Dextran: An OverviewIntroductionDextran is a polysaccharide made up of glucose molecules, and it is known for its medicinal properties. Its unique physical and chemical properties have made it widely used in various fields, including medicine, food industry, agriculture, and wastewater treatment. This article will explore the definition, structure, production, applications, and health benefits of dextran.DefinitionDextran is a complex branched polymer of glucose units connected by α-1,6-glycosidic bonds, with scattered α-1,3-glycosidic linkages. The molecular weight of dextran ranges from 3,000 to more than 2,000,000 Dalton, depending on the source and production conditions.StructureDextran has a linear backbone of glucose units linked by α-1,6-glycosidic bonds, with branching α-1,3-glycosidic bonds at every 15 to 30 glucose units. The branching pattern and length of the linear chain can vary, resulting in dextran molecules with different properties. Dextran molecules can be categorized into low-molecular-weight (LMW) dextran (MW<10 kDa), medium-molecular-weight (MMW) dextran (MW 10-40 kDa), high-molecular-weight (HMW) dextran (MW>100 kDa), and ultrahigh-molecular-weight (UHMW) dextran (MW>2,000 kDa).ProductionDextran can be produced by fermentation of sucrose using bacteria such as Leuconostoc mesenteroides, Streptococcus mutans, or Gluconobacter oxydans. Fermentation conditions, such as pH, temperature, oxygen supply, and substrate concentration, affect the molecular weight and structure of dextran. Dextran can also be chemically synthesized or extracted from natural sources such as sugar beet and wood.ApplicationsMedicine: Dextran is a valuable pharmaceutical ingredient due to its ability to form a viscous solution, bind metal ions, and prevent blood clotting. LMW dextran is used as a plasma expander to increase blood volume and reduce edema in critically ill patients. MMW and HMW dextrans are used as coatings for medical devices to improve biocompatibility and reduce thrombosis. Dextran can also be conjugated to drugs, antibodies, or proteins for targeted drug delivery or immunomodulation.Food industry: Dextran is used as a thickener, stabilizer, and emulsifier in food products such as ice cream, sauces, dressings, and bakery goods. LMW dextran is used as a sweetener, preservative, or dietary fiber additive in low-calorie or functional foods.Agriculture: Dextran is used as a soil conditioner to improve water retention, microbial activity, and nutrient availability. It can also be modified to produce biodegradable polymers for agricultural films, coatings, and packaging materials.Wastewater treatment: Dextran can be used as a bioflocculant to coagulate and settle suspended particles in wastewater, thus improving its quality and reducing the environmental impact. It can also be used as a biosorbent to remove heavy metals or organic pollutants from water.Health benefitsDextran has been shown to have various health benefits, including:- Lowering blood glucose levels in diabetic animals and humans by inhibiting glucosidase enzymes and increasing insulin sensitivity.- Stimulating immune responses and enhancing vaccine efficacy by activating dendritic cells and T cells.- Reducing oxidative stress and inflammation in aging animals and humans by scavenging free radicals and modulating cytokine production.- Improving the gut microbiota composition and diversity in humans by promoting the growth of beneficial bacteria and inhibiting harmful ones.ConclusionDextran is a versatile polysaccharide with numerous applications in various fields, including medicine, food industry, agriculture, and wastewater treatment. Its unique structure and physical/chemical properties make it an important ingredient in many commercial products. Dextran also has health benefits that warrant further research and exploration.