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α-Cyclodextrin (''alpha''-cyclodextrin), sometimes abbreviated as α-CD, is a hexa
saccharide
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or may ...
derived from glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...
. It is related to the β- (beta) and γ- (gamma) cyclodextrin
Cyclodextrins are a family of cyclic oligosaccharides, consisting of a macrocyclic ring of glucose subunits joined by α-1,4 glycosidic bonds. Cyclodextrins are produced from starch by enzymatic conversion. They are used in food, pharmaceutical, ...
s, which contain seven and eight glucose units, respectively. All cyclodextrins are white, water-soluble solids with minimal toxicity. Cyclodextrins tend to bind other molecules in their quasi-cylindrical interiors. This inclusion (and release) behavior leads to applications in medicine. The compound is of wide interest because it exhibits host–guest properties, forming inclusion compound
In host–guest chemistry, an inclusion compound (also known as an inclusion complex) is a chemical complex in which one chemical compound (the "host") has a cavity into which a "guest" compound can be accommodated. The interaction between the ho ...
s.
Structure
In α-cyclodextrin, the six glucose subunits are linked end to end via α-1, 4 linkages. The result has the shape of a tapered cylinder, with six primary alcohols on one face and twelve secondary alcohol groups on the other. The exterior surface of cyclodextrins is somewhat hydrophilic whereas the interior core is hydrophobic.
Applications
α-Cyclodextrin is marketed for a range of medical, healthcare, and food and beverage applications. For drug delivery, this cyclodextrin confers aqueous solubility to hydrophobic drugs and stability to labile drugs.Synthesis
Cyclodextrins are natural starch-conversion products. For industrial use, they are manufactured by enzymatic degradation from vegetable raw materials, such as corn or potatoes. First, the starch is liquified either by heat treatment or using α-amylase. Thencyclodextrin glycosyltransferase
In enzymology, a cyclomaltodextrin glucanotransferase (also cyclodextrin glycosyl transferase or CGTase for short) () is an enzyme that catalyzes the chemical reaction of cyclizing part of a 1,4-alpha-D-glucan molecule through the formation of a ...
(CGTase) is added for enzymatic conversion. CGTases produce diverse cyclodextrins. The selectivity of the synthesis can be improved by the addition of specific guests.
See also
*β-Cyclodextrin
β-Cyclodextrin sometimes abbreviated as β-CD, is a heptasaccharide derived from glucose. The α- (alpha), β- (beta), and γ- (gamma) cyclodextrins correspond to six, seven, and eight glucose units, respectively. β-Cyclodextrin is the most used ...
References
{{DEFAULTSORT:Cyclodextrin, alpha- Oligosaccharides Macrocycles