Garlic is a species of bulbous flowering plant in the genus Allium. Its close relatives include the onion, shallot, leek, chive, Welsh onion, and Chinese onion. It is native to Central Asia, South Asia and northeastern Iran and has long been used as a seasoning worldwide, with a history of several thousand years of human consumption and use. It was known to ancient Egyptians and has been used as both a food flavoring and a traditional medicine. China produced 73% of the world's supply of garlic in 2021.
Methionine is an essential amino acid in humans.
Allicin is an organosulfur compound obtained from garlic. When fresh garlic is chopped or crushed, the enzyme alliinase converts alliin into allicin, which is responsible for the aroma of fresh garlic. Allicin is unstable and quickly changes into a series of other sulfur-containing compounds such as diallyl disulfide. Allicin is an antifeedant, i.e. the defense mechanism against attacks by pests on the garlic plant.
Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula (CH3)2SO. This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water. It has a relatively high boiling point. DMSO is metabolised to compounds that leave a garlic-like taste in the mouth after DMSO is absorbed by skin.
Ajoene is an organosulfur compound found in garlic (Allium sativum) extracts. It is a colorless liquid that contains sulfoxide and disulfide functional groups. The name (and pronunciation) is derived from "ajo", the Spanish word for garlic. It is found as a mixture of up to four stereoisomers, which differ in terms of the stereochemistry of the central alkene (E- vs Z-) and the chirality of the sulfoxide sulfur (R- vs S-).
Organosulfur chemistry is the study of the properties and synthesis of organosulfur compounds, which are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature is abound with organosulfur compounds—sulfur is vital for life. Of the 20 common amino acids, two are organosulfur compounds, and the antibiotics penicillin and sulfa drugs both contain sulfur. While sulfur-containing antibiotics save many lives, sulfur mustard is a deadly chemical warfare agent. Fossil fuels, coal, petroleum, and natural gas, which are derived from ancient organisms, necessarily contain organosulfur compounds, the removal of which is a major focus of oil refineries.
In organic chemistry, a sulfoxide, also called a sulphoxide, is an organosulfur compound containing a sulfinyl functional group attached to two carbon atoms. It is a polar functional group. Sulfoxides are oxidized derivatives of sulfides. Examples of important sulfoxides are alliin, a precursor to the compound that gives freshly crushed garlic its aroma, and dimethyl sulfoxide (DMSO), a common solvent.
Alliin is a sulfoxide that is a natural constituent of fresh garlic. It is a derivative of the amino acid cysteine. When fresh garlic is chopped or crushed, the enzyme alliinase converts alliin into allicin, which is responsible for the aroma of fresh garlic. Allicin and other thiosulfinates in garlic are unstable and form a number of other compounds, such as diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DAT), dithiins and ajoene. Garlic powder is not a source of alliin, nor is fresh garlic upon maceration, since the enzymatic conversion to allicin takes place in the order of seconds.
Diallyl disulfide is an organosulfur compound derived from garlic and a few other plants in the genus Allium. Along with diallyl trisulfide and diallyl tetrasulfide, it is one of the principal components of the distilled oil of garlic. It is a yellowish liquid which is insoluble in water and has a strong garlic odor. It is produced during the decomposition of allicin, which is released upon crushing garlic and other plants of the family Alliaceae. Diallyl disulfide has many of the health benefits of garlic, but it is also an allergen causing garlic allergy. Highly diluted, it is used as a flavoring in food. It decomposes in the human body into other compounds such as allyl methyl sulfide.
Tetrahydrothiophene is an organosulfur compound with the formula (CH2)4S. The molecule consists of a five-membered saturated ring with four methylene groups and a sulfur atom. It is the saturated analog of thiophene or the sulfur analog of THF. It is a volatile, colorless liquid with an intensely unpleasant odor. It is also known as thiophane, thiolane, or THT.
In chemistry, a sulfenic acid is an organosulfur compound and oxoacid with the general formula R−S−OH. It is the first member of the family of organosulfur oxoacids, which also include sulfinic acids and sulfonic acids, respectively. The base member of the sulfenic acid series with R = H is hydrogen thioperoxide.
Petiveria is a genus of flowering plants in the pigeonberry family, Petiveriaceae. The sole species it contains, Petiveria alliacea, is native to Florida and the lower Rio Grande Valley of Texas in the United States, Mexico, Central America, the Caribbean, and tropical South America. Introduced populations occur in Benin and Nigeria. It is a deeply rooted herbaceous perennial shrub growing up to 1 m (3.3 ft) in height and has small greenish piccate flowers. The roots and leaves have a strong acrid, garlic-like odor which taints the milk and meat of animals that graze on it.
syn-Propanethial S-oxide (or (Z)-propanethial S-oxide), a member of a class of organosulfur compounds known as thiocarbonyl S-oxides (formerly "sulfines"), is a volatile liquid that acts as a lachrymatory agent (triggers tearing and stinging on contact with the eyes). The chemical is released from onions, Allium cepa, as they are sliced. The release is due to the breaking open of the onion cells and their releasing enzymes called alliinases, which then break down amino acid sulfoxides, generating sulfenic acids. A specific sulfenic acid, 1-propenesulfenic acid, formed when onions are cut, is rapidly rearranged by a second enzyme, called the lachrymatory factor synthase or LFS, giving syn-propanethial S-oxide. Vapors from this volatile liquid induces tearing.
In enzymology, an alliin lyase is an enzyme that catalyzes the chemical reaction
In organosulfur chemistry, thiosulfinate is a functional group consisting of the linkage R-S(O)-S-R. Thiolsulfinates are also named as alkanethiosulfinic acid esters.
Allium stipitatum, Persian shallot, is an Asian species of onion native to central and southwestern Asia.
Methylselenocysteine, also known as Se-methylselenocysteine, is an analog of S-methylcysteine in which the sulfur atom is replaced with a selenium atom. It is an inhibitor of DMBA-induced mammary tumors and a "chemopreventive agent that blocks cell cycle progression and proliferation of premalignant mammary lesions and induces apoptosis of cancer cell lines in culture."
Eric Block is an American chemist whose research has focused on the chemistry of organosulfur and organoselenium compounds, Allium chemistry, and the chemistry of olfaction. As of 2018, he is Distinguished Professor of Chemistry Emeritus at the University at Albany, SUNY.
S-Methylcysteine is the amino acid with the nominal formula CH3SCH2CH(NH2)CO2H. It is the S-methylated derivative of cysteine. This amino acid occurs widely in plants, including many edible vegetables.
In chemistry, a selenosulfide refers to distinct classes of inorganic and organic compounds containing sulfur and selenium. The organic derivatives contain Se-S bonds, whereas the inorganic derivatives are more variable.
