Alpha-cyclodextrin (α-CD)

Alpha-cyclodextrin is a cyclic oligosaccharide composed of six glucose units linked by alpha-1,4-glycosidic bonds, forming a torus-shaped structure with a hydrophobic internal cavity and a hydrophilic exterior. It is naturally produced from starch via enzymatic conversion by cyclodextrin glycosyltransferase and is widely utilized in the pharmaceutical, food, and cosmetic industries. In medicine, it primarily serves as a functional excipient to improve the aqueous solubility, stability, and bioavailability of hydrophobic drugs through the formation of non-covalent host-guest inclusion complexes. Beyond its role as a carrier, alpha-cyclodextrin acts as a soluble dietary fiber that can physically sequester dietary lipids and cholesterol in the gastrointestinal tract, thereby reducing their absorption and lowering serum lipid levels. It also demonstrates the ability to modulate glycemic response by interfering with carbohydrate digestion, potentially through the competitive inhibition of enzymes such as alpha-amylase. While generally recognized as safe (GRAS) for oral consumption, its systemic use is constrained by potential nephrotoxicity and hemolytic activity at high concentrations.

Other names

α-CyclodextrinAlfadexCyclomaltohexaoseSchardinger alpha-dextrinCyclohexaamylose

Alpha-cyclodextrin acts primarily through the formation of non-covalent host-guest inclusion complexes, where its hydrophobic internal cavity encapsulates lipophilic molecules to enhance their solubility and stability. In the gastrointestinal tract, it functions as a sequestering agent for dietary fats and cholesterol and may inhibit digestive enzymes such as alpha-amylase to modulate carbohydrate absorption.