Trigonelline

Trigonelline
IUPAC name 1-Methylpyridinium- 3-carboxylate
Other names Nicotinic acid N- methylbetaine Coffearine Caffearine Gynesine Trigenolline
Identifiers
CAS number	535-83-1 Y
PubChem	5570
ChemSpider	5369 Y
ChEBI	CHEBI:18123 N
ChEMBL	CHEMBL350675 Y, CHEMBL489961
Jmol-3D images	Image 1
SMILES O=C([O-])c1ccc[n+](c1)C
InChI InChI=1S/C7H7NO2/c1-8-4-2-3-6(5-8)7(9)10/h2-5H,1H3 Y Key: WWNNZCOKKKDOPX-UHFFFAOYSA-N Y InChI=1/C7H7NO2/c1-8-4-2-3-6(5-8)7(9)10/h2-5H,1H3 Key: WWNNZCOKKKDOPX-UHFFFAOYAV
Properties
Molecular formula	C7H7NO2
Molar mass	137.14 g mol−1
Density	? g/cm3
Melting point	230-233 °C (monohydrate) 258-259 °C (hydrochloride)
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Trigonelline is an alkaloid with chemical formula C₇H₇NO₂. It is an inner salt formed by the addition of a methyl group to the nitrogen atom of niacin. Trigonelline is a product of the metabolism of niacin (vitamin B₃) which is excreted in the urine.^[1]

Trigonelline occurs in many plants, it was isolated from fenugreek seeds (Trigonella foenum-graecum, thus the name),^[2] garden peas, hemp seed, oats,^[3] potatoes, Stachys species, dahlia,^[4] Strophanthus species^[5] and Dichapetalum cymosum.^[6] Holtz, Kutscher and Theilmann have recorded its presence in a number of animals.^[7]

Trigonelline is also found in coffee,^[8] where it may help to prevent dental caries by preventing the bacteria Streptococcus mutans from adhering to teeth.^[9] Higher levels of trigonelline is found in robusta coffee.

Trigonelline crystallises as a monohydrate from alcohol in hygroscopic prisms, mp. 130 °C or 218 °C (dry, dec.). It is readily soluble in water or warm alcohol, less so in cold alcohol, and slightly so in chloroform or ether. The salts crystallise well, the monohydrochloride, in leaflets, sparingly soluble in dry alcohol. The picrate forms shining prisms, mp. 198-200 °C, soluble in water but sparingly soluble in dry alcohol or ether. The alkaloid forms several aurichlorides: the normal salt, B•HCl•AuCl₃, is precipitated when excess of gold chloride is added to the hydrochloride, and after crystallisation from dilute hydrochloric acid containing some gold chloride, has mp. 198 °C. Crystallised from water or very dilute hydrochloric acid, slender needles of B₄•3 HAuCl₄, mp. 186 °C, are obtained.

References

1. ^ Merck Index, 11th Edition, 9606.
2. ^ Jahns, Ber., 1885, 18, 2518.
3. ^ Schulze and Frankfurt, Ber., 1894, 27, 709.
4. ^ Schulze and Trier, Zeit. physiol. Chem., 1912, 76, 258.
5. ^ Thoms, Ber., 1891, 31, 271, 404.
6. ^ Rimington, Onderstepoort J., 1935, 5, 81.
7. ^ Zeit. Biol., 1924, 81, 57.
8. ^ Gorter, Annalen, 1910, 372, 237; cf. Polstorff, Chem. Soc. Abstr., 1910, ii, 234; Palladino, ibid, 1894, ii, 214; 1895, i, 629; Graf, ibid, 1904, i, 915; Nottbohm and Mayer, Zeit. Unters. Lebensmitt., 1931, 61, 429.
9. ^ Daglia, M.; R. Tarsi, A. Papetti, P. Grisoli, C. Dacarro, C. Pruzzo, and G. Gazzani (2002). "Antiadhesive Effect of Green and Roasted Coffee on Streptococcus mutans' Adhesive Properties on Saliva-Coated Hydroxyapatite Beads". Journal of Agricultural and Food Chemistry 50 (5): 1225–1229. doi:10.1021/jf010958t. PMID 11853508.