Evaluation of chondroitin sulfate in shark cartilage powder as a dietary supplement: Raw materials and finished products

We evaluated the content and biochemical properties of chondroitin sulfate (CS) in shark cartilage powders being used as nutraceutical supplements. The quantities of CS in shark cartilage products (SCPs) and finished products containing shark cartilage powder were determined by analyzing unsaturated disaccharides after treatment with chondroitinase ABC, and the results were compared with the specifications on the product labels. This method was validated and good linearity (r ⩾ 0.999) was obtained. The recovery ranged from 95.27% to 102.39% with precision from 2.27% to 3.95%. Furthermore, the average molecular weights (MW) and the origins of CS in SCPs and finished products were evaluated by agarose gel-electrophoresis and assessment of disaccharide compositional patterns, respectively. Quantitative and compositional analysis of disaccharides after enzymatic depolymerization showed that the amount of CS in the samples of SCPs ranged from 0% to 28.92 ± 0.03%. All of the SCP samples except for SCP D had ΔDi-2,6diS and had more ΔDi-6S than ΔDi-4S, indicating that they originated from shark cartilage. In the finished products, the amount of CS ranged from 0.58 ± 0.01% to 21.30 ± 0.08%. With the exception of SCP D and two finished products (F and D), which contained CS with lower MWs, the average MW of CS in the SCPs and finished products was approximately 40 kDa or higher than that of MW standard (40 kDa) of CS. These analyses contribute to the evaluation of the quantity and quality of CS in SCPs and finished products containing CS, which is necessary for the manufacture of high-grade nutraceuticals.