1.1. ISOLATION AND CHARACTERIZATION OF THE TOXICITY OF DIPLONINE, A NEUROTOXIN FROM STENOCARPELLA MAYDIS
Diplodiosis, a nervous disorder of cattle and sheep, results from the ingestion of mouldy cobs infected by
Stenocarpella maydis. Diplodiosis is characterized by reluctance of the animals to move, a wide-based stance, incoordination, tremors, paralysis and death. We are currently at the final stages with the isolation and elucidation of the neurotoxin, diplonine from
S. maydis. This research activity contributes to the government imperative: Food security and safety.
Isolation and elucidation of the diplonine toxin has been completed recently (Snyman et al., 2011).
We are currently:
Optimizing the extraction method for production of diplonine in sufficient quantities (mass production)
Investigating the cytotoxicity and pathways affected by this toxin in in vitro systems
In the near future, we will be:
Developing and validating the use of an in vitro diagnostic system to replace the guinea pig model
1.2. PROTECTIVE EFFECT OF PLANT EXTRACTS AGAINST MYCOTOXIN-INDUCED MUTAGENICITY
It is well established that mutagenesis is one of the major factors for carcinogenesis. Mycotoxins, a group of compounds originates from secondary metabolism of moulds and occur naturally on human food and animal feed, are known mutagens and carcinogens. Many strategies have been used in attempts to prevent contamination of food and feed by mycotoxins. However, many of these attempts have limitations and mycotoxins enter animal and human body through food consumption. That is why it is necessary to combat their harmful effects specially carcinogenic effects. Therefore, antimutagenic agents could play a vital role in the prevention of the early stages of cancer development as a result of mycotoxins. Many such agents have already been isolated from plants of different origins and it is anticipated that many of the native South African plants could provide a valuable source of other promising antimutagenic and anticancer drugs. The major goal of our research is to identify plant species, from South Africa, with promising antimutagenic activity against mycotoxin-induced mutagenicity and to attempt isolation of the bioactive compounds there from.
1.3. EVALUATION OF SOUTHERN AFRICAN PLANTS USED IN ANIMAL HEALTH FOR EFFICACY AND SAFETY
In South Africa, the use of plants for treatment against diseases has been in existence for centuries. Recently, most of South African medicinal plants that have been investigated for pharmacological properties aimed at human ailments. However, investigation of plants used in ethno veterinary medicine has not received much attention. This calls for more research to validate the efficacy and safety of plants used in traditional ethno veterinary medicine as farmers in rural areas depend largely on plants for the treatment of animals from various diseases. Our research will pay much attention to screening
plants from southern Africa in various biological assays including antibacterial, anti-inflammatory, antiparasitic and central nervous system disorders. The plants will also be investigated for their safety using the in vitro cytotoxicity and genotoxicity assays as well as in vivo assays available at our laboratory. Plants extracts with strong biological activity will be pursued further for the isolation of bioactive compounds.
1.4. ASSESSMENT OF CYANBACTERIA AND THEIR TOXINS
The Toxicology laboratory is involved in the surveillance and characterization of the toxicity of cyanobacteria and their toxins in water bodies (dams, rivers and lakes) used as a drinking source by humans and animals. Recently, we concluded a similar study in some of the Kruger National Park dams (WRC Report No. 1850/1/11). We also focus on developing and using
in vitro (cell culture) assays in assessing the toxicity of microcystins in water samples.
In the near future, we will be:
Developing and validating molecular techniques for the identification of cyanobacteria in water samples
1.5 QUALITATIVE AND QUANTITATIVE ANALYSIS OF ANTI-NUTRITIVE FACTORS IN PLANTS
Most livestock animals depend on browsing on tree fodders in the rangelands to maintain their normal physiological processes. However, feed poisoning arising from plants is a serious concern across the globe. This is due to the presence of various organic and inorganic compounds including pesticides, industrial pollutants, naturally-occurring chemicals and heavy metals which frequently occur in feedstuff. On the other hand, plants contain endogenous toxins from specific primary and secondary metabolites that frequently interfere with utilization of nutrients and/or feed/food intake of plants or plant products to deprive living organisms of nutrients. Hence, they are commonly referred to as anti-nutritive factors and their abundance frequently lead to massive clinical trauma resulting in high morbidities and mortalities, declined exportation, high unemployment and poverty.
Due to the negative impact of feed poisoning on health of the livestock and the quality of livestock products viz, milk, eggs and meat for human consumption, there is an urgent need to develop low-cost animal feeds that are safe, nutritious and reliable for consumption to improve animal health. Thus, this research aims to mitigate feed poisoning by exploring various extraction techniques, conducting a qualitative and quantitative analysis of anti-nutritive factors in plants that are frequently consumed by livestock animals.
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