Abstract

Garlic is a widely used medicinal plant exhibiting beneficial health effects such as antidiabetic, antioxidant or hypolipidemic. However several controversies persist about the beneficial or toxic effects of garlic according to its mode of administration in rat. We studied the ability of high dosage garlic to modulate erythrocytes and plasma antioxidant status when administered orally (p.o.) or through intraperitoneal (i.p.) route. In erythrocytes, p.o. garlic treatment was found to be antioxidant as it decreased malondialdehyde (MDA), free iron and hydrogen peroxide (H₂O₂) and increased antioxidant enzyme activities as catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD). Garlic i.p treatment showed pro-oxidant activity as it increased MDA, free iron and H₂O₂. However, unexpectedly it increased the antioxidant enzyme activities. It was concluded that in plasma compartment, garlic treatment (p.o.) exhibited antioxidant nature whereas garlic (i.p.) treatment was clearly pro-oxidant. High garlic dosage was found to be relatively safe when administered orally.

Key words: Garlic, erythrocytes, plasma, redox status, administration mode, free iron, hydrogen peroxide.