While there currently exists no cure for Alzheimer’s disease (AD), preliminary studies with Rooibos extracts have shown that the tisane may be able to reduce the risk and onset of neurodegenerative diseases.
Alzheimer’s disease is a progressive illness that destroys memory and other important mental functions and affects an estimated 55 million people worldwide.
In recent decades, there has been a significant rise in Alzheimer’s cases globally and in South Africa – largely due to unhealthy lifestyles, which often lead to chronic illnesses like diabetes, hypertension and cardiovascular disease. Another risk is old age. As life expectancy increases, more people are reaching ages where neurodegenerative diseases are becoming more common, necessitating the development of new, more effective therapies.
Two prominent South African scientists, who have been studying Rooibos and brain health for several years, attribute the tisane’s neuroprotective effect to its unique combination of polyphenolic compounds, including other rare antioxidants, like Aspalathin and Nothofagin, that help the body to detoxify and rid itself of harmful free radicals caused by oxidative stress. Over time, oxidative stress leads to inflammation and many pathophysiological (abnormal) conditions in the body. Some of these include Parkinson’s disease, chronic fatigue syndrome, heart disease and Alzheimer’s.
Some animal studies have also shown that Rooibos extracts might positively influence specific memory and cognitive function pathways, however further examination is needed before firm conclusions can be drawn.
Novel research being done by Dr Taskeen Fathima Docrat, a scientist based at Cape Peninsula University of Technology (CPUT) aims to unravel the intricate biological mechanisms that are involved in brain health to gain a clearer understanding of how and to what extent Rooibos can prevent Alzheimer’s disease.
“We’ve delved explicitly into the intricate world of epigenetics, which is the study of how our behaviours and the environment can change the way our genes work without altering the underlying DNA sequence.
Unlike genetic changes, epigenetic changes are reversible and can change how your body reads a DNA sequence. Mitochondria are known as the powerhouse of a cell because they are responsible for generating energy in the form of adenosine triphosphate (ATP). Sometimes Mitochondria don’t work as well as they should due to another disease or condition in the cell – this is called Mitochondrial dysfunction.
Many conditions can lead to secondary mitochondrial dysfunction, including Alzheimer’s disease, muscular dystrophy and Type 1 diabetes. We’ve been particularly interested in understanding how Rooibos could influence oxidative stress-related biomarkers, and gene and microRNA regulation related to mitochondrial dysfunction in Alzheimer’s disease. This line of research takes a holistic approach by examining multiple factors and their interactions.
“We are comparing the effects of fermented (red) and unfermented (green) Rooibos to help us understand the potential benefits of different Rooibos types comprehensively. Comparing the effects of different Rooibos types not only contributes to a more nuanced understanding of their potential impacts in protecting against Alzheimer’s, but also provides insights into how variations in processing might influence their bioactive properties.
“Although we are still busy with these studies, preliminary findings look promising, suggesting that Rooibos could positively impact these factors.”
She says the insights they are gathering will guide the design of future human clinical trials to explore Rooibos’ effects in real-world scenarios.
“Currently we are laying the foundation for potentially developing supplements that could act preventatively,” remarks Dr Docrat.
Another prominent researcher from Stellenbosch University and professor of molecular physiology, Ben Loos, has done extensive research in the last 12 years on Alzheimer’s disease and neuronal ageing, malignant brain tumours, as well as neuronal injury and trauma. His research has focused specifically on autophagy activity, which is an intracellular degradation process that allows cells to recycle damaged components to generate energy and provide building blocks to create new cellular structures. In gist, autophagy acts as a housekeeping mechanism to ensure that damaged parts of the cell are rapidly digested (eaten) and cleared from the cell.
In recent years, defects in autophagy function, which happens with ageing, have been associated with the development of cancer and Alzheimer’s disease.
Various animal models and cellular studies indicate that increased autophagy activity may play a role in improved longevity and a longer lifespan.
Loos’ aim is to prevent or delay the dying of cells. He says over the last few years it has become very clear that the biggest risk for the development of AD is aging.
“We all age differently. Some age poorly – usually associated with poor lifestyle choices, while others age healthily. So, we started to look at the molecular hallmarks of aging, which include mitochondrial dysfunction, oxidative damage and the accumulation of toxic protein aggregates. In doing so, we came across the potential health benefits of Rooibos and was curious about how it would impact these markers. If it acted on some of those parameters positively, we thought, it could likely reduce the risk of neurodegeneration.
“Our current research assesses the effect of Rooibos extract on damaged/diseased mitochondria – mimicking AD, which has shown that when we treat neurons with the extract, mitochondrial volume increases. This indicates that Rooibos is indeed acting on a very important part that controls cell energetics and cell health. Preliminary data also shows that the Rooibos extract preserves cell membrane integrity.”
Applying leading edge imaging technologies to unravel the molecular make-up of a dying and diseased cell, allows Loos and his team to gain a deeper understanding of cell dynamics and how they respond (fight) to survive a stressful event.
Loos says they designed the research so that it is more translatable to humans.
“The cells are all treated with an equivalent amount of either three or six cups of Rooibos, so that a low and high concentration can be compared. We also use fermented (red) and non-fermented (green) Rooibos. Our results show that at both low and high concentrations of fermented and non-fermented Rooibos extract, mitochondrial function was improved.”
Once Loos and his team have completed their current study, they will turn their focus to how effective Rooibos impacts the process of ‘rubbish removal’ in the neuron (autophagy).
“If we can show that Rooibos extracts increases the cell’s ability to remove toxic protein cargo, such as amyloid beta, by enhancing autophagy, this would be a massive finding. Autophagy, which increases upon fasting or exercise, has been shown to directly rescue diseased Alzheimer’s neurons.
“Such a finding would be very direct evidence of the effect of Rooibos on cell health and healthy aging. We would also want to introduce an even better model for Alzheimer’s disease, where we can switch on the production of these toxic proteins and measure whether the presence of Rooibos can decrease the toxic burden. In the future, we would like to measure the effect of Rooibos on the mitochondria and autophagy in human blood cells to have an even better translational value,” says Loos.
Both Dr Docrat’s and Prof Loos’s research approaches offer multifaceted insights into Rooibos’s potential benefits against Alzheimer’s, covering cellular and molecular aspects.
World Alzheimer’s Month (this September) is set aside to raise more awareness and discussion around the disease and the worldwide necessity of finding new potential disease-modifying therapies. To date, only symptomatic treatments exist – all trying to counterbalance the neurotransmitter disturbance. Treatments capable of stopping or at least effectively modifying the course of Alzheimer’s, are encouraged given the rise in incidence. By 2050, the number of cases is set to increase to 139 million, with low- and middle-income countries experiencing the most significant increase.
Rooibos research is supported by the SARC in collaboration with the Department of Science & Innovation’s Sector Innovation Fund Programme.