METHODS: Animals were divided into three groups: (i) normal non-diabetic (NDM), (ii) diabetic treated (tocotrienol-rich fractions - TRF) and (iii) diabetic untreated (non-TRF). The treatment group received oral administration of tocotrienol-rich fractions (200 mg/kg body weight) daily for eight weeks. The normal non-diabetic and the diabetic untreated groups were fed standard rat feed. Blood glucose and lipid profiles, oxidative stress markers and morphological changes of the thoracic aorta were evaluated.
RESULTS: Tocotrienol-rich fractions treatment reduced serum glucose and glycated hemoglobin concentrations. The tocotrienol-rich fractions group also showed significantly lower levels of plasma total cholesterol, low-density lipoprotein cholesterol, and triglyceride, as compared to the untreated group. The tocotrienol-rich fractions group had higher levels of high-density lipoprotein cholesterol, as compared to the untreated group. Superoxide dismutase activity and levels of vitamin C in plasma were increased in tocotrienol-rich fractions-treated rats. The levels of plasma and aorta malondealdehyde + 4-hydroxynonenal (MDA + 4-HNE) and oxidative DNA damage were significant following tocotrienol-rich fractions treatment. Electron microscopic examination showed that the normal morphology of the thoracic aorta was disrupted in STZ-diabetic rats. Tocotrienol-rich fractions supplementation resulted in a protective effect on the vessel wall.
CONCLUSION: These results show that tocotrienol-rich fractions lowers the blood glucose level and improves dyslipidemia. Levels of oxidative stress markers were also reduced by administration of tocotrienol-rich fractions. Vessel wall integrity was maintained due to the positive effects mediated by tocotrienol-rich fractions.
OBJECTIVE: Here, we investigated the ability of Palmatine to reduce the up-regulation of chaperone proteins Glucose Regulatory Protein 78 (GRP78), and Calreticulin (CALR) protein in a Streptozotocin (STZ)-induced diabetic rat model.
METHODS: Streptozotocin (STZ) induced diabetes in Sprague Dawley rats treated with 2mg/kg of Palmatine for 12 weeks after the elevation of plasma glucose levels above 11mmol/L post-STZ administration. Proteins were extracted from the pancreas after treatment and Two-Dimensional gel electrophoresis (2-DE), PDQuest 2-D analysis software genomic solutions and mass spectrometer were used to analyze differentially expressed protein. Mass Spectrometry (MS/MS), Multidimensional Protein Identification Technology (MudPIT) was used for protein identification.
RESULTS: There was an up-regulation of the expression of chaperone proteins CALR and GRP78 and down-regulation of the expression of antioxidant and protection proteins peroxidoxin 4 (Prdx4), protein disulfide isomerase (PDIA2/3), Glutathione-S-Transferase (GSTs), and Serum Albumin (ALB) in non-diabetic rats. Palmatine treatment down-regulated the expression of chaperone proteins CALR and GRP78 and up-regulated the expression of Prdx4, PDIA2/3, GST, and ALB.
CONCLUSION: Palmatine may have activated antioxidant proteins, which protected the cells against reactive oxygen species and endoplasmic stress. The result is in consonance with our previous report on Palmatine.
METHODS: AE was administered to streptozotocin (STZ)-induced diabetic rats twice daily at three doses (1000, 500, and 250 mg/kg b.w.) for 12 days p.o. Several biochemical analyses and a histological study of the pancreas and liver were performed, accompanied by a cell culture assay.
RESULTS: As compared to diabetic control (DC), AE at the doses of 500 and 1000 mg/kg b.w. caused significant reduction (p < 0.05) of blood glucose, total cholesterol and triglycerides levels, with positive improvement of serum insulin levels. Interestingly, immunohistochemical staining of the pancreas suggested no β-cell regeneration, despite significant increase in insulin production. AE-treated groups, however, showed overall restoration of the hepatic histoarchitecture of STZ-induced liver damage, suggesting a possible hepatoprotective effect. The pancreatic effect of AE was further studied through RIN-5F cell culture, which revealed a positive stimulatory effect on insulin release at a basal glucose concentration (1.1 mM).
CONCLUSION: Nypa fruticans Wurmb. vinegar's aqueous extract exerts its antihyperglycaemic activity, at least in part, through insulin stimulatory and hepatoprotective effects.