Phenolic Compounds in Edible Tropaeolum majus L. Leaves and Its In Vitro Digestion

Tropaeolum majus L. is an edible plant known for its therapeutic and medicinal effects, as it possesses bioactive compounds (polyphenols, glucosinolates, fatty acids) and has various biological activities, which makes it interesting and makes it the research objective of this work. The aim of this study was to extract the phenolic compounds present in the T. majus plant by maceration and ultrasound-assisted extraction techniques using two solvents: 80% ethanol and water. In vitro digestion was performed to see how stable the phenolic components are after digestion. An LC-MS/MS instrument was used to identify and quantify the phenolic components. The highest extraction yield for the T. majus extract was obtained when 80% ethanol was used as the solvent after ultrasound-assisted extraction (32.63 ± 2.28 mg/0.5 g fresh material), while the opposite was true for the T. majus extract when water was used as the solvent and maceration as the technique (21.00 ± 3.26 mg/0.5 g fresh material). However, water extracted more phenolic components for identification. In general, the major compounds before in vitro digestion with commercial enzymes and with 80% ethanol and water as the solvents were p-hydroxybenzoic acid, protocatechuic acid, p-coumaric acid, caffeic acid and chlorogenic acid. After in vitro digestion using both solvents and extraction procedures, the stable phenolic compounds were p-hydroxybenzoic acid (>67%) and p-coumaric acid (>35%). Caffeic acid and quinic acid were not detected after digestion. The stability of certain phenolic components could influence the use of such extracts as dietary supplements with beneficial effects on human health, making them interesting for the general population.