Effect of Bangle (Zingiber purpureum) extract and low-intensity exercise on mTOR phosphorylation and autophagy flux in skeletal muscles of rats on a high-fat diet

Abstract High-fat diet (HFD) is associated with impairment of insulin sensitivity. We investigated the effects of Bangle ( Zingiber purpureum ) extract (Ba) with exercise training (Ex) on phosphorylation of Akt and mammalian target of rapamycin (mTOR), and autophagy flux in the gastrocnemius (GM) of HFD-fed rats. The rats, on a diet providing 45% of energy from fat, were divided into four groups: untreated (HFD), 1.5% Ba-treated (HFD + Ba), 1.5% Ba with Ex-treated (HFD + Ba + Ex), and Ex-treated (HFD + Ex) groups. The controls were fed a normal diet. The homeostatic model assessment of insulin resistance index and non-esterified fatty acid levels were decreased in the HFD + Ba + Ex. The HFD + Ba + Ex showed decreased phosphorylated Akt and mTOR levels, and increased levels of autophagy flux markers, LC3B-II and Beclin 1, compared to the HFD. In conclusion, the combination of Ba and Ex modulates Akt/mTOR phosphorylation and the autophagy flux in the GM and may attenuate insulin resistance induced by a HFD.