Bilberry Quality Story

In 2003 MediHerb received samples of Vaccinium myrtillus or bilberry fruit extracts which differed in behavior to that normally received. The standard method of determining the anthocyanin content at this time was a spectrophotometric assay. Using this method, anthocyanin levels of two extracts were found to be 25% as claimed by the manufacturers. When high-performance liquid chromatography (HPLC) was used, however, one extract was found to contain 9% anthocyanins probably not derived from V. myrtillus but from another species as well as an adulterant chemical. This adulterant was subsequently identified, using HPLC, mass spectroscopy, and nuclear magnetic resonance, as amaranth (3-hydroxy-4-[(4-sulfo-1-naphthalenyl)azo]-2,7-naphthalenedisulfonic acid trisodium salts) a synthetic dark red dye. It was evident that when deliberate adulteration occurs in an extract, a spectrophotometric assay is inadequate to accurately determine the levels of compounds such as anthocyanins. This has led to a change in the standard method of analysis for bilberry extracts to a more sophisticated method of analysis, (HPLC with photodiode array detection) to counter this form of adulteration. The results of this discovery by the MediHerb team were published (Journal of Agricultural Chemistry and Food Science 2006: 54: 7378-7382) and led to regulators around the world to review accepted test methods for Bilberry. The British Pharmacopoiea also changed the method of analysis for Bilberry as a result of this discovery.