Determination of free phenolic acids in plant-derived foods by high-performance thin-layer chromatography with direct 2,2′-diphenyl-1-picrylhydrazyl assay

Abstract

The healthy properties of functional food are associated with the presence of a wide range of phenolic antioxidants. Thus, the aim of this study was to develop a simple, rapid, and reproducible high-performance thin-layer chromatographic (HPTLC) method combined with a direct 2,2′-diphenyl-1-picrylhydrazyl (DPPH) assay, to compare antioxidant activity in terms of free radical scavenging activity in functional food. We wanted to quantify caffeic acid, chlorogenic, and gallic acid, three natural phenolic antioxidants commonly found in functional food, and determine their contribution to the total free radical scavenging activity. Antioxidant activities of organic cacao, green coffee, chia seeds, goji berries, spirulina, and chlorella were evaluated and compared. The most potent free radical scavenger was found to be chlorogenic acid. Free radical scavenging activity in the functional foods tested was mostly affected by the presence of chlorogenic and caffeic acid, while gallic acid, although present in highe...