Fingerprinting Food Supplements and Their Botanical Ingredients by Coupled UV/Vis/FTIR Spectrometry

Abstract

Medicinal plants are used as ingredients for a large variety of herbal supplements. Their quality and safety versus efficacy, according to present legal requirements, need to meet the minimum quality criteria to support their use. Specific biomarkers to evaluate and screen their authenticity are phenolic derivatives, phtosterols, lipids or alkaloids. We report here the data obtained  for  two herbal food supplements (A and B) obtained from  different mixtures of plants: Taraxacum officinalis, Cynara scolimus Silybum marianum as ingredients for product A)  and Hypericum perforatum, Chelidonium majus and Lycopodium clavatum as ingredients for product B). The combination of UV-Vis and FTIR spectrometry allowed a specific fingerprint of biomarkers in individual plants and derived supplements ( A and B), by discriminating the specific areas and peaks of individual plants and  mixtures, the significant differences between the methanolic and water extracts. The data were compared using chemometry ( PCA and Cluster analysis). Using Vis spectrometry combined with FTIR  peak intensities at 1732 cm-1 and calibration with gallic acid,  the total phenolics concentrations ranged from 5.31 to 9.58 mg gallic acid eq/ml methanol, with a positive and significant correlation between the two methods (R2= 0.979). The phenolics’ concentration were 2.5 to 4 times lower in water extracts comparing with methanol extracts of  products A and B.  Finally, we assume that herbal supplements can be adequately characterized for their quality and safety by combined UV-Vis spectrometry/FTIR spectrometry, with good, fast and cheap informations about the main biomarkers of authenticity.