Trigonelline

At Trigonelline it is a natural chemical substance found in coffee beans, among other things. Trigonelline is a raw material for the synthesis of nicotinic acid or vitamin B3 in the body. Nicotinic acid occurs in various coenzymes. A deficiency in vitamin B3 leads, among other things, to the skin disease pellagra, which can ultimately lead to dementia.

What is trigonelline?

Trigonelline is a substance that consists of an alkaloid of the trigonelline and an N-methyl derivative. The artificial synthesis of trigonelline is possible using nicotinic acid and iodomethane, which are first heated and then treated with silver (I) oxide.

In its pure form, Trigonelline is colorless. The molecular formula of the substance is C87H7NO2. Trigonelline is in a solid state and forms a hydrochloride. It dissolves in water as well as in warm ethanol and alcohol. Other names for trigonelline are:

• Caffearin or Coffearin,
• Gynesin,
• Betaine nicotinate,
• N-methyl nicotinate,
• 1-methylpyridine-1-lum-3-carboxylate and
• Nicotinic acid-N-methyl betaine.

Function, effect & tasks

Trigonelline forms, among other things, the starting material for vitamin B3 or nicotinic acid. Roasting coffee beans demythilizes the trigonelline in the beans and converts it to nicotinic acid. Nicotinic acid is involved in various metabolic processes in the human body and influences, among other things, the metabolism of protein, fat and carbohydrates.

Nicotinic acid is a component of the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). Biology describes biocatalysts as coenzymes which assist the actual enzymes in their work. NAD participates in both oxidative and reductive processes - depending on whether the coenzyme itself is in its reduced or oxidized form (NAD +). For example, it serves dehydrogenases as a biochemical assistant. Dehydrogenases are various specialized enzymes that, among other things, take part in the breakdown of alcohol in the liver. The dehydrogenases split off a negatively charged hydrogen atom from their substrate and pass it on to the NAD.

NADP is a coenzyme that also takes part in the redox reaction. It can exist in two different forms: NADP + is the oxidized form, NADPH is the reduced form. The coenzyme is part of the respiratory chain. In this process, NADH oxidizes to NADPH, creating ATP. NADPH also supports the synthesis and breakdown of fatty acids, the processing of glucose and the breakdown of amino acids.

Education, occurrence, properties & optimal values

Trigonelline occurs in many plants and is mainly found in the seeds. The substance serves as a base there. Coffee beans are rich in trigonelline: one bean contains about 0.3–1.3% of it. The fenugreek seeds contain 3% more trigonelline. The exact amount depends not only on how much trigonelline the plant itself produces, but also on how the coffee beans are roasted. On average, a cup of coffee (150 ml from 7.5 g of roasted coffee) contains 27 mg of trigonelline, with the Arabica variety forming a little more and the Robusta variety forming a little less trigonelline.

The heat of the roasting affects the molecular structure and can demethylize it, i.e. split off a methyl molecule. The product is nicotinic acid (niacin). The B vitamin consists of a pyridine ring and a carboxyl group. Humans need 15–20 mg of nicotinic acid per day. Foods that are high in nicotinic acid include poultry, game, fish, liver, dairy products, eggs, mushrooms, cashew nuts, whole grain products and brewer's yeast. An overdose is only reached with 1.5–3 g.

However, when roasting coffee beans, trigonelline can also decarboxylate: In this case, it is not methyl that separates from the molecule, but a carbon dioxide molecule. Enzymes can bring about this transformation even without heat.

Diseases & Disorders

Trigonelline is usually not the main source of nicotinic acid in the human body; however, it can be more important in the case of one-sided nutrition. A deficiency in nicotinic acid initially leads to irritability, sleep disorders, loss of appetite and difficulty concentrating. In the further course, dermatitis, diarrhea, inflammation of the mucous membranes of the mouth, stomach and intestines, and symptoms of depression can also occur.

A severe deficiency of nicotinic acid in the human body triggers pellagra. It is a skin disease that is found mainly in poorly developed regions of southern Europe and America. The clinical picture manifests itself in dermatitis, diarrhea and dementia. The dementia occurs in the form of an organic psychosyndrome, that is, it is of physiological origin, but expresses itself on a psychological level. Probably tryptophan plays a mediating role in this process. Pellagra is treated with nicotinic acid or nicotinamide.

In addition, the treatment of other deficiency symptoms may be necessary, since the hypovitaminosis often affects other vitamins and minerals.

An overdose of nicotinic acid is also possible. If a person ingests more than 1.5–3 g of nicotinic acid, they have hypervitaminosis. The consequences are dilation of the skin vessels (flushing) and cardiovascular symptoms. A severe overdose of more than 2.5 g per day can cause dizziness and / or a drop in blood pressure.

A drop in blood pressure or hypotension can be noticed as dizziness, headache, tremors, easy fatigue, difficulty concentrating, paleness, cold hands and feet, syncope and tachycardia. In the event of fainting spells, there is also an increased risk of injury. The nicotinic acid overdose is also manifested in the blood, which has elevated uric acid levels.