Anika E. Wagner

Enzymatic modification of gliadin peptides by calcium-dependent transglutaminase 2 (TG2) plays a central role in the pathogenesis of celiac disease (CD) and is considered a potential therapeutic target. Recently, anthocyanins (ACN) such as cyanidin-3-glucoside (C3G) and delphinidin-3-glucoside (D3G) have gained attention in CD research for their anti-inflammatory, antioxidant and gliadin-binding properties. This study examined whether C3G and D3G modulate TG2 activity and cytokine-induced inflammation in human intestinal cells. TG2 activity was analyzed using gliadin substrates and TG2 expression was assessed after IFN-γ and TNF-α stimulation. Cell viability after ACN, IFN-γ and TNF-α incubation was tested with a resazurin-based fluorometric assay. Docking and STD-NMR experiments were conducted to explore the molecular interactions involved. D3G significantly reduced TG2-mediated crosslinking of gliadin and C3G of 5-biotinamidopentylamine as a synthetic substrate of TG2. STD-NMR and in silico docking experiments revealed a molecular interaction of ACN with calcium binding sites of TG2 which are essential for its enzymatic function. In addition, C3G and D3G improved cell viability under IFN-γ and TNF-α exposure and D3G reduced upregulation of TG2 mRNA under IFN-γ stimulation. Here, in silico docking experiments suggested that both ACN may interact with the assembly of cytokines and their corresponding cellular receptors. In conclusion, our data indicates that C3G and D3G reduce TG2-activity and mitigate cytokine-mediated inflammatory effects by a direct molecular interaction. This supports their potential as natural modulators of TG2 in the context of CD.

Hypertension represents a major risk factor for cardiovascular diseases. As a diet high in sodium chloride is associated with hypertension, so‐called “blood pressure salts” are attracting increasing scientific interest. These are characterized by a partial replacement of sodium chloride by other salts, mainly potassium and magnesium compounds. The aim of this review is to evaluate the bioavailability of potassium and magnesium salts as dietary supplements and to identify potential sodium chloride substitutes. A literature search was conducted in the PubMed database using the PICO scheme. Randomized controlled trials in healthy adults investigating the bioavailability of defined potassium/magnesium salts were included. Potassium chloride and potassium citrate showed good bioavailability irrespective of the route of administration and dose. Magnesium citrate and magnesium chloride showed good bioavailability while magnesium oxide was poorly bioavailable. This may be partly due to its poor solubility in water. The results indicate that potassium chloride and potassium citrate as well as magnesium citrate and chloride are suitable for the use as salt substitutes and for increasing potassium and magnesium intake in addition to reducing sodium. Due to its poor water solubility and consequently low bioavailability magnesium oxide is less suitable.

Curcumin is a bioactive compound found in turmeric ( Curcuma longa ) and is widely recognized for its health‐promoting effects, including anti‐inflammatory, antioxidant, and anti‐carcinogenic properties. It can also mediate epigenetic effects by inhibiting histone acetylases (HATs) and deacetylases (HDACs) but the transgenerational context has not been studied in detail. Here, we used the fruit fly ( Drosophila melanogaster ) as a model organism to determine the epigenetic effects of 0.1% and 1% (w/v) curcumin, which have been shown to promote the health and prolong the lifespan of fruit flies. Both concentrations were found to significantly increase lifespan and climbing activity in male and female flies, but changes in HAT/HDAC gene expression and metabolism were sex‐specific. Unexpectedly, the F1 offspring of curcumin‐treated parental flies showed a significant reduction in lifespan that was also sex‐specific, as well as sex‐specific and dose‐dependent transgenerational changes in HAT/HDAC gene expression and metabolism. These results show that curcumin's beneficial effects in the parental generation are followed by deleterious effects in the offspring, highlighting the need to further investigate the potential transgenerational effects of nutrients and bioactive compounds that are used as dietary supplements for humans.

Insects are the most diverse organisms on earth, accounting for ~80% of all animals. They are valuable as model organisms, particularly in the context of genetics, development, behavior, neurobiology and evolutionary biology. Compared to other laboratory animals, insects are advantageous because they are inexpensive to house and breed in large numbers, making them suitable for high-throughput testing. They also have a short life cycle, facilitating the analysis of generational effects, and they fulfil the 3R principle (replacement, reduction and refinement). Many insect genomes have now been sequenced, highlighting their genetic and physiological similarities with humans. These factors also make insects favorable as whole-animal high-throughput models in nutritional research. In this review, we discuss the impact of insect models in nutritional science, focusing on studies investigating the role of nutrition in metabolic diseases and aging/longevity. We also consider food toxicology and the use of insects to study the gut microbiome. The benefits of insects as models to study the relationship between nutrition and biological markers of fitness and longevity can be exploited to improve human health.

