Protective Role of Flavonoids against Intestinal Pro-Inflammatory Effects of Silver Nanoparticles

Protective effects of quercetin on intestinal barrier and cellular viability against silver nanoparticle exposure: insights from an intestinal co-culture model

The intestinal epithelium plays a pivotal role as a vital barrier between the external environment and the human body, regulating nutrient absorption and preventing the entry of harmful substances. The human oral exposure to silver nanoparticles (AgNP) raises concerns about their potential toxicity, especially at the intestinal level. The objective of this work was to investigate the potential pro-inflammatory effects of polyvinylpyrrolidone (PVP)-AgNP of two different sizes, 5 and 50 nm, at the intestinal level, while also assessing the protective ability of quercetin against these effects. To address this, an intestinal co-culture model comprising C2BBe1 cells and THP-1 derived macrophages was established, and the effects of 5 or 50 nm PVP-AgNP were studied, alone or in combination with quercetin, over two-time points, 4 and 24 hours. PVP-AgNP, of both sizes, disrupted the barrier integrity within 4 hours of exposure. However, a notable intensification in pro-inflammatory effects was evident only after 24 hours of exposure, especially with smaller PVP-AgNP (5 nm). This resulted in heightened cellular death, increased levels of reactive species, activation of nuclear factor kappa B (NF-кB), and production of interleukin (IL)-8. Quercetin demonstrates the ability to maintain barrier integrity and mitigate oxidative stress, thereby offering protection against the detrimental effects induced by AgNP at the intestinal level.

Quercetin protective potential against nanoparticle-induced adverse effects

The rapid development of nanotechnology has resulted in the widespread use of nanoparticles (NPs) in various sectors due to their unique properties and diverse applications. However, the increased exposure of humans to NPs raises concerns about their potential negative impact on human health and the environment. The pathways through which NPs exert adverse effects, including inflammation and oxidative stress, are primarily influenced by their size, shape, surface charge, and chemistry, underscoring the critical need to comprehend and alleviate their potential detrimental impacts. In this context, the natural flavonoid quercetin is a promising candidate for counteracting the toxicity induced by NPs due to its anti-inflammatory and antioxidant properties. This review provides an overview of the existing literature on quercetin's protective effects against NPs-induced toxicity, highlighting its therapeutic benefits and mechanisms of action, focusing on its ability to alleviate oxidative stress, inflammation, and cellular damage caused by various types of NPs. Insights from both in vitro and in vivo studies demonstrate the effectiveness of quercetin in preserving cellular function, modulating apoptotic pathways, and maintaining tissue integrity in the presence of NPs. The potential of quercetin as a natural therapeutic agent against NPs-induced toxicity provides valuable insights for safer use of NPs in various daily applications.

Exploring quercetin's protective potential against the pro-inflammatory effects of silver nanoparticles in C57BL/6J mice

The increasing prevalence of silver nanoparticles (AgNP) in various applications has sparked concerns about their potential adverse effects on human health. Hence, it is crucial to devise strategies to minimize their detrimental effects. Quercetin, a naturally occurring flavonoid present in human diet is known for its broad biological effects, including anti-inflammatory properties. Considering this, quercetin could serve as a promising strategy to protect the body against the harmful effects of AgNP. Thus, this study aimed to evaluate the potential protective role of quercetin against the deleterious effects induced by 5 nm polyvinylpyrrolidone (PVP)-AgNP in C57BL/6J mice. Using a novel administration technology (HaPILLness), mice were given a daily oral dose of AgNP at 1 mg/kg body weight (bw) or 10 mg/kg bw for 14 days, combined with daily IP injections of quercetin at 1 mg/kg bw. Our findings demonstrate that quercetin effectively attenuated the AgNP-induced intestinal inflammatory response, as demonstrated by reduced histological vascular and cellular alterations, along with a notable decrease in cytokine production, attributed to the inhibition of the nuclear factor (NF)-кB inflammatory pathway. Quercetin's protective effects extended to the liver and lungs, by reversing changes in the inflammatory and antioxidant markers cluster of differentiation (CD)4, superoxide dismutase 1 (SOD1) and catalase.

An Adverse Outcome Pathway for food nanomaterial-induced intestinal barrier disruption

Introduction

The ingestion of nanomaterials (NMs) may impair the intestinal barrier, but the underlying mechanisms remain evasive, and evidence has not been systematically gathered or produced. A mechanistic-based approach would be instrumental in assessing whether relevant NMs disrupt the intestinal barrier, thereby supporting the NM risk assessment in the food sector.

Methods

In this study, we developed an adverse outcome pathway (AOP) based on biological plausibility and by leveraging information from an existing NM-relevant AOP that leads to hepatic outcomes. We then extracted the current evidence from the literature for a targeted selection of NMs with high relevance to the food sector, namely, ZnO, CuO, FeO, SiO2, and Ag NMs and nanocellulose.

