biology

Tropoflavin

Tropoflavin is a biology 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 Tropoflavin rather than just read about it. In short: Tropoflavin, also known as 7,8-dihydroxyflavone (7,8-DHF), is a naturally occurring flavone found in Godmania aesculifolia, Tridax procumbens, and Primula vulgaris. It has been found to act as a potent and selective small-molecule agonist of the tropomyosin receptor kinase B (TrkB) (Kd ≈ 320 nM), the main signaling receptor of the neurotrophin brain-derived neurotrophic factor (BDNF).

Key takeaways

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

Reference excerpt

Tropoflavin, also known as 7,8-dihydroxyflavone (7,8-DHF), is a naturally occurring flavone found in Godmania aesculifolia, Tridax procumbens, and Primula vulgaris. It has been found to act as a potent and selective small-molecule agonist of the tropomyosin receptor kinase B (TrkB) (Kd ≈ 320 nM), the main signaling receptor of the neurotrophin brain-derived neurotrophic factor (BDNF). Tropoflavin is both orally bioavailable and able to penetrate the blood–brain barrier. A prodrug of tropoflavin with greatly improved potency and pharmacokinetics, R13 (and, formerly, R7), is under development for the treatment of Alzheimer's disease. Tropoflavin has demonstrated therapeutic efficacy in animal models of a variety of central nervous system disorders, including depression, Alzheimer's disease, cognitive deficits in schizophrenia, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, traumatic brain injury, cerebral ischemia, fragile X syndrome, and Rett syndrome. Tropoflavin also shows efficacy in animal models of age-associated cognitive impairment and enhances memory consolidation and emotional learning in healthy rodents. In addition, tropoflavin possesses powerful antioxidant activity independent of its actions on the TrkB receptor, and protects against glutamate-induced excitotoxicity, 6-hydroxydopamine-induced dopaminergic neurotoxicity, and oxidative stress-induced genotoxicity. It was also found to block methamphetamine-induced dopaminergic neurotoxicity, an effect which, in contrast to the preceding, was found to be TrkB-dependent. In 2017, evidence was published suggesting that tropoflavin and various other reported small-molecule TrkB agonists might not actually be direct agonists of the TrkB and might be mediating their observed effects by other means. Tropoflavin has been found to act as a weak aromatase inhibitor in vitro (Ki = 10 μM), though there is evidence to suggest that this might not be the case in vivo. In addition, it has been found to inhibit aldehyde dehydrogenase and estrogen sulfotransferase in vitro (Ki = 35 μM and 1–3 μM, respectively), although similarly to the case of aromatase, these activities have not yet been confirmed in vivo. Unlike many other flavonoids, tropoflavin does not show any inhibitory activity on 17β-hydroxysteroid dehydrogenase. Tropoflavin has also been observed to possess in vitro antiestrogenic effects at very high concentrations (Ki = 50 μM). A variety of close structural analogues of tropoflavin have also been found to act as TrkB agonists in vitro, including diosmetin (5,7,3'-trihydroxy-4'-methoxyflavone), norwogonin (5,7,8-trihydroxyflavone), eutropoflavin (4'-dimethylamino-7,8-dihydroxyflavone), 7,8,3'-trihydroxyflavone, 7,3'-dihydroxyflavone, 7,8,2'-trihydroxyflavone, 3,7,8,2'-tetrahydroxyflavone, and 3,7-dihydroxyflavone. The highly hydroxylated analogue gossypetin (3,5,7,8,3',4'-hexahydroxyflavone), conversely, appears to be an antagonist of TrkB in vitro. Tropoflavin was also found to decrease mouse sleep in dark phase and reduce hypothalamus level of orexin A, but not orexin B, in mice.

See also List of investigational antidepressants Tropomyosin receptor kinase B § Agonists BrAD-R13 (Braegen-01) and Braegen-02

References

Illustrations

Worked examples

Example 1 — a first encounter with Tropoflavin

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

In research: Tropoflavin appears in biology 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 Tropoflavin 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: Tropoflavin is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antidepressants, Antioxidants, Aromatase inhibitors, so understanding it makes those chapters shorter.
In everyday life: Look for Tropoflavin 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 Tropoflavin in 20 minutes

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

Frequently asked questions

What is Tropoflavin in simple terms?

Why does Tropoflavin matter?

Because it connects several biology 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 Tropoflavin?

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 Tropoflavin.