Qualitative Differentiation of Species from Vaccinium by NMR, using the Assure-RMS Software
The genus Vaccinium contains approximately 450 species including bilberry, blueberry, cranberry, lingonberry, and huckleberry. The fruit of Vaccinium are widely eaten and touted for their health benefits, attributed to antioxidants and micronutrients. Blueberry leaf extract is a traditional Cree medicine, believed to have anti-diabetic properties. Given their widespread use in humans, it is important to have methods to verify the identity and purity of Vaccinium extracts. Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for characterizing mixtures such as plant extracts. An NMR spectrum, such as a 1D 1H spectrum, shows the superposition of the characteristic signals of all of the compounds in the mixture. This pattern is different for diverse samples and for different materials. When enough samples of a specific material are available, chemometric analysis using SIMCA (soft independent modeling of class analogies) produces a model that captures the key features of that material. New samples can be tested against the model to determine whether they represent the same material. We have added chemometric tools to the Assure – Raw Material Screening (RMS) software. In addition to identifying and quantitating specific compounds from a mixture spectrum, Assure-RMS can now compare the spectrum against a SIMCA model to verify the identity of the material. We demonstrate the power of these techniques using examples from our ongoing study of Vaccinium leaf extracts. Blueberry (for example, V. corymbosum) and cranberry (V. macrocarpon) are readily distinguished based on their NMR spectra but European bilberry (V. myrtillus) and dwarf bilberry (V. caespitosum) are more similar.