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Aspalathin improves glucose and lipid metabolism in 3T3‐L1 adipocytes exposed to palmitate
Author(s) -
Mazibuko Sithandiwe E.,
Joubert Elizabeth,
Johnson Rabia,
Louw Johan,
Opoku Andrew R.,
Muller Christo J. F.
Publication year - 2015
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.201500258
Subject(s) - insulin resistance , glut4 , medicine , endocrinology , irs1 , protein kinase b , insulin receptor , chemistry , carnitine , glucose uptake , insulin receptor substrate , glucose transporter , insulin , lipid metabolism , carbohydrate metabolism , phosphorylation , biology , biochemistry
Scope 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. Methods and 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. Conclusion 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.