Pigmented corn as a gluten-free source of polyphenols with anti-inflammatory and antioxidant properties in CaCo-2 cells

Supercritical CO2 Extraction of Bioactive Compounds from Corn Grains (Zea mays L., Hybrid Pri-15-7-16) with Metabolomic Profiling and Confocal Laser Microscopy

This study aimed to optimize supercritical CO2 extraction conditions, analyze bioactive compounds, and visualize their distribution in corn grains (Zea mays L., hybrid Pri-15-7-16). The optimal extraction conditions were identified as a pressure of 200 bar and a temperature of 55 °C, yielding 2.2 mg/g of bioactive compounds. The distribution of autofluorescent compounds within corn grain tissues was visualized using confocal laser scanning microscopy. Image analysis showed that the pericarp and aleurone layer cell walls were rich in autofluorescent compounds, while the endosperm cell walls exhibited low autofluorescence. Metabolomic analysis, combining high-performance liquid chromatography and mass spectrometry, identified 44 compounds in the extracts, including 30 polyphenolic compounds from subgroups such as polyphenolic acids, flavones, flavan-3-ols, flavonols, and anthocyanidins as well as 14 compounds from other chemical groups, including amino acids and fatty acids.

Co-encapsulation of vitamins B6 and B12 using zein/gum arabic nanocarriers for enhanced stability, bioaccessibility, and oral bioavailability

The present study aimed to fabricate a co-deliver system using zein/gum arabic (GA) polymers for enhanced stability and bioavailability of vitamins (B6 and B12). The anti-solvent evaporation method was used for the preparation of PC-ZG NPs (pyridoxine-cyanocobalamin zein-GA nanoparticles). The process conditions were statistically optimized using the design of Box-Behnken. The optimized conditions produced small-sized particles (∼170 nm) with high zeta potential (-31 mV) and efficient encapsulation for pyridoxine (61.6%) and cyanocobalamin (56.3%). Scanning electron microscopy, x-ray diffractometry, and Thermogravimetric analysis results confirmed that the developed formulation had a roughly spherical shape and an amorphous character with better thermal stability compared to free-forms of the vitamins. The results of the storage study showed no significant changes in nanoparticle size at 4, 25, and 37°C over a 90-day period. However, a slight variation in retention of the vitamins was observed during the initial period. The bioaccessibility of both the vitamins from PC-ZG NPs ranged between 56% and 62% post 6 h simulated digestion. In Caco-2 cells, the cellular uptake of vitamins was higher from nanoforms compared to the free-forms. Further, oral administration of PC-ZG NPs in rats exhibited 4.8- and 2.2-fold increases in relative bioavailability of vitamins B6 and B12, respectively. A significant reduction of plasma homocysteine level (p ˂ 0.05) in the treated group was also observed. Together, these results suggest that the developed nanoformulation has improved physicochemical properties with enhanced bioavailability and, hence, could be used as an effective delivery system for the vitamins in food and nutraceutical products.

Castanea sativa Mill. By-Products: Investigation of Potential Anti-Inflammatory Effects in Human Intestinal Epithelial Cells

Castanea sativa Mill. (C. sativa) processing and pruning generate several by-products, including leaves, burs, and shells (inner and outer teguments), which are considered an important source of high-value phytochemicals. Ellagitannins from C. sativa leaf extracts have been described to impair H. pylori viability and inflammation in gastric cells. Furthermore, chestnut shells showed an important anti-inflammatory effect in gastric epithelial cells. Dietary polyphenols, including tannins, have been reported to interfere with targets of inflammation, including the nuclear factor κB (NF-κB). A promising role as a further therapeutical target for gut disorders has been recently proposed for the regulatory subunit of hypoxia-inducible factor (HIF-1α), as a potential stabilizer of intestinal barrier integrity. Therefore, the main objective of this work is the chemical characterization of several chestnut by-products (bud, spiny bur, wood, pericarp and episperm), together with the exploitation of their anti-inflammatory properties in intestinal cells, scavenging capacity, and stability following gastrointestinal digestion. The chemical characterization confirmed the presence of bioactive polyphenols in the extracts, including ellagitannins. In CaCo-2 cells stimulated by an IL-1β-IFN-γ cocktail, nearly all chestnut by-products (50 µg/mL) inhibited the release of proinflammatory mediators (CXCL-10, IL-8, MCP-1, ICAM), along with the NF-κB-driven transcription, and induced the HRE-driven transcription. The stability of the most promising extracts, identified through PCA and cluster analysis, was addressed by in vitro gastrointestinal digestion. Despite the significant reduction in total polyphenol index of chestnut bud and wood after gastric and intestinal digestion, the activity of these extracts on both scavenging and anti-inflammatory parameters remained promising. These data contribute to exploit the potential of chestnut by-products as sources of dietary polyphenols with anti-inflammatory properties at the intestinal level. Moreover, this study could represent an important step to encourage the recycling and valorization of chestnut by-products, promoting the circular economy and reducing the environmental impact related to the management of agriculture waste.

