Polyprenols are natural long-chain

isoprenoid The terpenoids, also known as isoprenoids, are a class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeably with "terpene ...

alcohols In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl () functional group bound to a saturated carbon atom. The term ''alcohol'' originally referred to the primary alcohol ethanol (ethyl alcohol), which is ...

of the general formula H-(C₅H₈)n-OH where n is the number of

isoprene Isoprene, or 2-methyl-1,3-butadiene, is a common volatile organic compound with the formula CH2=C(CH3)−CH=CH2. In its pure form it is a colorless volatile liquid. Isoprene is an unsaturated hydrocarbon. It is produced by many plants and animals ...

units. Any

prenol Prenol, or 3-methyl-2-buten-1-ol, is a natural alcohol. It is one of the most simple terpenoids. It is a clear colorless oil that is reasonably soluble in water and miscible with most common organic solvents. It has a fruity odor and is used oc ...

with more than 4

units is a polyprenol. Polyprenols play an important function acting as natural bioregulators and are found in small quantities in various plant tissues.

Dolichol Dolichol refers to any of a group of long-chain mostly unsaturated organic compounds that are made up of varying numbers of isoprene units terminating in an α-saturated isoprenoid group, containing an alcohol functional group. Functions Dolicho ...

s, which are found in all living creatures, including humans, are their 2,3-dihydro derivatives.

Sources

Live trees are known to contain polyprenols. The needles of

conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ext ...

trees are one of the richest sources of polyprenols. They are also present in

shiitake mushrooms The shiitake (alternate form shitake) (; ''Lentinula edodes'') is an edible mushroom native to East Asia, which is now cultivated and consumed around the globe. It is considered a medicinal mushroom in some forms of traditional medicine. Ta ...

in trace amounts.

Research

Polyprenols have been studied for more than 30 years. Interest has been strongest in Russia, Europe, Japan, India, and the United States. In the early 1930s, a scientific team at the Forest Technical Academy in St Petersburg, Russia led by Fyodor Solodky, the founder of Forest Biochemistry, and Asney Agranet, began research into the composition of

tree needles. They were intrigued by the trees' ability to remain disease free in extremes of temperature ± 40 °C. Development of Solodky's research led Russian scientists to isolate a completely different class of organic substance from the needles, including polyprenols.

Functions

Polyprenols are low molecular natural bioregulators (physiologically active), playing a significant modulating role in the cellular process in plants referred to as

biosynthesis Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecul ...

. What polyprenols are to plants,

dolichol Dolichol refers to any of a group of long-chain mostly unsaturated organic compounds that are made up of varying numbers of isoprene units terminating in an α-saturated isoprenoid group, containing an alcohol functional group. Functions Dolicho ...

s are to all living creatures, including man. They are in fact of a very similar chemical composition. Dolichols are a derivative of polyprenols with a saturated

unit. Through dolichols, the dolichol phosphate cycle occurs. The dolichol phosphate cycle plays a major role in the

synthesis Synthesis or synthesize may refer to: Science Chemistry and biochemistry * Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors **Organic synthesis, the chemical synthesis of organ ...

glycoproteins Glycoproteins are proteins which contain oligosaccharide chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosy ...

. All proteins from

secretions 440px Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classical ...

membranes A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Bi ...

and intracellular glycoproteins form the basis for the building of membrane receptors which are used in the production of

insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabolism ...

adrenaline Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands an ...

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...

testosterone Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristi ...

and other

hormones A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...

and

enzymes Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. ...

. Seemingly, dolichols have an important role in maintenance of the correct

lipid Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids in ...

composition of

. Decreased levels of dolichols are registered with acute

rheumatism Rheumatism or rheumatic disorders are conditions causing chronic, often intermittent pain affecting the joints or connective tissue. Rheumatism does not designate any specific disorder, but covers at least 200 different conditions, including ar ...

and other immunodeficient conditions. The dolichol phosphate cycle facilitates the process of cellular membrane

glycosylation Glycosylation is the reaction in which a carbohydrate (or ' glycan'), i.e. a glycosyl donor, is attached to a hydroxyl or other functional group of another molecule (a glycosyl acceptor) in order to form a glycoconjugate. In biology (but not al ...

, that is, the synthesis of glycoproteins that control the interactions of cells, support the immune system and the stabilization of protein molecules. Out of all these glycoproteins, polyglycoprotein has the capacity to kill cancerous cells during

chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemother ...

whilst protecting healthy cells within the body. The pharmacological activity of polyprenols takes place in the liver where they are metabolized into dolichols.

Potential medical applications

The interest in polyprenols and dolichols is associated with their wide range of demonstrated biological activity and extremely low

toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

. Polyprenols stimulate the

immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...

(which raises serious concerns on their safety; however, evidence for their immunostimulatory activity is extremely weak), cellular reparation and

spermatogenesis Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubu ...

, and have antistress, adaptogenic, antiulcerogenic and wound-healing activity. Dolichols have

antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubrica ...

activity and protect

cell membranes The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (t ...

from

peroxidation Lipid peroxidation is the chain of reactions of oxidative degradation of lipids. It is the process in which free radicals "steal" electrons from the lipids in cell membranes, resulting in cell damage. This process proceeds by a free radical cha ...

. Experiments on mice have demonstrated that polyprenols have

antiviral Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Unlike most antibiotics, antiviral drugs do n ...

activity, in particular against

influenza Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptom ...

viruses. It has been established that the dolichol level in liver tumor cells are reduced in comparison with healthy hepatic cells.

References

{{reflist Fatty alcohols Alkene derivatives Polymers Terpenes and terpenoids