Abstract

Garlic is a commonly used spice in folk medicine which could also exert adverse health effects when given at high dosage. Grape seed extract (GSE) exhibit a variety of beneficial effects even when used at high dosage. In the present study, we evaluated the toxicity of high dosage garlic treatment on spleen and plasma as well as the protective effect of GSE. Rats were intraperitoneally injected with 5 g/kg bw crude garlic extract daily during one month and cotreated or not with GSE (500 mg/kg bw). Spleen and plasma antioxidant status were evaluated. Data confirmed that high dosage garlic induced plasma and spleen toxicity and a prooxidative state characterized by increased splenic and plasmatic malondialdehyde (MDA) and decreased antioxidant enzyme activities such as catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD). Garlic also increased intracellular and plasmatic H₂O₂, but decreased free iron in spleen and increased it in plasma. Moreover, garlic increased ionizable calcium in spleen but decreased it in plasma. GSE either alone or in cotreatment with garlic, had just an opposite role or counteracted almost all garlic-induced deleterious effects to near control level. In conclusion, high dosage garlic induces a prooxidative state characterized by the Fenton reaction between H₂O₂ and free iron inducing tissue calcium repletion and GSE exerts real antioxidant properties and calcium depletion.

Key words: Garlic, grape seed extract, spleen, plasma, oxidative stress, lipid peroxidation, protein carbonylation.