Different Concentrations Of Quercetin Research Articles

Development of a novel active edible coating containing hydroxyapatite for food shelf-life extension

In this work, active alginate-based coatings were developed using hydroxyapatite nanoparticles as potential carriers for quercetin glycoside compounds. The coatings were produced through the layer-by-layer method and loaded with different concentrations of quercetin and hydroxyapatite/quercetin complexes. In-vitro release studies of the quercetin through the coatings were performed in an aqueous medium: even if the hydroxyapatite nanocrystals slow down the diffusion process, quercetin released reached the equilibrium in one day for all coatings. Lastly, antimicrobial tests show that all active coatings display antibacterial activity against Pseudomonas fluorescens. This study highlights the real possibility of applying active edible coating loaded with hydroxyapatite/quercetin complexes to the food shelf life extension.

Quercetin Improves the Endocrine Function of Rat Testicular Tissue Under in Vitro Conditions

Summary Compounds of natural origin are often used for their beneficial effects on the male endocrine system and the synthesis of steroid biomolecules in testicular tissue. One of such compounds is quercetin (QUE), which belongs to the flavonoid family and is found in a wide range of vegetables, fruits and plant products. The purpose of this study is to evaluate the impact of QUE on the endocrine function of rat testicular fragments under in vitro conditions. Testicular fragments from adult Wistar rats (n=9), cultured in the D-MEM medium with different concentrations of QUE (namely 1, 10 and 100 µmol/L) for 24 h at 37°C (5% CO2), were used in the experiment conducted. Following culture, the medium was separated and the levels of cholesterol (CHOL) and male hormones were measured. CHOL values were quantified spectrophotometrically, whereas the concentrations of androstenedione (ANDRO), dehydropeiandrosterone (DHEA) and testosterone (TEST) were quantified using the enzyme-linked immunosorbent assay (ELISA) commercial kit. The results obtained indicate that 10 µmol/L QUE significantly increased (P<0.001; P<0.05) the concentrations of all the steroid biomolecules considered (CHOL, ANDRO, DHEA and TEST) when compared to the control samples. Accordingly, our findings confirm the positive impact of QUE on the endocrine function and steroidogenesis of rat testicular tissue under in vitro conditions.

Quercetin induces pro-apoptotic autophagy via SIRT1/AMPK signaling pathway in human lung cancer cell lines A549 and H1299 in vitro.

BackgroundQuercetin, a natural flavonoid compound, is a potent cancer therapeutic agent widely found in fruit and vegetables. It has been reported to induce growth inhibition and apoptosis in both A549 and H1299 human lung cancer cells. However, the effect of quercetin‐induced autophagy on apoptosis and the possible autophagy mechanism in A549 and H1299 cells have not yet been critically examined.MethodsA549 and H1299 cells were treated with different concentrations of quercetin for 24 hours. Cell growth was measured by cell counting kit‐8 (CCK‐8) assay, whereas apoptosis was assessed by western blotting analysis of apoptotic proteins. The levels of proteins and genes involved in autophagy were determined by western blotting and reverse transcription polymerase chain reaction (RT‐PCR), respectively. Autophagosomes were also observed by transmission electron microscopy (TEM) and LC3 immunofluorescence.ResultsQuercetin inhibited cell viability and induced mitochondria‐dependent apoptosis in both A549 and H1299 cells in a dose‐dependent. Moreover, quercetin also promoted the expression of LC3‐II and beclin 1 and suppressed the expression of p62. The mRNA levels of LC3‐II, beclin 1, Atg5, Atg7, and Atg12 were upregulated by quercetin treatment. Autophagy inhibition with 3‐methyladenine could effectively inhibit quercetin‐induced apoptosis. In addition, quercetin dose‐dependently elevated the levels of SIRT1 protein and the pAMPK–AMPK ratio. Quercetin‐induced autophagy was attenuated by SIRT1 inhibitor EX527 and SirT1 knockdown by small interfering RNA (siRNA).ConclusionsQuercetin‐induced autophagy contributes to apoptosis in A549 and H1299 lung cancer cells, which involved the SIRT1/AMPK signaling pathway.

Quercetin Arrests in G2 phase, Upregulates INXS LncRNA and Downregulates UCA1 LncRNA in MCF-7 Cells.

