In vitro effect of green tea and turmeric extracts on GLP-1 and CCK secretion: the effect of gastrointestinal digestion.

Plant extract activity can be modified by the digestion process. In order to assess the satiety effect of green tea and turmeric extracts, an in vitro gastrointestinal digestion process was performed and the STC-1 cell line was used. The enteroendocrine cell line was incubated (for 30, 60 and 120 minutes) with the digested and non-digested extracts measuring the secretion of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) by enzyme-linked immunosorbent assay (ELISA). The release of satiety hormones by the STC-1 cells showed similar or higher results for plant extracts compared to the positive controls reported as satiatogenic (proteins and short chain fatty acids). For the non-digested samples, the largest amount of CCK and GLP-1 was found for turmeric, with 379 ± 46 pg ml-1 (60 min) and 347 ± 125 pg ml-1 (120 min) respectively. For the digested samples, the highest level of CCK was found for turmeric at 30 minutes (43.3 ± 11) and for GLP-1 by green tea at 120 minutes (165.7 ± 52). The in vitro gastrointestinal digestion process affects the satiety of plant extracts, increasing for green tea and decreasing for turmeric. Green tea showed the most stable satiating capacity after the in vitro digestion process and this may be useful for using it as a stable food supplement to reduce hunger associated with overweight and obesity.

Cultivation of Solanum tuberosum in a former mining district for a safe human consumption integrating simulated digestion.

BACKGROUND: Potato (Solanum tuberosum) is a global crop and by far the most important non-cereal crop in the world. Therefore, it is necessary to assure its safe consumption. This is especially relevant in the case of its cultivation in abandoned mining areas, where the population tends to return to agriculture. In the present work, the objective is to evaluate the contribution to the diet of nutrients and contaminants of potato grown in soils from the Almadén area (mining district) by studying the intestinal absorption (in vitro) of the tuber, taking into account the preparation methods for its consumption. RESULTS: The results of contaminant and nutrient contents show that the potato peel retains significantly more elements (mainly in the case of toxic elements) than the flesh. Furthermore, potato (peel and flesh) is a good source of iron. CONCLUSION: It is recommended to boil potatoes with the peel in order to minimize nutrient loss and, before consumption, peeling them to eliminate possible risks due to contaminants. In addition, to minimize the risk due of mercury and to improve the levels of calcium, magnesium, potassium and sodium, it is recommended to add salt during the boiling process. © 2017 Society of Chemical Industry.

Influence of in vitro gastrointestinal digestion of fruit juices enriched with pine bark extract on intestinal microflora.

The selective antimicrobial effect of fruit juices enriched with pine bark extract (PBE) (0.5 g/L) has been studied before and after in vitro gastrointestinal digestion. PBE (a concentrate of water-soluble bioflavonoids, mainly including phenolic compounds) has been proven to have high stability to the digestion process. Pure phenolic compounds such as gallic acid had a high antimicrobial effect on Staphylococcus aureus and Escherichia coli, maintaining the lactic acid bacteria population (≈100%). Otherwise, E. coli O157:H7 only growth 50% when PBE was added to the culture media, while a slight increase on the growth of lactobacilli and bifidobacteria was observed after exposition to the bark extract. Fresh fruit juices enriched with PBE showed the highest inhibitory effect on pathogenic intestinal bacterial growth, mainly E. coli and Enterococcus faecalis. The in vitro digestion process reduced the antibacterial effect of juices against most pathogenic bacteria in approximately 10%. However, the beneficial effect of fruit juices enriched with PBE (0.5 g/L) on gut microbiota is still considerable after digestion.

Anti-inflammatory properties of fruit juices enriched with pine bark extract in an in vitro model of inflamed human intestinal epithelium: the effect of gastrointestinal digestion.

Enrichment of fruit juices with pine bark extract (PBE) could be a strategy to compensate for phenolic losses during the gastrointestinal digestion. A coculture system with Caco-2 cells and RAW 264.7 macrophages was established as an in vitro model of inflamed human intestinal epithelium for evaluating the anti-inflammatory capacity of fruit juices enriched with PBE (0.5 g L(-1)) before and after in vitro digestion. The digestion of both PBE-enriched pineapple and red fruit juice led to significant changes in most of the analysed phenolic compounds. The in vitro inflammatory state showed cell barrier dysfunction and overproduction of IL-8, nitric oxide (NO) and reactive oxygen species (ROS). In the inflamed cells, incubation with nondigested samples reduced (P<0.05) the production of IL-8 and NO compared with digested samples. ROS production increased in the inflamed cells exposed to digested commercial red fruit juice (86.8±1.3%) compared with fresh juice (77.4±0.8%) and increased in the inflamed cells exposed to digested enriched red fruit juice (82.6±1.6%) compared with the fresh enriched juice (55.8±6%). The anti-inflammatory properties of PBE-enriched fruit juices decreased after digestion; further research on the bioavailability of the assayed compounds is needed to properly assess their usefulness for the treatment of gut inflammation.

Evaluation of antioxidant activity and antiproliferative effect of fruit juices enriched with Pycnogenol® in colon carcinoma cells. The effect of in vitro gastrointestinal digestion.

The aim of this study was to examine the effect of in vitro gastrointestinal digestion on the antioxidant and antiproliferative effect of fruit juices enriched with Pycnogenol® (0.5 g/L) on a colon carcinoma cell line (Caco-2). The total phenolic concentration (TPC), antioxidant activity and inhibition cell growth were studied in fresh and digested pineapple juice and red fruits juice (both enriched with pine bark extract and not). After in vitro digestion the level of detectable phenolic compounds (expressed as gallic acid equivalent) was higher in both pineapple and red fruits juices enriched with Pycnogenol® than in non-enriched commercial juices (155.6 mg/100 mL vs 94.6 mg/100 mL and 478.5 mg/100 mL vs 406.9 mg/100 mL, respectively). Increased antioxidant activity (measured by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and oxygen radical absorbance capacity assay (ORAC) methods) was observed in digested enriched juices with respect to the same samples before digestion. Pycnogenol® enrichment led to a high antiproliferative effect between 24 and 72 h of incubation with undigested pineapple juice compared with the non-enriched juice. It can be concluded that enrichment of fruit juices with Pycnogenol® provides a source of phenolic compounds with high stability to in vitro gastrointestinal conditions; however, the antioxidant properties of fruit juices were affected to a different extent.