title: Oral green tea catechins transiently lower plasma glucose concentrations in female db/db mice.
abstract: Polyphenols, including green tea catechins, are secondary plant compounds often discussed in the context of health-promoting potential. Evidence for such effects is mainly derived from epidemiological and cell culture studies. The aim of the present study was to investigate antidiabetic, antiadipogenic, and anti-inflammatory effects at nonpharmacological doses in an obese diabetic mouse model that exerts early relevant clinical signs of non-insulin-dependent diabetes mellitus. Female db/db mice received a flavonoid-poor diet either without additive, with rosiglitazone (RSG, 0.02 g/kg diet), or with green tea extract (low-dose green tea extract [LGTE] and high-dose green tea extract [HGTE], 0.1 and 1 g/kg diet). Food and water were freely available. The body weight was monitored weekly. Blood was sampled (12-h fasted) from the tail vein on day 28 and analyzed for glucose, cholesterol, triacylglycerol, nonesterified fatty acids, insulin, adiponectin, and soluble intercellular adhesion molecule-1 (sICAM-1). Blood glucose was also analyzed on day 14. Furthermore, sICAM-1 release was investigated in tumor necrosis factor alpha-stimulated EAhy926 cells. After 14 days, fasting glycemia was improved by RSG or HGTE supplementation compared to controls. However, at the end of the study (day 28), only RSG exhibited glucose-lowering effects and induced plasma adiponectin concentrations, paralleled by higher body weight gain and reduced periuterine fat pads compared to controls. However, only GTE treatment reduced sICAM-1 release in vitro and in vivo. Nonpharmacological HGTE supplementation in db/db mice caused (1) no adiponectin-inducing or antiadipogenic effects, (2) reduced sICAM-1 release, thereby potentially exerting anti-inflammatory effects in the progressive diabetic state, and (3) a transient improvement in glycemia.
authors.affiliation: Institute of Animal Nutrition & Physiology, Christian Albrechts University of Kiel, Kiel, Germany. wein@aninut.uni-kiel.de
authors.forename: Silvia
authors.initials: S
authors.lastname: Wein
authors.forename: Eva
authors.initials: E
authors.lastname: Schrader
authors.forename: Gerald
authors.initials: G
authors.lastname: Rimbach
authors.forename: Siegfried
authors.initials: S
authors.lastname: Wolffram
mesh_terms: D052242:Adiponectin / Q000097:blood; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D001786:Blood Glucose / Q000378:metabolism*; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000494:pharmacology / Q000627:therapeutic use*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D019587:Dietary Supplements; D005260:Female; D005419:Flavonoids / Q000008:administration & dosage; D006943:Hyperglycemia / Q000188:drug therapy / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use; D007249:Inflammation / Q000378:metabolism / Q000517:prevention & control*; D018799:Intercellular Adhesion Molecule-1 / Q000097:blood; D051379:Mice; D018345:Mice, Knockout; D008820:Mice, Obese; D009765:Obesity / Q000097:blood / Q000188:drug therapy*; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology / Q000627:therapeutic use; D014409:Tumor Necrosis Factor-alpha; D015430:Weight Gain / Q000187:drug effects
chemical_list: D052242:Adiponectin; D000893:Anti-Inflammatory Agents; D001786:Blood Glucose; D005419:Flavonoids; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D045162:Thiazolidinediones; D014409:Tumor Necrosis Factor-alpha; D000077154:Rosiglitazone; D018799:Intercellular Adhesion Molecule-1; D002392:Catechin