Combo Method Yields Chondroitin Sulfate

By coupling microbiological and chemical techniques, Emiliano Bedini of the University of Naples Frederico II, in Italy, and coworkers have developed the first preparative-scale synthesis of the pharmacological version of chondroitin sulfate, a compound widely used to treat osteoarthritis (Angew. Chem. Int. Ed., DOI: 10.1002/anie.201101142). Chondroitin sulfate is a glycosaminoglycan polysaccharide variously substituted with sulfate groups that serves as a key structural component of cartilage. It’s popular as a dietary supplement in the U.S. and used as a prescription drug in Europe and elsewhere to improve joint health. The compound is currently sourced from cow, pig, and shark cartilage, but the low abundance of the raw material, its laborious purification, and the potential for disease transmission from animals have sparked efforts for a synthetic source. Using a fermentation process, Bedini’s team employed a strain of Escherichia coli known to produce a chondroitin-based polysaccharide, then added an enzyme to remove a fructose group to obtain pure chondroitin. They subsequently used pyridine-sulfur trioxide in a multistep procedure to selectively add sulfate groups to produce gram amounts of chondroitin sulfate with the requisite sulfation pattern (shown). The high-yield, low-cost synthesis could become the method of choice for chondroitin sulfate production, Bedini believes.