Results

We propose a new AOP (AOP 530) that starts with endocytic lysosomal uptake, leading to lysosomal disruption inducing mitochondrial dysfunction. Mitochondrial impairments can lead to cell injury/death and disrupt the intestinal barrier. The evidence collected supports that these food-related NMs can be taken up by intestinal cells and indicates that intestinal barrier disruption may occur due to Ag, CuO, and SiO2 NMs, while only few studies support this outcome for FeO and ZnO. Lysosomal disruption and mitochondrial dysfunction are rarely evaluated. For nanocellulose, none of the studies report toxicity-related events.

Conclusion

The collection of existing scientific evidence supporting our AOP linking NM uptake to intestinal barrier impairments allowed us to highlight current evidence gaps and data inconsistencies. These inconsistencies could be associated with the variety of stressors, biological systems, and key event (KE)-related assays used in different studies. This underscores the need for further harmonized methodologies and the production of mechanistic evidence for the safety regulatory assessment of NMs in the food sector.

Inhibition mechanism investigation of quercetagetin as a potential tyrosinase inhibitor

Tyrosinase is one important rate limiting enzyme in melanin synthesis, directly affecting the melanin synthesis. Quercetagetin is one active ingredient from marigold. Thence, the inhibition effects of quercetagetin against tyrosinase were investigated. The results showed quercetagetin could inhibit tyrosinase activity with IC50 value of 0.19 ± 0.01 mM and the inhibition type was a reversible mixed-type. Results of fluorescence quenching showed quercetagetin could quench tyrosinase fluorescence in static process. CD and 3D fluorescence results showed the interaction of quercetagetin to tyrosinase could change tyrosinase conformation to inhibit activity. Moreover, docking revealed details of quercetagetin's interactions with tyrosinase.

Epigallocatechin gallate alleviated the in vivo toxicity of ZnO nanoparticles to mouse intestine

To evaluate the oral toxicity of nanoparticles (NPs), it is necessary to consider the interactions between NPs and nutrient molecules. Recently, we reported that epigallocatechin gallate (EGCG), a healthy component in green tea, alleviated the toxicity of ZnO NPs to 3D Caco-2 spheroids in vitro. The present study investigated the combined effects of EGCG and ZnO NPs to mice in vivo. Mice were administrated with 35 or 105 mg/kg bodyweight ZnO NPs with or without the presence of 80 mg/kg bodyweight EGCG via gastric route, once a day, for 21 days, and the influences of EGCG on the toxicity of ZnO NPs to intestine were investigated. We found that EGCG altered the colloidal properties of ZnO NPs both in water and artificial intestine juice. As expected, ZnO NPs induced toxicological effects, such as decreased bodyweight, higher Chiu's scores, and ultrastructural changes in intestine, whereas EGCG alleviated these effects. Combined exposure to EGCG and ZnO NPs also changed trace element levels in mouse intestine. For example, the levels of Ti, Co, and Ni were only significantly elevated after co-exposure to EGCG and ZnO NPs, and Fe levels were only significantly decreased by ZnO NPs. Western blot analysis suggested that tight junction (TJ) and endoplasmic reticulum (ER) proteins were elevated by ZnO NPs, but EGCG inhibited this trend. Combined, these data suggested that gastric exposure to ZnO NPs induced intestinal damage, trace element imbalance, and TJ/ER protein expression in mouse intestine, whereas EGCG alleviated these effects of ZnO NPs.

Quercetagetin alleviates zearalenone-induced liver injury in rabbits through Keap1/Nrf2/ARE signaling pathway

Introduction: This study aimed to assess the alleviative effect of quercetagetin (QG) on zearalenone (ZEN)-induced liver injury in rabbits. Methods: Ninety 41-day-old healthy Hyla rabbits were randomly assigned into three groups, including a control (fed with basic diet), ZEN addition group (fed with basic diet + 600 μg/kg ZEN), and ZEN + QG addition group (fed with basic diet + 600 μg/kg ZEN + 100 mg/kg QG), with 30 rabbits per group. The duration of the experiment was 28 days. Results: The results revealed no significant differences in the average daily gain, average daily feed intake, the gain to feed ratio and the liver, kidney and spleen organ indexes (p > 0.05) between the rabbits across the three groups. However, the sacculus rotundus index of the rabbits in the control group was significantly higher than that in the ZEN + QG group (p < 0.05). The intake of ZEN-contaminated diet also significantly increased the activities or levels of alanine transaminase, alkaline phosphatase, total bile acid (TBA), total bilirubin, malondialdehyde, and interleukin-4 (IL-4) and enhanced the abundance of kelch-like ECH-associated protein 1 (Keap1), heat shock protein 70 (HSP70) and cysteine-aspartic acid protease-3 (Caspase-3) mRNA in the blood or liver tissue in ZEN group, compared to the control group (p < 0.05). On the contrary, the activities or levels of immunoglobulin A, complement 3, total antioxidant capacity, glutathione peroxidase (GSH-Px), superoxide dismutase, interleukin-10, and the abundance of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) mRNA were significantly decreased (p < 0.05). Supplementing the diet with QG still maintained significantly higher levels of TBA and IL-4, and the abundance of GSH-Px, HSP70, IL-4, and Caspase-3 mRNA in the blood and liver of rabbits in the ZEN + QG group than in the control group (p < 0.05). At the same time, the other indicators were restored to levels in the control group (p > 0.05). Discussion: In conclusion, QG alleviated the ZEN-induced oxidative damage and liver injury caused by inflammatory reaction through the Keap1-Nrf2-antioxidant response element (ARE) signal pathway, which protected the liver. This study revealed the alleviative effect of QG on the hepatotoxicity of ZEN in rabbits for the first time, providing a new perspective for applying QG and developing a ZEN antidote.

