Reuterin
[CAS# 2134-29-4]

Identification

• Classification: API >> Antibiotics
• Name: Reuterin
• Synonyms: 3-Hydroxypropanal; 3-Hydroxypropionaldehyde; 3-Oxo-1-propanol; Hydracrolein
• Molecular Formula: C₃H₆O₂
• Molecular Weight: 74.08
• CAS Registry Number: 2134-29-4
• EC Number: 218-365-1
• SMILES: C(CO)C=O

Properties

• Density: 1.0±0.1 g/cm³ Calc.^*
• Boiling point: 168.2±23.0 ºC 760 mmHg (Calc.)^*, 90 �ºC (18 torr) (Expl.)
• Flash point: 61.8±15.2 ºC (Calc.)^*
• Solubility: Freely soluble (413 g/L) (25 �C), Calc.^*
• Index of refraction: 1.4 (Calc.)^*, 1.4979 (589.3 nm 20 �C) (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software V11.02 (©1994-2013 ACD/Labs)

^** Stepanov, A. V.; J. Russ. Phys.-Chem. Soc. 1926, V58, P840-8.

^*** Hall, R. H.; Chemistry & Industry (London, United Kingdom) 1955, P1772-3.

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302-H312-H332
• Precautionary Statements: P261-P264-P270-P271-P280-P301+P317-P302+P352-P304+P340-P317-P321-P330-P362+P364-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H332

Discovory and Applicatios

Reuterin is a low-molecular-weight antimicrobial compound produced by certain strains of *Lactobacillus reuteri* during the anaerobic fermentation of glycerol. Its principal component is 3-hydroxypropionaldehyde (3-HPA), a reactive aldehyde that exists in equilibrium with its hydrate and dimer forms in aqueous solution. Reuterin was first described in the 1980s during investigations into the probiotic mechanisms of *L. reuteri*, a species of lactic acid bacteria commonly found in the gastrointestinal tract of humans and animals.

The discovery of reuterin arose from studies seeking to understand how *L. reuteri* could suppress the growth of pathogenic microorganisms in the gut. Researchers observed that cultures of *L. reuteri* grown in the presence of glycerol produced a compound with broad-spectrum antimicrobial activity. The active substance was identified as 3-HPA, and the collective equilibrium mixture was named reuterin in honor of the producing organism.

Reuterin is generated through the enzymatic activity of glycerol/diol dehydratase, a coenzyme B₁₂-dependent enzyme that converts glycerol into 3-HPA. This production process is strictly dependent on the presence of glycerol and anaerobic conditions. The equilibrium mixture that constitutes reuterin includes monomeric 3-HPA, its hydrate (1,1,3-propane-triol), and cyclic dimeric forms. The dynamic interconversion among these forms influences the stability and bioactivity of the compound.

The antimicrobial spectrum of reuterin is broad and includes activity against Gram-positive and Gram-negative bacteria, yeasts, fungi, and protozoa. It functions primarily by disrupting cellular thiol groups and interfering with redox homeostasis in target organisms. The aldehyde moiety in 3-HPA is highly reactive and can form adducts with cellular components, leading to protein dysfunction and oxidative stress. These properties make reuterin effective at relatively low concentrations and under diverse environmental conditions.

Reuterin’s antimicrobial action does not appear to affect *L. reuteri* itself, as the producing strain exhibits intrinsic resistance. This selective activity is thought to contribute to the competitive advantage of *L. reuteri* in microbial ecosystems such as the gut. Studies have demonstrated that the presence of reuterin-producing *L. reuteri* strains in the gastrointestinal tract can inhibit the colonization and proliferation of pathogens including *Escherichia coli*, *Salmonella enterica*, and *Clostridium difficile*.

In addition to its natural role in microbial competition, reuterin has been investigated for various applied uses. In food preservation, reuterin has potential as a natural antimicrobial agent capable of extending shelf life and enhancing microbial safety in meat, dairy, and vegetable products. Its ability to inhibit spoilage organisms and foodborne pathogens without affecting the sensory qualities of food has made it an attractive subject for research into biopreservation.

In medical and pharmaceutical contexts, reuterin has been studied for its potential in controlling infections and modulating gut microbiota. Experimental applications have included the use of reuterin-producing *L. reuteri* strains as probiotics, as well as the direct use of reuterin preparations to prevent microbial overgrowth or treat localized infections. However, because reuterin contains a reactive aldehyde, its safety and stability must be carefully considered in therapeutic applications.

Further research into reuterin includes its role in microbiome dynamics, mechanisms of resistance, and potential synergistic effects with other antimicrobial agents. The biochemical pathway for its production and regulation in *L. reuteri* has also been a subject of genetic and enzymological studies, particularly with regard to optimizing yields and enhancing the robustness of production strains.

Overall, reuterin represents an example of a naturally occurring antimicrobial compound with ecological, biotechnological, and clinical significance. Its discovery has contributed to a deeper understanding of how commensal bacteria can exert probiotic effects through metabolite production and offers opportunities for the development of alternative antimicrobial strategies.

References

1984 Propanediol-1,2-dehydratase and metabolism of glycerol of Lactobacillus brevis. Archives of Microbiology, 138(3).
DOI: 10.1007/bf00408381

2024 Reuterin Enhances the Efficacy of Peracetic Acid Against Multi-species Dairy Biofilm. Probiotics and Antimicrobial Proteins.
DOI: 10.1007/s12602-024-10351-y

2025 Isolation of Limosilactobacillus reuteri Strain with Anti-porcine Epidemic Diarrhea Virus from Swine Feces. Probiotics and Antimicrobial Proteins, 17(1).
DOI: 10.1007/s12602-023-10138-7