Reuterin is a potent antimicrobial multi-compound produced by Lactobacillus reuteri

Lactobacillus reuteri

Lactobacillus reuteri is a Gram-positive bacterium that naturally inhabits the gut of mammals and birds. First described in the early 1980s, some strains of L. reuteri are used as probiotics. BioGaia AB in Sweden owns several commercially important strains and a large number of different patents...

, during the metabolism of glycerol

Glycerol

Glycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids...

 to 1,3-propanediol

1,3-Propanediol

1,3-Propanediol is the organic compound with the formula CH22. This three-carbon diol is a colorless viscous liquid that is miscible with water.-Products:...

 catalysed by the coenzyme B12-dependent diol dehydrase. Reuterin consists of 3-hydroxypropionaldehyde, its hydrate, and its dimer in dynamic equilibrium. At concentrations above 1.4M, the HPA dimer is predominant; at concentrations relevant for biological systems, however, HPA hydrate is the most abundant, followed by the aldehyde form.

Reuterin inhibits the growth of some harmful Gram-negative

Gram-negative

Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

 and Gram-positive

Gram-positive

Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...

 bacteria, along with yeast

Yeast

Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...

s, mold

Mold

Molds are fungi that grow in the form of multicellular filaments called hyphae. Molds are not considered to be microbes but microscopic fungi that grow as single cells called yeasts...

s, and protozoa

Protozoa

Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...

. 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 flora

Gut flora consists of microorganisms that live in the digestive tracts of animals and is the largest reservoir of human flora. In this context, gut is synonymous with intestinal, and flora with microbiota and microflora....

 intact.

Reuterin is water soluble, effective in a wide range of pH

PH

In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

, resistant to proteolytic and lipolytic enzymes, and has been studied as a food preservative or auxiliary therapeutic agent.