Nanocurcumin modulates Th17 cell responses in moderate and severe COPD patients.

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory process in the airways that results in airflow obstruction. It is mainly linked to cigarette smoke exposure. Th17 cells have a role in the pathogenesis of COPD by secreting pro-inflammatory cytokines, which cause hyperinflammation and progression of the disease. This study aimed to assess the potential therapeutic effects of nanocurcumin on the Th17 cell frequency and its responses in moderate and severe COPD patients. This study included 20 patients with severe COPD hospitalized in an intensive care unit (ICU) and 20 patients with moderate COPD. Th17 cell frequency, Th17-related factors gene expression (RAR-related orphan receptor t (RORγt), IL-17, IL-21, IL-23, and granulocyte-macrophage colony-stimulating factor), and serum levels of Th17-related cytokines were assessed before and after treatment in both placebo and nanocurcumin-treated groups using flow cytometry, real-time PCR, and ELISA, respectively. According to our findings, in moderate and severe nanocurcumin-treated COPD patients, there was a substantial reduction in the frequency of Th17 cells, mRNA expression, and cytokines secretion level of Th17-related factors compared to the placebo group. Furthermore, after treatment, the metrics mentioned above were considerably lower in the nanocurcumin-treated group compared to before treatment. Nanocurcumin has been shown to decrease the number of Th17 cells and their related inflammatory cytokines in moderate and severe COPD patients. As a result, it might be used as an immune-modulatory agent to alleviate the patient's inflammatory state.

Harnessing tumor-derived exosomes: A promising approach for the expansion of clinical diagnosis, prognosis, and therapeutic outcome of prostate cancer.

Prostate cancer is the second leading cause of men's death worldwide. Although early diagnosis and therapy for localized prostate cancer have improved, the majority of men with metastatic disease die from prostate cancer annually. Therefore, identification of the cellular-molecular mechanisms underlying the progression of prostate cancer is essential for overcoming controlled proliferation, invasion, and metastasis. Exosomes are small extracellular vesicles that mediate most cells' interactions and contain membrane proteins, cytosolic and nuclear proteins, extracellular matrix proteins, lipids, metabolites, and nucleic acids. Exosomes play an essential role in paracrine pathways, potentially influencing Prostate cancer progression through a wide variety of mechanisms. In the present review, we outline and discuss recent progress in our understanding of the role of exosomes in the Prostate cancer microenvironment, like their involvement in prostate cancer occurrence, progression, angiogenesis, epithelial-mesenchymal transition, metastasis, and drug resistance. We also present the latest findings regarding the function of exosomes as biomarkers, direct therapeutic targets in prostate cancer, and the challenges and advantages associated with using exosomes as natural carriers and in exosome-based immunotherapy. These findings are a promising avenue for the expansion of potential clinical approaches.

Exosomes from Adipose Tissue-derived Mesenchymal Stem Cells Induce Regulatory T Cells in COVID-19 Patients.

An imbalance between regulatory T (Treg) and T-helper (Th)-17 cells has been implicated in the pathogenesis of coronavirus disease 2019 (COVID-19). Mesenchymal stem cells (MSCs) exert immunomodulatory properties through secreting exosomes. This study aimed to assess the effect of MSC-derived exosomes (MSC-Exo) on the differentiation of peripheral blood mononuclear cells (PBMCs) into  Tregs from patients with COVID-19. Exosomes were isolated from adipose tissue-derived MSCs. PBMCs were separated from the whole blood of COVID-19 patients (n=20). Treg frequency was assessed before and 48 hours after treatment of PBMCs with MSC-Exo using flow cytometry. Expression of FOXP3 and cytokine genes, and the concentration of cytokines associated with Tregs, were assessed before and after treatment with MSC-Exo. The frequency of CD4+CD25+CD127-  Tregs was significantly higher after treating PBMCs with MSC-Exo (6.695±2.528) compared to before treatment (4.981±2.068). The expressions of transforming growth factor (TGF)-ß1, interleukin (IL)-10, and FOXP3 were significantly upregulated in MSC-Exo-treated PBMCs. The concentration of IL-10 increased significantly after treatment (994.7±543.9 pg/mL) of PBMCs with MSC-Exo compared with before treatment (563.5±408.6 pg/mL). The concentration of TGF-ß was significantly higher in the supernatant of PBMCs after treatment with MSC-Exo (477.0±391.1 pg/mL) than PBMCs before treatment (257.7±226.3 pg/mL). MSC-Exo has the potential to raise anti-inflammatory responses by induction of  Tregs, potentiating its therapeutic effects in COVID-19.