One of the most prevalent malignancies, which have severe effects on women's health, is breast cancer. Quercetin, a flavonoid found in vegetables, tea, and fruits, is known to have bioactive properties, such as anti-inflammatory, anti-oxidant, as well as anti-cancer. Long non-coding RNAs (lncRNAs) have been recognized to function as primary regulators of diverse cellular processes, including differentiation, development, and cell fate. INXS and UCA1 are lncRNAs that are up regulated and down regulated respectively in cancer cells. This research aimed to assess the impact of quercetin on the expression of INXS and UCA1 genes in MCF-7 cells. Various quercetin concentrations at different times were used to treat MCF-7 cells. The cell viability and IC50 values were determined using MTT assay. Then, MCF-7 cells were incubated with various quercetin concentrations for 24, 48, and 72 h. Cell cycle analyses were evaluated by flow cytometry. The levels of INXS and UCA1 gene expression compared with the GAPDH gene at different concentrations of quercetin were quantified using real-time PCR method. Based on the results, quercetin exerted a dose- and time-dependent inhibitory impact on the viability of MCF-7 cells. Furthermore, quercetin induced cell cycle arrest at the G2 phase in MCF-7 cells. Also, quercetin induced INXS upregulation and UCA1 downregulation in the MCF-7 cell line. These data suggest that quercetin might increase cell death by up regulating INXS and down regulating UCA1 lncRNAs in MCF-7 cells.

Quercetin inhibits virulence properties of Porphyromas gingivalis in periodontal disease

Porphyromonas gingivalis is a causative agent in the onset and progression of periodontal disease. This study aims to investigate the effects of quercetin, a natural plant product, on P. gingivalis virulence properties including gingipain, haemagglutinin and biofilm formation. Antimicrobial effects and morphological changes of quercetin on P. gingivalis were detected. The effects of quercetin on gingipains activities and hemolytic, hemagglutination activities were evaluated using chromogenic peptides and sheep erythrocytes. The biofilm biomass and metabolism with different concentrations of quercetin were assessed by the crystal violet and MTT assay. The structures and thickness of the biofilms were observed by confocal laser scanning microscopy. Bacterial cell surface properties including cell surface hydrophobicity and aggregation were also evaluated. The mRNA expression of virulence and iron/heme utilization was assessed using real time-PCR. Quercetin exhibited antimicrobial effects and damaged the cell structure. Quercetin can inhibit gingipains, hemolytic, hemagglutination activities and biofilm formation at sub-MIC concentrations. Molecular docking analysis further indicated that quercetin can interact with gingipains. The biofilm became sparser and thinner after quercetin treatment. Quercetin also modulate cell surface hydrophobicity and aggregation. Expression of the genes tested was down-regulated in the presence of quercetin. In conclusion, our study demonstrated that quercetin inhibited various virulence factors of P. gingivalis.

Potential Implications of Quercetin and its Derivatives in Cardioprotection.

Quercetin (QCT) is a natural polyphenolic compound enriched in human food, mainly in vegetables, fruits and berries. QCT and its main derivatives, such as rhamnetin, rutin, hyperoside, etc., have been documented to possess many beneficial effects in the human body including their positive effects in the cardiovascular system. However, clinical implications of QCT and its derivatives are still rare. In the current paper we provide a complex picture of the most recent knowledge on the effects of QCT and its derivatives in different types of cardiac injury, mainly in ischemia-reperfusion (I/R) injury of the heart, but also in other pathologies such as anthracycline-induced cardiotoxicity or oxidative stress-induced cardiac injury, documented in in vitro and ex vivo, as well as in in vivo experimental models of cardiac injury. Moreover, we focus on cardiac effects of QCT in presence of metabolic comorbidities in addition to cardiovascular disease (CVD). Finally, we provide a short summary of clinical studies focused on cardiac effects of QCT. In general, it seems that QCT and its metabolites exert strong cardioprotective effects in a wide range of experimental models of cardiac injury, likely via their antioxidant, anti-inflammatory and molecular pathways-modulating properties; however, ageing and presence of lifestyle-related comorbidities may confound their beneficial effects in heart disease. On the other hand, due to very limited number of clinical trials focused on cardiac effects of QCT and its derivatives, clinical data are inconclusive. Thus, additional well-designed human studies including a high enough number of patients testing different concentrations of QCT are needed to reveal real therapeutic potential of QCT in CVD. Finally, several negative or controversial effects of QCT in the heart have been reported, and this should be also taken into consideration in QCT-based approaches aimed to treat CVD in humans.

