Trigonelline is an

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

with

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

. It is a

zwitterion In chemistry, a zwitterion ( ; ), also called an inner salt or dipolar ion, is a molecule that contains an equal number of positively- and negatively-charged functional groups. : With amino acids, for example, in solution a chemical equilibrium wil ...

formed by the

methylation In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These t ...

of the nitrogen atom of

niacin Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variet ...

(vitamin B₃). Trigonelline is a product of niacin metabolism that is excreted in urine of mammals. Trigonelline occurs in many plants. It has been isolated from the Japanese

radish The radish (''Raphanus raphanistrum'' subsp. ''sativus'') is an Eating, edible root vegetable of the family Brassicaceae that was domesticated in Asia prior to Roman Empire, Roman times. Radishes are grown and consumed throughout the world, be ...

(''Raphanus sativus'' cv. Sakurajima Daikon),

fenugreek Fenugreek (; ''Trigonella foenum-graecum'') is an annual plant in the family Fabaceae, with leaves consisting of three small obovate to oblong leaflets. It is cultivated worldwide as a semiarid crop. Its seeds and leaves are common ingredients ...

seeds (''Trigonella foenum-graecum'', hence the name), garden peas, hemp seed, oats, potatoes, ''

Stachys ''Stachys'' is a genus of plants, one of the largest in the mint family Lamiaceae.Harley, R. M., et al. 2004. "Labiatae". pages 167–275. In: Kubitzki, K. (editor) and J. W. Kadereit (volume editor). ''The Families and Genera of Vascular Plants ...

'' species,

dahlia Dahlia (, ) is a genus of bushy, tuberous, herbaceous perennial plants native to Mexico and Central America. A member of the Asteraceae (former name: Compositae) family of dicotyledonous plants, its garden relatives thus include the sunflower, ...

, ''

Strophanthus ''Strophanthus'' is a genus of flowering plants in the family Apocynaceae, first described as a genus in 1802. It is native primarily to tropical Africa, extending to South Africa, with a few species in Asia from southern India to New Guinea and ...

'' species, and ''

Dichapetalum cymosum ''Dichapetalum cymosum'', commonly known as gifblaar from Afrikaans, or occasionally by its English translation, poison leaf, is a small prostrate shrub occurring in northern parts of Southern Africa in the family Dichapetalaceae. It is nota ...

''. Trigonelline is also found in

coffee Coffee is a drink prepared from roasted coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulant, stimulating effect on humans, primarily due to its caffeine content. It is the most popular hot drink in the world. S ...

. Higher levels of trigonelline is found in

arabica coffee ''Coffea arabica'' (), also known as the Arabic coffee, is a species of flowering plant in the coffee and madder family Rubiaceae. It is believed to be the first species of coffee to have been cultivated and is currently the dominant cultivar, r ...

. Holtz, Kutscher, and Theilmann have recorded its presence in a number of animals.

Chemistry

Trigonelline

crystallizes Crystallization is the process by which solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some ways by which crystals form are precipitating from a solution, freezing, or more rarely deposi ...

as a monohydrate from

alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...

in hygroscopic prisms (m.p. 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 Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to ...

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...

. The salts crystallize well, the monohydrochloride, in leaflets, sparingly soluble in dry alcohol. The

picrate A picrate is a salt containing the anion (O2N)3C6H2O− or an ester derivative of the picrate anion. These salts are often produced by reactions of picric acid (2,4,6-trinitrophenol). The picrate ion is intensely yellow, although many of its salt ...

forms shining prisms (m.p. 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 Gold chloride can refer to: * Gold(I) chloride (gold monochloride), AuCl * Gold(I,III) chloride (gold dichloride, tetragold octachloride), Au4Cl8 * Gold(III) chloride (gold trichloride, digold hexachloride), Au2Cl6 * Chloroauric acid Chloroauric ...

is added to the hydrochloride, and, after crystallization from dilute hydrochloric acid containing some gold chloride, has m.p. 198 °C. Crystallized from water or very dilute hydrochloric acid, slender needles of B₄•3 HAuCl₄ (m.p. 186 °C) are obtained. When trigonelline is heated in closed tubes with

barium hydroxide Barium hydroxide is a chemical compound with the chemical formula Ba(OH)2. The monohydrate (''x'' = 1), known as baryta or baryta-water, is one of the principal compounds of barium. This white granular monohydrate is the usual commercial form. P ...

at 120 °C, it gives rise to methylamine, and, if treated similarly with hydrochloric acid at 260 °C creates

chloromethane Chloromethane, also called methyl chloride, Refrigerant-40, R-40 or HCC 40, is an organic compound with the chemical formula . One of the haloalkanes, it is a colorless, odorless, flammable gas. Methyl chloride is a crucial reagent in industrial ...

and

nicotinic acid Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variet ...

(a form of vitamin B₃). Trigonelline is a methyl

betaine A betaine () in chemistry is any neutral chemical compound with a positively charged cationic functional group, such as a quaternary ammonium or phosphonium cation (generally: onium ions) that bears no hydrogen atom and with a negatively charged ...

of nicotinic acid.''The Plant Alkaloids''
/ref>

References

{{reflist Alkaloids Quaternary ammonium compounds Nicotinates Coffee chemistry Zwitterions