Down-regulation and Clinic-pathological Correlation of SIK-1 and SIK-1-LNC in Non-small Cell Lung Cancer Patients

BACKGROUND: Non-small-cell lung cancer (NSCLC) is currently the leading cause of mortality cancer. Introducing noninvasive approaches to diagnose NSCLC, especially at an early phase, might improve the disease's prognosis. Long noncoding RNAs (lncRNAs), which are important regulators of the expression genes inside the cells, have been linked to a range of biological processes, such as cancer progression and metastasis, including NSCLC. The present work aims to determine the potential involvement of SIK-1-LNC and SIK-1 in NSCLC pathogenesis and the possible use of these molecules as novel biomarkers or therapeutic targets. METHODS: In this work, the expression levels of SIK-1-LNC and SIK-1 in 50 pairs of NSCLC tumor and tumor marginal tissues were evaluated. So, after total RNA extraction and complementary DNA synthesis, the SIK-1-LNC and SIK-1 expression levels were evaluated by real-time PCR. In the study groups, clinical and pathological characteristics of the NSCLC patients were also examined. RESULTS: Our findings showed that tumor samples had much lower levels of SIK-1 and SIK-1-LNC expression than tumor margin samples. SIK-1-LNC expression was correlated with SIK-1 levels in NSCLC samples. Interestingly, both stage and lymph node metastasis features of the tumor were associated significantly with SIK-1 and SIK-1-LNC expression levels. A ROC curve analysis indicated a biomarker index of 0.69 and 0.74 for SIK-1 and SIK-1-LNC, respectively. CONCLUSION: Collectively, our study emphasized the role of SIK-1-LNC and SIK-1 downregulation in NSCLC oncogenesis. Additionally, SIK-1 and SIK-1-LNC, particularly the latter, have shown remarkable potential to be utilized as new NSCLC biomarkers and therapeutic targets.

Immunomodulatory role of Nanocurcumin in COVID-19 patients with dropped natural killer cells frequency and function.

The ongoing COVID-19 pandemic is still a challenging problem in the case of infection treatment. The immunomodulatory effect of Nanocurcumin was investigated in the present study in an attempt to counterbalance the immune response and improve the patients' clinical symptoms. 60 confirmed COVID-19 patients and 60 healthy controls enrolled in the study. COVID-19 patients were divided into Nanocurcumin and placebo received groups. Due to the importance of the role of NK cells in this disease, the frequency, cytotoxicity, receptor gene expression of NK cells, and serum secretion levels of inflammatory cytokines IL-1ß, IL-6, TNF-α, as well as circulating C5a as a chemotactic factor an inflammatory mediator was evaluated by flow cytometry, real-time PCR and enzyme-linked immunosorbent assay in both experimental groups before and after the intervention. Given the role of measured factors in the progression and pathogenesis of COVID-19 disease, the results can help find appropriate treatments. The results of this study indicated that the Nanocurcumin could significantly increase the frequency and function of NK cells compared to the placebo-treated group. As an immunomodulatory agent, Nanocurcumin may be a helpful choice to improve NK cell function in COVID-19 patients and improve the clinical outcome of patients.

The potential use of mesenchymal stem cells and their exosomes in Parkinson's disease treatment.

