Sulfur compounds of garlic

Block, E. The Chemistry (Sulfur Compounds) of Garlic and Onions, Sci. 

The allyl sulfur compounds of garlic also have an anticoagulant action (by inhibiting platelet coagulability) and inhibit cholesterol synthesis by inactivating HMG-CoA reductase. 

Another German investigator (Semmler, 1892) also produced garlic oil via steam distillation. The oil yielded diallvl disulfide, CH2=CHCH2SSCH2 CH = CH2, with minor amounts of diallyl trisulfide and diallyl tetrasulfide present. The oil yielded by similar experimentation with onions was different, containing essentially propionaldehyde, C2H5CHO, plus a number of sulfur compounds, of which dipropyl disulfide, C5H12S2, was one. 

In addition to its chemopreventive effects, some of the sulfur compounds in garlic also inhibit the growth of induced and transplantable tumors in animal models. ... 

Three major classes of secondary metabolites are involved in these phytochemicals, which are alkaloids, terpenes, and phenoUcs [16]. There are many phytochemicals recognized with health benefits such as sulfur-containing compounds of garlic family, various terpenoids, and polyphenols (anthocyanins, flavones, flavanols, isoflavones, stilbenes, ellagic acid, etc.). 

Plants of the genus Allium, e.g. garlic Allium sativum), leek Allium amp-eloprasum), and onion Allium cepa), produce a bewildering variety of sulfur compounds. Selenium analogs for some of these have also been found (Section 11.1.3.6). Much work has focused on garlic (contains more than 100 such materials) and onion.56,66,67 Key compounds for formation of the Allium sulfur-containing secondary metabolites are sulfoxides of cysteine derivatives,... 

A tree, Scorodocarpus borneensis, native to Borneo and the Malay peninsula, has a garlic-like smell and is known as wood garlic . The fruit is used locally for seasoning. The major volatile flavor compounds from wood garlic are similar to those of garlic itself. Some of these materials are polysulfur compounds and have antimicrobial activity against some bacteria and fungi. These materials contain four sulfur atoms.75 They are either 2,4,6-trithiaheptane-5-thione-2,2-dioxide (CH3-SO2-CH2-S-CS-S-CH3) or derivatives of tetrathia-octane (CH3-S-CH2-S-S-CH2-S-CH 3, CH3-SO2-CH2-S-S-CH2-S-CH3, CH3-S-CH2-SO2-S-CH2-S-CH3). 

There are only a few reports on the absorption, metabolism, and excretion of garlic s sulfur compounds available. Further, until now it is not known what metabolic form of allicin actually reaches the target cells, and it is still unknown how garlic compounds might function in the body. 

Movies have depicted its power to repel werewolves and vampires. The characteristic garlic odor derives from the many sulfur compounds it contains. One of the major constituents is allicin, a compound with antibacterial properties. 

Oxidation of the thiosulfinate ester up to the sulfonate level gives the compound responsible for the lell of raw onions, while a hydrogen shift on the conjugated sulfenic acid (not possible with the garlic impound) gives a sulfine, the sulfur analogue of a ketene. The compound has the Z configuration cted from the mechanism and is the lachrymator that makes you cry when you cut into a raw onion. 

Garlic, Allium sativum L., is a species in the onion family, Alliaceae. Onion, shallot, and leek are close relatives. Garlic has been used throughout history for both culinary and medicinal purposes. It has a pungent hot sensation that mellows and sweetens considerably with cooking. A large number of sulfur compounds contribute to the smell and taste of members of the onion family. Diallyl disulfide and diallyl sulfide are... 

Members of the allium family (onions, garlic, and leeks) contain cysteine sulfoxide derivatives (allyl sulfur compounds), such as allicin and alliin (see Figure 14.9). When the plant cells are damaged, the enzyme alliinase is released from vacuoles and catalyzes the formation of thiosulfinates and thiols, including the lachrymator thiopropanal S-oxide. Their function in the plant is presumably to provide protection against attack by pests. 

A large number of organic sulfur compounds have been detected in extracts or distillates prepared from garlic, onions, or other Allium species. This chemistry has been reviewed by Block. Polysulfanes have been detected in many of these preparations but most recent results show that fresh extracts of garlic, prepared under mild conditions (20 °C), did not show any polysulfanes R-S -R n > 2) when analyzed by RP-HPLC analysis. ... 

The exclusion of selenium from the proteins of accumulator plants is thought to be the basis for their selenium tolerance. Their selenium metabolism is based mainly on water-soluble nonprotein forms such as selenium methylselenomethionine (Jacobs, 1989). The garlic odor characteristic of selenium-accumulator plants reflects the volatile organic compounds dimethylselenide and dime-thyldiselenide. Plants can suffer selenium toxicity as a result of selenium competition with essential metabolites for biochemical sites, replacement of essential ions by selenium, mainly major cations, selenate occupation of the sites of essential groups such as phosphate and nitrate, or selenium substimtion in essential sulfur compounds. 

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