Biochemical effects following ingestion of Allium cepa (onion) and Allium sativum (garlic) by normal and iodine treated albino Wistar rats have been studied. The determination of the effect of the oral administration of onion and garlic extract on the activity of some serum enzymes specifically alanine aminotransferase, ALT, aspartate aminotransferase, AST, alkaline phosphatase, ALP, including the AST: ALT ratio was studied. Oral administration of onion and garlic led to a statistically significant (P < 0.05) decrease in the serum ALT activity of the experimental animals when compared with the control. The mean values for aspartate aminotransferase (AST) were 89.50 ± 14.92 U/L for iodine treated high dose garlic group and 76.38 ± 10.39 U/L for the iodine treated high dose onion group. Oral administration of onion and garlic extract led to a statistically significant (P < 0.05) increase in the AST: ALT ratio of both normal and iodine treated rats. There was a significant (P < 0.05) decrease in alkaline phosphatase (ALP) activity in both normal and iodine treated rats when compared with the control due to oral administration of onion and garlic extract. The increase in serum AST activity upon administration of onion and garlic extracts respectively in high doses and a rise in the AST: ALT ratio suggests that some phytochemical components in onion and garlic may have heart directed toxicity and calls for caution on the use of these spices by people suffering from cardiac related disorders. The results are discussed in relation to the fight against iodine deficiency eradication.
