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

Effect of In Vitro Digestion on Anticancer and Antioxidant Activity of Phenolic Extracts From Latex of Fig Fruit (Ficus carica L.)

In this study, changes in total phenolic content (TPC), phenolic profile, and antioxidant activity and anticancer activity against cervix cancer and colorectal cancer cell lines of phenolic extracts of black and white fig (Ficus carica L.) latex (milk) were investigated during in vitro gastrointestinal digestions for the first time. The findings indicated that the in vitro digestion process exerted a significant effect on TPC of the phenolic extract from white fig milk (WFM-PE) and phenolic extract from black fig milk (BFM-PE), and TPC tended to decrease after in vitro digestion (p < 0.05). As consistent with these findings, antioxidant activity (by the CUPRAC method) of the samples decreased (p < 0.05) during in vitro digestion. The IC50 value of the undigested BFM-PE was significantly lower than that of the undigested WFM-PE (p < 0.05). The undigested and the digested WFM-PE and BFM-PE did not show any cytotoxic activity against normal cells. However, anticancer activity of WFM-PE on cervix and colorectal cancer cell lines (p < 0.05) and anticancer activity of BFM-PE against colorectal cancer cell lines decreased after in vitro digestion (p < 0.01). On the other hand, the dominant phenolic was catechin hydrate and was syringic acid.

Comprehensive Strategies for Metabolic Syndrome: How Nutrition, Dietary Polyphenols, Physical Activity, and Lifestyle Modifications Address Diabesity, Cardiovascular Diseases, and Neurodegenerative Conditions

Several hallmarks of metabolic syndrome, such as dysregulation in the glucose and lipid metabolism, endothelial dysfunction, insulin resistance, low-to-medium systemic inflammation, and intestinal microbiota dysbiosis, represent a pathological bridge between metabolic syndrome and diabesity, cardiovascular, and neurodegenerative disorders. This review aims to highlight some therapeutic strategies against metabolic syndrome involving integrative approaches to improve lifestyle and daily diet. The beneficial effects of foods containing antioxidant polyphenols, intestinal microbiota control, and physical activity were also considered. We comprehensively examined a large body of published articles involving basic, animal, and human studie, as well as recent guidelines. As a result, dietary polyphenols from natural plant-based antioxidants and adherence to the Mediterranean diet, along with physical exercise, are promising complementary therapies to delay or prevent the onset of metabolic syndrome and counteract diabesity and cardiovascular diseases, as well as to protect against neurodegenerative disorders and cognitive decline. Modulation of the intestinal microbiota reduces the risks associated with MS, improves diabetes and cardiovascular diseases (CVD), and exerts neuroprotective action. Despite several studies, the estimation of dietary polyphenol intake is inconclusive and requires further evidence. Lifestyle interventions involving physical activity and reduced calorie intake can improve metabolic outcomes.

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

(Poly)phenolic-rich Mediterranean plants such as Thymbra spicata have been associated with several health-promoting effects. The nutritional value, as well as physiological interaction of T. spicata with the gastrointestinal tract, has not been investigated before. The nutritional composition of T. spicata leaves was here characterized by standard analytical methods. T. spicata leaves were subjected to ethanolic extraction, simulated gastrointestinal digestion, and anaerobic microbial gut fermentation. Phenols/flavonoid contents and radical scavenging activity were assessed by colorimetric methods. The volatile organic compounds (VOCs) were detected by gas chromatography coupled with mass spectrometry. The effect on intestinal integrity was evaluated using a Caco-2 monolayers mounted in a Ussing chamber. T. spicata contains a high amount of fiber (12.3%) and unsaturated fatty acids (76% of total fat). A positive change in VOCs including short-chain fatty acids was observed without significant change in viable microbe. T. spicata and carvacrol (main phenolic compound) enhanced ionic currents in a concentration-dependent manner without compromising the Caco-2 monolayer's integrity. These effects were partially lost upon simulated digestion and completely abolished after colonic fermentation in line with polyphenols and carvacrol content. Conclusion: T. spicata represents a promising nutrient for the modulation of gut microbiota and the gut barrier. Further studies must better define its mechanisms of action.

