Renoprotective effect of umbelliferone in high-fat diet/streptozotocin-induced type 2 diabetic rats

To evaluate the renoprotective effect of umbelliferone in high-fat diet/streptozotocin-induced type 2 diabetic rats. Methods: We established a streptozotocin-induced type 2 diabetic model in male Wistar rats. The rats were fed with high-fat diet (45 kcal% lard fat) and injected with 35 mg/kg streptozotocin. Diabetic rats were treated with umbelliferone for 8 weeks. At the end of the experimental period, the serum and kidney were used for measuring biochemical parameters, protein expression and histological analysis. Results: After 8-week treatment, umbelliferone decreased fasting plasma glucose, concentrations of malondialdehyde and monocyte chemoattractant protein-1 in the plasma and tissues. It also significantly reduced serum creatinine, blood urea nitrogen, serum advanced glycation end products, as well as kidney weight in type 2 diabetic rats (P<0.05). Moreover, umbelliferone reduced the 24-h urine albumin, but increased 24-h urine creatinine excretion (P<0.05). In renal protein expression, umbelliferone decreased the levels of transforming growth factor-b1 and fibronectin while increasing the levels of superoxide dismutase and catalase (P<0.05). Renal histological examination revealed an enlarged glomerular size in diabetic rats, which was smaller in umbelliferone-treated diabetic rats. Conclusions: Umbelliferone alleviates renal dysfunction in diabetes via decreasing hyperglycemia, oxidative stress, inflammation and glycation.

Pandanus amaryllifolius leaf extract increases insulin sensitivity in high-fat diet-induced obese mice

Objective To examine the effect of Pandanus amaryllifolius (P. amaryllifolius) leaf extract on the insulin resistance state in obese ICR mice. Methods Obesity was induced in mice fed with high-fat diet (45% fat) for 12 weeks. After the first six weeks on the diet, the obese mice were administered with the water extract of P. amaryllifolius leaf at 125 and 250 mg/kg/day, respectively for another six weeks. At the 5th week of treatment, oral glucose tolerance test was conducted. After six weeks of treatment, the levels of blood glucose, serum insulin, leptin, adiponectin, and lipid profiles were determined. The liver, muscle and epididymal fat tissues were removed for measuring the biochemical parameters and protein expression, as well as histological examination. Results Six weeks of treatment with P. amaryllifolius led to a significant reduction in the blood glucose level as well as improvement in the insulin resistance. P. amaryllifolius also increased the liver glycogen storage and serum adiponectin and decreased the serum leptin levels. A reduction in the serum and hepatic triglyceride, and non-esterified fatty acid levels was also observed. The histological examination showed that the obese mice treated with P. amaryllifolius reduced the lipid droplet in liver tissue and adipocyte size in epididymal fat tissue. The treatment also increased the protein expression of glucose transporter 4 in the muscle and fat tissues. Conclusions The treatment with P. amaryllifolius could decrease several parameters of impaired glucose and lipid metabolism. To the best of our knowledge, this is the first report on the role of P. amaryllifolius leaf extract in alleviating the insulin dysfunction in obesity state.