Antioxidant and anti-acetylcholinesterase activity of commercially available medicinal infusions after in vitro gastrointestinal digestion

Abstract

Cynara cardunculus, Fraxinus angustifolia  and Pterospartum tridentatum are plants commercialized in Portugal for digestion-related ailments, among others. The aim of this study was to identify the chemical composition of the infusions and determine the inhibition of acetylcholinesterase, the antioxidant activity, and to evaluate if the chemical composition and activities remained after in vitro gastrointestinal digestion. These activities can be related with the traditional uses of these plants. The toxicity of the infusions was also tested with Caco-2 cells, a model of intestinal cells. The composition of the plant extracts revealed mainly flavonoids and phenolic acids. The antioxidant activity measured as half maximal effective concentration (EC50) values ranged from 19 to 120 µg/ml and the acetylcholinesterase inhibition activity of the three extracts determined as half inhibitory concentration (IC50) was between 1 and 2.5 mg/ml. The composition and the biochemical activities remained after the in vitro gastrointestinal digestion. The infusions showed no toxicity against Caco-2 cell lines. The antioxidant activity and inhibition of acetylcholinesterase were maintained during the digestive process, and therefore can be important mechanisms for the therapeutic effects attributed to the infusions under evaluation, namely to treat digestive problems. Even though the infusions presented biochemical activities, they were not toxic for the intestine cell line.   Key words: Antioxidant activity, acetylcholinesterase inhibition, chlorogenic acid, flavonoid, gastrointestinal problems, Cynara cardunculus, Fraxinus angustifolia, Pterospartum tridentatum.