Vaccinium macrocarpon (Cranberry)-based dietary supplements: Variation in mass uniformity, proanthocyanidin dosage and anthocyanin profile demonstrates quality control standard needed

Vaccinium macrocarpon (syn. American Cranberry) is employed in dietary supplements (DS) with the aim to improve urinary tract well-being. This property is linked to the antiadhesion-activity of proanthocyanidins (PACs) against uropathogenic-bacteria. However, the current European legislation has been criticized for being weak and ineffective. Indeed, recent scientific works report mislabeled, contaminated, and adulterated supplements containing dangerous or unknown compounds, or sold at toxic doses. In this work, we analysed 24 DS that claim to contain cranberry, and to have a specific dosage of PACs. Our tests included the control of the good manufacturing practice according to the European Pharmacopoeia, and the verification of the claimed dosage of PACs. Moreover, in order to confirm the real presence of cranberry in DS, chemical fingerprinting via HPLC-UV/Vis-MS/MS was employed. Our results showed that 17 DS did not comply with the uniformity test of dosage forms, and only five contained cranberry. Finally, 16 DS claimed an incorrect amount of PACs. These data suggest that several cranberry-based DS are present in the European market with insufficient quality controls. Considering that often DS are self-prescribed by consumer relying on their claim, the data obtained in this work should encourage more controls and stricter rules.