The mode of action of allicin: its ready permeability through phospholipidmembranes may contribute to its biological activity

Allicin (diallyl thiosulfinate) is the main biologically active component o f the freshly crushed garlic extracts. In the present work the ability of a llicin to cross through membranes (artificial and biological) was studied. Partition coefficients of allicin in water/octanol, water/hexadecane and wa ter/phospholipids mixtures were determined. Using phospholipid vesicles loa ded with hydrophilic thiols (reduced glutathione or 2-nitro-5-thiobenzoate) , we observed that allicin freely permeates through phospholipid bilayers a nd interacts with the SH groups. The reaction rate of allicin with SH conta ining molecules after crossing the membrane was the same as in solution. Fa st diffusion and permeation of allicin across human red blood cell membrane s was also demonstrated. Allicin does not induce leakage, fusion or aggrega tion of membrane. The high permeability of allicin through membranes may gr eatly enhance the intracellular interaction with thiols. (C) 2000 Elsevier Science B.V. All rights reserved.