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Effect of annatto-extracted tocotrienols and green tea polyphenols on glucose homeostasis and skeletal muscle metabolism in obese male mice

Chung E, Campise SN, Joiner HE, Tomison MD, Kaur G, Dufour JM, Cole L, Ramalingam L, Moustaid-Moussa N, Shen CL (2019) J Nutr Biochem.  2019 Feb;67: 36-43. doi: 10.1016/j.jnutbio.2019.01.021. [Epub ahead of print] 

Web URL: Read this and related abstracts on PubMed here


Skeletal muscle is the major site for glucose uptake and thus plays an important role in initiating insulin resistance in type 2 diabetes mellitus. This study evaluated the effects of tocotrienols (TT) and green tea polyphenols (GTP) individually or in combination on glucose homeostasisand skeletal muscle metabolism in obese mice with insulin resistance and elevation of blood glucose.

male mice were fed a high-fat diet and assigned to 4 groups in a 2 (no TT vs. 400 mg TT/kg diet) × 2 (no GTP vs. 0.5% vol/wt GTP in water) for 14 weeks. Both GTP and TT improved area under curve of insulin intolerance; while GTP increased serum insulin levels in obese mice, probably due to the addition of sweetener in drinking water. An interaction (TT×GTP) was observed in glucose tolerance test, total pancreas insulin concentration, and citrate synthase activity of soleus in mice. Neither TT nor GTP affected insulin and glucagon protein expression in pancreas based on immunohistochemistry.

Both TT and GTP individually increased soleus 
muscle weight of mice; while only GTP increased gastrocnemius muscle weight of mice. The TT+GTP group had the greatest gastrocnemius muscle cross sectional area than other groups. GTP, not TT, induced cytochrome c oxidase activity and reduced thiobarbituric acid reactive substances levels in soleus muscle.

Our results suggest that TT and GTP, individually or synergistically have the potential to improve 
skeletal muscle metabolism in obese mice by improving glucosehomeostasis, reducing lipid peroxidation, and increasing rate limiting enzymes of oxidative phosphorylation.


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