Journal List > J Korean Endocr Soc > v.23(2) > 1003425

Shin and Ihm: Effects of S-allylcysteine on Oxidative Stress in Streptozotocin-Induced Diabetic Rats



An increase in oxidative stress is postulated to contribute to the development of diabetic complications and the use of antioxidant therapy could be protective against these processes. This study was performed to investigate the role of the antioxidant S-allylcysteine (SAC), a water-soluble component of aged garlic, for reducing levels of oxidative stress that occurs in diabetic rats.


SAC (100 mg/head/day) was administered orally to streptozotocin-induced diabetic rats for eight weeks. The effects of SAC on the levels of markers of oxidative stress (malondialdehyde and glutathione) and mRNA expression of antioxidant enzymes were measured in the liver and kidney.


SAC-fed rats showed lower cholesterol and triacylglyceride levels than untreated diabetic rats. Malondialdehyde levels were increased in the liver and kidney of diabetic rats and SAC administration lowered the levels in both organs. Glutathione levels were lower in the liver and kidney of diabetic rats, and SAC administration restored the glutathione to a level similar in non-diabetic rats. In the liver and kidney of untreated diabetic rats, mRNA expression of catalase, superoxide dismutase and glutathione reductase were down regulated, and administration of SAC increased expression of these enzymes.


Our results have shown that administration of SAC to diabetic rats can lower blood lipid levels and alleviate oxidative stress in the diabetic tissues, suggesting that SAC might have beneficial effects in a prevention trial for diabetic complications.

Figures and Tables

Fig. 1
Structure of S-allylcysteine (SAC).
Fig. 2
Messenger RNA expression levels of antioxidant enzymes in the liver and kidney. *P < 0.005 vs. control, P < 0.05 vs. control. P < 0.005 vs. diabetic. §P < 0.01 vs. diabetic.
Table 1
Primers used for antioxidant enzymes
Table 2
Body weight changes and daily food consumption

Values are means ± SD. *P < 0.01 vs. control.

Table 3
Plasma glucose, cholesterol, triacylglyceride and HbA1c levels

Values are means ± SD. *P < 0.001 vs. control. P < 0.002 vs. control. P < 0.02 vs. diabetic. §P < 0.002 vs. diabetic.

Table 4
MDA (malondialdehyde) levels in the liver and kidney

Values are means ± SD. *P < 0.002 vs. control. P < 0.001 vs. control. P < 0.02 vs. diabetic. §P < 0.05 vs. diabetic.

Table 5
GSH (glutathione) levels in the liver and kidney

Values are means ± SD. *P < 0.001 vs. control. P < 0.005 vs. control. P < 0.005 vs. diabetic. §P < 0.001 vs. diabetic.


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