title: Aspalathin improves glucose and lipid metabolism in 3T3-L1 adipocytes exposed to palmitate.
abstract: METHODS
  Saturated-free fatty acids, such as palmitate, are associated with insulin resistance. This study aimed to establish if an aspalathin-enriched green rooibos extract (GRE) and, its major flavanoid, aspalathin (ASP) could contribute significantly to the amelioration of experimentally induced insulin resistance in 3T3-L1 adipocytes.
  
  
  RESULTS
  3T3-L1 adipocytes were cultured in DMEM containing 0.75 mM palmitate for 16 h to induce insulin resistance before treatment for 3 h with GRE (10 μg/mL) or ASP (10 μM). GRE and ASP reversed the palmitate-induced insulin resistance. At a protein level GRE and ASP suppressed nuclear factor kappa beta (NF-κB), insulin receptor substrate one (serine 307) (IRS1 (Ser (307) )) and AMP-activated protein kinase phosphorylation and increased serine/threonine kinase AKT (AKT) activation, while only GRE increased glucose transporter four (Glut4) protein expression. Peroxisome proliferator-activated receptor alpha and gamma (PPARα and γ), and carnitine palmitoyltransferase one (CPT1) expression were increased by ASP alone.
  
  
  CONCLUSIONS
  Together these effects offer a plausible explanation for the ameliorative effect of GRE and ASP on insulin-resistance, an underlying cause for obesity and type 2 diabetes.
authors: Diabetes Discovery Platform, South African Medical Research Council, Tygerberg, South Africa.|Department of Biochemistry and Microbiology, University of Zululand, Kwa-Dlangezwa, South Africa.
authors: Sithandiwe E
authors: SE
authors: Mazibuko
authors: Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Stellenbosch, South Africa.|Department of Food Science, Stellenbosch University, Matieland, South Africa.
authors: Elizabeth
authors: E
authors: Joubert
authors: Diabetes Discovery Platform, South African Medical Research Council, Tygerberg, South Africa.
authors: Rabia
authors: R
authors: Johnson
authors: Diabetes Discovery Platform, South African Medical Research Council, Tygerberg, South Africa.
authors: Johan
authors: J
authors: Louw
authors: Department of Biochemistry and Microbiology, University of Zululand, Kwa-Dlangezwa, South Africa.
authors: Andrew R
authors: AR
authors: Opoku
authors: Diabetes Discovery Platform, South African Medical Research Council, Tygerberg, South Africa.
authors: Christo J F
authors: CJ
authors: Muller
mesh_terms: D041721:3T3-L1 Cells; D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D036903:Aspalathus; D047188:Chalcones / Q000494:pharmacology*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000235:genetics; D007328:Insulin / Q000494:pharmacology; D007333:Insulin Resistance; D050356:Lipid Metabolism / Q000187:drug effects*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D010168:Palmitates / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*
chemical_list: D047188:Chalcones; D051275:Glucose Transporter Type 4; D007328:Insulin; D016328:NF-kappa B; D010168:Palmitates; D010936:Plant Extracts; C495693:Slc2a4 protein, mouse; C517016:aspalathin; D000255:Adenosine Triphosphate; D055372:AMP-Activated Protein Kinases; D005947:Glucose
keywords: Aspalathin; Aspalathus linearis; Dihydrochalcone C-glucoside; Insulin resistance; Palmitate