Parkinson's disease (PD) is the second most predominant neurodegenerative disease worldwide. It is recognized clinically by severe complications in motor function caused by progressive degeneration of dopaminergic neurons (DAn) and dopamine depletion. As the current standard of treatment is focused on alleviating symptoms through Levodopa, developing neuroprotective techniques is critical for adopting a more pathology-oriented therapeutic approach. Regenerative cell therapy has provided us with an unrivalled platform for evaluating potentially effective novel methods for treating neurodegenerative illnesses over the last two decades. Mesenchymal stem cells (MSCs) are most promising, as they can differentiate into dopaminergic neurons and produce neurotrophic substances. The precise process by which stem cells repair neuronal injury is unknown, and MSC-derived exosomes are suggested to be responsible for a significant portion of such effects. The present review discusses the application of mesenchymal stem cells and MSC-derived exosomes in PD treatment.

Chronic obstructive pulmonary disease and asthma: mesenchymal stem cells and their extracellular vesicles as potential therapeutic tools.

Chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, are one of the most frequent causes of morbidity and mortality in the global. COPD is characterized by progressive loss of lung function through inflammation, apoptosis, and oxidative stress caused by chronic exposure to harmful environmental pollutants. Airway inflammation and epithelial remodeling are also two main characteristics of asthma. In spite of extensive efforts from researchers, there is still a great need for novel therapeutic approaches for treatment of these conditions. Accumulating evidence suggests the potential role of mesenchymal stem cells (MSCs) in treatment of many lung injuries due to their beneficial features including immunomodulation and tissue regeneration. Besides, the therapeutic advantages of MSCs are chiefly related to their paracrine functions such as releasing extracellular vesicles (EVs). EVs comprising exosomes and microvesicles are heterogeneous bilayer membrane structures loaded with various lipids, nucleic acids and proteins. Due to their lower immunogenicity, tumorigenicity, and easier management, EVs have appeared as favorable alternatives to stem cell therapies. Therefore, in this review, we provided an overview on the current understanding of the importance of MSCs and MSC-derived EVs from different sources reported in preclinical and clinical COPD and asthmatic models.

Evaluating the effect of Edaravone on clinical outcome of patients with severe COVID-19 admitted to ICU: a randomized clinical trial.

Cytokine storm is the most prominent hallmark in patients with coronavirus disease 2019 (COVID-19) that stimulates the free radical storm, both of which induce an overactive immune response during viral infection. We hypothesized that owning to its radical-scavenging and anti-inflammatory properties, Edaravone could reduce multi-organ injury, clinical complications, and mortality in severe COVID-19 cases. This single-center randomized clinical trial was accompanied in the intensive care units (ICUs) of the teaching hospital of Tabriz University of Medical Sciences to evaluate the effect of Edaravone on the outcome of patients with severe COVID-19. Thirty-eight patients admitted to ICU were included and randomized into two control and intervention arms. Patients in the intervention group received 30 mg Edaravone by slow intravenous infusion for three days in addition to receiving national therapy. The primary outcome was the need for intubation, the intubation length, and mortality rate. Secondary endpoints were clinical improvement. Edaravone administration improved the primary outcomes; it decreased the need for endotracheal intubation and mechanical ventilation [10.52% (n = 2) versus 42.1% (n = 8); p = 0.03] and intubation length [3 (1-7) versus 28 (4-28), p = 0.04] compared to control group. Baseline characteristics and laboratory tests were similar between the studied groups. No marked differences were observed in secondary endpoints (p > 0.05). Administration of Edaravone could decrease the need for mechanical ventilation and length of intubation in severe COVID-19 patients admitted to ICU.

Relationship between chest CT scan findings with SOFA score, CRP, comorbidity, and mortality in ICU patients with COVID-19.

