Quercetin protects jejunal mucosa from experimental intestinal ischemia reperfusion injury by activation of CD68 positive cells

Amplification of Cardioprotective Response of Remote Ischemic Preconditioning in Rats by Quercetin: Potential Role of Activation of mTOR-dependent Autophagy and Nrf2

OBJECTIVES

Noninvasive remote ischemic preconditioning (RIPC) is a practical, acceptable, and feasible conditioning technique reported to provide cardioprotection in myocardial ischemia-reperfusion injury (MIRI). It has been well-reported that quercetin possesses antioxidant and anti-inflammatory properties. This study investigates the modification of the cardioprotective response of RIPC by quercetin.

METHODS

Adult Wistar rats were randomized into 12 groups of six animals each. MIRI was induced by subjecting the isolated hearts of Wistar rats to global ischemia for 30 min, succeeded by reperfusion of 120 min after mounting on the Langendorff PowerLab apparatus. Hind limb RIPC was applied in four alternate cycles of ischemia and reperfusion of 5 min each by tying the pressure cuff before isolation of hearts.

RESULTS

MIRI was reflected by significantly increased infarct size, LDH-1, and CK-MB, TNF-α, TBARS, and decreased GSH, catalase, and hemodynamic index, and modulated Nrf2. Pretreatment of quercetin (25 and 50 mg/kg; i.p.) significantly attenuated the MIRI-induced cardiac damage and potentiated the cardioprotective response of RIPC at the low dose. Pretreatment of ketamine (10 mg/kg; i.p.), an mTOR-dependent autophagy inhibitor, significantly abolished the cardioprotective effects of quercetin and RIPC.

CONCLUSIONS

The findings highlight the modification of the cardioprotective effect of RIPC by quercetin and that quercetin protects the heart against MIRI through multiple mechanisms, including mTOR-dependent activation of autophagy and Nrf-2 activation.

The Synergistic Effect of Quince Fruit and Probiotics (Lactobacillus and Bifidobacterium) on Reducing Oxidative Stress and Inflammation at the Intestinal Level and Improving Athletic Performance during Endurance Exercise

Endurance exercise promotes damage at the intestinal level and generates a variety of symptoms related to oxidative stress processes, inflammatory processes, microbiota dysbiosis, and intestinal barrier damage. This study evaluated the effects of quince (Cydonia oblonga Mill.) and probiotics of the genera Lactobacillus and Bifidobacterium on intestinal protection and exercise endurance in an animal swimming model. Phytochemical characterization of the quince fruit demonstrated a total dietary fiber concentration of 0.820 ± 0.70 g/100 g and a fiber-bound phenolic content of 30,218 ± 104 µg/g in the freeze-dried fruit. UPLC-PDA-ESI-QqQ analyses identified a high content of polyphenol, mainly flavanols, hydroxycinnamic acids, hydroxybenzoic acids, flavonols, and, to a lesser extent, dihydrochalcones. The animal model of swimming was performed using C57BL/6 mice. The histological results determined that the consumption of the synbiotic generated intestinal protection and increased antioxidant (catalase and glutathione peroxidase enzymes) and anti-inflammatory (TNF-α and IL-6 and increasing IL-10) activities. An immunohistochemical analysis indicated mitochondrial biogenesis (Tom2) at the muscular level related to the increased swimming performance. These effects correlated mainly with the polyphenol content of the fruit and the effect of the probiotics. Therefore, this combination of quince and probiotics could be an alternative for the generation of a synbiotic product that improves exercise endurance and reduces the effects generated by the practice of high performance sports.

