Researchers have widely believed that the organic compound, allicin – which gives garlic its aroma and flavour – acts as the world's most powerful antioxidant. But until now it hasn't been clear how allicin works, or how it stacks up compared to more common antioxidants such as Vitamin E and coenzyme Q10, which stop the damaging effects of radicals.
"We didn't understand how garlic could contain such an efficient antioxidant, since it didn't have a substantial amount of the types of compounds usually responsible for high antioxidant activity in plants, such as the flavanoids found in green tea or grapes," says Chemistry professor Derek Pratt, who led the study. "If allicin was indeed responsible for this activity in garlic, we wanted to find out how it worked."
The research team questioned the ability of allicin to trap damaging radicals so effectively, and considered the possibility that a decomposition product of allicin may instead be responsible. Through experiments with synthetically-produced allicin, they found that an acid produced when the compound decomposes rapidly reacts with radicals.
Their findings are published in the January 2009 issue of the international chemistry journal Angewandte Chemie.