OBJECTIVE: This study aimed to investigate the relationship between chest computed tomography (CT) scan findings with sequential organ failure assessment (SOFA) score, C-reactive protein (CRP), comorbidity, and mortality in intensive care unit (ICU) patients with coronavirus disease 19 (COVID-19). METHOD: Adult patients (≥18 years old) with COVID-19 who were consecutively admitted to the Imam-Reza Hospital, Tabriz, East-Azerbaijan Province, North-West of Iran between March 2020 and August 2020 were screened and total of 168 patients were included. Demographic, clinical, and mortality data were gathered. Severity of disease was evaluated using the SOFA score system. CRP levels were measured and chest CT scans were performed. RESULTS: Most of patients had multifocal and bilateral ground glass opacity (GGO) pattern in chest CT scan. There were significant correlations between SOFA score on admission with multifocal and bilateral GGO (P = .010 and P = .011, respectively). Significant relationships were observed between unilateral and bilateral GGO patterns with CRP (P = .049 and P = .046, respectively). There was significant relationship between GGO patterns with comorbidities including overweight/obesity, heart failure, cardiovascular diseases, and malignancy (P < .05). No significant relationships were observed between chest CT scan results with mortality (P > .05). CONCLUSION: Multifocal bilateral GGO was the most common pattern. Although chest CT scan characteristics were significantly related with SOFA score, CRP, and comorbidity in ICU patients with COVID-19, a relationship with mortality was not significant.

Nanocurcumin improves Treg cell responses in patients with mild and severe SARS-CoV2.

In Coronavirus disease 2019 (COVID-19), a decreased number of regulatory T (Treg) cells and their mediated factors lead to a hyperinflammatory state due to overactivation of the inflammatory cells and factors during the infection. In the current study, we evaluated the Nanocurcumin effects on the Treg cell population and corresponding factors in mild and severe COVID-19 patients. To investigate the Nanocurcumin effects, 80 COVID-19 patients (40 at the severe stage and 40 at the mild stage) were selected and classified into Nanocurcumin and placebo arms. In both the Nanocurcumin and placebo groups, the Treg cell frequency, the gene expression of Treg transcription factor forkhead box P3 (FoxP3), and cytokines (IL-10, IL-35, and TGF-ß), as well as the serum levels of cytokines were measured before and after treatment. In both mild and severe COVID-19 patients, Nanocurcumin could considerably upregulate the frequency of Treg cells, the expression levels of FoxP3, IL-10, IL-35, and TGF-ß, as well as the serum secretion levels of cytokines in the Nanocurcumin-treated group compared to the placebo group. The abovementioned factors were remarkably increased in the post-treatment with Nanocurcumin before pre-treatment conditions. By contrast, it has been observed no notable alteration in the placebo group. Our findings revealed the SinaCurcumin® effective function in a significant increase in the number of Treg cells and their mediated factors in the Nanocurcumin group than in the placebo group in both mild and severe patients. Hence, it would be an efficient therapeutic agent in rehabilitating COVID-19 infected patients.

Immunomodulatory effects of nanocurcumin on Th17 cell responses in mild and severe COVID-19 patients.

In novel coronavirus disease 2019 (COVID-19), the increased frequency and overactivation of T helper (Th) 17 cells and subsequent production of large amounts of proinflammatory cytokines result in hyperinflammation and disease progression. The current study aimed to investigate the therapeutic effects of nanocurcumin on the frequency and responses of Th17 cells in mild and severe COVID-19 patients. In this study, 40 severe COVID-19 intensive care unit-admitted patients and 40 patients in mild condition were included. The frequency of Th17 cells, the messenger RNA expression of Th17 cell-related factors (RAR-related orphan receptor γt, interleukin [IL]-17, IL-21, IL-23, and granulocyte-macrophage colony-stimulating factor), and the serum levels of cytokines were measured in both nanocurcumin and placebo-treated groups before and after treatment. A significant decrease in the number of Th17 cells, downregulation of Th17 cell-related factors, and decreased levels of Th17 cell-related cytokines were found in mild and severe COVID-19 patients treated by nanocurcumin compared to the placebo group. Moreover, the abovementioned parameters were significantly decreased in the nanocurcumin-treated group after treatment versus before treatment. Curcumin could reduce the frequency of Th17 cells and their related inflammatory factors in both mild and severe COVID-19 patients. Hence, it could be considered as a potential modulatory compound in improving the patient's inflammatory condition.

