text: Acarbose is a pseudotetrasaccharide mimicking maltotetraose (a substructure of starch). One of the glucose units has been replaced by valienamine - a carbasugar, linked to the next carbohydrate by an amine bridge. Another of the glucose units appears as a 6-deoxy variant. Acarbose is an enzyme inhibitor that is used as a drug against type 2 diabetes.