Stevia rebaudiana Bertoni, an American plant used as sweetener: Study of its effects on body mass control and glycemia reduction in Wistar male and female rats.

Stevia rebaudiana Bertoni water extracts have been used as a natural sweetener and customary medicine by the indigenous inhabitants of South America for several hundred years. This plant was sent to Europe in the 16th century and was described by Peter Jacob Esteve in Spain. Recently the food industry has started to employ S. rebaudiana as sweetener using its glycosides after purification. Advertisement claims that Stevia glycosides is good for controling body mass and reducing glycemia. This study's objective was to evaluate the effect of S. rebaudiana leaf extract on Wistar rats as animal model to prove its effectiveness on body mass control, glycemia reduction, and other biochemical parameters. Three groups were randomly formed with 24 males and 24 females: A blank group without any sweetener, a control group drinking water with 10% glucose, and the test group ingesting a 0.94% water extract of S. rebaudiana. Body mass measurements as well as food and drink consumption were daily performed. The experiment lasted 120 days after the specimens were weaned and got used to eating solid food. Euthanasia was done and blood serum was collected to evaluate the following biochemical parameters: Glucose, triglycerides, cholesterol, insulin, glucagon, leptin, ghrelin, and glucose-dependent insulinotropic peptide, GIP. Results indicated that only female rats had statistical differences in body mass gain. No relevant effects either positive or negative were found in the biochemical parameters measured. The crude extracts of S. rebaudiana did not show any relevant changes in biochemical and hormonal profiles, changes nor body mass with respect to the blank and control groups of young and healthy rats in the age range of infancy to youth. According to the results obtained, the therapeutic properties that have been associated to S. rebaudiana consumption especially for body mass control and glycemia reduction, did not occur in young and healthy male and female rats in equivalent age to infants, young children, and youths.

Vitamin E (α-Tocopherol) Does Not Ameliorate the Toxic Effect of Bisphenol S on the Metabolic Analytes and Pancreas Histoarchitecture of Diabetic Rats.

This study investigated whether the coadministration of vitamin E (VitE) diminishes the harmful effects provoked by plasticizer bisphenol S (BPS) in the serum metabolites related to hepatic and renal metabolism, as well as the endocrine pancreatic function in diabetic male Wistar rats. Rats were divided into five groups (n = 5-6); the first group was healthy rats (Ctrl group). The other four groups were diabetic rats induced with 45 mg/kg bw of streptozotocin: Ctrl-D (diabetic control); VitE-D (100 mg/kg bw/d of VitE); BPS-D (100 mg/kg bw/d of BPS); The animals from the VitE + BPS-D group were administered 100 mg/kg bw/d of VitE + 100 mg/kg bw/d of BPS. All compounds were administered orally for 30 days. Body weight, biochemical assays, urinalysis, glucose tolerance test, pancreas histopathology, proximate chemical analysis in feces, and the activity of antioxidants in rat serum were assessed. The coadministration of VitE + BPS produced weight losses, increases in 14 serum analytes, and degeneration in the pancreas. Therefore, the VitE + BPS coadministration did not have a protective effect versus the harmful impact of BPS or the diabetic metabolic state; on the contrary, it partially aggravated the damage produced by the BPS. VitE is likely to have an additive effect on the toxicity of BPS.

Effects on weaned male Wistar rats after 104, 197, and 288 days of chronic consumption of nutritive and non-nutritive additives in water.

ABSTRACT: It has been suggested that the consumption of artificial sweeteners is related to greater body mass gain and diverse metabolic alterations. In this study, the effect of chronic consumption of nutritive sweeteners (fructose 7% and sucrose 10%) and non-nutritive or low-calorie sweeteners (acesulfame 0.015%, aspartame 0.3%, aspartame:acesulfame mixture 0.04%, saccharin 0.3%, and sucralose 0.19%), in drinking water, as well as a control group with no sweeteners, was evaluated. Body mass gain and glucose, insulin, triglycerides, and total cholesterol levels in blood were the parameters considered. For this purpose, 120 weaned male Wistar rats of the HsdHan:WIST line were used, 15 per group in first stage, then 10 and 5 per group for 2nd and 3rd stages, respectively. Body mass gain, food intake, and beverage consumption were daily quantified. After 104, 197, and 288 days of experimentation the concentrations of glucose, triglycerides, cholesterol, and insulin were determined. Only in the first stage there were significant differences in the body mass gain. In the three stages there were significant differences in the patterns of beverage intake and food consumption. The trend was the same in all 3 stages: rats drank more in the groups of drinks sweetened with nutritive sweeteners and ate more in the groups that drank non-nutritive artificial sweeteners. Regarding the biochemical profile, no sweetener either nutritive or non-nutritive caused that the serum levels of glucose, triglycerides, and cholesterol were at pathological levels. It is concluded that the sweeteners by themselves can modify certain biochemical parameters but not at a pathological level. Furthermore, by themselves they are not capable of triggering excess of body mass or obesity in the early and medium stages of life when consumed together with a balanced diet.

Consumption of sweeteners at different stages of life: effects on body mass, food and drink intake in male and female Wistar rats.

