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20 September 2024 | Story André Damons | Photo Supplied
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Zebrafish blue in an aquarium.

A researcher from the University of the Free State (UFS) hopes to make living with epilepsy and other diseases of the central nervous system (CNS) easier by using South African plants extracts which may have anti-epileptic properties and testing them on zebrafish larvae.

Prof Anke Wilhelm, Associate Professor and Divisional Head of Organic Chemistry in the UFS Department of Chemistry, focuses her research on the isolation of active GABAergic compounds (substances that affect the brain’s GABA system, which helps control nervous system activity) by using a test that measures the movement of zebrafish larvae.

Even though obtaining regulatory approval for use as a treatment for epilepsy is a long and complex process, Prof Wilhelm hopes to contribute to the better pain management of people suffering from epilepsy and diseases of the CNS through an affordable alternative drug with less side effects.

The tests are done in a zebrafish bioassay (an analytical method to determine the potency of a substance by its effect on living animals) housed at the UFS’ Chemistry Department.

Why zebrafish larvae?

Prof Wilhelm, who is a National Research Foundation Y2-rated synthetic organic chemist, says zebrafish share about 70% of their genes with humans, and about 84% of human genes known to be associated with diseases have a counterpart in zebrafish. This makes them a valuable model for studying human biology and disease.

“Zebrafish are powerful tools for modelling a wide range of CNS diseases, contributing significantly to the understanding of disease mechanisms and the development of potential treatments,” she says. “Mood disorders, anxiety, insomnia, and attention deficit hyperactivity disorder (ADHD) are all diseases which may be studied through this bioassay.”

She explains that the zebrafish larvae are studied seven days after fertilisation in their bioassay. The larvae are incubated with the specific plant extract at a certain (non-toxic) concentration for three hours. Pentylenetetrazol (PTZ), a GABAA receptor antagonist that has been extensively used in rodent models for acute seizure and anxiety, is then administered to induce concentration-dependent seizures in the zebrafish larvae.

“GABA receptor antagonists are drugs that inhibit the action of gamma-aminobutyric acid, the chief inhibitory neurotransmitter in the mammalian central nervous system,” Prof Wilhelm says. “A specialised infrared camera is then used to track the movement of the larvae inside a chamber. The data is then converted into a graph which shows the movement of each larva over 30 minutes.

“If lowering of movement is observed at a specific concentration it means that the plant extract may have the potential to be used as an epileptic drug, since it has the ability to counteract the induced seizure in the larvae. This bioassay is extremely useful in drug discovery and toxicity screening of plant extracts.”

Zebrafish embryos, she says, develop quickly, with major organs forming within 36 hours of fertilisation. This rapid development allows researchers to observe the effects of experiments in a short period. The maintenance of a zebrafish model is less costly and labour-intensive than using a rodent model. “The use of zebrafish larvae allows for high-throughput screening due to their small size and transparency, which facilitates observation of CNS-related effects. Their genetic and physiological similarities to humans make them a valuable model for early-stage drug discovery.”

Potential uses

The next step in the research, according to Prof Wilhelm, is to identify a single compound from a natural source which may have potential anti-epileptic activity while causing less side effects than current drugs on the market. Researchers would then investigate the possibility of synthesising such a compound on a large scale, to eliminate the use of a natural resource and promote sustainability.

“Many plant extracts which I have screened show a synergistic effect in the zebrafish bioassay, meaning that the extract or the combination of compounds shows potential, but the isolated compounds are inactive. Even if a plant extract shows promise in preclinical and early clinical studies, obtaining regulatory approval for use as a treatment for epilepsy is a long and complex process.

“This includes demonstrating consistent efficacy, safety, and quality in large-scale clinical trials. One of the major challenges in using plant extracts is the lack of standardisation. The concentration of active compounds in plant extracts can vary depending on factors like the plant's growing conditions, harvest time, and extraction methods. This variability makes it difficult to ensure consistent efficacy and safety, therefore this is a time-consuming process.”

Green chemistry

After being approached by Dr Glen Taylor, Senior Director of the UFS Directorate Research Development (DRD), in 2017, regarding funding for Noldus Daniovision equipment, Prof Wilhelm received training from Prof Matthias Hamburger of the University of Basel in Switzerland on how to use such equipment. The larval zebrafish locomotive bioassay was established at the UFS Chemistry Department during 2017 and 2018 and now provides a third-stream income for the department, in conjunction with the Department of Genetics, where the adult zebrafish are housed.

Prof Wilhelm’s other research interests include green chemistry, food sustainability, and recycling. She is looking into green extraction techniques using non-conventional extraction methods to recover valuable bioactive compounds from agricultural and food residues. “Techniques like ultrasound, microwave-assisted extraction, and the use of deep eutectic solvents are becoming popular for their efficiency and alignment with circular economy principles.”

News Archive

Self-help building project helps to change lives
2017-12-15


 Description: Eco house read more Tags: Anita Venter, Start Living Green’, Earthship Biotecture Academy, construction skills 

Anita Venter, lecturer in the Centre for Development Support, with the residents of
the eco friendly house. Photo: Supplied

UFS PhD student Anita Venter did not know it in the beginning, but her doctoral research would eventually change her life and the lives of many others. 

The research was whether South Africa’s housing policies were socially and culturally responsive to grassroots reality in informal settlements. Venter agreed her research approach might have raised a few eye brows, but it was a journey she holds had more benefits than failures. 

Green living
For her case studies, Venter looked at ‘Start Living Green’ as a concept and further examined the implementation models of Earthship Biotecture Academy in New Mexico and Central America and the Long Way Home non-profit organisation in Guatemala. 

These groups train people with no specialised construction skills in applying and managing environmentally sound self-help building projects. Furthermore, their primary objectives were not building-related, but people-centred, with an advocacy role to create social, environmental and educational change through utilising the building technologies. 

It resulted in Venter signing up for a course in Guatemala to get the skills to implement her case studies here at home in Bloemfontein. 

An experimental mud, straw and waste material structure in her back yard grew into similar houses built in informal settlements, through the transfer of knowledge of indigenous building methods.  

Are rickety corrugated iron shacks only alternative?

Her case studies, one in Freedom Square in the Mangaung Metro Municipality, highlighted, among others, baffling tenure insecurities and “tangible conflicts” entrenched between Westernised and African perspectives on home ownership.

Venter says her thesis, in essence, did not oppose existing housing strategies but did challenge the applicability of an economically inclined model as the most appropriate housing option for millions of households living in informal settlements. 

The main findings of the case studies were that self-help building technologies and skills transfer could make a significant contribution to addressing housing shortages in the country; in particular in geographical locations such as the Free State province and other rural areas.

Venter’s own words after her academic endeavour are insightful: “These grassroots individuals’ courage to engage with me in unknown territories, gave me hope in humanity and inherent strength to keep on pursuing our vision of transforming informal settlements into evolving indigenous neighbourhoods of choice instead of only being living spaces of last resort.”

Positive results 
The study has had many positive results. The City of Cape Town is now looking at new innovative building technologies as a result. Most importantly Venter's study will open further discussions that necessarily challenge the status quo views in housing development. 

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