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Mol Nutr Food Res. 2015 Nov;59(11):2199-208. doi: 10.1002/mnfr.201500258. Epub 2015 Sep 15.

Aspalathin improves glucose and lipid metabolism in 3T3-L1 adipocytes exposed to palmitate.

Author information

1
Diabetes Discovery Platform, South African Medical Research Council, Tygerberg, South Africa.
2
Department of Biochemistry and Microbiology, University of Zululand, Kwa-Dlangezwa, South Africa.
3
Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Stellenbosch, South Africa.
4
Department of Food Science, Stellenbosch University, Matieland, South Africa.

Abstract

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.

KEYWORDS:

Aspalathin; Aspalathus linearis; Dihydrochalcone C-glucoside; Insulin resistance; Palmitate

PMID:
26310822
DOI:
10.1002/mnfr.201500258
[Indexed for MEDLINE]

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