Th17 and Treg cells function in SARS-CoV2 patients compared with healthy controls.

In the course of the coronavirus disease 2019 (COVID-19), raising and reducing the function of Th17 and Treg cells, respectively, elicit hyperinflammation and disease progression. The current study aimed to evaluate the responses of Th17 and Treg cells in COVID-19 patients compared with the control group. Forty COVID-19 intensive care unit (ICU) patients were compared with 40 healthy controls. The frequency of cells, gene expression of related factors, as well as the secretion levels of cytokines, were measured by flow cytometry, real-time polymerase chain reaction, and enzyme-linked immunosorbent assay techniques, respectively. The findings revealed a significant increase in the number of Th17 cells, the expression levels of related factors (RAR-related orphan receptor gamma [RORγt], IL-17, and IL-23), and the secretion levels of IL-17 and IL-23 cytokines in COVID-19 patients compared with controls. In contrast, patients had a remarkable reduction in the frequency of Treg cells, the expression levels of correlated factors (Forkhead box protein P3 [FoxP3], transforming growth factor-ß [TGF-ß], and IL-10), and cytokine secretion levels (TGF-ß and IL-10). The ratio of Th17/Treg cells, RORγt/FoxP3, and IL-17/IL-10 had a considerable enhancement in patients compared with the controls and also in dead patients compared with the improved cases. The findings showed that enhanced responses of Th17 cells and decreased responses of Treg cells in 2019-n-CoV patients compared with controls had a strong relationship with hyperinflammation, lung damage, and disease pathogenesis. Also, the high ratio of Th17/Treg cells and their associated factors in COVID-19-dead patients compared with improved cases indicates the critical role of inflammation in the mortality of patients.

Nano-curcumin therapy, a promising method in modulating inflammatory cytokines in COVID-19 patients.

BACKGROUND: As an ongoing worldwide health issue, Coronavirus disease 2019 (COVID-19) has been causing serious complications, including pneumonia, acute respiratory distress syndrome (ARDS), and multi-organ failure. However, there is no decisive treatment approach available for this disorder, which is primarily attributed to the large amount of inflammatory cytokine production. We aimed to identify the effects of Nano-curcumin on the modulation of inflammatory cytokines in COVID-19 patients. METHOD: Forty COVID-19 patients and 40 healthy controls were recruited and evaluated for inflammatory cytokine expression and secretion. Subsequently, COVID-19 patients were divided into two groups: 20 patients receiving Nano-curcumin and 20 patients as the placebo group. The mRNA expression and cytokine secretion levels of IL-1ß, IL-6, TNF-α and IL-18 were assessed by Real-time PCR and ELISA, respectively. RESULT: Our primary results indicated that the mRNA expression and cytokine secretion of IL-1ß, IL-6, TNF-α, and IL-18 were increased significantly in COVID-19 patients compared with healthy control group. After treatment with Nano-curcumin, a significant decrease in IL-6 expression and secretion in serum and in supernatant (P = 0.0003, 0.0038, and 0.0001, respectively) and IL-1ß gene expression and secretion level in serum and supernatant (P = 0.0017, 0.0082, and 0.0041, respectively) was observed. However, IL-18 mRNA expression and TNF-α concentration were not influenced by Nano-curcumin. CONCLUSION: Nano-curcumin, as an anti-inflammatory herbal based agent, may be able to modulate the increased rate of inflammatory cytokines especially IL-1ß and IL-6 mRNA expression and cytokine secretion in COVID-19 patients, which may cause an improvement in clinical manifestation and overall recovery.

Effect of bromhexine on clinical outcomes and mortality in COVID-19 patients: A randomized clinical trial.

