Garlic - Active Components
The major constituents of the oily portion of garlic bulbs are sulfuric compounds, which are believed to be the primary active substances.
Garlic contains a large number of active compounds that are linked by an intricate chemistry.
Intact garlic cloves contain allins-stable odorless compounds-such as alliin.
Crushed cloves release an enzyme called alliinase, which transforms alliin into the pungent and potent allicin (Block, 1985) and similar substances that carry the typical flavor of fresh garlic.
Garlic chopped in oil or cut, pressed, and left for a few hours or days at room temperature transforms these short-lived flavorful compounds into more stable products, such as ajoene, methyl ajoene, and dithiins.
Cooked garlic produces diallyl sulfide (DAS), diallyl disulfide (DADS), diallyl trisulfide (DATS), and similar compounds.
When garlic is aged, alliin and allicin are converted to S-allyl cysteine, S-allyl mercaptocystine, and other compounds that are stable, survive cooking, have little odor, and are found in aged garlic extract preparations
