All Polyphenols Are Not Created Equal: Exploring the Diversity of Phenolic Metabolites

Assessing the stability of polyphenol content in red rooibos herbal tea using traditional methods and high-resolution mass spectrometry: Implications for studying dietary interventions in preclinical rodent studies

Preclinical rodent models are used to examine the relationship between tea consumption and bone health, where tea is available for rodents and typically replaced weekly. However, the extent to which the tea polyphenols change over time remains uncertain, despite its importance in preparing tea during preclinical rodent trials. Using an untargeted molecular approach, we applied a liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOFMS) system to assess the molecular profile of red rooibos teas throughout a 6-day aging period. We found a significant, 3-fold decrease of polyphenols involved in bone metabolism, including m-coumaric acid, catechin derivatives and courmaroyl tartaric acid over 6 days, likely due to photochemical decomposition and autooxidation within tea extracts. Using a novel untargeted workflow for polyphenol characterization, our findings revealed the complexity of polyphenols in red rooibos teas that can inform the evidence-based decisions of how often to change teas during in vivo rodent trials.

A pH-sensitive silica nanoparticles for colon-specific delivery and controlled release of catechin: Optimization of loading efficiency and in vitro release kinetics

Catechin is a naturally occurring flavonoid of the flavan-3-ol subclass with numerous biological functions; however, these benefits are diminished due to several factors, including low water solubility and degradation in the stomach's harsh environment. So, this study aimed to develop an intelligent catechin colon-targeting delivery system with a high loading capacity. This was done by coating surface-decorated mesoporous silica nanoparticles with a pH-responsive enteric polymer called Eudragit®-S100. The pristine wormlike mesoporous silica nanoparticles (< 100 nm) with high surface area and large total pore volume were effectively synthesized and modified with the NH2 group using the post-grafting strategy. Various parameters, including solvent polarity, catechin-carrier mass ratio, and adsorption time, were studied to improve the loading of catechin into the aminated silica nanoparticles. Next, the negatively charged Eudragit®-S100 was electrostatically coated onto the positively charged aminated nanocarriers to shield the loaded catechin from the acidic environment of the stomach (pH 1.9) and to facilitate site-specific delivery in the acidic environment of the colon (pH 7.4). The prepared nanomaterials were evaluated using several methods, including The Brauner-Emmett-Teller, surface area analyzer, zeta sizer, Field Emission Scanning Electron Microscope, Powder X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, Energy-Dispersive X-ray Spectroscopy, and Differential Scanning Calorimetry. In vitro dissolution studies revealed that Eudragit®-S100-coated aminated nanomaterials prevented the burst release of the loaded catechin in the acidic environment, with approximately 90% of the catechin only being released at colonic pH (pH > 7) with a supercase II transport mechanism. As a result, silica nanoparticles coated with Eudragit®-S100 would provide an innovative and promising approach in targeted nanomedicine for the oral delivery of catechin and related medicines for treating diseases related to the colon, such as colorectal cancer and irritable bowel syndrome.

Food Polyphenols as Preventive Medicine

Reactive oxygen species (ROS) are the initiators in foods and in the stomach of oxidized dietary lipids, proteins, and lipid-oxidation end-products (ALEs), inducing in humans the development of several chronic diseases and cancer. Epidemiological, human clinical and animal studies supported the role of dietary polyphenols and derivatives in prevention of development of such chronic diseases. There is much evidence that polyphenols/derivatives at the right timing and concentration, which is critical, acts mostly in the aerobic stomach and generally in the gastrointestinal tract as reducing agents, scavengers of free radicals, trappers of reactive carbonyls, modulators of enzyme activity, generators of beneficial gut microbiota and effectors of cellular signaling. In the blood system, at low concentration, they act as generators of electrophiles and low concentration of H2O2, acting mostly as cellular signaling, activating the PI3K/Akt-mediated Nrf2/eNOS pathways and inhibiting the inflammatory transcription factor NF-κB, inducing the cells, organs and organism for eustress, adaptation and surviving.

Progression to Obesity: Variations in Patterns of Metabolic Fluxes, Fat Accumulation, and Gastrointestinal Responses

Obesity is a multifactorial disorder that is remarkably heterogeneous. It presents itself in a variety of phenotypes that can be metabolically unhealthy or healthy, associate with no or multiple metabolic risk factors, gain extreme body weight (super-responders), as well as resist obesity despite the obesogenic environment (non-responders). Progression to obesity is ultimately linked to the overall net energy balance and activity of different metabolic fluxes. This is particularly evident from variations in fatty acids oxidation, metabolic fluxes through the pyruvate-phosphoenolpyruvate-oxaloacetate node, and extracellular accumulation of Krebs cycle metabolites, such as citrate. Patterns of fat accumulation with a focus on visceral and ectopic adipose tissue, microbiome composition, and the immune status of the gastrointestinal tract have emerged as the most promising targets that allow personalization of obesity and warrant further investigations into the critical issue of a wider and long-term weight control. Advances in understanding the biochemistry mechanisms underlying the heterogenous obesity phenotypes are critical to the development of targeted strategies to maintain healthy weight.

