Reuterin (3-hydroxypropionaldehyde) is the

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

with the formula HOCH₂CH₂CHO. It is a bifunctional molecule, containing both a hydroxy and aldehyde

functional group In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

s. The name reuterin is derived from ''

Lactobacillus reuteri ''Limosilactobacillus reuteri'' is a lactic acid bacterium found in a variety of natural environments, including the gastrointestinal tract of humans and other animals. It does not appear to be pathogenic and may have health effects. Discove ...

'', which produces the compound biosynthetically from glycerol as a broad-spectrum antibiotic (

bacteriocin Bacteriocins are proteinaceous or peptide, peptidic toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strain(s). They are similar to yeast and paramecium killing factors, and are structurally, functionally ...

). ''L. reuteri'' itself is named after the microbiologist Gerhard Reuter, who did early work in distinguishing it as a distinct species.

Solution structure

In aqueous solution 3-hydroxypropionaldehyde exists in equilibrium with its hydrate (1,1,3-propanetriol), in which the aldehyde group converts to a

geminal diol A geminal diol (or gem-diol for short) is any organic compound having two hydroxyl functional groups () bound to the same carbon atom. Geminal diols are a subclass of the diols, which in turn are a special class of alcohols. Most of the geminal ...

: :HOCH₂CH₂CHO + H₂O → HOCH₂CH₂CH(OH)₂ The hydrate is also in equilibrium with its

dimer Dimer may refer to: * Dimer (chemistry), a chemical structure formed from two similar sub-units ** Protein dimer, a protein quaternary structure ** d-dimer ** TH-dimer * Dimer model, an item in statistical mechanics, based on ''domino tiling'' * ...

(2-(2-hydroxyethyl)-4-hydroxy-1,3-dioxane), which dominates at high concentrations. These three components - the aldehyde, its dimer, and the hydrate are therefore in a dynamic equilibrium. Besides, 3-hydroxypropionaldehyde suffers a spontaneous dehydration in aqueous solution, and the resulting molecule is called

acrolein Acrolein (systematic name: propenal) is the simplest unsaturated aldehyde. It is a colorless liquid with a foul and acrid aroma. The smell of burnt fat (as when cooking oil is heated to its smoke point) is caused by glycerol in the burning fat ...

. In fact, the term reuterin is the name given to the dynamic system formed by 3-hydroxypropionaldehyde, its hydrate, the dimer, and acrolein. This last molecule, acrolein, was recently included in reuterin definition. HOCH2CH2CHOdimerimproved

Synthesis and reactions

3-Hydroxypropionaldehyde is formed by the condensation of

acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic compound, organic chemical compound with the chemical formula, formula , sometimes abbreviated as . It is a colorless liquid or gas, boiling near room temperature. It is one of the most ...

and

formaldehyde Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as ...

. This reaction, when conducted in the gas-phase, was the basis for a now obsolete industrial route

: :CH₃CHO + CH₂O → HOCH₂CH₂CHO :HOCH₂CH₂CHO → CH₂=CHCHO + H₂O Presently 3-hydroxypropionaldehyde is an intermediate in the production of

pentaerythritol Pentaerythritol is an organic compound with the formula C(CH2OH)4. The molecular structure can be described as a neopentane with one hydrogen atom in each methyl group replaced by a hydroxyl (–OH) group. It is therefore a polyol, specifically a ...

. Hydrogenation of reuterin gives 1,3-propanediol.

Biological activity

Reuterin is an intermediate in the metabolism of

glycerol Glycerol () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pha ...

to 1,3-propanediol catalysed by the coenzyme B12-dependent glycerol dehydratase. Reuterin is a potent

antimicrobial An antimicrobial is an agent that kills microorganisms (microbicide) or stops their growth (bacteriostatic agent). Antimicrobial medicines can be grouped according to the microorganisms they are used to treat. For example, antibiotics are used aga ...

compound produced by ''

''. It inhibits the growth of some harmful

Gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

and

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain is ...

bacteria, along with

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom (biology), kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are est ...

mold A mold () or mould () is one of the structures that certain fungus, fungi can form. The dust-like, colored appearance of molds is due to the formation of Spore#Fungi, spores containing Secondary metabolite#Fungal secondary metabolites, fungal ...

s, and

protozoa Protozoa (: protozoan or protozoon; alternative plural: protozoans) are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically ...

. ''L. reuteri'' can secrete sufficient amounts of reuterin to inhibit the growth of harmful gut organisms, without killing beneficial gut bacteria, allowing ''L. reuteri'' to remove gut invaders while keeping normal

gut flora Gut microbiota, gut microbiome, or gut flora are the microorganisms, including bacteria, archaea, fungi, and viruses, that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the g ...

intact. Reuterin is water-soluble, effective in a wide range of pH, resistant to proteolytic and lipolytic enzymes, and has been studied as a

food preservative A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by ...

or auxiliary therapeutic agent. Reuterin as an extracted compound has been shown capable of killing ''Escherichia coli'' O157:H7 and ''

Listeria monocytogenes ''Listeria monocytogenes'' is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the ho ...

'', with the addition of

lactic acid Lactic acid is an organic acid. It has the molecular formula C3H6O3. It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as wel ...

increasing its

efficacy Efficacy is the ability to perform a task to a satisfactory or expected degree. The word comes from the same roots as '' effectiveness'', and it has often been used synonymously, although in pharmacology a distinction is now often made betwee ...

. It has also been demonstrated to kill ''Escherichia coli'' O157:H7 when produced by ''L. reuteri''.

References

{{reflist, 2 Antibiotics Biochemistry Bacteriology Primary alcohols