Liquid Chromatographic Fingerprints for the Characterization of Flavanol-Rich Nutraceuticals Based on 4-Dimethylaminocinnamaldehyde Precolumn Derivatization

Abstract

Flavanols consist of a great family of bioactive molecules displaying a wide range of health-promoting attributes for humans, including antioxidant, antimicrobial or anti-inflammatory effects. As a result, botanical species rich in this type of compound are often used to develop nutraceutical products or dietary supplements with recognized healthy attributes. This paper aims at characterizing nutraceutical products using liquid chromatographic fingerprints related to flavanol composition. Catechins and their oligomers were exploited to characterize and authenticate various commercial products prepared with extracts of red berries and medicinal plants. These compounds resulted in interesting descriptors of some fruits and vegetables, thus providing an additional perspective for the study of nutraceuticals. For such a purpose, a new method based on liquid chromatography with UV/Vis detection (HPLC–UV/Vis) with precolumn derivatization with 4-dimethylaminocinnamaldehyde was developed. Results indicated that the separation of flavanols was very complex due to the degradation of procyanidin derivatives. The resulting data sets were analyzed using chemometric methods such as principal component analysis and partial least square–discriminant analysis. Despite the complexity of chromatographic fingerprints, nutraceutical samples could be discriminated according to their main ingredients. In general, catechin and epicatechin were the most abundant compounds in the different samples, and procyanidin A2 was highly specific to cranberry.

Analytical Methods for Exploring Nutraceuticals Based on Phenolic Acids and Polyphenols

“…A type of trendy nutraceutical and dietary supplement consists of mixtures of fruit and medicinal plant extracts such as American cranberry and other red and blackberries, turmeric, grapevine, and green tea, with exceptional detoxifying, antiaging, and antioxidant features [32].…”

Extraction and Characterization of Flavanol-Rich Nutraceuticals Based on High-Performance Liquid Chromatography

“…The spectrophotometric assay, based on 4-dimethylaminocinnamaldehyde (DMAC), is currently used in the pharmaceutical industry to determine the total flavanol content. This assay shows some advantages over other spectrophotometric methods (n-butanol hydrochloride and vanillin-acid), such as the reduction of reagent consumption, simplicity, shorter analysis time, and a better selectivity regarding other polyphenolic interferences [6][7][8][9]. The reaction mechanism relies on forming an electrophilic carbocation in acid media that reacts with C8 of the flavanol phenyl ring, involving derivatives detected at 640 nm [8].…”

“…Consequently, HPLC techniques using mass spectrometry (MS), such as HPLC-MS and HPLC-MS/MS, were applied to identify and characterize the oligomeric compounds [5,10,11,[16][17][18][19]. As an alternative to the direct detection of flavanols, Vidal-Casanella et al proposed a new method utilizing RP-HPLC-UV/Vis with pre-column derivatization using DMAC [9].…”