GARLIC CHEMISTRY - STABILITY OF S-(2-PROPENYL) 2-PROPENE-1-SULFINOTHIOATE (ALLICIN) IN BLOOD, SOLVENTS, AND SIMULATED PHYSIOLOGICAL FLUIDS

S-(2-Propenyl) 2-propene-1-sulfinothioate (allicin), which is one of the constituents of freshly crushed garlic (garlic homogenate), was synthesized, and its stability in blood, ethyl acetate, methanol, simulated gastric fluid (SGF, pH 1.2), simulated intestinal fluid (STF, pH 7.5), and water (pH 1.2 and 7.5) and under simulated digestive conditions (sequential combination of SGF and SIF) was investigated by HPLC. Although neat allicin decomposes rapidly at 37 degrees C, it is more stable in protic polar methanol than in aprotic polar ethyl acetate. Approximately 90% of the allicin remained after incubation at 37 degrees C for 5 h in water at pH 1.2 and 7.5, Only traces of allicin could be detected after it was incubated in blood for 5 min. The allicin content and allicin-producing potential of commercial garlic preparations were also analyzed. The allicin contents in these garlic preparations were less than 1 ppm, and the allicin-producing potential was severely suppressed under simulated digestive conditions (sequential combination of SGF and SIE). The transformation products of allicin. [(E)-ajoene, 2-ethenyl-4H-1,3-dithiin, diallyl disulfide] were identified.