Supplementation of Dietary Quercetin and Vitamin E Promotes the Intestinal Structure and Immune Barrier Integrity in Aged Breeder Hens

In aged animals, the physiological functions of the gastrointestinal tract (GIT) are reduced. Dietary intervention is necessary to re-activate GIT functions. The objective of this study was to investigate the impacts of dietary combination of quercetin (Q) and vitamin E (VE) on the intestinal structure and barrier integrity in aged breeder chickens. A sum of 400 (65-wks-old) Tianfu breeder hens were randomly allotted into four (4) groups with four (4) replicates, and fed with basal diet; basal diet supplemented with 0.4g/kg of Q; basal diet supplemented with 0.2g/kg of VE; and basal diet supplemented with the combination of Q (0.4 g/kg) and VE (0.2 g/kg) for 14 weeks. At the end of the 14^th week, serum and gut segments were collected from eight hens per group for analyses. The results showed that Q+VE exerted synergistic effects on intestinal morphology by promoting villi height and crypt depth (P < 0.05), as well as mitigated the intestinal inflammatory damage of the aged hens, but decreased the concentration of serum D-lactate and diamine oxidase; and increased the levels of secretory immunoglobulin A (sIgA) and Mucin-2 mRNA (P < 0.05). Furthermore, the mRNA expression of intestinal tight junction proteins including occludin, ZO1, and claudin-1 was increased by Q+VE (P < 0.05). Moreover, Q+VE decreased the mRNA expression of the pro-inflammatory genes (TNF-α, IL-6, and IL-1β), and increased the expression of anti-inflammatory genes (IL-10 and IL-4) (P < 0.05). These results were consistent with the mRNA expression of Bax and Bcl-2. In addition, Q+VE protected the small intestinal tract from oxidative damage by increasing the levels of superoxide dismutase, total antioxidant capacity, glutathione peroxidase, catalase (P < 0.05), and the mRNA expression of SOD1 and GPx-2. However, Q+VE decreased malondialdehyde levels in the intestine compared to the control (P < 0.05). These results indicated that dietary Q+VE improved intestinal function in aged breeder hens, by protecting the intestinal structure and integrity. Therefore, Q+VE could act as an anti-aging agent to elevate the physiological functions of the small intestine in chickens.

Focus on the high therapeutic potentials of quercetin and its derivatives

BACKGROUND

Polyphenols and particularly flavonoids are of constant interest to the scientific community. Flavonoids are investigated for their biological and pharmacological purposes, notably as antioxidant, anticancer, antiviral and for their anti-inflammatory activities. Certainly, one of the best-known flavonols recognized for its therapeutic and preventive properties, is quercetin. Despite its biological interest, quercetin suffer from some drawbacks, mainly related to its bioavailability. Hence, its synthetic or biosynthetic derivatives have been the subject of intensive research. The health-promoting biological activities of flavonols and derivatives mainly arise from their capacity to disrupt the host-pathogen interactions and/or to regulate host cellular functions including oxidative processes and immunological responses. In the age of coronavirus pandemic, the anti-inflammatory and antiviral potential of flavonols should be put forward to explore these substances for decreasing the viral load and inflammatory storm caused by the infection.

PURPOSE OF STUDY

The present review will decipher and discuss the antioxidant, anti-inflammatory and antiviral capacities of major flavonol with a focus on the molecular basis and structure-activity relationships.

STUDY DESIGN

Current study used a combination of quercetin derivatives, pathway, antioxidant, anti-inflammatory, antiviral activities as keywords to retrieve the literature. This study critically reviewed the current literature and presented the ability of natural analogs of quercetin having superior antioxidant, anti-inflammatory and antiviral effects than the original molecule.

RESULTS

This review allowed the identification of relevant key structure-activity relationship elements and highlight approaches on the mechanisms governing the antioxidant, antiviral and anti-inflammatory activities.

CONCLUSION

Through a critical analysis of the literature, flavonols and more precisely quercetin derivatives reviewed and found to act simultaneously on inflammation, virus and oxidative stress, three key factors that may lead to life threatening diseases.