In Vitro Insights into the Dietary Role of Glucoraphanin and Its Metabolite Sulforaphane in Celiac Disease

Sulforaphane is considered the bioactive metabolite of glucoraphanin after dietary consumption of broccoli sprouts. Although both molecules pass through the gut lumen to the large intestine in stable form, their biological impact on the first intestinal tract is poorly described. In celiac patients, the function of the small intestine is affected by celiac disease (CD), whose severe outcomes are controlled by gluten-free dietary protocols. Nevertheless, pathological signs of inflammation and oxidative stress may persist. The aim of this study was to compare the biological activity of sulforaphane with its precursor glucoraphanin in a cellular model of gliadin-induced inflammation. Human intestinal epithelial cells (CaCo-2) were stimulated with a pro-inflammatory combination of cytokines (IFN-γ, IL-1β) and in-vitro-digested gliadin, while oxidative stress was induced by H2O2. LC-MS/MS analysis confirmed that sulforaphane from broccoli sprouts was stable after simulated gastrointestinal digestion. It inhibited the release of all chemokines selected as inflammatory read-outs, with a more potent effect against MCP-1 (IC50 = 7.81 µM). On the contrary, glucoraphanin (50 µM) was inactive. The molecules were unable to counteract the oxidative damage to DNA (γ-H2AX) and catalase levels; however, the activity of NF-κB and Nrf-2 was modulated by both molecules. The impact on epithelial permeability (TEER) was also evaluated in a Transwell® model. In the context of a pro-inflammatory combination including gliadin, TEER values were recovered by neither sulforaphane nor glucoraphanin. Conversely, in the context of co-culture with activated macrophages (THP-1), sulforaphane inhibited the release of MCP-1 (IC50 = 20.60 µM) and IL-1β (IC50 = 1.50 µM) only, but both molecules restored epithelial integrity at 50 µM. Our work suggests that glucoraphanin should not merely be considered as just an inert precursor at the small intestine level, thus suggesting a potential interest in the framework of CD. Its biological activity might imply, at least in part, molecular mechanisms different from sulforaphane.

Polyphenols in Cereals: State of the Art of Available Information and Its Potential Use in Epidemiological Studies

Cereals are the basis of much of the world's daily diet. Recently, there has been considerable interest in the beneficial properties of wholegrains due to their content of phytochemicals, particularly polyphenols. Despite this, the existing data on polyphenolic composition of cereal-based foods reported in the most comprehensive databases are still not updated. Many cereal-based foods and phenolic compounds are missing, including pigmented ones. Observational epidemiological studies reporting the intake of polyphenols from cereals are limited and inconsistent, although experimental studies suggest a protective role for dietary polyphenols against cardiovascular disease, diabetes, and cancer. Estimating polyphenol intake is complex because of the large number of compounds present in foods and the many factors that affect their levels, such as plant variety, harvest season, food processing and cooking, making it difficult matching consumption data with data on food composition. Further, it should be taken into account that food composition tables and consumed foods are categorized in different ways. The present work provides an overview of the available data on polyphenols content reported in several existing databases, in terms of presence, missing and no data, and discusses the strengths and weaknesses of methods for assessing cereal polyphenol consumption. Furthermore, this review suggests a greater need for the inclusion of most up-to-date cereal food composition data and for the harmonization of standardized procedures in collecting cereal-based food data and adequate assessment tools for dietary intake.