GISLENE BONGIOVANI

Título da Dissertação: ANÁLISES FÍSICO-QUÍMICAS DE RAÇÃO CONTENDO FOLHAS DE STEVIA REBAUDIANA E AVALIAÇÃO DE PROPRIEDADES FUNCIONAIS EM RATOS DIABÉTICOS.

Orientador: Prof. Dr. Silvio Cláudio da Costa 

Data da Defesa: 25/03/2015

RESUMO GERAL

INTRODUCTION: The diabetes mellitus (DM) is one of the most common chronic diseases nowadays. A better metabolic control in diabetic ones has been associated with a lower incidence of chronic complications. Owing to diabetes changes the metabolism of carbohydrates, proteins and fats, the nutrition performs important role in treatment. Diabetic patients can benefit from diets which helps in the lipid and glycemic control. The Stevia rebaudiana, native plant from the border between Brazil and Paraguay, is a source of natural non-caloric sweeteners and the empirical knowledge of Paraguayan natives that diabetics who were using stevia tea showed improvement in blood glucose levels, stimulated investigation of potential hypoglycemic properties. Antidiabetic properties of the total extract or isolated products of this plant were found in recent decades, but it has almost studies with the total payroll. In this study, we investigated the hypothesis that diabetic rats fed with diets supplemented with Stevia rebaudiana leaves could have better metabolic control.
OBJECTIVE: Formulate a ration containing Stevia rebaudiana leaves, know their physicochemical properties and test their chronic effects in diabetic rats.
MATERIALS AND METHODS: It was used Stevia rebaudiana leaves (seminal variety Stevia UEM-13), dryed and milled. This product was added to the ration Nuvilab, in a proportion of 2%. After being homogenized, the mix was moistened, divided in small pellets, dehydrated in a greenhouse with air circulation. In the control ration were added 2% of carboxymethylcellulose. It was performed physic-chemical analysis of the reactions for the obtaining of total proteins, ethereal extract, fixed mineral residues (ashes), total umidity total acidity values and gross fiber values. Wistar male rats 60 days old suffered diabetes induction (streptozotocin application; Sigma; 45mg/Kg p.c.;
i.v; solved in citrate buffer 0,05M; pH 4,5). It was selected the animals which presented fast glycemia equal or higher than 200mg/dL. After two days, It was established four experimental groups, two of normal animals (NC and NT) and two of diabetic animals (DC and DT). The animals of the groups NC and DC were fed with Nuvilab ration containing 2% of carboxymethylcellulose and the animals from the NT and DT groups received the same ration containing 2% of stevia rebaudiana leaves. It was recorded the body weight gain, the food intake and several glycemia values, so as in fast as fed. By the end of the four weeks treatment, the animals were put in metabolic individual cages for the collect of urine and glycosuria evaluation. Several biochemical parameters were compared, as the weight of several organs and tissues and the amount of liver glycogen. The results were expressed as average ± average standart error and submitted to ANOVA test – two way – Bonferroni or T test, significancy level p < 0.05 ( GraphPad Prism 4.0 program).
RESULTS AND DISCUSSION: This is the first study that has knowledge that investigate the chronic effects of the ration supplementation with Stevia rebaudiana leaves in the metabolic control of streptozotocin diabetic rats. The supplemented diet with stevia leaves (10%) had good acceptability by the rats, not changing the food intake. Didn´t change the body weight gain in the normal rats even the weight loss in diabetic animals. The diabetic animals which received the supplemented diet with stevia leaves presented significantly reduction in glycemia, in the triglycerides concentration and of total cholesterol. The amount of liver glycogen was significantly bigger in the diabetic animals treated when compared with the control group.
CONCLUSIONS : The ration supplemented with 2% of Stevia rebaudiana leaves improved the glycemic control (reduction in fast glycemia and raised in the liver glycogen) and the lipid control (reduction of tryglicerides and total cholesterol in the blood concentration) in diabetic rats, without causing effects in the food intake and body weight gain.
KEYWORDS: Stevia rebaudiana leaves, diabetes, streptozotocin.

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