The consumption of non-nutritive sweeteners has increased in the last decades. However, there are doubts about its consumption and its impact on body mass and metabolic alterations. For this reason, this study investigates the effects of the consumption of nutritive and non-nutritive sweeteners on body mass in different life stages of male and female Wistar rats: Childhood, adolescence, young adult, adulthood, and aged. For this purpose, 8 groups of male and female rats were used (10 per group/gender): sucrose 10%, glucose 14%, fructose 7%, acesulfame K 0.05%, aspartame:acesulfame mixture 1.55%, sucralose 0.017%, saccharin 0.033%, and a control group. Only in aged male rats (504 days) there were significant differences in body mass. In both genders, there were differences in food, drink, and energy intake along all life stage. It is concluded that non-nutritive sweeteners when consumed together with a balanced diet did not cause a greater body mass gain.

Functional Effects of Prebiotic Fructans in Colon Cancer and Calcium Metabolism in Animal Models.

Inulin-type fructans are polymers of fructose molecules and are known for their capacity to enhance absorption of calcium and magnesium, to modulate gut microbiota and energy metabolism, and to improve glycemia. We evaluated and compared the effects of Chicory inulin "Synergy 1®" and inulin from Mexican agave "Metlin®" in two experimental models of colon cancer and bone calcium metabolism in mice and rats. Inulins inhibited the development of dextran sulfate sodium-induced colitis and colon cancer in mice; these fructans reduced the concentration of tumor necrosis factor alpha and prevented the formation of intestinal polyps, villous atrophy, and lymphoid hyperplasia. On the other hand, inulin treatments significantly increased bone densitometry (femur and vertebra) in ovariectomized rats without altering the concentration of many serum biochemical parameters and urinary parameters. Histopathology results were compared between different experimental groups. There were no apparent histological changes in rats treated with inulins and a mixture of inulins-isoflavones. Our results showed that inulin-type fructans have health-promoting properties related to enhanced calcium absorption, potential anticancer properties, and anti-inflammatory effects. The use of inulin as a prebiotic can improve health and prevent development of chronic diseases such as cancer and osteoporosis.

Comparison between the antiproliferative effect and intracellular glutathione depletion induced by Casiopeína IIgly and cisplatin in murine melanoma B16 cells.

BACKGROUND: Casiopeína IIgly (Cas IIgly) [Cu(4,7-dimethyl-1,10-phenanthroline)(glycinate)]NO(3) induce oxidative damage in different human tumour cell strains, as the known anticancer agent cisplatin (CDDP) does. PURPOSE: To compare glutathione (GSH) depletion induced by Cas IIgly and CDDP in murine melanoma B16 cells and its relationship with their antiproliferative effect. MATERIALS AND METHODS: Cell growth was determined according to the sulforhodamine B assay. Intracellular GSH levels were measured by the reduction of Ellman's reagent (DTNB). RESULTS: Cas IIgly IC50 in B16 cells was 54.5 µM (24.21 µg/mL), which depleted GSH from 1092 to 585 ng per million cells in a 30 min incubation period. In the other hand, CDDP was less toxic at the same conditions with an IC50 equal to 197.76 µM (59.33 µg/mL), and depleted GSH to 50% of the normal only after a longer exposure period (4h). The addition of 1.8mM ascorbic acid (Asc) or 1mM buthionine sulfoximine (BSO) enhanced Cas IIgly toxicity, whereas it was prevented by 100 U/mL catalase. BSO sensitised B16 cells to CDDP, but neither Asc or catalase modified CDDP effects. CONCLUSIONS: The antiproliferative effect of both drugs correlated to intracellular GSH levels. Unlike CDDP, GSH depletion induced by Cas IIgly occurs earlier, it is enhanced by ascorbic acid and preventable by catalase. Redox cycles, feasible only with Cas IIgly, may be an important difference in their mode of action.

Induction of oxidative damage by copper-based antineoplastic drugs (Casiopeínas).

PURPOSE: The aim of the present study is to determine in HeLa cells and in human lymphocytes, by an easy and fast method, the induction of oxidative damage to plasma membrane lipids and nuclear DNA by Casiopeínas, which are recently synthesized coordination complexes that have been considered as a promising chemotherapeutic alternative for the treatment of cancer, since they have shown cytotoxicity and genotoxicity in several cancer cell lines and xenotransplanted tumours. The presence of an oxidized copper atom in their structure strongly suggests that their mode of action seems to be related to reactive oxygen species (ROS) generation after copper atom reduction through the Fenton and Haber-Weiss system. METHOD: Lipid peroxidation was evaluated as thiobarbituric acid reactive malondialdehyde, cytotoxicity by the fluorescein diacetate/ethidium bromide stain and genotoxicity as DNA fragmentation by the comet assay. Cells were treated with ten different Casiopeínas in a concentration range higher than their IC(50) (10-100 microM), both oxidized and reduced in the presence of ascorbic acid. RESULTS: In almost all the cases, copper reduction enhanced cytotoxicity but, unlike copper nitrate used as positive control, none of them induced appreciable lipid peroxidation. Three Casiopeínas: Cas Igly, Cas-III-H-a and Cas-III-E-a, showed low, moderate and high rates of genotoxicity, respectively, and this effect was enhanced upon addition of ascorbic acid. CONCLUSION: These results suggest that ROS generation might be the cause of cytotoxicity, which seems to be related to initial genetic damage rather than to lipid peroxidation. HeLa cells showed to be more sensitive than normal cells.