Rhamnose is a naturally occurring deoxy sugar

Deoxy sugar

Deoxy sugars are sugars that have had a hydroxyl group replaced with a hydrogen atom.Examples include:* Deoxyribose * Fucose* Rhamnose-External links:*...

. It can be classified as either a methyl-pentose

Pentose

A pentose is a monosaccharide with five carbon atoms. Pentoses are organized into two groups. Aldopentoses have an aldehyde functional group at position 1...

 or a 6-deoxy-hexose

Hexose

In organic chemistry, a hexose is a monosaccharide with six carbon atoms, having the chemical formula C6H12O6. Hexoses are classified by functional group, with aldohexoses having an aldehyde at position 1, and ketohexoses having a ketone at position 2....

. Rhamnose occurs in nature in its L-form as L-rhamnose (6-deoxy-L-mannose

Mannose

Mannose is a sugar monomer of the aldohexose series of carbohydrates. Mannose is a C-2 epimer of glucose. It is not part of human metabolism, but is a component of microbial cell walls, and is therefore a target of the immune system and also of antibiotics....

). This is unusual, since most of the naturally occurring sugars are in D-form. Exceptions are the methyl pentoses L-fucose

Fucose

Fucose is a hexose deoxy sugar with the chemical formula C6H12O5. It is found on N-linked glycans on the mammalian, insect and plant cell surface, and is the fundamental sub-unit of the fucoidan polysaccharide...

 and L-rhamnose and the pentose L-arabinose

Arabinose

Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde functional group.For biosynthetic reasons, most saccharides are almost always more abundant in nature as the "D"-form, or structurally analogous to D-glyceraldehyde.For sugars, the D/L...

.

Rhamnose can be isolated from Buckthorn

Buckthorn

The Buckthorns are a genus of about 100 species of shrubs or small trees from 1-10 m tall , in the buckthorn family Rhamnaceae...

 (Rhamnus), poison sumac

Poison Sumac

Poison sumac is a woody shrub or small tree growing to 7 m tall. All parts of the plant contain a resin called urushiol that causes skin and mucous membrane irritation to humans...

, and plants in the genus Uncaria

Uncaria

Uncaria is a genus of flowering plants in the family Rubiaceae. It has about 40 species. Their distribution is pantropical, with most species native to tropical Asia, three from Africa and the Mediterranean and two from the neotropics. They are known colloquially as Gambier, Cat's Claw or Uña de...

. High-rhamnose extracts from the latter have found use in anti-wrinkle creams.

Rhamnose is commonly bound to other sugars in nature. It is a common glycone component of glycosides

Glycoside

In chemistry, a glycoside is a molecule in which a sugar is bound to a non-carbohydrate moiety, usually a small organic molecule. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme...

 from many plants. Rhamnose is also a component of the outer cell membrane of acid-fast bacteria in the Mycobacterium

Mycobacterium

Mycobacterium is a genus of Actinobacteria, given its own family, the Mycobacteriaceae. The genus includes pathogens known to cause serious diseases in mammals, including tuberculosis and leprosy...

 genus, which includes the organism that causes tuberculosis

Tuberculosis

Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...

.

External links

• Use of L-rhamnose to Study Irreversible Adsorption of Bacteriophage PL-1 to a Strain of Lactobacillus casei Journal of General Virology