science

Noscapine

Noscapine is a science 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 Noscapine rather than just read about it. In short: Noscapine, also known as narcotine, nectodon, nospen, anarcotine and (archaic) opiane, is a benzylisoquinoline alkaloid of the phthalideisoquinoline structural subgroup, which has been isolated from numerous species of the Papaveraceae (poppy) family. It lacks effects associated with opioids such as sedation, euphoria, or analgesia (pain-relief) and lacks addictive potential.

Key takeaways

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

Reference excerpt

Noscapine, also known as narcotine, nectodon, nospen, anarcotine and (archaic) opiane, is a benzylisoquinoline alkaloid of the phthalideisoquinoline structural subgroup, which has been isolated from numerous species of the Papaveraceae (poppy) family. It lacks effects associated with opioids such as sedation, euphoria, or analgesia (pain-relief) and lacks addictive potential. Noscapine is primarily used for its antitussive (cough-suppressing) effects.

Medical uses Noscapine is often used as an antitussive medication. A 2012 Dutch guideline, however, does not recommend its use for acute coughing.

Side effects Nausea Vomiting Loss of coordination Hallucinations (auditory and visual) Loss of sexual drive Swelling of prostate Loss of appetite Dilated pupils Increased heart rate Shaking and muscle spasms Chest pain Increased alertness Increased wakefulness Loss of stereoscopic vision

Interactions Noscapine can increase the effects of centrally sedating substances such as alcohol and hypnotics. The drug should not be taken with monoamine oxidase inhibitors (MAOIs), as unknown and potentially fatal effects may occur. Noscapine should not be taken in conjunction with warfarin as the anticoagulant effects of warfarin may be increased.

Biosynthesis

The biosynthesis of noscapine in P. somniferum begins with chorismic acid, which is synthesized via the shikimate pathway from erythrose 4-phosphate and phosphoenolpyruvate. Chorismic acid is a precursor to the amino acid tyrosine, the source of nitrogen in benzylisoquinoline alkaloids. Tyrosine can undergo a PLP-mediated transamination to form 4-hydroxyphenylpyruvic acid (4-HPP), followed by a TPP-mediated decarboxylation to form 4-hydroxyphenylacetaldehyde (4-HPAA). Tyrosine can also be hydroxylated to form 3,4-dihydroxyphenylalanine (DOPA), followed by a PLP-mediated decarboxylation to form dopamine. Norcoclaurine synthase (NCS) catalyzes a Pictet-Spengler reaction between 4-HPAA and dopamine to synthesize (S)-norcoclaurine, providing the characteristic benzylisoquinoline scaffold. (S)-Norcoclaurine is sequentially 6-O-methylated (6OMT), N-methylated (CNMT), 3-hydroxylated (NMCH), and 4′-O-methylated (4′OMT), with the use of cofactors S-adenosyl-methionine (SAM) and NADP+ for methylations and hydroxylations, respectively. These reactions produce (S)-reticuline, a key branchpoint intermediate in the biosynthesis of benzylisoquinoline alkaloids. The remainder of the noscapine biosynthetic pathway is largely governed by a single biosynthetic 10-gene cluster. Genes comprising the cluster encode enzymes responsible for nine of the eleven remaining chemical transformations. First, berberine bridge enzyme (BBE), an enzyme not encoded by the cluster, forms the fused four-ring structure in (S)-scoulerine. BBE uses O2 as an oxidant and is aided by cofactor flavin adenine dinucleotide (FAD). Next, an O-methyltransferase (SOMT) methylates the 9-hydroxyl group. Canadine synthase (CAS) catalyzes the formation of a unique C2-C3 methylenedioxy bridge in (S)-canadine. An N-methylation (TNMT) and two hydroxylations (CYP82Y1, CYP82X2) follow, aided by SAM and O2/NADPH, respectively. The C13 alcohol is then acetylated by an acetyltransferase (AT1) using acetyl-CoA. Another cytochrome P450 enzyme (CYP82X1) catalyzes the hydroxylation of C8, and the newly formed hemiaminal spontaneously cleaves, yielding a tertiary amine and aldehyde. A methyltransferase heterodimer (OMT2:OMT3) catalyzes a SAM-mediated O-methylation on C4′. The O-acetyl group is then cleaved by a carboxylesterase (CXE1), yielding an alcohol which immediately reacts with the neighboring C1 aldehyde to form a hemiacetal in a new five-membered ring. The apparent counteractivity between AT1 and CXE1 suggests that acetylation in this context is employed as a protective group, preventing hemiacetal formation until the ester is enzymatically cleaved. Finally, an NAD+-dependent short-chain dehydrogenase (NOS) oxidizes the hemiacetal to a lactone, completing noscapine biosynthesis.

Mechanism of action Noscapine's antitussive effects appear to be primarily mediated by its σ–receptor agonist activity. Evidence for this mechanism is suggested by experimental evidence in rats. Pretreatment with rimcazole, a σ-specific antagonist, causes a dose-dependent reduction in antitussive activity of noscapine. Noscapine, and its synthetic derivatives called noscapinoids, are known to interact with microtubules and inhibit cancer cell proliferation

Structure analysis The lactone ring is unstable and opens in basic media. The opposite reaction is presented in acidic media. The bond (C1−C3′) connecting the two optically active carbon atoms is also unstable. In aqueous solution of sulfuric acid and heating it dissociates into cotarnine (4-methoxy-6-methyl-5,6,7,8-tetrahydro-[1,3]dioxolo[4,5-g]isoquinoline) and opic acid (6-formyl-2,3-dimethoxybenzoic acid). When noscapine is reduced with zinc/HCl, the bond C1−C3′ saturates and the molecule dissociates into hydrocotarnine (2-hydroxycotarnine) and meconine (6,7-dimethoxyisobenzofuran-1(3H)-one).

History Noscapine was first isolated and characterized in chemical breakdown and properties in 1803 under the denomination of "Narcotine" by Jean-François Derosne, a French chemist in Paris. In 1817, Pierre-Jean Robiquet, another French chemist, reinvestigated the substance and named it "Narcotine". He proved narcotine and morphine to be distinct alkaloids in 1831. Finally, Pierre-Jean Robiquet conducted over 20 years between 1815 and 1835 a series of studies in the enhancement of methods for the isolation of morphine, and also isolated in 1832 another very important component of raw opium, that he called codeine, currently a widely used opium-derived compound.

Society and culture

Recreational use There are anecdotal reports of the recreational use of over-the-counter drugs in several countries, being readily available from local pharmacies without a prescription. The effects, beginning around 45 to 120 minutes after consumption, are similar to dextromethorphan and alcohol intoxication. Unlike dextromethorphan, noscapine is not an NMDA receptor antagonist.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Noscapine

Start with the simplest possible case. Write down what Noscapine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Noscapine 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 Noscapine 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 Noscapine

In research: Noscapine appears in science 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 Noscapine 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: Noscapine is common in secondary-school and first-year university syllabi. It links to neighbouring topics 3-(5,6,7,8-tetrahydro-(1,3)dioxolo(4,5-g)isoquinolin-5-yl)-3H-2-benzofuran-1-ones, Antitussives, Methylenedioxyphenethylamines, so understanding it makes those chapters shorter.
In everyday life: Look for Noscapine 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Noscapine in 20 minutes

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

Frequently asked questions

What is Noscapine in simple terms?

Why does Noscapine matter?

Because it connects several science 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 Noscapine?

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 Noscapine.