title: Insulin sensitizing and alpha-glucoamylase inhibitory action of sennosides, rheins and rhaponticin in Rhei Rhizoma.
abstract: 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.
authors.affiliation: Department of Internal Medicine, Konkuk University, Chungjoo, Chungbuk, Korea.
authors.forename: Soo Bong
authors.initials: SB
authors.lastname: Choi
authors.forename: Byoung Seob
authors.initials: BS
authors.lastname: Ko
authors.forename: Seong Kyu
authors.initials: SK
authors.lastname: Park
authors.forename: Jin Sun
authors.initials: JS
authors.lastname: Jang
authors.forename: Sunmin
authors.initials: S
authors.lastname: Park
mesh_terms: D017667:Adipocytes / Q000187:drug effects; D000818:Animals; D000880:Anthraquinones / Q000302:isolation & purification / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D000431:Ethanol; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005087:Glucan 1,4-alpha-Glucosidase / Q000037:antagonists & inhibitors*; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007333:Insulin Resistance; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D012676:Senna Extract; D000081226:Sennosides; D012997:Solvents; D013267:Stilbenes / Q000302:isolation & purification / Q000494:pharmacology*; D014280:Triglycerides / Q000378:metabolism
chemical_list: D000880:Anthraquinones; D004791:Enzyme Inhibitors; D007004:Hypoglycemic Agents; D007328:Insulin; D010936:Plant Extracts; D000081226:Sennosides; D012997:Solvents; D013267:Stilbenes; D014280:Triglycerides; D000431:Ethanol; D012676:Senna Extract; D005087:Glucan 1,4-alpha-Glucosidase; C023538:rhapontin; C020491:rhein