Effects of Different Cooking Methods on Phenol Content and Antioxidant Activity in Sprouted Peanut

Peanut sprout is a high-quality healthy food, which not only has beneficial effects, but also a higher phenol content than peanut seed. In this study, peanut sprout was treated with five cooking methods, namely boiling, steaming, microwave heating, roasting, and deep-frying, and the phenol content, monomeric phenol composition, and antioxidant activity were determined. The results showed that, compared with unripened peanut sprout, the total phenol content (TPC) and total flavonoid content (TFC) decreased significantly after the five ripening processes, and the highest retention of phenols and flavonoids was associated with microwave heating (82.05% for TPC; 85.35% for TFC). Compared with unripened peanut sprout, the monomeric phenol composition in germinated peanut was variable after heat processing. After microwave heating, except for a significant increase in the cinnamic acid content, no changes in the contents of resveratrol, ferulic acid, sinapic acid, and epicatechin were observed. Furthermore, there was a significant positive correlation of TPC and TFC with 2,2-diphenyl-1-picrylhydrazyl scavenging capacity, 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging capacity, and ferric ion reducing antioxidant power in germinated peanut, but not with hydroxyl free radical scavenging capacity, in which the main monomer phenolic compounds were resveratrol, catechin, and quercetin. The research results indicate that microwave heating can effectively retain the phenolic substances and antioxidant activity in germinated peanuts, making it a more suitable ripening and processing method for germinated peanuts.

Berries in Microbiome-Mediated Gastrointestinal, Metabolic, and Immune Health

PURPOSE OF REVIEW

Current research has shown that berry-derived polymeric substrates that resist human digestion (dietary fibers and polyphenols) are extensively metabolized in the gastrointestinal tract dominated by microbiota. This review assesses current epidemiological, experimental, and clinical evidence of how berry (strawberry, blueberry, raspberry, blackberry, cranberry, black currant, and grapes) phytochemicals interact with the microbiome and shape health or metabolic risk factor outcomes.

RECENT FINDINGS

There is a growing evidence that the compositional differences among complex carbohydrate fractions and classes of polyphenols define reversible shifts in microbial populations and human metabolome to promote gastrointestinal health. Interventions to prevent gastrointestinal inflammation and improve metabolic outcomes may be achieved with selection of berries that provide distinct polysaccharide substrates for selective multiplication of beneficial microbiota or oligomeric decoys for binding and elimination of the pathogens, as well as phenolic substrates that hold potential to modulate gastrointestinal mucins, reduce luminal oxygen, and release small phenolic metabolites signatures capable of ameliorating inflammatory and metabolic perturbations. These mechanisms may explain many of the differences in microbiota and host gastrointestinal responses associated with increased consumption of berries, and highlight potential opportunities to intentionally shift gut microbiome profiles or to modulate risk factors associated with better nutrition and health outcomes.

Effect of Wild Blueberry Metabolites on Biomarkers of Gastrointestinal and Immune Health In Vitro

Wild blueberries (Vaccinium angustifolium Aiton.) are a rich source of dietary fiber and (poly)phenols with gastrointestinal and immune health-promoting properties, however, their mechanisms of action on the intestinal epithelial cells and transient tissue macrophages remain to be elucidated. In this study, we evaluated the individual effects of anthocyanins, short-chain fatty acids (metabolites derived from fiber), and a series of hydroxycinnamic and hydroxybenzoic acid metabolites common to anthocyanins and other polyphenols on epithelial gut homeostasis in human colon epithelial CCD-18 cells and murine RAW 264.7 macrophages. Gastrointestinal cell migration was enhanced in response to anthocyanin glucosides with the maximum effect observed for malvidin-3-glucoside, and a structural subset of hydroxybenzoic acids, especially 2-hydroxybenzoic acid. Enhanced staining for ZO-1 protein in the junctional complexes was observed in CCD-18 cells treated with malvidin and butyrate, as well as several phenolic metabolites, including hydroxybenzoic and hydroxycinnamic acids. Nitric oxide production and pro-inflammatory gene expression profiles in the LPS-stimulated macrophages were mostly affected by treatments with 3-caffeoylquinic (chlorogenic) and 3,4-dihydroxycinnamic (caffeic) acids, as well as 2-hydroxybenzoic acid. This study lays the foundation for future investigations evaluating the effects of dietary interventions on managing gastrointestinal and inflammatory pathophysiological outcomes.