Thesis (MSc (Biochemistry))--University of Limpopo (Medunsa Campus), 2009. / Background and Purpose The stem bark, roots and leaves of Sclerocarya birrea (S. birrea), {(A. Rich) Hochst}, subspecies caffra (Sond) Kokwaro are widely used in South Africa and some African countries as folk medicine in the treatment and management of a variety of human ailments, including diabetes mellitus. Although the blood glucose lowering effect of the stem bark extract of S. birrea have been confirmed using experimental animal models of diabetes, there is no clear understanding of the mechanism(s) whereby S. birrea stem bark extracts and/or their components exert their blood glucose lowering effects. The primary aim of the current study was to study the in vitro inhibitory effects of S. birrea stem bark extracts on the activities of selected diabetic related carbohydrate metabolizing enzymes (α-amylase, α-glucosidase and glucose 6-phosphatase). The current study also investigated the acute in vivo effect of S. birrea stem bark acetone extract on postprandial blood glucose levels after oral sucrose loading as well as the effect of S. birrea stem bark aqueous extract on hepatic glucose 6-phosphatase activity. In addition, the long term (21 days) effects of S. birrea stem bark acetone extract on fasting blood glucose levels, plasma insulin levels, plasma triglyceride and body weight in normal and alloxan induced diabetic rats were also investigated. Methods For in vitro studies: Crude hexane, acetone, methanolic and aqueous extracts of the stem bark extract of S. birrea were prepared by means of a sequential solvent extraction procedure and screened for inhibitory activities against human urinary α-amylase, rat pancreatic α-amylase, Bacillus stearothermophilus α-glucosidase and rabbit liver glucose 6-phosphatase using standard procedures for assaying the activities of these enzymes. IC50 values and mode of inhibition of extracts demonstrating appreciable inhibitory activity against α-amylase and α-glucosidase were determined and compared with those of acarbose, a known inhibitor of these two enzymes. The IC50 value and mode of inhibition of extracts demonstrating appreciable inhibitory activity against glucose 6-phosphatase were determined and compared with those of sodium orthovavadate and sodium tungstate, known inhibitors of glucose 6-phosphatase. In vivo studies: In vivo studies were conducted in normal and alloxan induced diabetic male WKY rats. Diabetes was induced in rats that had been fasted for 12 h by a single intraperitoneal injection of 140 mg/kg body weight of alloxan monohydrate freshly dissolved in sterile normal saline. The effect of S. birrea stem bark acetone extract on postprandial blood glucose level was determined in 18 h fasted diabetic and normal rats by administering orally, the plant extract (300 mg/kg) 30 minutes before an oral sucrose loading and measuring postprandial blood glucose levels after sucrose loading by means of a MediSense’s Optimum Xceed Glucometer (MOXG). In addition, rat intestinal dissacharidase (α-glucosidase/sucrase) activity was determined in homogenate of small intestine of rats sacrificed one hour after given orally either plant extract or acarbose. The in vivo effect of S. birrea stem bark extract on glucose 6-phosphatase was determined by measuring the activity of hepatic glucose 6-phosphatase at the end of the study. For the determination of the long term (chronic) effect of S. birrea stem bark crude acetone extract on blood glucose levels, body weight and water intake, alloxan induced diabetic and normal WKY rats were treated daily with S. birrea stem bark crude acetone extract (300 mg/kg) for 21 days. Fasting blood glucose levels and changes in body weight were determined on day 0, 7, 14 and 21 after initiation of treatment by means of a MOXG and gravimetrically respectively. Water intake was determined on the same days that blood glucose levels were determined by measuring the amount of water left overnight by each rat and subtracting this amount from the initial amount water given to each rat. Blood was also collected at the end of the study for the measurement of plasma glucose, triglyceride and insulin levels. Plasma glucose and plasma triglyceride levels were measured using commercially available kits based respectively on the glucose oxidase and the glycerol blanked methods (Beckman Coulter®’s UniCell DXC 800 Synchron® Clinical System). Plasma insulin levels were determined by means of an enzyme linked immunosorbant assay (ELISA) adapted to the Beckman Coulter® Ireland Inc’s UniCell DXI 800 Access® Immunoassay System. Results In vitro studies: The crude methanolic and acetone S. birrea stem bark extracts strongly inhibited both human urinary α-amylase and rat pancreatic α-amylase in a competitive manner. The inhibitory effect of the crude methanolic extract on both enzymes was significantly stronger than acarbose. Hexane and acetone crude extracts of the stem-bark of S. birrea demonstrated the highest percentage inhibition against B. stearothermophilus α-glucosidase. The mode of inhibition of the crude hexane extract on B. stearothermophilus α-glucosidase appeared to be a noncompetitive one. However, the this plant extract appeared to be a less potent inhibitor of α-glucosidase enzyme than acarbose. Rabbit liver glucose 6-phophatase was strongly inhibited by the crude aqueous S, birrea stem bark extract in a competitive manner. In vivo studies: Administration of S birrea stem bark acetone extract 30 min before oral sucrose loading significantly suppressed (P < 0.01) the rise in postprandial blood glucose levels in treated rats compared to control rats. The crude extract also decreased significantly the intestinal disaccharidase activity of experimental rats compared to control rats. These observations suggest that the in vitro inhibitory effects of the crude hexane extract on α-glucosidase enzymes are applicable in vivo Daily, continuous oral treatment of alloxan–induced diabetic and normal WKY rats with S. birrea stem bark extract for 3 weeks resulted in significant reductions in fasting blood glucose levels and water intake of treated diabetic rats compared with diabetic controls. The extract, however, failed to bring about any significant change in the body weight, plasma insulin levels, plasma triglyceride levels and hepatic glucose 6-phosphatase of treated diabetic rats compared to diabetic control rats Conclusions The results of the current study suggest that the observed in vitro inhibitory effect of S. birrea stem bark acetone extract on alpha glucosidase enzymes are applicable in vivo whereas the observed in vitro inhibitory effect of S. birrea stem bark aqueous extract on glucose 6-phosphatase are not applicable in vivo. Furthermore, in the current study S. birrea stem bark acetone extract appears to lower blood glucose levels of alloxan induced diabetic rats without increasing their plasma insulin levels. Thus, it can be concluded on the basis of the current study that S. birrea stem bark acetone and hexane extracts exert their blood glucose lowering effect in alloxan induced diabetic rats in part, through inhibition of intestinal brush border α-glucosidase enzymes.

Thesis (M. Sc.(Biochemistry)) -- University of Limpopo, 2020 / Diabetes mellitus has become a global epidemic, particularly type 2 diabetes. Obesity is one of the causes of type 2 diabetes mellitus due to its link with induced insulin resistance. There is no cure for diabetes mellitus and, as such, it is managed by using standard drugs which have side effects, and can be toxic, expensive and unavailable. People have resorted to the use of medicinal plants to treat diabetes and its complications. The aim of this study was to test the anti-obesity and anti diabetic properties of Bidens pilosa crude extract and its sub-fractions using C2C12 myoblasts and 3T3-L1 adipocytes. The crude extract and the most active sub fractions were selected for further analysis because of their ability to stimulate glucose uptake and induction of adipogenesis. Bidens pilosa leaves were selected for this current study. They were firstly extracted using absolute methanol and further subjected to solvent-solvent fractionation to obtain the n-butanol, ethyl acetate, water, hexane, chloroform and 35% water in methanol sub-fractions. Qualitative phytochemical analysis was performed using thin layer chromatography (TLC) and standard chemical tests. Total phenolic and flavonoid content were determined quantitatively using a calorimetric method with Folin-Ciocalteu’s reagent. For their antidiabetic potential, the extracts were evaluated chromogenically and calorimetrically for antiglycation and α-amylase inhibitory activity. The cytotoxicity