A review of the protective effects of quercetin-rich natural compounds for treating ischemia-reperfusion injury

Ischemia-reperfusion (IR) injury causes dysfunction of tissues and organs, and oxidative stress plays an important role. During IR, reactive oxygen species (ROS) are increased. Antioxidants are used to decrease ROS associated with IR. We review the protective effects of quercetin-rich natural antioxidants against IR. We searched PubMed, ScienceDirect, Scopus and Cochrane databases using the keywords: ischemic reperfusion, quercetin, antioxidant and herbal medicine. The effects of quercetin during IR have been reported for animal models in vitro and in vivo. Quercetin-rich plants including Abelmoschus esculentus, coriander, Hypericum perforatum, onion, Psidium guajava, buckwheat and Rosa laevigata Michx have been used to reduce oxidative stress damage to various organs during IR.

Occlusion of the Superior Mesenteric Artery in Rats Reversed by Collateral Pathways Activation: Gastric Pentadecapeptide BPC 157 Therapy Counteracts Multiple Organ Dysfunction Syndrome; Intracranial, Portal, and Caval Hypertension; and Aortal Hypotension

Gastric pentadecapeptide BPC 157 therapy counteracts multiple organ dysfunction syndrome in rats, which have permanent occlusion of the superior mesenteric artery close to the abdominal aorta. Previously, when confronted with major vessel occlusion, its effect would rapidly activate collateral vessel pathways and resolve major venous occlusion syndromes (Pringle maneuver ischemia, reperfusion, Budd-Chiari syndrome) in rats. This would overwhelm superior mesenteric artery permanent occlusion, and result in local, peripheral, and central disturbances. Methods: Assessments, for 30 min (gross recording, angiography, ECG, pressure, microscopy, biochemistry, and oxidative stress), included the portal hypertension, caval hypertension, and aortal hypotension, and centrally, the superior sagittal sinus hypertension; systemic arterial and venous thrombosis; ECG disturbances; MDA-tissue increase; and multiple organ lesions and disturbances, including the heart, lung, liver, kidney, and gastrointestinal tract, in particular, as well as brain (cortex (cerebral, cerebellar), hypothalamus/thalamus, hippocampus). BPC 157 therapy (/kg, abdominal bath) (10 µg, 10 ng) was given for a 1-min ligation time. Results: BPC 157 rapidly recruits collateral vessels (inferior anterior pancreaticoduodenal artery and inferior mesenteric artery) that circumvent occlusion and ascertains blood flow distant from the occlusion in the superior mesenteric artery. Portal and caval hypertension, aortal hypotension, and, centrally, superior sagittal sinus hypertension were attenuated or eliminated, and ECG disturbances markedly mitigated. BPC 157 therapy almost annihilated venous and arterial thrombosis. Multiple organ lesions and disturbances (i.e., heart, lung, liver, and gastrointestinal tract, in particular, as well as brain) were largely attenuated. Conclusions: Rats with superior mesenteric artery occlusion may additionally undergo BPC 157 therapy as full counteraction of vascular occlusion-induced multiple organ dysfunction syndrome.

Effects of dietary quercetin on the antioxidative status and cecal microbiota in broiler chickens fed with oxidized oil

