Grape Seeds Proanthocyanidins: Advanced Technological Preparation and Analytical Characterization

Effects of acetylated polysaccharide on the prebiotic properties of grape seed proanthocyanidins - Based on in vitro fermentation with Artemisia sphaerocephala Krasch glucomannan

This study evaluated the impact of Artemisia sphaerocephala Krasch glucomannan with different degrees of acetyl group substitution (DS) on the prebiotic properties of grape seed proanthocyanidins (GSP). UV spectra, CIELab, and dynamic light scattering analyses indicated DS-influenced variable interactions between GSP and glucomannan. In vitro fermentation demonstrated that glucomannan enhanced the solubility of some phenolic compounds, and decreased the pH value of fermentation liquids. The production of acetate acid and total short chain fatty acids in the GSP fermentation liquid increased with the degree of DS of glucomannan. Notably, acetylated glucomannan exerted dramatic effects on GSP-induced gut microbiota modulation. The relative abundances of Bacteroides ovatus and Bacteroides decreased as DS increased. Meanwhile, Bacteroides acidifaciens and Akkermansia muciniphila have a positive correlation, even though the GSP-promoted enrichment of A. muciniphila was inhibited by the added glucomannan. Moreover, glucomannan enhanced the metabolism of nucleotides, secondary bile acid, and glycan inhibited by GSP. These findings suggest that acetylated glucomannan affect the prebiotic properties of GSP with its DS serving as a key factor.

Improved analysis of grape seed extract by liquid chromatography-high resolution mass spectrometry (LC-HRMS) reveals that proanthocyanidin-protein interaction mechanisms in cream depend on degree of polymerization

This study aimed to comprehensively characterize chemical profiles of proanthocyanidins (PACs) from grape seed extract (GSE), examine their interactions with proteins in a cream system, and define the mechanisms mediating PAC-protein interactions. GSE PACs were fractionated and characterized by thiolysis followed by liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis. New PACs with a degree of polymerization (DP) up to 16 were identified by improved HRMS data processing methods. In the model cream system, high-DP PACs exhibited greater precipitation capacity and protein binding than low-DP PACs. Low-DP PACs primarily engaged in hydrogen bonding, while high-DP PACs predominantly utilized multiple hydrophobic interaction sites to form cream protein aggregates. Furthermore, particle size and viscosity measurement of cream revealed a progressively DP-dependent increase in aggregated fat globules and cream viscosity. These findings enhanced our understanding of PACs' structural intricacies and highlighted their functional role as PAC-rich natural ingredients in creating structured cream systems.

Unraveling the parahormetic mechanism underlying the health-protecting effects of grapeseed procyanidins

Proanthocyanidins (PACs), the predominant constituents within Grape Seed Extract (GSE), are intricate compounds composed of interconnected flavan-3-ol units. Renowned for their health-affirming properties, PACs offer a shield against a spectrum of inflammation associated diseases, such as diabetes, obesity, degenerations and possibly cancer. While monomeric and dimeric PACs undergo some absorption within the gastrointestinal tract, their larger oligomeric and polymeric counterparts are not bioavailable. However, higher molecular weight PACs engage with the colonic microbiota, fostering the production of bioavailable metabolites that undergo metabolic processes, culminating in the emergence of bioactive agents capable of modulating physiological processes. Within this investigation, a GSE enriched with polymeric PACs was employed to explore in detail their impact. Through comprehensive analysis, the present study unequivocally verified the gastrointestinal-mediated transformation of medium to high molecular weight polymeric PACs, thereby establishing the bioaccessibility of a principal catabolite termed 5-(3',4'-dihydroxyphenyl)-γ-valerolactone (VL). Notably, our findings, encompassing cell biology, chemistry and proteomics, converge to the proposal of the notion of the capacity of VL to activate, upon oxidation to the corresponding quinone, the nuclear factor E2-related factor 2 (Nrf2) pathway-an intricate process that incites cellular defenses and mitigates stress-induced responses, such as a challenge brought by TNFα. This mechanistic paradigm seamlessly aligns with the concept of para-hormesis, ultimately orchestrating the resilience to stress and the preservation of cellular redox equilibrium and homeostasis as benchmarks of health.