Potential Therapeutic Anti-Inflammatory and Immunomodulatory Effects of Dihydroflavones, Flavones, and Flavonols

Systemic inflammation, circulating immune cell activation, and endothelial cell damage play a critical role in vascular pathogenesis. Flavonoids have shown anti-inflammatory effects. In this study, we investigated the effects of different flavonoids on the production of pro-inflammatory interleukin (IL) 1β, 6, and 8, and tumor necrosis factor α (TNF-α), in peripheral blood cells. Methods: We studied the whole blood from 36 healthy donors. Lipopolysaccharide (LPS)-stimulated (0.5 μg/mL) whole-blood aliquots were incubated in the presence or absence of different concentrations of quercetin, rutin, naringenin, naringin, diosmetin, and diosmin for 6 h. Cultures were centrifuged and the supernatant was collected in order to measure IL-1β, TNF-α, IL-6, and IL-8 production using specific immunoassay techniques. This production was significantly inhibited by quercetin, naringenin, naringin, and diosmetin, but in no case by rutin or diosmin. Flavonoids exert different effects, maybe due to the differences between aglycons and glucosides present in their chemical structures. However, these studies suggest that quercetin, naringenin, naringin, and diosmetin could have a potential therapeutic effect in the inflammatory process of cardiovascular disease.

Quercetin radiosensitizes non-small cell lung cancer cells through the regulation of miR-16-5p/WEE1 axis.

Quercetin, a widely distributed bioflavonoid, plays a role in combating diverse human cancers including non-small cell lung cancer (NSCLC). However, the role of quercetin in reversing the radioresistance of NSCLC cells and its underlying mechanism are far from being elucidated. Radiation-resistant NSCLC cell lines were established. Quantitative real-time PCR (qRT-PCR) was used to detect the expression of miR-16-5p and WEE1 G2 checkpoint kinase (WEE1) mRNA in radiation-resistant cells. After being treated with different concentrations of quercetin and different doses of X-ray, cell proliferation and apoptosis were monitored by CCK-8 assay, colony formation assay, and flow cytometry, respectively. Ultimately, the targeting relationship between miR-16-5p and WEE1 was verified via a dual fluorescent reporter gene assay. The expression of miR-16-5p was down-regulated in radiation-resistant cells, while the expression of WEE1 was up-regulated. Quercetin enhanced the radiosensitivity of NSCLC cells in a dose- and time-dependent manner. Furthermore, quercetin treatment increased the expression of miR-16-5p and decreased the expression of WEE1. The function of quercetin was reversed by miR-16-5p inhibitors or the transfection of WEE1 overexpressing plasmids. In conclusion, quercetin enhanced the radiosensitivity of NSCLC cells via modulating the expression of miR-16-5p and WEE1.

Quercetin induced NUPR1-dependent autophagic cell death by disturbing reactive oxygen species homeostasis in osteosarcoma cells

Osteosarcoma is a primary bone aggressive cancer, affecting adolescents worldwide. Quercetin (a natural polyphenolic compound) is a polyphenolic flavonoid compound found in a variety of plants. It has been demonstrated to exert cytostatic activity against a variety of human cancer, including the human osteosarcoma. However, its efficacy in the treatment of osteosarcoma and the underlying antitumor mechanism has not been fully elucidated yet. In this study, we exposed MG-63 cells to different concentrations of quercetin (50, 100 and 200 µM) for 24 h. Here, we show that quercetin increased autophagic flux in the MG-63 cells, as evidenced by the upregulation of LC3B-II/LC3B-I and downregulation of P62/SQSTM1. Moreover, the autophagy inhibitor Bafilomycin A1 or genetic blocking autophagy with ATG5 knockdown decreased quercetin-induced cell death, indicating quercetin triggered autophagic cell death in MG-63 cells. Specifically, quercetin increased NUPR1 expression and activated of NUPR1 reporter activity, which contributed to the expression of autophagy-related genes and subsequent initiated autophagic cell death in osteosarcoma cells. Importantly, the increased expression NUPR1 were tightly related to the disturbance of reactive oxygen species (ROS) homeostasis, which could be prevented by inhibiting intracellular ROS with NAC. Finally, NAC also abolished quercetin-induced autophagic cell death in vivo. Taken together, these data demonstrate that quercetin induces osteosarcoma cell death via inducing excessive autophagy, which is mediated through the ROS-NUPR1 pathway. Quercetin application may be a promising and practical strategy for osteosarcoma treatment in clinical practice.