of the extracts on 3T3-L1 preadipocytes and C2C12 myotubes were determined using the MTT assay. The adipogenesis inducing effect of the extract was tested using the adipogenesis kit. More compounds were found on chromatograms eluted in EMW mobile phase (Ethyl acetate: methanol: water). The extracts were shown to contain a variety of secondary metabolites, and high phenolic and flavonoids contents. Crude, chloroform, n butanol and water sub-fractions had high antioxidant activity. Alpha amylase activity was highly inhibited in the crude extract and all sub-fractions, with the highest inhibitory activity observed in the crude extract and the chloroform, n-butanol and water Sub-fractions (IC50 1.25 ± 2.5 mg/ml). The cytotoxic profiles indicated that all extracts are non-cytotoxic at concentrations of 15.63 µg/ml. Extracts at a concentration of 31.25 µg/ml were shown to stimulate the accumulation of triglycerides using 3T3-L1 adipocytes. The extracts also exhibited significant (P < 0.05) glucose uptake activity. In conclusion, Bidens pilosa contains constituents that inhibit α-amylase, antiglycation formation and modulates uptake of glucose in 3T3-L1 adipocytes. The use of B. pilosa in combination with insulin revealed the synergistic effects in facilitating glucose uptake in both C2C12 myotubes and 3T3- L1 adipocytes. This suggests that there might be some binding compounds found in the plant extracts that are responsible for the stimulation of expression of several genes that encode for proteins involved in the metabolism of glucose. However, the use of B. pilosa, in combination with metformin, results in a decreased glucose uptake. Bidens pilosa have the fast-acting insulin mimetic properties. Furthermore, the plant was shown to stimulate the accumulation of triglycerides in 3T3-L1 adipocytes, signifying the plant can induce adipogenesis at 30µg/ml / South African Medical Research Council (SAMRC)

Made available in DSpace on 2016-04-27T18:11:45Z (GMT). No. of bitstreams: 1 Alessandra Dias Rodor.pdf: 674917 bytes, checksum: 39d9831c38537dd865617e485f091e2c (MD5) Previous issue date: 2010-10-13 / Introduction: diabetic mellitus type 1 (DM1) is a disease which attacks especially developing children and causes many complications to them. Among all the effective ones, pay our attention the aspects related to the difficulties on concentration and learning disorders reported and noticed. Aim: investigate the audiologic peripheral and central overview of type 1 mellitus diabetic children, from 8 to 10 years old. Material and methodology: it is an exploring, transverse, descriptive and analytic study made from a sample of 28 diabetic type 1 children, which are seen in the outpatients clinic of the Regional Hospital of Taguatinga HRT, area of research of the Diabetic Foot endocrinology, in Taguatinga city DF. It has been done the amnesis process with the parents caretakers and the children in the same hospital. Then, several exams have been done in neurologic otorhinolaryngologic private clinics / Introdução: Diabetes Mellitus do Tipo 1 (DM1) é uma doença que acomete principalmente crianças em desenvolvimento e ocasiona várias complicações para as mesmas. Dentre todas as complicações vigentes nos chama atenção os aspectos relacionados às dificuldades de concentração e os transtornos de aprendizagem relatados e observados. Objetivo: investigar o quadro audiológico periférico e central de crianças com DM1, com idade entre 8 e 10 anos. Material e Método: é um estudo de caráter exploratório, transversal, descritivo e analítico, realizado a partir de uma amostrar de 28 crianças diabéticas do tipo 1, que são atendidas no ambulatório do Hospital Regional de Taguatinga - HRT, setor de pesquisa do Pé Diabético - endocrinologia, na cidade de Taguatinga DF. Foi realizado anamnese com os pais/cuidadores juntamente com as crianças no próprio Hospital. Em seguida iniciou-se uma bateria de exames que foram realizados em clínicas particulares de Neurologia e Otorrinolaringologia. Todas as crianças foram submetidas aos procedimentos de meatoscopia, audiometria tonal e vocal, imitanciometria, emissões otoacústicas, PEATE, P300 e avaliação do processamento auditivo central (PAC)

