The Antidiabetic Effect of Garlic Oil is Associated with Ameliorated Oxidative Stress but Not Ameliorated Level of Pro-inflammatory Cytokines in Skeletal Muscle of Streptozotocin-induced Diabetic Rats

Abstract

Oxidative stress and inflammatory condition has been broadly accepted being associated with the progression of diabetes. On the other hand, garlic (大蒜 dà suàn, bulb of Allium sativum) has been shown to possess both antioxidant and anti-inflammatory action in several clinical conditions. Our previous study demonstrated that treatment with garlic oil improves oral glucose tolerance and insulin tolerance and improves the insulin-stimulated utilization of glucose to synthesize glycogen in skeletal muscle in streptozotocin (STZ)-induced diabetes, in vivo and ex vivo, respectively. The aim of the present study is to investigate the antioxidant and anti-inflammatory effects of garlic oil (GO) in the skeletal muscle of diabetic rats. Rats with STZ-induced diabetes received GO (10, 50, or 100 mg/kg body weight) or corn oil by gavage every other day for 3 weeks. Control rats received corn oil only. GO dose-dependently improved insulin sensitivity, as assessed by the insulin tolerance test, and oral glucose tolerance. GO significantly elevated total glutathione and glutathione peroxidase activity and lowered the nitrate/nitrite content in skeletal muscle at 50 and 100 mg/kg and significantly elevated glutathione reductase activity and lowered lipid peroxidation at 100 mg/kg. By contrast, GO did not reverse diabetes-induced elevation of IL-1β and TNF-α in skeletal muscle at any tested dose. On the other hand, GO elevated the expression of GLUT4 in skeletal muscle along with glycogen content as observed with PAS staining. In conclusion, the antidiabetic effect of garlic oil is associated with ameliorated oxidative stress in skeletal muscle.

In Vitro and In Vivo Immunomodulator Activities of Allium sativum L.

“…Liu et al found an hypoglycemic effect of garlic oil, associated with a lowered level of NO in skeletal muscle [ 70 ], which is consistent with the finding of another study showing that, in diet-induced metabolic syndromes in rats, treatment with raw garlic homogenate efficiently improves insulin sensitivity and normalizes serum levels of nitric oxide [ 71 ]. These hypoglycemic effects of garlic products might be explained partially by inhibition of proinflammatory mediators.…”

“…These hypoglycemic effects of garlic products might be explained partially by inhibition of proinflammatory mediators. In fact, inflammation could trigger insulin resistance, and the identified inflammatory factors involved in this process include molecules such as TNF- α , IL-1 β , and NO [ 70 , 72 , 73 ].…”

An update on natural compounds in the remedy of diabetes mellitus: A systematic review

“…The hypoglycemic activity of garlic oil has shown to improve GLUT4 expression in STZ induced diabetic rats. 38 The ethanol extract of Symplocos cochinchinesis bark has also shown to have effects in regulating insulin resistance. The oral administration of S. cochinchinesis extract at 250 and 500 mg kg −1 .day −1 significantly reduced the plasma glucose level in diabetic induced rats with insulin resistant on day 20.…”

Diallyl disulfide, a garlic-rich compound ameliorates trichloromethane-induced renal oxidative stress, NFkB activation and apoptosis in rats

“…The significant increase in the level of kidney GSH as well as significant and non-significant decrease in CAT and GPx activities respectively following CHCl 3 administration is an indication of free radical generation (H 2 O 2 ), which the endogenous antioxidant enzymes were responsive to. Antioxidant potentials of DADS was exerted which resulted to the restoration of the renal CAT [63,78e80] and GPx [25,63,81,82] activities.…”