Introduction: Bromhexine is a potential therapeutic option in COVID-19, but no data from a randomized clinical trial has been available. The present study aimed to evaluate the efficacy of bromhexine in intensive care unit (ICU) admission, mechanical ventilation, and mortality in patients with COVID-19. Methods: An open-label randomized clinical trial study was performed in Tabriz, North-West of Iran. They were randomized to either the treatment with the bromhexine group or the control group, in a 1:1 ratio with 39 patients in each arm. Standard therapy was used in both groups and those patients in the treatment group received oral bromhexine 8 mg three times a day additionally. The primary outcome was a decrease in the rate of ICU admissions, intubation/mechanical ventilation, and mortality. Results: A total of 78 patients with similar demographic and disease characteristics were enrolled. There was a significant reduction in ICU admissions (2 out of 39 vs. 11 out of 39, P = 0.006), intubation (1 out of 39 vs. 9 out of 39, P = 0.007) and death (0 vs. 5, P = 0.027) in the bromhexine treated group compared to the standard group. No patients were withdrawn from the study because of adverse effects. Conclusion: The early administration of oral bromhexine reduces the ICU transfer, intubation, and the mortality rate in patients with COVID-19. This affordable medication can easily be administered everywhere with a huge positive impact(s) on public health and the world economy. Altogether, the verification of our results on a larger scale and different medical centers is strongly recommended. Trial Registration: IRCT202003117046797N4; https://irct.ir/trial/46969.

Vaccine development and therapeutic design for 2019-nCoV/SARS-CoV-2: Challenges and chances.

The ongoing outbreak of the recently emerged 2019 novel coronavirus (nCoV), which has seriously threatened global health security, is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high morbidity and mortality. Despite the burden of the disease worldwide, still, no licensed vaccine or any specific drug against 2019-nCoV is available. Data from several countries show that few repurposed drugs using existing antiviral drugs have not (so far) been satisfactory and more recently were proven to be even highly toxic. These findings underline an urgent need for preventative and therapeutic interventions designed to target specific aspects of 2019-nCoV. Again the major factor in this urgency is that the process of data acquisition by physical experiment is time-consuming and expensive to obtain. Scientific simulations and more in-depth data analysis permit to validate or refute drug repurposing opportunities predicted via target similarity profiling to speed up the development of a new more effective anti-2019-nCoV therapy especially where in vitro and/or in vivo data are not yet available. In addition, several research programs are being developed, aiming at the exploration of vaccines to prevent and treat the 2019-nCoV. Computational-based technology has given us the tools to explore and identify potentially effective drug and/or vaccine candidates which can effectively shorten the time and reduce the operating cost. The aim of the present review is to address the available information on molecular determinants in disease pathobiology modules and define the computational approaches employed in systematic drug repositioning and vaccine development settings for SARS-CoV-2.

Epigenetic Modifications and Therapy in Chronic Obstructive Pulmonary Disease (COPD): An Update Review.

Chronic obstructive pulmonary disease (COPD) that is one of the most prevalent chronic adult diseases and the third leading cause of fatality until 2020. Elastase/anti-elastase hypothesis, chronic inflammation, apoptosis, oxidant-antioxidant balance and infective repair cause pathogenesis of COPD are among the factors at play. Epigenetic changes are post-translational modifications in histone proteins and DNA such as methylation and acetylation as well as dysregulation of miRNAs expression. In this update review, we have examined recent studies on the upregulation or downregulation of methylation in different genes associated with COPD. Dysregulation of HDAC activity which is caused by some factors and miRNAs plays a key role in the suppression and reduction of COPD development. Also, some therapeutic approaches are proposed against COPD by targeting HDAC2 and miRNAs, which have therapeutic effects.

Acute kidney injury in pregnant women following SARS-CoV-2 infection: A case report from Iran.

