Ajoene is a sulphur-containing compound derived from allicin.

In an oil maceration process of garlic bulb, a mixture of other organosulfur compounds was formed. In general, oil-macerated garlic products contained primarily vinyldithiins as well as some dialk(en)yl sulphides, mainly diallyl trisulfide and ajoene (Table 1). Ajoene is typically not found in steam-distilled garlic but only in oil-macerated garlic. An important structural feature of ajoene is that the central double bond is capable of existing in E or Z forms. It was found that Z-Ajoene is the dominant isomer in fresh preparations of oil-macerated garlic. Gradually, Z-isomer will be converted to the E-isomer and it was thought that E-ajoene is more stable during storage. The E/Z ratio and yield depend on the polarity of the solvent system, the reaction condition during processing and cultivar (Lawson et al, 1990).