Effect of quercetin on micellization behaviour of Tween-20 in hydro-ethanolic solvent system: An electrolyte induced thermodynamic study

The thermodynamic studies for non-ionic surfactant Tween-20 has been performed in presence of a well known flavonoid quercetin. The conductivity studies have been carried out with different concentrations of quercetin in 30% v/v ethanolic solution at five different temperatures (20 °C to 40 °C with difference of 5 °C). Since Tween-20 is non-ionic in nature, 1% w/v sodium chloride solution has been added as an electrolyte. Critical micelle concentration (CMC) and XCMC values as a function of temperature have been determined from conductance studies. Furthermore, various thermodynamic parameters viz. change in enthalpy (ΔH°m), entropy (ΔS°m) and Gibb’s free energy (ΔG°m) of micellization have been calculated. Overall, the changes in micellization process of Tween-20 in presence of quercetin has been studied and reported.

Localised delivery of quercetin by thermo-sensitive PLGA-PEG-PLGA hydrogels for the treatment of brachial plexus avulsion

Accumulating evidence indicates that oxidative stress and inflammation are implicated in brachial plexus avulsion (BPA). Quercetin has anti-inflammatory, anti-oxidant, anti-apoptotic, and neuroprotective properties. This study investigated the therapeutic efficacy of a temperature-sensitive poly(D,L-lactide-co-glycolide)-poly(ethylene-glycol)-poly(D,L-lactide-co-glycolide) (PLGA-PEG-PLGA) hydrogel sustained-release system of quercetin in BPA. In situ injections of the hydrogel loaded with different concentrations of quercetin were conducted in a rat model of BPA. Significantly reduced reactive oxygen species and interleukin-6 levels in the injured spinal cord 24 h post-surgery, increased number of anterior horn motor and functional neurons in the spinal cord 6 weeks post-surgery, thickened biceps muscle fibres and enlarged endplate area with clear structure, reduced demyelinated peripheral nerves, and significantly increased Terzis grooming test scores were found in the groups with 50 or 100 mg/mL quercetin-loaded hydrogels compared with the control and blank hydrogel groups. In conclusion, the temperature-sensitive quercetin loaded PLGA-PEG-PLGA hydrogel sustained-release system can alleviate oxidative damage and inflammation in the spinal cord, increase neuron survival rate, and promote nerve regeneration and motor function recovery in rats with early BPA. The findings suggest that this drug-loaded hydrogel has potential applications in the clinical treatment of BPA.

Naturally Derived Polyphenols Protect Against Corticosterone-Induced Changes in Primary Cortical Neurons.

BackgroundPolyphenols are phytochemicals that have been associated with therapeutic effects in stress-related disorders. Indeed, studies suggest that polyphenols exert significant neuroprotection against multiple neuronal injuries, including oxidative stress and neuroinflammation, but the mechanisms are unclear. Evidence indicates that polyphenol neuroprotection may be mediated by activation of Nrf2, a transcription factor associated with antioxidant and cell survival responses. On the other hand, in stress-linked disorders, Fkbp5 is a novel molecular target for treatment because of its capacity to regulate glucocorticoid receptor sensitivity. However, it is not clear the role Fkbp5 plays in polyphenol-mediated stress modulation. In this study, the neuroprotective effects and mechanisms of the naturally derived polyphenols xanthohumol and quercetin against cytotoxicity induced by corticosterone were investigated in primary cortical cells.MethodsPrimary cortical cells containing both neurons and astrocytes were pre-incubated with different concentrations of quercetin and xanthohumol to examine the neuroprotective effects of polyphenols on cell viability, morphology, and gene expression following corticosterone insult.ResultsBoth polyphenols tested prevented the reduction of cell viability and alterations of neuronal/astrocytic numbers due to corticosterone exposure. Basal levels of Bdnf mRNA were also decreased after corticosterone insult; however, this was reversed by both polyphenol treatments. Interestingly, the Nrf2 inhibitor blocked xanthohumol but not quercetin-mediated neuroprotection. In contrast, we found that Fkbp5 expression is exclusively modulated by quercetin.ConclusionsThese results suggest that naturally derived polyphenols protect cortical cells against corticosterone-induced cytotoxicity and enhance cell survival via modulation of the Nrf2 pathway and expression of Fkbp5.

