Browsing by Author "Jansen, Vereneque"

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    The anti-diabetic and insulin sensitizing potential of a watery extract of Agathosma tested in rat models of type 1 and type 2 diabetes
    (Stellenbosch : Stellenbosch University, 2015-03) Jansen, Vereneque; Huisamen, Barbara; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Medical Physiology.
    ENGLISH SUMMARY: Introduction: Epidemiological data highlights that South Africa is currently facing a quadruple burden of disease of which non-communicable diseases (NCDs) are estimated to account for 29% of all deaths. These NCDs include, amongst others, cardiovascular disease, type 2 diabetes, hypertension, cancer, chronic lung disease and depression. Diabetes has become a major problem worldwide and in South Africa and is currently rated as the 5th largest cause of death by Statistics South Africa in 2011. This creates an enormous burden of disease on populations and the utilization of herbal remedies has escalated in popularity because of this. Buchu water is one of these herbal remedies advertised as having anti-diabetic properties. This water is a by-product of the extraction of the oil from the leaves of Agathosma and is already freely available to the public. The aim of this study was therefore to use animal models of type 1 diabetes, and obesity and insulin resistance to scientifically verify or refute these claims. Methods: We utilized male Wistar rats. Two different rat models were used: (i) a type 1 diabetic model; induced via a once-off intraperitoneal Streptozotocin (40mg/kg) injection ablating ~50% of pancreatic beta cells (T1D); (ii) A diet-induced obese model, rendering rats insulin resistant after receiving a high caloric diet for 16 weeks. Half of each experimental group was treated with diluted Buchu water for a period of 14 weeks and 16 weeks, respectively, while the rest consumed normal water. Water and food consumption were monitored, body weight and intraperitoneal fat measured, blood was collected to determine serum glucose and insulin levels, skeletal muscle was removed to test insulin sensitivity using radiolabelled deoxyglucose, pancreas and skeletal muscle harvested and stored in liquid nitrogen for further biochemical analysis. Results: One of the main findings of this study was that ingestion of Buchu water results in weight loss despite no decrease in food consumption. This occurred in both the pathological models and control animals. In the obese animals, this weight loss was due to a decrease in intra-peritoneal fat. A second important finding was that the ingestion of Buchu water in all instances, whether given as treatment (treated with Buchu water 3 weeks after the start of the experiment) or as prophylactic (treated with Buchu water from the start of the start of the experiment), resulted in normalization of glucose levels in a type-1 diabetic model with residual beta-cell mass. An insulin-sensitizing effect was not clearly established in skeletal muscle but this may be because of a large variation in values obtained, as well as the use of a slow-twitch muscle. A definite effect on pancreatic insulin secretion has been demonstrated by raised C-peptide levels in the diet-induced obese model. Conclusion: This study, with regard to the type 1 diabetic model, has confirmed the anti-diabetic effect of Buchu water by significantly lowering blood glucose levels of fasted and non-fasted blood and normalizing Intraperitoneal glucose tolerance test (IPGTT) curves. This was however not so evident in the obese model utilized. Despite this, animals lost weight which was mainly intra-peritoneal fat.