Single-Laboratory Validation for the Determination of Cocoa Flavanols and Procyanidins (by Degree of Polymerization DP1-7) in Cocoa-Based Products by Hydrophilic Interaction Chromatography Coupled with Fluorescence Detection: First Action 2020.05.

Background: Flavanols and procyanidins are complex bioactives found in many foods such as cocoa. As their consumption is associated with health benefits, cocoa flavanols and procyanidins are receiving increasing attention from consumers, industry, researchers, and regulators.

Objective: The objective of this study is to validate a method using hydrophilic interaction chromatography (HILIC) with fluorescence detection (FLD) and a commercially available reference material for the determination of flavanols and procyanidins (CF) in cocoa-based products.

Reliable, accessible and transferable method for the quantification of flavanols and procyanidins in foodstuffs and dietary supplements.

Flavanols and procyanidins are plant-derived bioactives that are receiving increasing attention because of their potential health benefits. Analytical tools that can accurately identify and reproducibly quantify these bioactives are critical to researchers for test material characterization, as well as to the food industry and regulators, notably for product labeling. However, the chemical complexity of procyanidins, and the absence of analytical standards have prevented the development of methods that could serve the needs of these different sectors.

A Fluorescence Quenching Analysis of the Binding of Fluoroquinolones to Humic Acid.

Fluorescence quenching was used to investigate the interaction of six fluoroquinolones with humic acid. Static quenching was observed for the binding of ciprofloxacin, enoxacin, fleroxacin, levofloxacin, norfloxacin, and ofloxacin to humic acid. The equilibrium binding constants were found from Stern-Volmer plots of the data.

Silanediol inhibitors of angiotensin-converting enzyme. Synthesis and evaluation of four diastereomers of Phe[Si]Ala dipeptide analogues.

Four stereoisomers of a Phe-Ala silanediol dipeptide mimic have been evaluated as inhibitors of angiotensin-converting enzyme (ACE) and compared to ketone-based inhibitors reported by Almquist et al. One stereogenic center of the isomers was derived from the individual enantiomers of methyl 3-hydroxy-2-methylpropionate, with separation of diastereomers after introduction of the second stereogenic center. The diastereomeric identities were established by X-ray crystallography of an intermediate.