Effects of Quercetin and Resveratrol on in vitro Properties Related to the Functionality of Potentially Probiotic Lactobacillus Strains.

The ability of probiotics to exert benefits on host has been associated with different physiological functionalities in these microorganisms, namely cell surface hydrophobicity, autoaggregation, coaggregation with pathogens, antagonistic activity against pathogens and ability to survive the exposure to gastrointestinal conditions. This study assessed the effects of different concentrations of quercetin (QUE) and resveratrol (RES) on the ability of six potentially probiotic Lactobacillus strains to tolerate different pH values and bile salt concentrations, to autoaggregate, coaggregate with and antagonize pathogens and survive the exposure to simulated gastrointestinal conditions. QUE and RES presented low inhibitory effects on all tested Lactobacillus strains, with minimum inhibitory concentration (MIC) ranging from 512 to >1024 μg/mL. In most cases, QUE and RES at all tested concentrations (i.e., MIC, 1/2 MIC, and 1/4 MIC) did not affect the tolerance of the Lactobacillus strains to acidic pH and bile salts. QUE increased cell surface hydrophobicity of most of the tested Lactobacillus strains and increases or decreases in cell surface hydrophobicity varied in the presence of different RES concentrations among some strains. QUE and RES increased the ability of tested Lactobacillus strains to autoaggregate and coaggregate with pathogens. QUE and RES did not negatively affect the antagonistic activity of the tested Lactobacillus strains against pathogens and did not decrease their survival rates when exposed to in vitro gastrointestinal conditions. In a few cases, the ability of some tested Lactobacillus strains to antagonize pathogens, as well as to survive specific steps of the in vitro digestion was increased by QUE and RES. QUE exerted overall better protective effects on the measured in vitro properties of tested Lactobacillus strains than RES, and L. fermentum and L. plantarum strains presented better responses when treated with QUE or RES. These results showed that probiotic Lactobacillus strains could present low susceptibility to QUE and RES. Combined use of QUE and RES with probiotic Lactobacillus could improve their functionalities on the host; however, the concentration of these polyphenols should be carefully selected to achieve the desirable effects and vary according to the selected probiotic strain.

Quercetin suppresses glomerulosclerosis and TGF‑β signaling in a rat model.

The transforming growth factor-β (TGF-β) signaling pathway is an important regulatory pathway in renal fibrosis and is abnormally activated in glomerulosclerosis. Quercetin is a common Chinese herbal medicine and has been reported to inhibit TGF-β signaling pathway activation. In the present study a glomerulosclerosis rat model was constructed and mice were treated with different concentrations of quercetin. Biochemical parameters, pathological indices and expression levels of TGF-β signaling pathway-associated proteins were detected using immunohistochemistry and western blotting. It was demonstrated that quercetin significantly improved physiological indices and altered the expression levels of TGF-β signaling pathway-associated proteins in rats with glomerulosclerosis. In conclusion, quercetin can regulate the TGF-β signaling pathway and reduce the progression of glomerulosclerosis.

Quercetin Affects the Growth and Development of the Grasshopper Oedaleus asiaticus (Orthoptera: Acrididae).

Flavonoids are secondary metabolites that help plants resist insect attack, but pest insects have evolved enzymes that reduce the toxicity of these secondary metabolites. We studied the response of the grasshopper Oedaleus asiaticus Bey-Bienko fed different concentrations of quercetin, a representative flavonoid. Oedaleus asiaticus growth (survival rate and growth rate) was significantly reduced at high quercetin concentrations. Reactive oxygen species (ROS) increased significantly in response to the diet stress associated with high quercetin concentrations. Gene expression and protein phosphorylation level of the IGF→FOXO cascade related to the stress response in the O. asiaticus insulin-like signaling pathway (ILP) were also reduced. Multiple protective enzyme activities were regulated by FOXO. Mixed-function oxidase (MFO), superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), were all significantly increased with exposure to high quercetin concentrations. Quercetin negatively regulated the ILP pathway, and was detrimental to O. asiaticus growth and survival, as more energy was required for detoxification. This study showed how flavonoids impact on O. asiaticus biochemical pathways, physiology, and development. Flavonoids offer a new option for the development of biological pesticides for application to grasshopper biological control.