THESIS SUBMITED IN FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE OF DOCTOR OF TECHNOLOGY OF BIOMEDICAL TECHNOLOGTY IN THE FACULTY OF HEALTH AND WELLNESS SCIENCES AT THE CAPE PENINSULA UNIVERSITY OF TECHNOLOGY SUPERVISORS: PROF T.E. MATSHA PROF R.T. ERASMUS DR A. ZEMLIN SUBMITED DECEMBER 2013 / Introduction: Cardiovascular diseases (CVD) have become the leading cause of morbidity and mortality amongst the global population. Originally thought to be a health burden of high income countries, the prevalence is rapidly increasing in developing countries. For example, in 2008, an estimated 17.3 million died from CVD, and 80% of these (13.8 mil) were from low to middle income countries. Epidemiological data on CVD in Africa is scanty and of poor quality and national vital registration is available in only 5% of Africa’s 53 countries. Furthermore, data on CVD risk amongst the South African population and specifically the mixed ancestry community is poorly described. The increasing global population of people with CVD has been largely attributed to increasing rates of determinants and risk factors which include obesity, metabolic syndrome (MetS), type 2 diabetes mellitus (DM) and chronic kidney diseases (CKD). The prevalence of DM in South Africa is known to be on the rise with more affected communities being South African Asians followed by coloureds. Aims and objectives: The aim of this study was to determine the CVD risk profile of the Bellville South community during a baseline and three year follow-up study, by assessment of known risk factors, MetS, type 2 DM, obesity and CKD. Methods: Participants for this study were drawn from an urban community of the Bellville South suburb of Cape Town. At baseline (January 2008 and March 2009) 946 individuals aged 16 to 95 participated. All participants received a standardized interview and physical examination during which anthropometric measurements were performed three times and their average used for analysis: weight (kg), height (cm), waist (cm) and hip (cm) circumferences. Body Mass Index (BMI) was calculated as weight per square metre (kg/m2). A blood sample was obtained from all participants after an overnight fast for the determination of biochemical profiles: glucose, glycated haemoglobin, creatinine, total cholesterol, high density lipoprotein cholesterol (HDL-C), triglycerides and low density lipoprotein cholesterol (LDL-C) which was calculated using Friedewald’s formula. Kidney function test was assessed through estimated glomerular filtration rate (eGFR) using the cockcroft-Gault and MDRD equations. Blood pressure was measured according to the World Health Organisation (WHO) guidelines. Participants with no history of doctor diagnosed DM underwent a 75 g oral glucose tolerance test as recommended by the WHO. Metabolic syndrome was determined using JIS, NCEP ATPIII and IDF criteria. The follow-up examination was conducted in 2011 (3 years from vii baseline) using similar procedures. A total of 198 participants formed the follow-up cohort whose measurements were compared to those of the baseline. Finally, the prediction and processes/progression of the risk factors were determined. Results: At both baseline and follow-up studies, females had a higher BMI compared to their male counterparts. The crude prevalence of type 2 DM, including the previously diagnosed type 2 DM was 28.59% (age-adjusted = 33.5%, 95%CI: 30.01 – 36.92), and that of undiagnosed type 2 DM was 17.8% (age-adjusted = 12.4%, 95%CI: 9.8 – 14.8). The overall prevalence of CKD was 28.7% (269) and was higher in females (31.4%) compared to 20.2% in males. MetS was present in 46.5% of the participants. Gender-specific prediction for CVD risk calculated using the 30-year CVD interactive risk calculator showed that high CVD risk was present in normoglycaemic and younger subjects (under 35 years). At follow-up, the cumulative incidence of progression in glucose tolerance status was: 16.2% (32 participants including 11 with new-onset diabetes), and increased in a stepwise fashion with the number of components of MetS. Between baseline and 3-year evaluation glomerular filtration rate (eGFR) increased by 8.7 ml/min (95% confidence interval: 6.9-10.7), reflecting variables trajectories across baseline strata of kidney functions. Conclusion: Given the findings of this study and the estimated increases in the determinants and risk factors of CVD in the mixed ancestry population of South Africa this trend may continue to worsen if current trajectories do not change.