An in-vitro study on cultured endothelial cells, conducted by the Tel-Aviv University, demonstrated the antioxidant role of allicin and its derivatives by up-regulating the phase II detoxifying enzymes and increasing the cellular glutathione level [1]. The researchers examined the effect of allicin on gene expression and glutathione cellular level in vascular endothelial cells. Using a micro-array and real-time PCR, they found that allicin up-regulated and down-regulation of 116 and 100 genes, respectively. The phase II detoxifying enzymes thioredoxin reductase 1 and 2, heme oxygenase-1 and glutamate cysteine lygaze modifier subunit were all up-regulated. Allicin also increased glutathione level in a concentration and time-dependent manner.
Okada and colleagues at the Kyorin University, Japan, determined the rate constant of the reaction of allicin reacted with peroxyl radicals derived from cumene and methyl linoleate [2]. They also demonstrated that an allylic hydrogen atom of the allicin is responsible for the antioxidant activity. Okada also found that antioxidant properties of garlic extract were mostly attributed to the presence of allicin [3]. The removal of allicin from garlic extract significantly reduced the antioxidant effect on methyl linoleate in a acetonitrile solution. Allicin also reduced to dose-dependently peroxyl radical formation in to 2,2'-azobis(2,4-dimethylvaleronitrile)-peroxyl radical solution.
[1] Allicin up-regulates cellular glutathione level in vascular endothelial cells. Eur J Nutr. 2009 Mar;48(2):67-74.
[2] Kinetic and mechanistic studies of allicin as an antioxidant. Org Biomol Chem. 2006 Nov 21;4(22):4113-7.
[3] Antioxidant activity of thiosulfinates derived from garlic. Redox Rep. 2005;10(2):96-102.
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