Saccharin and sucralose are worldwide used tabletop non‐caloric artificial sweeteners (NAS), and although they are considered metabolically inert and safe for consumption, recent studies observed an NAS‐mediated modulation of the intestinal microbiota, which may result in the development of intestinal inflammatory diseases. The present study investigated the effects of NAS alone and in combination with dextran sodium sulfate (DSS), a chemical known to induce gut inflammation, on parameters of overall fitness including longevity and climbing ability of female Drosophila melanogaster. DSS‐exposed flies were subjected to saccharin or sucralose, and their effects on survival and the gene expression levels of different antimicrobial peptides (AMPs) were assessed. Saccharin supplementation significantly increased the lifespan of D. melanogaster, while DSS significantly decreased the survival in a dose‐dependent manner. Additionally, DSS exposure of flies resulted in a trend toward an up‐regulation of the mRNA levels of the AMPs, drosocin and metchnikowin. This effect was more pronounced in the NAS‐supplemented group reaching significance. This may indicate that NAS supplementation improves intestinal immune reactions during an inflammatory metabolic state.

Several studies have been published introducing Drosophila melanogaster as a research model to investigate the effects of high-calorie diets on metabolic dysfunctions. However, differences between the use of high-sugar diets (HSD) and high-fat diets (HFD) to affect fly physiology, as well as the influence on sex and age, have been seldom described. Thus, the aim of the present work was to investigate and compare the effects of HSD (30% sucrose) and HFD (15% coconut oil) on symptoms of metabolic dysfunction related to obesity and type-2 diabetes mellitus, including weight gain, survival, climbing ability, glucose and triglycerides accumulation and expression levels of Drosophila insulin-like peptides (dIlps). Female and male flies were subjected to HSD and HFD for 10, 20 and 30 days. The obtained results showed clear differences in the effects of both diets on survival, glucose and triglyceride accumulation and dIlps expression, being gender and age determinant. The present study also suggested that weight gain does not seem to be an appropriate parameter to define fly obesity, since other characteristics appear to be more meaningful in the development of obesity phenotypes. Taken together, the results demonstrate a key role for both diets, HSD and HFD, to induce an obese fly phenotype with associated diseases. However, further studies are needed to elucidate the underlying molecular mechanisms how both diets differently affect fly metabolism.

The gastrointestinal system is responsible for the digestion and the absorption of nutrients. At the same time, it is essentially involved in the maintenance of immune homeostasis. The strongest antigen contact in an organism takes place in the digestive system showing the importance of a host to develop mechanisms allowing to discriminate between harmful and harmless antigens. An efficient intestinal barrier and the presence of a large and complex part of the immune system in the gut support the host to implement this task. The continuous ingestion of harmless antigens via the diet requires an efficient immune response to reliably identify them as safe. However, in some cases the immune system accidentally identifies harmless antigens as dangerous leading to various diseases such as celiac disease, inflammatory bowel diseases and allergies. It has been shown that the intestinal immune function can be affected by bioactive compounds derived from the diet. The present review provides an overview on the mucosal immune reactions in the gut and how bioactive food ingredients including secondary plant metabolites and probiotics mediate its health promoting effects with regard to the intestinal immune homeostasis.

Solanum anguivi Lam. fruits (SALF) are traditionally consumed as a remedy for type 2 diabetes mellitus (T2DM).

Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder of glucose homeostasis associated with a status of insulin resistance, impaired insulin signaling, β-cell dysfunction, impaired glucose and lipid metabolism, sub-clinical inflammation, and increased oxidative stress. Consuming fruits and vegetables rich in phytochemicals with potential antidiabetic effects may prevent T2DM and/or support a conservative T2DM treatment while being safer and more affordable for people from low-income countries. Solanum anguivi Lam. fruits (SALF) have been suggested to exhibit antidiabetic properties, potentially due to the presence of various phytochemicals, including saponins, phenolics, alkaloids, ascorbic acid, and flavonoids. For the saponin fraction, antidiabetic effects have already been reported. However, it remains unclear whether this is also true for the other phytochemicals present in SALF. This review article covers information on glucose homeostasis, T2DM pathogenesis, and also the potential antidiabetic effects of phytochemicals present in SALF, including their potential mechanisms of action.