Design of an Herbal Preparation Composed by a Combination of Ruscus aculeatus L. and Vitis vinifera L. Extracts, Magnolol and Diosmetin to Address Chronic Venous Diseases through an Anti-Inflammatory Effect and AP-1 Modulation

Chronic venous disease (CVD) is an often underestimated inflammatory pathological condition that can have a serious impact on quality of life. Many therapies have been proposed to deal with CVD, but unfortunately the symptoms recur with increasing frequency and intensity as soon as treatments are stopped. Previous studies have shown that the common inflammatory transcription factor AP-1 (activator protein-1) and nuclear factor kappa-activated B-cell light chain enhancer (NF-kB) play key roles in the initiation and progression of this vascular dysfunction. The aim of this research was to develop a herbal product that acts simultaneously on different aspects of CVD-related inflammation. Based on the evidence that several natural components of plant origin are used to treat venous insufficiency and that magnolol has been suggested as a putative modulator of AP-1, two herbal preparations based on Ruscus aculeatus root extracts, and Vitis vinifera seed extracts, as well as diosmetin and magnolol, were established. A preliminary MTT-based evaluation of the possible cytotoxic effects of these preparations led to the selection of one of them, named DMRV-2, for further investigation. First, the anti-inflammatory efficacy of DMRV-2 was demonstrated by monitoring its ability to reduce cytokine secretion from endothelial cells subjected to LPS-induced inflammation. Furthermore, using a real-time PCR-based protocol, the effect of DMRV-2 on AP-1 expression and activity was also evaluated; the results obtained demonstrated that the incubation of the endothelial cells with this preparation almost completely nullified the effects exerted by the treatment with LPS on AP-1. Similar results were also obtained for NF-kB, whose activation was evaluated by monitoring its distribution between the cytosol and the nucleus of endothelial cells after the different treatments.

Enhanced UV-B Radiation Induced the Proanthocyanidins Accumulation in Red Rice Grain of Traditional Rice Cultivars and Increased Antioxidant Capacity in Aging Mice

Proanthocyanidins are major UV-absorbing compounds. To clarify the effect of enhanced UV-B radiation on the proanthocyanidin synthesis and antioxidant capacity of traditional rice varieties in Yuanyang terraced fields, we studied the effects of enhanced UV-B radiation (0, 2.5, 5.0, 7.5 kJ·m^-2·d^-1) on the rice grain morphology, proanthocyanidins content, and synthesis. The effects of UV-B radiation on the antioxidant capacity of rice were evaluated by feeding aging model mice. The results showed that UV-B radiation significantly affected the grain morphology of red rice and increased the compactness of starch grains in the starch storage cells of central endosperm. The content of proanthocyanidin B2 and C1 in the grains was significantly increased by 2.5 and 5.0 kJ·m^-2·d^-1 UV-B radiation. The activity of leucoanthocyanidin reductase was higher in rice treated by 5.0 kJ·m^-2·d^-1 than other treatments. The number of neurons in the hippocampus CA1 of mice brain fed red rice increased. After 5.0 kJ·m^-2·d^-1 treatment, red rice has the best antioxidant effect on aging model mice. UV-B radiation induces the synthesis of rice proanthocyanidins B2 and C1, and the antioxidant capacity of rice is related to the content of proanthocyanidins.

