Abstract

Hepatoprotective and antioxidative efficacy of garlic was investigated against cadmium induced toxicity in young and old rats. Animals were co-administered with 250 μl/kg garlic through gastric intubation for consecutive four days and 5 mg/kg cadmium chloride intraperitoneally (ones in last day of garlic administration). The results demonstrate that cadmium induced toxicity was less pronounced in old animals. Unchanged levels of membrane-bound cytochrome P-450 and lipid hydroperoxides were observed. Co-administration of garlic in old rats provided essential protection against cadmium toxicity. Significant depletion of the cadmium-dependent carbonyl proteins level and restored activity of antioxidant enzymes was also observed. In young rats, concomitant administration of garlic leads to less pronounced hepatoprotective effect compared to that in old rats as evident by higher levels of carbonyl proteins and incomplete recovery of cytochrome P-450 and antioxidant enzymes. On the other hand, in young rats elevated levels of non-enzymatic antioxidants were also observed. It can be concluded from the present results that cadmium toxicity is mediated through oxidative stress which can significantly restored by co-administration of garlic. We also suggest that in young rats the protective effect of garlic is associated with maintaining an adequate level of non-enzymatic antioxidant defense system, whereas in old rats these effects are associated with activation of the enzymatic antioxidant defense system.

Key words: Age; Cadmium; Garlic; Oxidative stress