This study was conducted to evaluate the effects of quercetin on the antioxidant ability, intestinal barrier functions, and cecal microbiota in broiler chickens fed with oxidized soya oil. Four hundred eighty male Arbor Acres broilers were randomly assigned to 5 treatments, each involving 8 cages (12 birds per cage). The treatment groups were as follows: the control group, birds fed with basal diets containing oxidized oil, and birds fed with basal diets containing oxidized oil and supplemented with 200 ppm of quercetin, 400 ppm of quercetin, and 800 ppm of quercetin. The results showed that dietary supplementation with quercetin at a dose of 400 ppm or 800 ppm alleviated the increased serum malondialdehyde (MDA) level induced by oxidized oil on day 11 (P = 0.005) and reversed the increased MDA level in the mucosa on day 11 (P = 0.021). Quercetin significantly upregulated the transcription of nuclear factor erythroid 2–related factor 2 (Nrf2) and its downstream genes such as catalase (P < 0.001), superoxide dismutase 1 (P < 0.001), glutathione peroxidase 2 (P = 0.018), heme oxygenase-1 (HO-1) (P = 0.0), and thioredoxin (P = 0.002) and reversed the mRNA expression of HO-1 (P = 0.007) in the ileal mucosa. Tight junction protein 1 was only downregulated by oxidized oil (P = 0.013). In addition, quercetin (800 ppm) alleviated the decreased mRNA expression of mucin 2 (MUC2), which contributed to the intestinal chemical barrier (P = 0.039). The supplemental dose of 400 ppm of quercetin was able to promote Lactobacillus in the cecum, which enhanced the gastrointestinal tract health. In summary, these results indicated that quercetin ameliorated the oxidized oil–induced oxidative stress by upregulating the transcription of Nrf2 and its downstream genes to restore redox balance and reinforced the intestinal barrier via higher expression and secretion of MUC2 and facilitating the growth of Lactobacillus in the cecum. Therefore, quercetin could be a potential feed additive that can be applied in poultry production for amelioration of oxidative stress caused by oxidized oil and preventing the potential invasion of exogenous pathogens.

Enhancing the potential preclinical and clinical benefits of quercetin through novel drug delivery systems

Quercetin is reported to have numerous pharmacological actions, including antidiabetic, anti-inflammatory and anticancer activities. The main mechanism responsible for its pharmacological activities is its ability to quench reactive oxygen species (ROS) and, hence, decrease the oxidative stress responsible for the development of various diseases. Despite its proven therapeutic potential, the clinical use of quercetin remains limited because of its low aqueous solubility, bioavailability, and substantial first-pass metabolism. To overcome this, several novel formulations have been reported. In this review, we focus on the applications of quercetin extract as well as its novel formulations for treating different disorders. We also examine its proposed mechanism of action of quercetin.

Quercetin protects against intestinal barrier disruption and inflammation in acute necrotizing pancreatitis through TLR4/MyD88/p38 MAPK and ERS inhibition

OBJECTIVE

To investigate the effects of quercetin on intestinal barrier disruption and inflammation in acute necrotizing pancreatitis (ANP) in rats, and its possible mechanism.

METHODS

ANP was established by retrograde injection of 3.5% sodium taurocholate into the biliopancreatic duct, and quercetin (50 mg/kg × 3) was administered by intraperitoneal injection prior to and after ANP induction. Pancreatitis was assessed by pancreatic histopathology, plasma amylase, pancreatic myeloperoxidase (MPO) activity, IL-1β, TNFα and IL-6 levels. Injury of the distal ileum was assessed by histological evaluation. The ultrastructural changes of ileal epithelial cells were examined by transmission electron microscope (TEM). Intestinal barrier function was estimated by plasma diamine oxidase (DAO), d-lactate, endotoxin; and intestinal tight junction proteins including zonula occludens-1 (ZO-1), claudin 1, occludin; and bacterial translocation. Intestinal inflammation was determined by IL-1β, TNFα and IL-17 A expression. TLR4, MyD88, pp38 MAPK, and endoplasmic reticulum stress (ERS)-related molecules (Bip, p-IRE1α, sXBP1, p-eIF2α, ATF6) were measured by immunohistochemistry and WB.

RESULTS

Quercetin intervention attenuated pancreatic and ileal pathological damages in ANP (P < 0.05), ameliorated intestinal barrier disruption and inflammation (P < 0.05). Meantime, QE significantly suppressed intestinal TLR4/MyD88/p38 MAPK pathway and ERS activation.

CONCLUSIONS

Quercetin plays a protective role against intestinal barrier disruption and inflammation in ANP, probably partly by inhibiting TLR4/MyD88/p38 MAPK and ERS activation.