rhapontin and rhein

Extracts from Rhei Rhizoma extracts (RR) have been reported to attenuate metabolic disorders such as diabetic nephropathy, hypercholesterolemia and platelet aggregation. With this study we investigated the anti-diabetic action of 70% ethanol RR extract in streptozotocin-induced diabetic mice, and determined the action mechanism of active compounds of RR in vitro. In the diabetic mice, serum glucose levels at fasting and post-prandial states and glucose area under the curve at modified oral glucose tolerance tests were lowered without altering serum insulin levels, indicating that RR contained potential anti-diabetic agents. The fractions fractionated from RR extracts by XAD-4 column revealed that 60%, 80% and 100% methanol fractions enhanced insulin sensitivity and inhibited alpha-glucoamylase activity. The major compounds of these fractions were sennosides, rhein and rhaponticin. Rhaponticin and rhein enhanced insulin-stimulated glucose uptake in 3T3-L1 adipocytes. Rhaponticin increased adipocytes with a differentiating effect similar to pioglitazone, but rhein and sennoside B decreased triglyceride accumulation. Sennoside A and B inhibited alpha-glucoamylase activity as much as acarbose. In conclusion, a crude extract of RR improves glucose intolerance by enhancing insulin-stimulated glucose uptake and decreasing carbohydrate digestion via inhibiting alpha-glucoamylase activity. Rhein and rhaponticin are potential candidates for hypoglycemic agents.

Topics: Adipocytes; Animals; Anthraquinones; Blood Pressure; Body Weight; Cell Differentiation; Cell Line; Diabetes Mellitus, Experimental; Enzyme Inhibitors; Ethanol; Fibroblasts; Glucan 1,4-alpha-Glucosidase; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Mice; Mice, Inbred C57BL; Plant Extracts; Senna Extract; Sennosides; Solvents; Stilbenes; Triglycerides

To determine six effective components (aloe-emodin, rhein, emodin, rhaponticin, physcion and chrysophanol) in Rheum.. Using buffer solution containing 20 mmol.L-1 borax, 20 mmol.L-1 sodium deoxycholate (SDC), 20 mmol.L-1 sodium taurocholate (STC), 15 mmol.L-1 beta-cyclodextrin (beta-CD) and O-phthalic acid as the internal standard, the six components were determined by cyclodextrin modified micellar electrokinetic chromatography.. In less than 25 min, aloe-emodin, rhein, emodin, rhaponticin, physion and chrysophanol were separated. The separation conditions were optimized by adjusting buffer pH, concentrations of SDC, STC and beta-CD. The linearity ranges of aloe-emodin, rhein, emodin, rhaponticin, physcion and chrysophanol were 4-34, 5-40, 4-60, 5-80, 6-90 and 5-85 micrograms.mL-1 respectively. Relative standard deviation (RSD) of the method was less than 2.2%. The recoveries of aloe-emodin, rhein, emodin, rhaponticin, physcion and chrysophanol were 100.0%, 98.3%, 100.4%, 94.6%. 95.2% and 93.8% respectively. Raw Rheum, Mongolian Rheum and Rheum tanguticum samples were analyzed.. This method can be an effective one for identification of Rhubarb.

Topics: Anthraquinones; Chromatography, Micellar Electrokinetic Capillary; Cyclodextrins; Emodin; Plants, Medicinal; Quality Control; Rheum; Stilbenes