Quantitative and Qualitative Evaluation of ChondroitinSulfate in Dietary Supplements

We propose to evaluate the amount and quality ofchondroitin sulfate (CS) from several food supplementpreparations in the form of tablets, caplets, or capsulescontaining CS in varying contents and formulations in thepresence of various additives and ingredients, with noother pretreatment than centrifugation to remove insolublematerial. To quantify CS, two different analytical approacheswere applied after their validation: specific and sensitiveagarose-gel electrophoresis and strong-anion exchange–highperformanceliquid chromatography (SAX-HPLC) determinationof the constituent disaccharides after treatment withspecific chondroitin lyases. The CS content in finishedproducts evaluated using the two specific validated methodswere found to conform to the label specifications. It is worthmentioning that the quantitative determinations have beenperformed using a very high pure European Pharmacopeia CSreference standard having substantially the same properties asthe food supplement CS samples. Furthermore, by means ofthe specific agarose-gel elctrophoresis approach, we canexclude the presence in the nutraceuticals of other sulfatedpolysaccharides produced by extraction from tissues, inparticular heparin, heparan sulfate, and dermatan sulfate.The SAX-HPLC separation of unsaturated disaccharides forthe nutraceutical CS was also used to evaluate its qualityand the possible origin. No disulfated disaccharides typical ofCS from cartilaginous fishes, making the charge densitylower than 1.0, were found, thus confirming the bovine orporcine origin, the most common sources of this “terrestrial” polysaccharide. Finally, high-performance size-exclusionchromatography (HPSEC) analysis was applied to evaluatethe CS molecular mass in food supplements also in thepresence of additives and other ingredients. This analyticalapproach confirmed that the nutraceutical CS samples are ofhigh molecular mass and are not degraded during the foodsupplement preparations. In conclusion, this multianalyticalapproach can be used in the direct quantitation and evaluationof the quality and the possible origin of CS contained in foodsupplement formulations.