A spectrophotometric assay for allicin and alliinase (alliin lyase) activity: Reaction of 2-nitro-5-thiobenzoate with thiosulfinates

Allicin (diallylthiosulfinate) is the main biologically active component of freshly crushed garlic cloves. It is produced upon the interaction of the nonprotein amino acid alliin with the enzyme alliinase (alliin lyase, EC 4. 4.1.4), A simple and rapid spectrophotometric procedure for determination o f allicin and alliinase activity, based on the reaction between 2-nitro-5-t hiobenzoate (NTB) and allicin, is described, NTB reacts with the activated disulfide bond -S(O)-S- of allicin, forming the mixed-disulfide allylmercap to-NTB, as characterized by NMR. The method can be used for determination o f allicin and total thiosulfinates in garlic preparations and garlic-derive d products. The method was applied for determination of pure alliinase acti vity and for the activity of the enzyme in crude garlic extracts. (C) 1998 Academic Press.