Quantification and Characterization of Allicin in Garlic Extract

Garlic (Allium sativum) is a plant well known for its extensive use in traditional and modern medicine. Its healing properties are attributed to thiosulfinates, compounds formed through an enzymatic reaction when garlic cloves are crushed. One of the most prominent thiosulfinate found in garlic is diallyl thiosulfinate or allicin. The condition in this research mimics Malaysian climate conditions. This allows allicin to be studied and characterized for its uses in the local agricultural sector as potential urea inhibitor. A spectophotometric method is used in this research to quantify allicin found in garlic extract. L-cysteine is used to react with allicin in garic extract with the knowledge that one molecule of allicin reacts rapidly with two molecules of cysteine to form two molecules of S-allyl mercaptocysteine. 5,5’-dithiobis-(2-nitrobenzoic acid) (DTNB) is added to the mixture so that spectrophotometrically active 2-nitro-5-thiobenzoate (NTB) is formed after residual cysteine reacts with DTNB. Quantification of allicin is done at 30°C with garlic extract concentration ranging from 0.005 g/mL to 0.03 g/mL. This is followed by tests on allicin stability at pH 4 – 8 at 30°C and effects of temperature on allicin from 30°C to 85°C.