Garlic as a Functional Food: A Status Report

While worldwide sales continue to grow for herbal products derived from garlic, perhaps the most popular of all herbal curealls, researchers continue to debate their health value and manufacturers challenge each others' claims. The organosulfur and organoselenium chemistry of garlic is briefly reviewed. The "natural flavor" of garlic is not present as such in the intact plant but is formed upon crushing the cloves. The cloves contain alliin and related S -alk(en)yl cysteine S -oxides which when co-mingled with alliinase enzymes produce allicin and other thiosulfinates. The latter compounds can be further transformed into allyl polysulfides, ajoene, dithiins, etc. Selenium is found in garlic primarily in the form of derivatives of selenocysteine. Also discussed is the effect of processing on garlic constituents, the metabolism of garlic derived compounds, the nature of commercial garlic formulations, and the health effects of garlic and garlic products.