Phytol

Key takeaways

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

Reference excerpt

Phytol (florasol, phytosol) is an acyclic hydrogenated diterpene alcohol. It is naturally found in many plants as a result of chlorophyll degradation and is used by them to produce vitamin E and vitamin K1. It smells grassy and dominates the aroma of certain green teas. In human industry, phytol can be used to chemically synthesize vitamins E and K1. It is also used as a fragrance and flavoring in cosmetics, shampoos, toilet soaps, and detergents, as well as in some cannabis distillates as a diluent or for flavoring. Its worldwide use has been estimated to be approximately 0.1–1.0 metric tons per year.

Roles in nature

Plants Phytol is mainly produced by plants from chlorophyll degradation. In the biosynthesis of chlorophyll in the mouse-ear cress chloroplast, the chlorophyll synthase attaches a chlorophyllide ring to geranylgeranyl pyrophosphate (GGPP). Two steps of reduction then convert the GG tail into a phytyl tail. When this phytyl tail is hydrolyzed off, it becomes phytol. Older theories of chlorophyll synthesis instead holds that the chlorophyll synthase directly acts on a chlorophyllide and a phytyl pyrophosphate (phytyl-PP), with the phytyl-PP directly produced by reduction of GGPP. Although this can happen using isolated enzymes in vitro, there is little evidence for this happening in vivo. Phytol, or more precisely phytyl-PP, is used to build vitamin E (tocotrienol, tocopherol) and vitamin K1 (the reduced form, phylloquinol) in the chloroplast. The former protects the plant against oxidative stress and the latter acts as an essential part of the Photosystem I electron transport chain, without which photosynthesis cannot occur.

Invertebrates Insects, such as the sumac flea beetle, are reported to use phytol and its metabolites (e.g. phytanic acid) as chemical deterrents against predation. These compounds originate from host plants.

Vertebrates In shark liver it is converted to pristane.

Mammals In ruminants, the gut fermentation of ingested plant materials liberates phytol, a constituent of chlorophyll, which is then converted to phytanic acid and stored in fats. Indirect evidence has been provided that, in contrast to humans, diverse non-human primates can derive significant amounts of phytol from the hindgut fermentation of plant materials.

Modulator of transcription Phytol and/or its metabolites have been reported to bind to and/or activate the transcription factors PPAR-alpha and retinoid X receptor (RXR). The metabolites phytanic acid and pristanic acid are naturally occurring ligands. In mice, oral phytol induces massive proliferation of peroxisomes in several organs.

Possible biomedical applications Phytol has been investigated for its potential anxiolytic, metabolism-modulating, cytotoxic, antioxidant, autophagy- and apoptosis-inducing, antinociceptive, anti-inflammatory, immune-modulating, and antimicrobial effects.

Toxicology

Oral: refsum disease Free phytol is converted by humans into phytanic acid, a natural compound also found in ruminant meat. Phytanic acid is dangerous for people with the autosomal recessive disorder Refsum disease (also known as adult Refsum disease), in which genetic changes renders them unable to break down this fatty acid and frequently manifests as a variable combination of peripheral polyneuropathy, cerebellar ataxia, retinitis pigmentosa, anosmia, and hearing loss. As a result, those suffering from this illness should avoid both free phytol and phytanic acid. They do not need to avoid chlorophyll as the human digestive system cannot effectively cleave off the phytol sidechain of chlorophyll. A list of free phytol content in various convenience store foods is available.

Inhalation In 2021, phytol was found to cause pulmonary hemorrhage and necrosis of nose, throat and lung tissue when exposed in aerosol to Sprague Dawley rats, with no safe dose range being established. A majority of the phytol rats turned out dead or moribund, leading to 2nd-day termination of the 14-day study.

Vape controversy In 2020, Tokyo Smoke, a Canadian cannabis company owned by Canopy Growth at the time; pulled every phytol-containing product from their shelves and issued a 48 hour deadline to suppliers, demanding 'written confirmation' if it was included. A year later, David Heldreth, a former CSO of True Terpenes, a company that still listed it as a product; along with Andrew Freedman, investigated the matter, filing a request under the Access to Information Act to unredact the Health Canada study causing the product removals. In the same year, the Canadian government published an amendment to Canadian cannabis regulations regarding "flavours in cannabis extracts".

Geochemical biomarker Phytol has been described as "perhaps the most studied biomarker of those found in modern aquatic environments" in the context of biogeochemical tracers in aquatic environments. It is likely the most abundant acyclic isoprenoid compound present in the biosphere, being the ester sidechain of chlorophyll-a,b,c and bacteriochlorophyll-a (altogether produced by plants, algae, and many photosynthetic bacteria). It is degraded into a wide variety of products, including phytone, phytyldiol, dihydrophytol, pristane and many others, by biological and geological means. Some of these products such as pristane can be produced by other processes (such as oil spills) and are unusuable as a marker related to photosynthesis, while others such as dihydrophytol appear quite selective. An example of this use of phytol is in the estimation of carbon isotopic fractionation during photosynthesis by Rubisco using ancient sediments.

Worked examples

Example 1 — a first encounter with Phytol

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

In research: Phytol 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 Phytol 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: Phytol is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alkene derivatives, Diterpenes, Primary alcohols, so understanding it makes those chapters shorter.
In everyday life: Look for Phytol 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.

How to study Phytol in 20 minutes

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

Frequently asked questions

What is Phytol in simple terms?

Phytol (florasol, phytosol) is an acyclic hydrogenated diterpene alcohol. It is naturally found in many plants as a result of chlorophyll degradation and is used by them to produce vitamin E and vitamin K1.

Why does Phytol 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 Phytol?

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 Phytol.