Betaine-modified hydroxyethyl cellulose (HEC): A biodegradable mucoadhesive polysaccharide exhibiting quaternary ammonium substructures

The aim of this study was to improve the mucoadhesive properties of hydroxyethyl cellulose (HEC) via the covalent attachment of betaine. Synthesis was carried out through esterification of HEC utilizing N-chlorobetainyl chloride. Betaine-modified HEC was characterized via FTIR and NMR analyses, ester quantification and zeta potential measurements. Enzymatic degradation and cell viability were also investigated. Moreover, rheological and mucoadhesive properties were evaluated. FTIR and NMR analyses confirmed the covalent attachment of betaine to HEC. Betaine-modified HEC contained 228.45±11.63 µmol/g ester bonds and its zeta potential was 0.37±0.19 mV. Enzymatic degradation studies showed the ability of lipase to cleave off betaine from HEC. Cytotoxicity studies demonstrated that betaine-modified HEC is up to a concentration of 0.3% not toxic. In comparison to unmodified HEC, betaine-modified HEC showed with mucus a 2.3- and 4-fold higher viscosity within 3 h and 6 h, respectively. Furthermore, betaine-modified HEC exhibited 23.5-fold higher mucoadhesive properties on porcine intestinal mucosa compared to unmodified HEC. In conclusion, betaine-modified HEC might be a useful biodegradable mucoadhesive polymer.

Effects of dietary supplementation with quercetagetin on nutrient digestibility, intestinal morphology, immunity, and antioxidant capacity of broilers

Quercetagetin (QG) is gaining increased attention as a potential alternative to in-feed antioxidants due to its antioxidant activity. This experiment was conducted to investigate the effects of dietary supplementation with QG on nutrient digestibility, intestinal morphology, immunity, and antioxidant capacity of broilers. Four hundred 1-day-old Ross 308 broilers were randomly assigned into 4 groups with 10 replicates in each group and 10 broilers in each replicate. The four dietary treatments included the basal diet supplemented with 0, 3.2, 4.8, or 6.4 mg/kg QG. The results showed that dietary supplementation with QG significantly promoted the broilers' apparent digestibility of phosphorus (P < 0.05), increased the villus height in jejunum and ileum, and reduced the crypt depth in jejunum and ileum, which significantly increased the ratio of villus height to crypt depth in the jejunum and ileum (P < 0.05). The dietary supplementation with QG also significantly enhanced the immunoglobulin G (IgG) and complement 4 (C4) levels in the blood (P < 0.05), the activity of total antioxidant capacity (T-AOC) in serum, jejunum mucosa, and ileum mucosa, the activity of superoxide dismutase (SOD) in the serum and liver (P < 0.05), and significantly up-regulated the kelch-like ECH-associated protein 1 (Keap1), nuclear factor E2 related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NAD(P)H: quinone oxidoreductase 1 (NQO-1), glutathione peroxidase (GSH-Px) and superoxide dismutase 1 (SOD1) mRNA expression levels in the jejunum mucosa, ileum mucosa, and liver tissues of broilers. Therefore, supplementing broilers' diets with QG can enhance the apparent digestibility of phosphorus, improve the structure and morphology of jejunum and ileum, promote immunity, and increase the activity of antioxidant enzymes and the antioxidantive capacity through the Nrf2/antioxidant response element (ARE) signaling pathway mediated by Keap1.

Interactions between Nanoparticles and Intestine

The use of nanoparticles (NPs) has surely grown in recent years due to their versatility, with a spectrum of applications that range from nanomedicine to the food industry. Recent research focuses on the development of NPs for the oral administration route rather than the intravenous one, placing the interactions between NPs and the intestine at the centre of the attention. This allows the NPs functionalization to exploit the different characteristics of the digestive tract, such as the different pH, the intestinal mucus layer, or the intestinal absorption capacity. On the other hand, these same characteristics can represent a problem for their complexity, also considering the potential interactions with the food matrix or the microbiota. This review intends to give a comprehensive look into three main branches of NPs delivery through the oral route: the functionalization of NPs drug carriers for systemic targets, with the case of insulin carriers as an example; NPs for the delivery of drugs locally active in the intestine, for the treatment of inflammatory bowel diseases and colon cancer; finally, the potential concerns and side effects of the accidental and uncontrolled exposure to NPs employed as food additives, with focus on E171 (titanium dioxide) and E174 (silver NPs).