Synergistic effects of quercetin and selenium on oxidative stress in endometrial adenocarcinoma cells.

The effects of quercetin and selenium on oxidative stress in endometrial adenocarcinoma cells are unclear. In this study, the effects of quercetin and selenium on oxidative stress caused by both hydrogen peroxide and UV radiation in endometrial adenocarcinoma cells were examined. The viability of endometrial adenocarcinoma cells cultured in vitro and treated with different concentrations of quercetin and sodium selenite was measured using the MTT assay. Malondialdehyde (MDA) levels were investigated, and expression levels of BAD and p53 genes were analysed using real‑time quantitative polymerase chain reaction. Acridine orange/ethidium bromide staining technique was applied to detect apoptosis. Mass attenuation coefficient of each quercetin and sodium selenite combinations was evaluated using Monte Carlo simulation. The combination of quercetin and sodium selenite enhanced cell viability, and reduced MDA levels. The expression levels of BAD and p53 genes decreased by combined treatment with quercetin and selenium while showing synergistic effects in terms of gene expression. Fluorescent microscopic examination showed a decrease in apoptotic cells in endometrial adenocarcinoma cells treated with the combination of quercetin and selenium. For the first time, selenium and quercetin have synergistic cytoprotective and radioprotective effects on oxidative stress caused by hydrogen peroxide in endometrial adenocarcinoma cells for the first time (Tab. 1, Fig. 7, Ref. 39).

Neuroprotective effect of quercetin against radiation-induced endoplasmic reticulum stress in neurons.

The endoplasmic reticulum (ER) plays an important role in the regulation and maintenance of cellular homeostasis. However, unresolved ER stress leads to deleterious effects by inducing the accumulation of unfolded proteins in the cell. Here we have demonstrated the protective aspects of quercetin against radiation-induced ER stress and against inflammation in primary cultured dorsal root ganglion (DRG) neurons. The mature DRG neurons were pretreated with different concentrations of quercetin (5-100 μM) for 24 hours before 2 Gy gamma radiation exposure and then subjected to a cytotoxicity assay, quantitative real-time polymerase chain reaction and Western blot analysis. The results showed that quercetin decreased the expression of BiP and C/EBP-homologous protein, the ER stress marker genes along with downregulation of tumor necrosis factor-α, JNK in irradiated DRG neurons. Furthermore, quercetin pretreatment significantly increased the cytoskeletal protein Tuj1 and the neurotrophin brain-derived neurotrophic factor in the neuron. These results indicate that quercetin plays a neuroprotective role against radiation-mediated ER stress and inflammatory responses.

The effects of Quercetin on miRNA-21 expression in MCF-7 cells

Background: Cancer prevention, by the use of natural dietary or secondary metabolites in plants is one of the strategies has been attracting some of the scientific interests. One of these natural agents is Quercetin, which has anti-metastatic and anti-cancer effects. MiR-21 among different miRNAs is one of the most important frequently up-regulated miRs in numerous cancers including breast and increase cell proliferation and decrease apoptosis and therefore leads to increases in cancer incidence. We assessed the effects of Quercetin on cell viability, MiR-21, Maspin and PTEN gene expression in the MCF-7 cell line.Materials & Methods: The human MCF-7 breast cancer cell line was cultured in RPMI1640 and treated with different concentrations of Quercetin (0.01-100 μM) for 24 hours. The cytotoxic effect of Quercetin on MCF-7 viability was determined using Methyl-Thiazolyl-Tetrazolium (MTT) assay by IC50 determination. The relative expression of MiR-21, Maspin, and PTEN gene expression were determined by real-time Polymerase Chain Reaction (PCR).Results: The maximum inhibitory effect of Quercetin on cell viability was observed at 100 μM after 24-hour incubation. The expression of MiR-21 in the treated cells compared to controls was significantly decreased after treatment with three different concentrations of Quercetin. In addition, expression of Maspin and PTEN in the treated cells compared to controls was significantly increased.Conclusions: Quercetin decreases cell viability and miR-21 gene expression in a dose-dependent manner. Also, Quercetin decreases mir-21 gene expression and increases Maspin and PTEN expression in MCF-7 breast cancer cell line. The growth inhibitory properties and therapeutic effect of Quercetin on the breast cancer may be mediated by reduction of miR-21 expression, and for verifying this hypothesis and the possible therapeutic implication of Quercetin in this direction further studies are necessary.

