L-Rhamnose
[CAS# 10485-94-6]

Identification

• Classification: Biochemical >> Carbohydrate >> Monosaccharide
• Name: L-Rhamnose
• Synonyms: (3R,4R,5R,6S)-6-methyloxane-2,3,4,5-tetrol
• Molecular Formula: C₆H₁₂O₅
• Molecular Weight: 164.16
• CAS Registry Number: 10485-94-6
• EC Number: 895-480-9
• SMILES: C[C@H]1[C@@H]([C@H]([C@H](C(O1)O)O)O)O

Properties

• Density: 1.4±0.1 g/cm³ Calc.^*
• Melting point: 91 - 93 ºC (Expl.)
• Boiling point: 399.1±35.0 ºC 760 mmHg (Calc.)^*
• Flash point: 209.3±22.4 ºC (Calc.)^*
• Index of refraction: 1.531 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Discovory and Applicatios

L-Rhamnose is a naturally occurring monosaccharide, a type of sugar, that is classified as a deoxy sugar. It is a hexose sugar, meaning it contains six carbon atoms, and its structure is based on the sugar L-fucose. L-Rhamnose is found in the form of its various glycosidic derivatives in the cell walls of many plants and microorganisms, often acting as a structural component or as part of oligosaccharides and polysaccharides. It is commonly present in the form of rhamnogalacturonan, a type of pectin in plant cell walls, and is often found in the composition of glycoproteins and glycolipids.

The chemical structure of L-rhamnose consists of a six-carbon backbone, with a hydroxymethyl group at the 6-position, and it is typically found in its L-configuration, which is the enantiomer that occurs in nature. L-Rhamnose is a ketose sugar, with a methyl group (-CH3) attached to the carbon atom at the 6-position, distinguishing it from its parent sugar, L-fucose, which has a hydroxyl group at the same position.

L-Rhamnose was first isolated in 1883 from plant sources, and its presence has since been identified in a variety of natural products. It is found in many different plant species, including citrus fruits, and is commonly used in the study of plant biochemistry and microbiology.

The primary application of L-rhamnose is as a building block in the synthesis of oligosaccharides and polysaccharides. It has potential applications in the food industry, particularly in the form of functional oligosaccharides, which may have prebiotic effects. Due to its low digestibility in humans, L-rhamnose is often used to study the breakdown and fermentation processes of non-digestible carbohydrates in the gastrointestinal tract.

L-Rhamnose has also been explored in pharmaceutical applications. For example, it has been incorporated into the synthesis of prodrugs, where it can be used to target specific tissues or enhance the bioavailability of therapeutic compounds. Some research has indicated that L-rhamnose-containing structures can serve as bioactive agents, with potential antimicrobial, anti-inflammatory, and anticancer properties.

In addition to these applications, L-rhamnose plays a role in the immune response, particularly in the way that certain bacteria use rhamnose-containing polysaccharides to evade immune detection. As a result, L-rhamnose has been studied for its potential in modulating immune function, particularly with respect to bacterial infections.

L-Rhamnose is also significant in the field of microbiology. It is a key component of bacterial polysaccharides, including those of some pathogens like *Pseudomonas aeruginosa* and *Escherichia coli*, where it contributes to virulence factors, biofilm formation, and host-pathogen interactions. This has led to its consideration as a potential target for developing antibacterial agents or vaccines.

Overall, L-rhamnose is a versatile sugar with applications in multiple scientific fields, from plant biology and microbiology to pharmaceutical development and food science. Its presence in plant cell walls, role in microbial metabolism, and potential as a therapeutic agent make it a subject of ongoing research.

References

1979. Xylose, Arabinose, and Rhamnose Fermentation by Bacteroides ruminicola. Applied and Environmental Microbiology, 38(1).
DOI: 10.1128/aem.38.1.7-12.1979

2024. Regulatory potential of a xylated rhamnoglycan from Ulva reticulata on inflammatory cytokines. Journal of Applied Phycology, 36(5).
DOI: 10.1007/s10811-024-03352-5

1971. Isolation and Purification of a Peptido-Rhamnomannan from the Yeast Form of Sporothrix Schenckii. Structural and Immunochemical Studies. Journal of Immunology, 107(3).
DOI: 10.4049/jimmunol.107.3.663