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

We investigated the impact of simulated in vitro gastrointestinal digestion on the levels of total polyphenols, total flavonoids, carotenoids, and antioxidant capacity in cherry tomatoes. The initial total polyphenol content of fresh tomatoes was 220.51 μg GAE/g, which decreased to 203.24 μg GAE/g after 120 min of stomach treatment and further decreased to 138.23 μg GAE/g after 120 min of small intestine treatment. Similarly, the initial total flavonoid content in fresh tomatoes was 43.28 μg QE/g, but after 120 min of small intestine digestion, it decreased by approximately 50.72% to 21.33 μg QE/g. Lycopene, lutein, and β-carotene also experienced a decrease of 69.71∼78.38% during the digestion process compared to fresh tomatoes. The antioxidant activity exhibited a reduction of 34.95∼37.67% compared to fresh tomatoes after digestion in the stomach and intestines. The bioactive compounds present in tomatoes undergo decomposition and conversion into other substances during digestion, and these degradation products are believed to inhibit the growth of SK-Hep1 human hepatoma cells while enhancing antioxidant activity within the intracellular environment.

Characterization and Biological Activities of In Vitro Digested Olive Pomace Polyphenols Evaluated on Ex Vivo Human Immune Blood Cells

Olive pomace (OP) represents one of the main by-products of olive oil production, which still contains high quantities of health-promoting bioactive compounds. In the present study, three batches of sun-dried OP were characterized for their profile in phenolic compounds (by HPLC-DAD) and in vitro antioxidant properties (ABTS, FRAP and DPPH assays) before (methanolic extracts) and after (aqueous extracts) their simulated in vitro digestion and dialysis. Phenolic profiles, and, accordingly, the antioxidant activities, showed significant differences among the three OP batches, and most compounds showed good bioaccessibility after simulated digestion. Based on these preliminary screenings, the best OP aqueous extract (OP-W) was further characterized for its peptide composition and subdivided into seven fractions (OP-F). The most promising OP-F (characterized for its metabolome) and OP-W samples were then assessed for their potential anti-inflammatory properties in ex vivo human peripheral mononuclear cells (PBMCs) triggered or not with lipopolysaccharide (LPS). The levels of 16 pro-and anti-inflammatory cytokines were measured in PBMC culture media by multiplex ELISA assay, whereas the gene expressions of interleukin-6 (IL-6), IL-10 and TNF-α were measured by real time RT-qPCR. Interestingly, OP-W and PO-F samples had a similar effect in reducing the expressions of IL-6 and TNF-α, but only OP-W was able to reduce the release of these inflammatory mediators, suggesting that the anti-inflammatory activity of OP-W is different from that of OP-F.

The Impact of Za'atar Antioxidant Compounds on the Gut Microbiota and Gastrointestinal Disorders: Insights for Future Clinical Applications

Since the gut microbiota plays a pivotal role in host homeostasis and energy balance, changes in its composition can be associated with disease states through the promotion of immune-mediated inflammatory disorders and increasing intestinal permeability, ultimately leading to the impairment of intestinal barrier function. Za'atar is one of the most popular plant-based foods in the Eastern Mediterranean region. Za'atar is a mixture of different plant leaves, fruits, and seeds and contains hundreds of antioxidant compounds, especially polyphenols, and fiber, with pre-clinical and clinical evidence suggesting health-promoting effects in cardiovascular and metabolic disease. Za'atar compounds have also been studied from a gastrointestinal perspective, concerning both gut microbiota and gastrointestinal diseases. Antioxidants such as Za'atar polyphenols may provide beneficial effects in the complex interplay between the diet, gut microbiota, and intestinal permeability. To our knowledge, no studies have reported the effects of the whole Za'atar mixture, however, based on the pre-clinical studies published on components and single compounds found in Za'atar, we provide a clinical overview of the possible effects on the gastrointestinal tract, focusing mainly on carvacrol, rosmarinic acid, gallic acid, and other polyphenols. We also cover the potential clinical applications of Za'atar mixture as a possible nutraceutical in disorders involving the gastrointestinal tract.