European chondroitin sulfate and glucosamine food supplements: A systematic quality and quantity assessment compared to pharmaceuticals

[Display omitted] •A systematic multi-analytical approach for CS and GlcN food supplement was set up.•25 European food supplements were compared to pharmaceutical products.•CS Animal origin was determined by enzyme treatments and HPCE and SEC-TDA.•Human synoviocites and chondrocytes based in vitro model for osteoarthritis.•Only 1 of 5 food supplements was biologically active compared to pharmaceutical. Chondroitin sulfate and glucosamine, commercialized as anti-osteoarthritis food supplements, do not undergo the strict quality controls of pharmaceuticals. In this paper a systematic multi-analytical approach was designed to analyse 25 food supplements from 8 European countries compared to 2 pharmaceuticals by using high performance anion-exchange chromatography with pulsed amperometric detection, size exclusion chromatography with triple detector array, capillary electrophoresis, mono and bi-dimensional NMR. Furthermore the biological activity was assessed on in vitro human synoviocyte and chondrocyte primary cell models. Most of the samples (over 19 out of 25) showed lower condroitin sulfate and glucosamine contents than the declared ones (up to -60.3%) while all of them showed a KS contamination (up to 47.1%). Mixed animal origin chondroitin sulfate and multiple molecular weight species were determined in more than 32% of the samples. Only 1 on 5 biologically screened samples had an effective action in vitro almost comparable to the pharmaceuticals.