Enzyme inhibition by allicin, the active principle of garlic

Abstract

All enzyme inhibitory effects observed with garlic extracts may be explained by the presence of allicin. Alliin (0.002[image]) did not inhibit any enzyme tested, but 0.0005 [image] allicin inhibited nearly all sulfhydryl enzymes but very few non-sulfhydryl enzymes tested. Some enzymes, such as triosephosphate dehydrogenase, were inhibited by 0.00005 [image] allicin. Sulfhydryl enzymes could be protected by cysteine or glutathione against inhibition by allicin, but only partial recovery of enzyme activity was obtainable after the allicin and enzyme had been in contact for a short period. Inhibition of sulfhydryl enzymes has been shown to be associated with the presence of the SO-S-grouping and not the -SO-, -S-S- or -S- groups.