Thiosulfinates

Allicin is an organosulfur compound obtained from garlic and leeks. When fresh garlic is chopped or crushed, the enzyme alliinase converts alliin into allicin, which is responsible for the aroma of fresh garlic. Allicin is unstable and quickly changes into a series of other sulfur-containing compounds such as diallyl disulfide. Allicin is an antifeedant, i.e. the defense mechanism against attacks by pests on the garlic plant.

thumb|right|150px|General structure of a thiosulfinate ester, drawn in expanded octet style