chemistry

Piperine

Piperine 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 Piperine rather than just read about it. In short: Piperine is an alkaloid extracted from the plant, Piper nigrum. Responsible for the pungency of black pepper, it is used in food flavorings as a spice, in fragrances, as an insecticide, and as an animal pest repellent.

Key takeaways

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

Reference excerpt

Piperine is an alkaloid extracted from the plant, Piper nigrum. Responsible for the pungency of black pepper, it is used in food flavorings as a spice, in fragrances, as an insecticide, and as an animal pest repellent. Along with its isomer chavicine, piperine from black pepper and long pepper has pungency effects via activation of TRPV1. Piperine also inhibits CYP2J2. It has been used in some forms of traditional medicine. It can be acutely toxic if swallowed in high doses.

Preparation

Extraction Due to its poor solubility in water, piperine is typically extracted from black pepper by using organic solvents like dichloromethane or ethanol. The amount of piperine varies from 1–2% in long pepper, to 5–10% in commercial white and black peppers. Piperine can also be prepared by treating the solvent-free residue from a concentrated alcoholic extract of black pepper with a solution of potassium hydroxide to remove resin (said to contain chavicine, an isomer of piperine). The solution is decanted from the insoluble residue and left to stand overnight in alcohol. During this period, the alkaloid slowly crystallizes from the solution.

Chemical synthesis Piperine has been synthesized by the reaction of piperonoyl chloride with piperidine.

Biosynthesis The biosynthesis of piperine is only partially known.

The last step is catalyzed by piperine synthase (piperoyl-CoA:piperidine piperoyl transferase). As suggested by its systematic name, it converts piperoyl-CoA and piperidine into piperine. Piperoyl-CoA is made by piperoyl-CoA ligase from piperic acid, which is in turn made from feruperic acid by CYP719A37. Feruperic acid is presumably made from ferulic acid. Piperine is presumably made from lysine. In addition to piperine synthase PipBAHD2, there is an orthologous enzyme with broader substract specificity in Piper nigrum with gene symbol PipBAHD1, called a "piperamide synthase". This other enzyme is responsible for the many piperamide compounds (see ) besides piperine found in black pepper. Both enzymes are BAHD acyltransferases.

Reactions Piperine forms salts only with strong acids. The platinichloride B4·H2PtCl6 forms orange-red needles ("B" denotes one mole of the alkaloid base in this and the following formula). Iodine in potassium iodide added to an alcoholic solution of the base in the presence of a little hydrochloric acid gives a characteristic periodide, B2·HI·I2, crystallizing in steel-blue needles with melting point 145 °C. Piperine can be hydrolyzed by an alkali into piperidine and piperic acid. In light, especially ultraviolet light, piperine is changed into its isomers chavicine, isochavicine and isopiperine, which are tasteless.

History Piperine was discovered in 1819 by Hans Christian Ørsted, who isolated it from the fruits of Piper nigrum, the source plant of both black and white pepper. Piperine was also found in Piper longum and Piper officinarum (Miq.) C. DC. (=Piper retrofractum Vahl), two species called "long pepper".

Uses Piperine gives black pepper its pungency properties, making it favorable in food flavorings as a spice and in fragrances. It can be used as an insecticide and to deter animal pests.

See also Piperidine – a cyclic six-membered amine that results from hydrolysis of piperine Piperic acid – the carboxylic acid also derived from hydrolysis of piperine Capsaicin – the active piquant chemical in chili peppers Allyl isothiocyanate – the active piquant chemical in mustard, radishes, horseradish, and wasabi Allicin – the active piquant flavor chemical in raw garlic and onions (see those articles for discussion of other chemicals in them relating to pungency, and eye irritation) Ilepcimide Piperlongumine

References

Illustrations

Worked examples

Example 1 — a first encounter with Piperine

Start with the simplest possible case. Write down what Piperine 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 Piperine 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 Piperine 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 Piperine

In research: Piperine 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 Piperine 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: Piperine is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1-Piperidinyl compounds, Benzodioxoles, CYP1A2 inhibitors, so understanding it makes those chapters shorter.
In everyday life: Look for Piperine 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 Piperine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Piperine 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 Piperine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Piperine in simple terms?

Why does Piperine 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 Piperine?

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 Piperine.