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It was widely believed that the organic compound, allicin – which gives the pungent vegetable its aroma and flavour – acts as an 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 Dr. Derek Pratt. “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 sulfenic acid produced when the compound decomposes rapidly reacts with radicals.

“While garlic has been used as a herbal medicine for centuries and there are many garlic supplements on the market, until now there has been no convincing explanation as to why it is beneficial,” says Dr. Pratt. “I think we have taken the first step in uncovering a fundamental chemical mechanism which may explain garlic’s medicinal benefits.”

Interesting to learn that a variable like the rate of decomp governs the production of sulfenic acid. Raises questions about imparting a similar mechanism to other alliums? We’re getting to where genomics has such capabilities.