iridoids and Diabetes-Mellitus--Type-1

The effects of extracts of red and yellow fruits of cornelian cherries have been evaluated in rats with streptozotocin-induced diabetes mellitus. Cornus mas L. active compounds were analyzed by ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC-ESI-qTOF-MS/MS) in positive and negative ion modes and by HPLC-PDA, followed by the identification of iridoids, anthocyanins, phenolic acids and flavonols. Rats with type 1 diabetes mellitus were orally dosed with the extracts in amounts of 20 mg kg-1 of body weight for 14 days. The cornelian cherry extracts lowered blood glucose and improved glucose tolerance. The treatments significantly decreased the amount of glycated hemoglobin (by 25%) and increased erythrocyte resistance to acid hemolysis. Importantly, only treatment with the extract of yellow fruits of the cornelian cherry increased the level of reduced glutathione and mean cell hemoglobin in diabetic rats. The active compounds of Cornus mas L. demonstrated the antidiabetic and antioxidant effects via the attenuation of hyperglycemia and inhibition of oxidative modifications of proteins and lipids, advanced glycation and oxidation protein formation or accumulation. The results suppose that cornelian cherries can be considered as a food supplement to alleviate diabetes mellitus and its complications.

Topics: Animals; Antioxidants; Blood Glucose; Cornus; Diabetes Mellitus, Type 1; Fruit; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Iridoids; Male; Plant Extracts; Polyphenols; Rats; Rats, Wistar; Streptozocin; Tandem Mass Spectrometry

Amarogentin is a bitter-tasting secoiridoid glycoside isolated from an herb. Inhibition of aldose reductase by amarogentin has been documented as an antidiabetic action. However, the mechanisms of action of amarogentin in diabetic disorders remain unknown. The present study employed streptozotocin-induced type 1 diabetic (T1DM) rats to investigate the antihyperglycemic action of amarogentin. Changes in the protein expression of glucose transporter 4 (GLUT4) and phosphoenolpyruvate carboxykinase (PEPCK) in skeletal muscle and liver, respectively, were also detected by Western blotting. Additionally, a type 2 diabetes (T2DM) animal model induced using a fructose-rich diet was also applied to assess the effect of amarogentin on insulin resistance according to the homeostasis model assessment-insulin resistance (HOMA-IR). Amarogentin dose-dependently attenuated hyperglycemia in the T1DM rats lacking insulin. The action of amarogentin was further supported in rats administered the oral glucose tolerance test. Western blotting showed that amarogentin reversed the decreased GLUT4 level in skeletal muscle and reduced the elevated PEPCK expression in livers isolated from the T1DM rats. Moreover, amarogentin decreased the HOMA-IR and increased insulin sensitivity in the T2DM rats. These data show that amarogentin may ameliorate glucose homeostasis in diabetic rats, indicating its potential for future development as an antidiabetic drug.

Topics: Animals; Biomarkers; Blood Glucose; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Dietary Carbohydrates; Dose-Response Relationship, Drug; Fructose; Glucose Tolerance Test; Glucose Transporter Type 4; Hypoglycemic Agents; Insulin; Insulin Resistance; Intracellular Signaling Peptides and Proteins; Iridoids; Liver; Male; Muscle, Skeletal; Phosphoenolpyruvate Carboxykinase (GTP); Rats, Wistar; Streptozocin

Diabetic nephropathy (DN) is one of the foremost causes of renal failure and a primary cause of diabetes mellitus related death. Previously, we have reported that aqueous extract of Enicostemma littorale has potential antidiabetic activity. In the present study, we have investigated the effect of aqueous extract of E. littorale 1 g/kg, p.o. and swertiamarin 50 mg/kg, p.o. daily for 3 weeks in type 1 DN complications in SD rats. DN was assessed by serum urea, creatinine, lipid profile and water intake levels. Treatment with aqueous extract of E. littorale and swertiamarin significantly decreased serum urea and creatinine and other parameters associated with the development of DN in type 1 diabetic rats. We have also found considerable improvement in histology of glomerular function of aqueous extract of E. littorale and swertiamarin-treated animals.

Topics: Administration, Oral; Animals; Biomarkers; Blood Glucose; Creatinine; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Drinking; Gentianaceae; Glucosides; Hypertrophy; Hypoglycemic Agents; Iridoid Glucosides; Iridoids; Kidney Glomerulus; Lipids; Male; Plant Extracts; Pyrones; Rats; Rats, Sprague-Dawley; Urea