chemistry

Trigonelline

Trigonelline is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Trigonelline rather than just read about it. In short: Trigonelline is an alkaloid with chemical formula C7H7NO2. It is a zwitterion formed by the methylation of the nitrogen atom of niacin (vitamin B3).

Key takeaways

Trigonelline belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Trigonelline to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Trigonelline from memory before moving on to harder problems.

Reference excerpt

Trigonelline is an alkaloid with chemical formula C7H7NO2. It is a zwitterion formed by the methylation of the nitrogen atom of niacin (vitamin B3). Trigonelline is a product of niacin metabolism that is excreted in the urine of mammals. Trigonelline occurs in many plants. It has been isolated from the Japanese radish (Raphanus sativus cv. Sakurajima Daikon), fenugreek seeds (Trigonella foenum-graecum, hence the name), garden peas, hemp seed, oats, potatoes, Stachys species, dahlia, Strophanthus species, and Dichapetalum cymosum. Trigonelline is also found in coffee. Higher levels of trigonelline are found in arabica coffee. Holtz, Kutscher, and Theilmann have recorded its presence in a number of animals.

Chemistry Trigonelline crystallizes as a monohydrate from alcohol 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 or ether. The salts crystallize well, the monohydrochloride, in leaflets, sparingly soluble in dry alcohol. The picrate 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 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 at 120 °C, it gives rise to methylamine, and, if treated similarly with hydrochloric acid at 260 °C creates chloromethane and nicotinic acid (a form of vitamin B3). Trigonelline is a methyl betaine of nicotinic acid.

Biosynthesis Nicotinate N-methyltransferase is the enzyme which converts nicotinic acid to trigonelline. The methyl group comes from the cofactor, S-adenosyl methionine (SAM), which becomes S-adenosyl-L-homocysteine (SAH).

References

Illustrations

Worked examples

Example 1 — a first encounter with Trigonelline

Start with the simplest possible case. Write down what Trigonelline claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Trigonelline before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Trigonelline ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Trigonelline

In research: Trigonelline appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Trigonelline in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Trigonelline is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alkaloids, Coffee chemistry, Nicotinates, so understanding it makes those chapters shorter.
In everyday life: Look for Trigonelline outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Trigonelline in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Trigonelline means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Trigonelline out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Trigonelline in simple terms?

Trigonelline is an alkaloid with chemical formula C7H7NO2. It is a zwitterion formed by the methylation of the nitrogen atom of niacin (vitamin B3).

Why does Trigonelline matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Trigonelline?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Trigonelline.