Fabrication and Optimization of Bilayered Nanoporous Anodic Alumina Structures as Multi-Point Interferometric Sensing Platform.

Herein, we present an innovative strategy for optimizing hierarchical structures of nanoporous anodic alumina (NAA) to advance their optical sensing performance toward multi-analyte biosensing. This approach is based on the fabrication of multilayered NAA and the formation of differential effective medium of their structure by controlling three fabrication parameters (i.e., anodization steps, anodization time, and pore widening time). The rationale of the proposed concept is that interferometric bilayered NAA (BL-NAA), which features two layers of different pore diameters, can provide distinct reflectometric interference spectroscopy (RIfS) signatures for each layer within the NAA structure and can therefore potentially be used for multi-point biosensing. This paper presents the structural fabrication of layered NAA structures, and the optimization and evaluation of their RIfS optical sensing performance through changes in the effective optical thickness (EOT) using quercetin as a model molecule. The bilayered or funnel-like NAA structures were designed with the aim of characterizing the sensitivity of both layers of quercetin molecules using RIfS and exploring the potential of these photonic structures, featuring different pore diameters, for simultaneous size-exclusion and multi-analyte optical biosensing. The sensing performance of the prepared NAA platforms was examined by real-time screening of binding reactions between human serum albumin (HSA)-modified NAA (i.e., sensing element) and quercetin (i.e., analyte). BL-NAAs display a complex optical interference spectrum, which can be resolved by fast Fourier transform (FFT) to monitor the EOT changes, where three distinctive peaks were revealed corresponding to the top, bottom, and total layer within the BL-NAA structures. The spectral shifts of these three characteristic peaks were used as sensing signals to monitor the binding events in each NAA pore in real-time upon exposure to different concentrations of quercetin. The multi-point sensing performance of BL-NAAs was determined for each pore layer, with an average sensitivity and low limit of detection of 600 nm (mg mL−1)−1 and 0.14 mg mL−1, respectively. BL-NAAs photonic structures have the capability to be used as platforms for multi-point RIfS sensing of biomolecules that can be further extended for simultaneous size-exclusion separation and multi-analyte sensing using these bilayered nanostructures.

Quercetin decreases the activity of matrix metalloproteinase-2 and ameliorates vascular remodeling in renovascular hypertension

Background and aimsIncreased activity of matrix metalloproteinase (MMP)-2 is observed in aortas of different models of hypertension, and its activation is directly mediated by oxidative stress. As quercetin is an important flavonoid with significant antioxidant effects, the hypothesis here is that quercetin will reduce increased MMP-2 activity by decreasing oxidative stress in aortas of hypertensive rats and then ameliorate hypertension-induced vascular remodeling. MethodsMale two-kidney one-clip (2K1C) hypertensive Wistar rats and controls were treated with quercetin (10 mg/kg/day) or its vehicle for three weeks by gavage. Rats were then analyzed at five weeks of hypertension. Systolic blood pressure (SBP) was determined by tail-cuff plethysmography. Aortas were used to determine MMP activity by in situ zymography and reactive oxygen species (ROS) levels by dihydroethidium. Western blot was performed to detect focal adhesion kinase (FAK) and phosphorylated-FAK levels. ResultsSBP was increased in 2K1C rats and only a borderline reduction in SBP was observed after treating 2K1C rats with quercetin. Cross-sectional area and the number of vascular smooth muscle cells were significantly increased in aortas of hypertensive rats, and quercetin reduced them. Quercetin reduced ROS levels in aortas of 2K1C rats and the increased activity of gelatinases in situ. However, quercetin did not affect the levels of tissue inhibitor of MMP (TIMP)-2 and did not interfere with FAK and p-FAK levels in aortas of hypertensive rats. Furthermore, different concentrations of quercetin did not directly reduce the activity of human recombinant MMP-2 in vitro. ConclusionsQuercetin reduces hypertension-induced vascular remodeling, oxidative stress and MMP-2 activity in aortas.