Asparagusic acid

Source: Wikipedia, the free encyclopedia.

Asparagusic acid[1]
Asparagusic acid
Asparagusic acid
Asparagusic acid
Asparagusic acid
Names
Preferred IUPAC name
1,2-Dithiolane-4-carboxylic acid
Other names
1,2-Dithiacyclopentane-4-carboxylic acid
Identifiers
3D model (
JSmol
)
ChEBI
ChemSpider
KEGG
UNII
  • InChI=1S/C4H6O2S2/c5-4(6)3-1-7-8-2-3/h3H,1-2H2,(H,5,6) checkY
    Key: AYGMEFRECNWRJC-UHFFFAOYSA-N checkY
  • InChI=1/C4H6O2S2/c5-4(6)3-1-7-8-2-3/h3H,1-2H2,(H,5,6)
    Key: AYGMEFRECNWRJC-UHFFFAOYAA
  • O=C(O)C1CSSC1
Properties
C4H6O2S2
Molar mass 150.21 g·mol−1
Appearance Colorless solid
Density 1.50 g cm−3
Melting point 75.7 to 76.5 °C (168.3 to 169.7 °F; 348.8 to 349.6 K)[2]
Boiling point 323.9 °C (615.0 °F; 597.0 K) at 760mmHg
Hazards
Flash point 149.7 °C (301.5 °F; 422.8 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Asparagusic acid is an

heterocyclic disulfide functional group (a 1,2-dithiolane) with a carboxylic acid side chain. It is found in asparagus and is believed to be the metabolic precursor to odorous sulfur compounds responsible for the distinctive smell of urine which has long been associated with eating asparagus.[3][4]

Isolation and biosynthesis

The material was originally isolated from an aqueous extract of

heterocycle. Biosynthetic studies revealed that asparagusic acid is derived from isobutyric acid.[6] Asparagusic acid is a colorless solid with a melting point of 75.7–76.5 °C,[2] higher than that of the corresponding dithiol: dihydroasparagusic acid (or γ,γ-dimercaptoisobutyric acid), at 59.5–60.5 °C.[7]

Laboratory synthesis

A convenient synthesis of asparagusic acid has been developed from a commercially available diethyl malonate derivative starting material, improving on the prior method of Jansen.[5] Diethyl bis(hydroxymethyl)malonate is treated with hydroiodic acid to yield β,β'-diiodoisobutyric acid after decarboxylation and ester hydrolysis (with removal of volatile ethanol and carbon dioxide). Dihydroasparagusic acid, the reduced (dithiol) form of asparagusic acid, is produced by sequential reaction with sodium trithiocarbonate (Na2CS3) and sulfuric acid; subsequent oxidation with hot dimethyl sulfoxide yields asparagusic acid.[1]

Effect on urine

Observations that eating asparagus results in a detectable change in the odour of urine have been recorded over time. In 1702, Louis Lémery noted "a powerful and disagreeable smell in the urine",[8] whilst John Arbuthnot noted that "asparagus ... affects the urine with a foetid smell."[9][10] Benjamin Franklin described the odour as "disagreable",[11] whilst Marcel Proust claimed that asparagus "transforms my chamber-pot into a flask of perfume."[10][12] As early as 1891, Marceli Nencki had attributed the smell to methanethiol.[13][14] The odour is attributed to a mixture of sulfur-containing metabolites of asparagusic acid.[3][4][15][16]

The origin of asparagus urine is asparagusic acid, a substance unique to this vegetable.[17][18] Most studies of the compounds responsible for the odour of asparagus urine have correlated the appearance of the compounds above with asparagus consumption; they appear as little as 15 minutes after consumption.[10] However, this does not provide information on the biochemical processes that lead to their formation.

Asparagusic acid and

between subject variability of 43.4%.[20]

In the small minority of people who do not produce these metabolites after consuming asparagus, the reason may be as simple as asparagusic acid not being taken into the body from the digestive tract[3] or that these individuals metabolise it in such a way as to minimise the release of volatile sulfur-containing products.[10]

References

  1. ^
    doi:10.1055/s-1973-22265
    .
  2. ^
    doi:10.3891/acta.chem.scand.12-1810
    .
  3. ^
    PMID 11259347
    .
  4. ^
    PMID 20876394
    .
  5. ^
    PMID 18889921
    .
  6. doi:10.1021/ja00294a051
    .
  7. doi:10.1021/ja00159a046
    .
  8. ISBN 9781416556374
    .
  9. ^ Arbuthnot, J. (1735). An Essay Concerning the Nature of Aliments, and the Choice of Them, According to the Different Constitutions of Human Bodies: In which the Different Effects, Advantages, and Disadvantages of Animal and Vegetable Diet, are Explain'd (3rd ed.). London: Jacob Tonson. p. 64. An Essay Concerning the Nature of Ailments.
  10. ^ a b c d Stromberg, J. (3 May 2013). "Why Asparagus Makes Your Urine Smell". smithsonian.com. Retrieved 19 June 2016.
  11. ISBN 9780898048018
    .
  12. Gallimard
    . changer mon pot de chambre en un vase de parfum
  13. S2CID 26430677
    .
  14. PMID 2757887
    .
  15. PMID 1162354
    .
  16. PMID 3433805
    .
  17. S2CID 20606694
    .
  18. ^
    PMID 24099657
    .
  19. PMID 11353754
    .
  20. ISSN 1871-6032
    . Retrieved 7 July 2016.

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Asparagusic_acid&oldid=1173996654"