Allyl sulfides are characteristic flavor components obtained from garlic. These sulfides are thought to be responsible for their epidemiologically proven anticancer effect on garlic eaters. This study was aimed at clarifying the molecular basis of this anticancer effect of garlic by using human colon cancer cell lines HCT-15 and DLD-1. The growth of the cells was significantly suppressed by diallyl trisulfide (DATS, HCT-15 IC 50 ‫؍‬ 11.5 M, DLD-1 IC 50 ‫؍‬ 13.3 M); however, neither diallyl monosulfide nor diallyl disulfide showed such an effect. The proportion of HCT-15 and that of DLD-1 cells residing at the G 1 and S phases were decreased by DATS, and their populations at the G 2 /M phase were markedly increased for up to 12 h. The cells with a sub-G 1 DNA content were increased thereafter. Caspase-3 activity was also dramatically increased by DATS. Fluorescence-activated cell sorter analysis performed on the cells arrested at the G 1 /S boundary revealed cell cycle-dependent induction of apoptosis through the transition of the G 2 /M phase to the G 1 phase by DATS. DATS inhibited tubulin polymerization in an in vitro cell-free system. DATS disrupted microtubule network formation of the cells, and microtubule fragments could be seen at the interphase. Peptide mass mapping by liquid chromatography-tandem mass spectrometry analysis for DATS-treated tubulin demonstrated that there was a specific oxidative modification of cysteine residues Cys-12␤ and Cys-354␤ to form S-allylmercaptocysteine with a peptide mass increase of 72.1 Da. The potent antitumor activity of DATS was also demonstrated in nude mice bearing HCT-15 xenografts. This is the first paper describing intracellular target molecules directly modified by garlic components.Allyl sulfides, e.g. diallyl monosulfide (DAS), 4 diallyl disulfide (DADS), and diallyl trisulfide (DATS), are characteristic flavor components of the essential oil prepared from garlic (Allium sativum L.). Garlic is widely served around the world, and it has been reported that allyl sulfides inhibit both the initiation and promotion stages of tumorigenesis in experimental carcinogenesis models for various types of cancer (1-5). Recently, several lines of investigation have shown that allyl sulfides suppress cell growth and induce apoptosis in multiple cancer cell lines (6 -12). We previously reported that the sulfur-containing volatile oils prepared from garlic and onion inhibit proliferation and induce differentiation of the human promyelocytic leukemia cell line HL-60 (13). However, the molecular mechanisms underlying the antitumorigenesis of allyl sulfides are still not fully understood.Microtubules are ubiquitous proteins present in eukaryotes as components of the cytoskeleton and play pivotal roles in a variety of cellular processes involving cell division, motility, and intracellular trafficking (14). The microtubules are dynamic polymers composed of ␣␤-tubulin heterodimers, and they form the mitotic spindles, which are known to introduce the replicated DNA molecules to the res...

This study verifies the instability of garlic (Allium sativum L.)-derived allyl 2-propenylthiosulfinate (allicin) in various aqueous and ethanolic solutions as well as in vegetable oil through chemical and biological analyses performed simultaneously. Crushed fresh garlic cloves generated antibacterial activity and chemically detectable allicin, a major antibacterial principle, and both declined on a daily basis in aqueous and ethanolic solutions at room temperature, showing biological and chemical half-lives of about 6 and 11 days, respectively. Allicin was more stable in 20% alcohol than in water, but surprisingly unstable in vegetable oil, with an activity half-life 0.8 h, as estimated from its antibacterial activity toward Escherichia coli, and a chemical half-life of 3.1 h, based on chromatographic quantification. In alcoholic and aqueous extracts, the biological half-life of allicin tended to be longer than the chemical one, suggesting the occurrence of bioactive compounds other than allicin in the extracts.

Garlic (Allium sativum L.) has a long history as being a food having a unique taste and odor along with some medicinal qualities. Modern scientific research has revealed that the wide variety of dietary and medicinal functions of garlic can be attributed to the sulfur compounds present in or generated from garlic. Although garlic produces more than 20 kinds of sulfide compounds from a few sulfur-containing amino acids, their functions are different from one another; e.g., allicin, methyl allyl trisulfide, and diallyl trisulfide have antibacterial, antithrombotic, and anticancer activities, respectively. The present paper reviews the physiological functions of garlic in the limited study fields of its antithrombotic and anticancer effects. Before describing these effects, however, we will discuss briefly some characteristics of garlic as a plant and some modes of absorption of orally-administered sulfur compounds from garlic.

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Effects of pre-germinated brown rice (PGBR) on streptozotocin-induced diabetic rats were studied. The feeding of a PGBR diet to diabetic rats ameliorated the elevation of blood glucose and PAI-1 concentrations significantly, and tended to decrease the plasma lipid peroxide concentrations in comparison with rats fed a white rice diet. These results suggest that intake of PGBR instead of white rice is effective for the prevention of diabetic vascular complications.