What does dextran mean?
Dextran is a complex, branched polysaccharide — essentially a long chain of glucose molecules — produced naturally by certain lactic acid bacteria, particularly Leuconostoc species, as they ferment sucrose. First noticed in the nineteenth century as a slimy contaminant in sugar processing, it was later purified and put to work in human medicine: solutions of dextran are given intravenously as plasma expanders, restoring blood volume in patients with hemorrhage or shock, while specialized derivatives serve as anticoagulants and as carriers for drugs such as iron supplements. Beyond the clinic, dextrans are valuable in laboratories for chromatography, cell separation, and nanoparticle coatings. The word derives from Latin 'dexter' ('right'/'on the right'), reflecting its chemical kinship with dextrose, the rotating form of glucose. Dextran remains a technical term confined largely to medical and biochemical registers.
A high-molecular-weight, branched glucan polysaccharide synthesized by bacteria (chiefly Leuconostoc and Streptococcus species) from sucrose, consisting of α(1→6)-linked glucose chains with side branches; used industrially and, in refined form, clinically.
"Bacterial fermentation of sucrose yielded a viscous dextran suitable for pharmaceutical use."
When referring to the substance generically, dextran is usually treated as uncountable; plural forms appear mainly when discussing different molecular-weight grades.
A medicinal preparation of this polysaccharide, typically fractionated by molecular weight (such as dextran 40 or dextran 70) and administered intravenously as a colloid plasma-volume expander, or formulated with other agents (as in iron dextran injections).
"Iron dextran is commonly prescribed to treat severe iron-deficiency anemia when oral supplementation fails."
Rarely needed; the plural is used only when referring to multiple distinct types, grades, or molecular-weight fractions rather than the substance in general, which is normally uncountable.
"Clinical practice relies on several dextrans, each defined by its average molecular weight."
Dextran was discovered in spoiled sugarcane juice — a sticky 'slime' made by bacteria that ended up saving lives in operating rooms as a blood-volume replacer.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dextran
The word dextran combines 'dextro-' (from Latin 'dexter', meaning 'right' or 'right-hand', applied chemically because dextrose rotates polarized light to the right) with the '-an' suffix characteristic of polysaccharides such as glycogen and chitin. It was coined in the late nineteenth century following the identification of the glucose polymer responsible for the 'ropy' slime formed by bacteria in sugarcane juice and sugar-beet extracts. Its closest cognates are other chemistry words built on 'dexter': dextrose, dextrin, and dexterity.
Related word forms
How dextran is actually used
Strictly a technical term belonging to medicine, biochemistry, and food science; it is rarely encountered outside professional contexts. In clinical settings it is almost always qualified by molecular weight (e.g., dextran 40, dextran 70) because the properties differ substantially. It is uncountable when referring to the substance generally, countable when referring to specific grades or preparations.
Easily confused with dextran
Dextran is a bacterial glucose polymer used medically as a plasma expander, whereas dextrin is a starch-derived carbohydrate produced by heating or hydrolyzing starch.
Dextrose is simple glucose sugar itself, while dextran is a large branched polymer made of many glucose units.