Influence of Simulated In Vitro Gastrointestinal Digestion on the Phenolic Profile, Antioxidant, and Biological Activity of Thymbra spicata L. Extracts

Abstract

Plants or plant extracts are widely investigated for preventing/counteracting several chronic disorders. The oral route is the most common route for nutraceutical and drug administration. Currently, it is still unclear as to whether and how the pattern of phenolic compounds (PCs) found in the plants as well as their bioactivity could be modified during the gastrointestinal transit. Recent studies have revealed antioxidant and anti-steatotic properties of Thymbra spicata. Here, we investigated the possible loss of phytochemicals that occurs throughout the sequential steps of a simulated in vitro gastrointestinal (GI) digestion of aqueous and ethanolic extracts of aerial parts of T. spicata. Crude, digested, and dialyzed extracts were characterized in terms of their phenolic profile and biological activities. Total contents of carbohydrates, proteins, PCs, flavonoids, and hydroxycinnamic acids were quantified. The changes in the PC profile and in bioactive compounds upon the simulated GI digestion were monitored by HPLC–MS/MS analysis. The antioxidant activity was measured by different spectrophotometric assays, and the antiproliferative potential was assessed by using three representative human cancer cell lines. We observed that the simulated GI digestion reduced the phytochemical contents in both aqueous and ethanolic T. spicata extracts and modified the PC profile. However, T. spicata extracts improved their antioxidant potential after digestion, while a partial reduction in the antiproliferative activity was observed for the ethanolic extract. Therefore, our results could provide a scientific basis for the employment of T. spicata extract as valuable nutraceutical.

Nutritional and Physiological Properties of Thymbra spicata: In Vitro Study Using Fecal Fermentation and Intestinal Integrity Models

“…The ability of the T. spicata to increase the ionic permeability and the transepithelial resistance was maintained after simulated gastrointestinal digestion (FMDT sample), although with lower efficacy due to the partial loss of phytochemical compounds during digestion, as reported by our previous study [ 28 ], and CVL, which was lower in the digested sample than the ethanolic extract. However, when pre-digested T. spicata were subjected to human microbial fermentation, mimicking the physiological interaction between digested food and healthy human gut microbiota, an effect on Caco-2 monolayers was not observed.…”

“…Previously, we reported an antisteatotic effect, as well as the albumin-binding properties in a high-fat environment, of CVL using in vitro models [ 27 ]. In addition, we have recently reported possible patterns of phenolic compounds in T. spicata and their bioactivity during gastrointestinal transit via a simulated in vitro gastrointestinal (GI) digestion of T. spicata [ 28 ]. The simulated GI digestion reduced the phytochemical contents in T. spicata extracts but improved their antioxidant potential.…”

Investigation of the cytotoxic effects of Thymbra spicata polysaccharides on MCF-7 breast cancer cell proliferation and migration in vitro conditions

“…In that comparative experiment, it was revealed by the increase in IC50 as a result of MTT analysis that enzymatically treated ethanolic extract lost some of its toxic effects. Besides, carvacrol, a known toxic agent, was used as a positive control [29]. In our experiment, we used the polysaccharides, which obtained a powder form as a result of isolation, by dissolving it into cell culture media.…”

“…It grows in countries in the eastern Mediterranean region and is used as a spice and herbal tea by the local people for different purposes, such as antitussive, carminative, etc. In studies, the antioxidant, antiseptic, antihypercholesterolaemic, anti-in ammatory, antifungal, antiviral, antimicrobial, and cytotoxic properties of Thymbra spicata of Thymbra genus, their extracts, essential oils or components, have been demonstrated [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Nevertheless, there was no data about the Thymbra spicata polysaccharides' cytotoxicity on cancer cells.…”

Effect of In Vitro Gastrointestinal Digestion on Phytochemicals and Antioxidant Activities in Cherry Tomatoes (Solanum lycopersicum var. cerasiforme)

“…The pH of the oral cavity is typically slightly acidic at pH 6.0; however, the pH rapidly drops to pH 1.5∼2.0 in the stomach due to the release of hydrochloric acid and is then restored to slightly acidic in the small intestine by combining bile acid and sodium sulfate ( Hwang et al, 2019 ; Diab et al, 2022 ). The environment in each digestive system influences the pH and acidity of food while it is being broken down throughout the digestive process ( Bell et al, 2016 ).…”