Alliin

Alliin /ˈæli.ɪn/ is a sulfoxide that is a natural constituent of fresh garlic.[1] 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.

Alliin
Names
IUPAC name
(2R)-2-amino-3-[(S)-prop-2-enylsulfinyl]propanoic acid
Other names
3-(2-Propenylsulfinyl)alanine
(S)-3-(2-Propenylsulfinyl)-L-alanine
3-((S)-Allylsulfinyl)-L-alanine
S-Allyl-L-cysteine sulfoxide
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.008.291
EC Number
  • 209-118-9
KEGG
UNII
Properties
C6H11NO3S
Molar mass 177.22 g/mol
Appearance White to off white crystalline powder
Melting point 163–165 °C (325–329 °F)
Soluble
Hazards
Safety data sheet External MSDS
GHS pictograms
GHS Signal word Warning
H315, H319, H335
P261, P264, P271, P280, P302+352, P304+340, P305+351+338, P312, P321, P332+313, P337+313, P362, P403+233, P405, P501
NFPA 704 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
1
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Garlic has been used since antiquity as a therapeutic remedy for certain conditions now associated with oxygen toxicity, and, when this was investigated, garlic did indeed show strong antioxidant and hydroxyl radical-scavenging properties, it is presumed owing to the alliin contained within.[2] Alliin has also been found to affect immune responses in blood.[3]

Alliin was the first natural product found to have both carbon- and sulfur-centered stereochemistry.[4]

Chemical synthesis

The first reported synthesis, by Stoll and Seebeck in 1951,[5] begins the alkylation of L-cysteine with allyl bromide to form deoxyalliin. Oxidation of this sulfide with hydrogen peroxide gives both diastereomers of L-alliin, differing in the orientation of the oxygen atom on the sulfur stereocenter.

A newer route, reported by Koch and Keusgen in 1998,[6] allows stereospecific oxidation using conditions similar to the Sharpless asymmetric epoxidation. The chiral catalyst is produced from diethyl tartrate and titanium isopropoxide.

References
  1. Iberl, B; et al. (1990). "Quantitative Determination of Allicin and Alliin from Garlic by HPLC". Planta Med. 56 (3): 320–326. doi:10.1055/s-2006-960969. PMID 17221429.
  2. Kourounakis, PN; Rekka, EA (November 1991). "Effect on active oxygen species of alliin and Allium sativum (garlic) powder". Res Commun Chem Pathol Pharmacol. 74 (2): 249–252. PMID 1667340.
  3. Salman, H; et al. (September 1999). "Effect of a garlic derivative (alliin) on peripheral blood cell immune responses". Int J Immunopharmacol. 21 (9): 589–597. doi:10.1016/S0192-0561(99)00038-7. PMID 10501628.
  4. Eric Block (2009). Garlic and other alliums: the lore and the science. Royal Society of Chemistry. pp. 100–106.
  5. Stoll , Seeback, Arthur, Ewald (1951). "Chemical investigations on alliin, the specific principle of garlic". Advanced Enzymology. 11: 377–400.
  6. Koch, Keusgen (1998). "Diastereoselective synthesis of alliin by an asymmetric sulfur oxidation". Pharmazie. 53 (668–671).
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