Allicin is a thiosulphinate that gives rise to dithiines, allyl sulphides and ajoenes, the three groups of active compounds in Allium species. Allicin is synthesised from sulfoxide cysteine derivatives by alliinase (EC:4.4.1.4), whose C-S lyase activity cleaves C(beta)-S(gamma) bonds. It is thought that this enzyme forms part of a primitive plant defence system. This family represents the N-terminal EGF-like domain [1].

1: The active principle of garlic at atomic resolution. Kuettner EB, Hilgenfeld R, Weiss MS; J Biol Chem 2002;0:0-0. PMID:12235163