title: Polyphenol-rich Rutgers Scarlet Lettuce improves glucose metabolism and liver lipid accumulation in diet-induced obese C57BL/6 mice.
abstract: OBJECTIVE
  The aims of the following experiments were to characterize antidiabetic in vitro and in vivo activity of the polyphenol-rich aqueous extract of Rutgers Scarlet Lettuce (RSL).
  
  
  METHODS
  RSL extract (RSLE) and isolated compounds were evaluated for inhibitory effects on glucose production as well as tumor necrosis factor alpha-dependent inhibition of insulin activity in H4IIE rat hepatoma cells. Additionally, high-fat diet-induced obese mice were treated with RSLE (100 or 300 mg/kg), metformin (250 mg/kg), or vehicle (water) for 28 d by oral administration and insulin and oral glucose tolerance tests were conducted. Tissues were harvested at the end of the study and evaluated for biochemical and physiological improvements in metabolic syndrome conditions.
  
  
  RESULTS
  A polyphenol-rich RSLE, containing chlorogenic acid, cyanidin malonyl-glucoside, and quercetin malonyl-glucoside, was produced by simple boiling water extraction at pH 2.0. In vitro, RSLE and chlorogenic acid demonstrated dose-dependent inhibition of glucose production. In vivo, RSLE treatment improved glucose metabolism measured by oral glucose tolerance tests, but not insulin tolerance tests. RSLE treated groups had a lower ratio of liver weight to body weight as well as decreased total liver lipids compared with the control group after 28 d of treatment. No significant differences in plasma glucose, insulin, cholesterol, and triglycerides were observed with RSLE-treated groups compared with vehicle control.
  
  
  CONCLUSIONS
  RSLE demonstrated antidiabetic effects in vitro and in vivo and may improve metabolic syndrome conditions of fatty liver and glucose metabolism.
authors.affiliation: Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA. Electronic address: Cheng@aesop.rutgers.edu.
authors.forename: Diana M
authors.initials: DM
authors.lastname: Cheng
authors.affiliation: Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA.
authors.forename: Natalia
authors.initials: N
authors.lastname: Pogrebnyak
authors.affiliation: Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Kuhn
authors.affiliation: Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Poulev
authors.affiliation: Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA.
authors.forename: Carrie
authors.initials: C
authors.lastname: Waterman
authors.affiliation: Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA.
authors.forename: Patricio
authors.initials: P
authors.lastname: Rojas-Silva
authors.affiliation: Department of Biostatistics, Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA.
authors.forename: William D
authors.initials: WD
authors.lastname: Johnson
authors.affiliation: Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA.
authors.forename: Ilya
authors.initials: I
authors.lastname: Raskin
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002726:Chlorogenic Acid / Q000494:pharmacology / Q000627:therapeutic use; D059305:Diet, High-Fat; D005234:Fatty Liver / Q000378:metabolism / Q000517:prevention & control*; D005947:Glucose / Q000096:biosynthesis / Q000378:metabolism*; D005951:Glucose Tolerance Test; D007004:Hypoglycemic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D007328:Insulin / Q000378:metabolism; D018545:Lactuca / Q000737:chemistry*; D050356:Lipid Metabolism / Q000187:drug effects*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D009765:Obesity / Q000150:complications / Q000209:etiology / Q000378:metabolism*; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D059808:Polyphenols / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D010936:Plant Extracts; D059808:Polyphenols; D002726:Chlorogenic Acid; D005947:Glucose
keywords: Anthocyanins; Chlorogenic acid; Flavonols; Metabolic syndrome; Red lettuce