A Comparative Study of the Influence of Various Fungal-Based Pretreatments of Grape Pomace on Phenolic Compounds Recovery

Wineries produce considerable amounts of grape pomace, which is a readily available natural source of bioactive phenolic compounds. In this study, grape pomace was used as a substrate for the cultivation of eleven filamentous fungi (Trametes versicolor TV6, Trametes versicolor TV8, Trametes versicolor AG613, Trametes gibbosa, Phanerochaete chrysosporium, Ceriporiopsis subvermispora, Pleurotus eryngii, Ganoderma lucidum, Ganoderma resinaceum, Humicola grisea, and Rhizopus oryzae) under solid-state conditions (SSF) for 15 days with the aim of improving the recovery of the individual phenolic compounds. Twenty-one phenolic compounds were quantified and the recovery of seventeen of them (gallic acid, ellagic acid, p-hydroxybenzoic acid, syringic acid, vanillic acid, 3,4-dihydroxybenzoic acid, ferulic acid, o-coumaric acid, p-coumaric acid, epicatechin gallate, galocatechin gallate, quercetin, kaempferol, procyanidin B1, procyanidin B2, resveratrol, and ε-viniferin) were positively affected by SSF. Ellagic acid is the most recovered compound, whose content increased 8.8-fold after 15 days of biological treatment with Ceriporiopsis subvermispora compared to the untreated initial sample. Among the microorganisms tested, the fungi Pleurotus eryngii and Rhizopus oryzae proved to be the most effective in increasing the recovery of most phenolic compounds (1.1–4.5-fold). In addition, the nutrient composition (proteins, ash, fats) of grape pomace was positively affected by the biological treatments.

Highly Active TiO2 Photocatalysts for Hydrogen Production through a Combination of Commercial TiO2 Material Selection and Platinum Co-Catalyst Deposition Using a Colloidal Approach with Green Reductants

In this contribution, four different commercial TiO2 catalysts (P25, P90, PC105, and PC500) were screened for the photocatalytic production of hydrogen using ethanol as the sacrificial agent. The physico-chemical properties of the TiO2 powders were characterized by using different methods. The photocatalysts mainly vary in the ratio of anatase and rutile phases, and in the surface area. It was found that the photocatalytic activity is governed by the surface area of the photocatalyst. Pure TiO2,PC500 showed the best performance, and in comparison to P25, the activity was more than twenty times higher due to its high surface area of about 270 m2 g−1. For further improvement of the photocatalytic activity, platinum nanoparticles (PtNPs) were immobilized onto TiO2,PC500 using two methods: a colloidal approach and a photodeposition method. For the reduction of the platinum salt precursor in the colloidal approach, different green reducing agents were used in comparison to ascorbic acid. The obtained platinum nanoparticles using natural reductants showed a higher photocatalytic activity due to the formation of smaller nanoparticles, as proven by transmission electron microscopy (TEM). The highest activity was obtained when mangosteen was used as the green reducing agent. Compared to ascorbic acid as a classical reducing agent, the photocatalytic activity of the Pt@TiO2,PC500 prepared with mangosteen was about 2–3 times higher in comparison to other as-prepared photocatalysts. The Pt@TiO2,PC500 catalyst was further studied under different operating conditions, such as catalyst and sacrificial agent concentration.

Proanthocyanidins and Where to Find Them: A Meta-Analytic Approach to Investigate Their Chemistry, Biosynthesis, Distribution, and Effect on Human Health

Proanthocyanidins (PACs) are a class of polyphenolic compounds that are attracting considerable interest in the nutraceutical field due to their potential health benefits. However, knowledge about the chemistry, biosynthesis, and distribution of PACs is limited. This review summarizes the main chemical characteristics and biosynthetic pathways and the main analytical methods aimed at their identification and quantification in raw plant matrices. Furthermore, meta-analytic approaches were used to identify the main plant sources in which PACs were contained and to investigate their potential effect on human health. In particular, a cluster analysis identified PACs in 35 different plant families and 60 different plant parts normally consumed in the human diet. On the other hand, a literature search, coupled with forest plot analyses, highlighted how PACs can be actively involved in both local and systemic effects. Finally, the potential mechanisms of action through which PACs may impact human health were investigated, focusing on their systemic hypoglycemic and lipid-lowering effects and their local anti-inflammatory actions on the intestinal epithelium. Overall, this review may be considered a complete report in which chemical, biosynthetic, ecological, and pharmacological aspects of PACs are discussed.