2'-Fucosyllactose (2'-FL) - Human Milk Oligosaccharide

2'-Fucosyllactose (2'-FL) - Properties, Mechanisms, and Applications

1. Introduction

2'-Fucosyllactose (2'-FL, CAS 41263-94-9) is a fucosylated neutral trisaccharide and the most abundant human milk oligosaccharide (HMO), accounting for approximately 30% of all HMOs in human breast milk. It consists of lactose (glucose and galactose) with an L-fucose residue attached via an α-1,2-glycosidic bond. With a molecular formula of C₁₈H₃₂O₁₅ and a molecular weight of 488.44 g/mol, 2'-FL is a white crystalline powder that is highly soluble in water. Due to its well-established prebiotic, immunomodulatory, and antimicrobial properties, 2'-FL has become a key ingredient in infant formula and functional foods.

2. Chemical and Physical Properties

2'-FL is a non-reducing trisaccharide composed of three monosaccharide units: L-fucose, D-galactose, and D-glucose. The fucose residue is linked to galactose through an α-1,2-glycosidic bond. Key properties include:

• Molecular Formula: C₁₈H₃₂O₁₅

• Molecular Weight: 488.44 g/mol

• CAS Number: 41263-94-9

• Appearance: White to off-white crystalline powder

• Purity: ≥95% (HPAEC), with some grades ≥98%

• Melting Point: >203°C (decomposes)

• Solubility: Highly soluble in water and DMSO; soluble in aqueous buffers

• Density: 1.68 g/cm³

• Boiling Point: 902.2°C at 760 mmHg

• Storage: Store at 2–8°C, protected from moisture and light

3. Mechanism of Action

2'-FL exerts its biological effects through several distinct mechanisms:

Prebiotic Activity: 2'-FL is not digested in the upper gastrointestinal tract and reaches the colon intact, where it serves as a selective substrate for beneficial bacteria, particularly Bifidobacterium species. It promotes the growth of these health-promoting microbes while inhibiting pathogenic bacteria.

Antimicrobial Defense: 2'-FL acts as a soluble glycan that mimics cell surface receptors, preventing the adhesion of pathogens such as enteropathogenic E. coli, Campylobacter, and Salmonella to intestinal epithelial cells. This reduces the risk of gastrointestinal infections.

Immunomodulation: 2'-FL modulates immune responses by influencing cytokine production and the activity of immune cells. It has demonstrated anti-inflammatory properties through TLR4/p38 MAPK-dependent pathways.

Gut Barrier Function: By promoting the growth of beneficial bacteria and enhancing mucus production, 2'-FL strengthens the intestinal epithelial barrier, reducing translocation of harmful substances and pathogens.

4. Applications

Infant Formula: 2'-FL is widely used in infant formula to mimic the composition of breast milk. It supports the development of a healthy gut microbiome, improves digestion, and reduces the risk of infections, colic, and atopic dermatitis in infants. Maximum permitted levels in infant formula are up to 2.4 g/L.

Functional Foods and Supplements: Due to its prebiotic and immunomodulatory properties, 2'-FL is incorporated into functional beverages, dietary supplements, and foods for adults, supporting gut health, immune function, and healthy aging.

Clinical and Research Applications: 2'-FL is studied for its potential benefits in cognitive development, neuroprotection, metabolic health, and as a precision prebiotic targeting gut inflammation.

5. Safety and Regulatory Status

2'-FL is recognized as Generally Recognized as Safe (GRAS) by the U.S. FDA. It has also been approved as a novel food by the European Food Safety Authority (EFSA). It is permitted for use in infant formula and other food products in many countries, with maximum levels established for specific applications.

6. Storage and Handling

2'-FL should be stored in tightly sealed containers at 2–8°C, protected from light, moisture, and heat. Under recommended conditions, the product remains stable for extended periods.

7. Conclusion

2'-Fucosyllactose (CAS 41263-94-9) is the most abundant oligosaccharide in human breast milk, with well-established prebiotic, antimicrobial, and immunomodulatory properties. Its ability to promote beneficial gut bacteria, inhibit pathogen adhesion, and modulate immune responses makes it a key ingredient in infant formula and functional foods for all ages. With GRAS status and regulatory approval in multiple regions, 2'-FL continues to be a focus of research for its potential benefits in gut health, immune function, cognitive development, and overall well-being.