We reported a 33-year-old female case with novel coronavirus disease 2019 (COVID-19) accompanied by Acute tubular necrosis (ATN). She had a gestational age of 34 weeks. The patient referred to treatment clinic for COVID-19 in Imam Reza hospital of Tabriz (Iran) after having flu-like symptoms. In radiologic assessment, ground glass opacity (GGO) with consolidation was found in upper right lobe. Lopinavir/ritonavir (200mg/50mg) two tablet tow times, Ribavirin 200mg every 6 h, and Oseltamivir 75mg tow times were given for the treatment of COVID-19. The medications used for treatment of pneumonia were Meropenem, Ciprofloxacin, Vancomycin. All doses of medications were administrated by adjusted dose assuming the patient is anephric. Also, a few supplements were also given after ATN development including daily Rocaltrol and Nephrovit (as a multivitamin appropriate for patients with renal failure), Folic acid and Calcium carbonate. The patient is still under ventilator with a Fraction of inspired oxygen (FiO2) of 60% and Positive end-expiratory pressure (PEEP) of eight. SpO2 is 94% but the patient's ATN problem has been resolved. We started weaning from mechanical ventilator. The patient is conscious with full awareness to time, person and place. The maternal well-being is achieved and her neonate was discharged.

A carbon paste electrode modified with a metal-organic framework of type MIL-101(Fe) for voltammetric determination of citric acid.

A carbon paste electrode (CPE) modified with a metal-organic framework composite of type MIL-101(Fe) is described for determination of citric acid (CA). The electrochemical activity of the modified CPE was studied by cyclic voltammetry and differential pulse voltammetry. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, N2 adsorption-desorption isotherms and X-ray powder diffraction were used for characterization of the MIL-101(Fe). Under optimized electrochemical conditions, the anodic peak current, best measured at working potentials around 0.02 V (vs. Ag/AgCl); decreases linearly in the 5.0 to 100 µM CA concentration range, and the detection limit is 4.0 µM (at S/N = 3). The electrode exhibits good selectivity for CA, with no significant interference in the wide pH range of 3.0 to 9.0. The electrochemical sensitivity of the MIL-CPE is -0.67 µA·µM-1·cm-2. The method was successfully applied to the determination of CA in some commercial beverages. The good recoveries (98-102%) and the agreement of data with those obtained by HPLC indicate the applicability of the method. Graphical abstract Schematic presentation of a new modified carbon paste electrode based on the metal-organic framework of type MIL-101(Fe) for the simple and sensitive determination of citric acid. The results show the MIL-101(Fe)-modified electrode to have good selectivity for citric acid and to enable real sample analysis.

Ascorbic Acid Determination Based on Electrocatalytic Behavior of Metal-Organic Framework MIL-101-(Cr) at Modified Carbon-Paste Electrode.

Background: Metal-organic frameworks (MOFs) are classified as microporous materials. They have large surface areas, low framework densities, accessible cages, and tunnels with modifiable pores. Objective: The MOF MIL-101(Cr) with a large pore volume was synthesized hydrothermally and used in the electrochemical reactions as an electrocatalyst for the determination of ascorbic acid (AA). The synthesized MOF was characterized by scanning electron microscopy and X-ray powder diffraction. Methods: The electrocatalytic behavior of a carbon-paste electrode modified with MIL-101(Cr) was studied through electro-oxidation of AA by cyclic voltammetry and square wave voltammetry. The conventional three-electrode cell system, consisting of Ag/AgCl (3 M KCl) as the reference, platinum wire as the counter electrode, and modified carbon paste as the working electrode, was used in the experiment. Results: Under optimized experimental conditions, the electrode revealed a linear relationship between the oxidation peak current and concentration of AA over a wide range from 0.01 to 10 mM with the LOD of 0.006 mM (3 Sb/m). The results showed that 100-fold of Na+, K+, Mg²+, Ca2+, Cl-, SO42-, sorbitol, sucrose, fructose, citric acid, 40-fold of NO3-, glucose, sucrose, urea, and 10-fold of uric acid had no significant interference. The method was adapted for the determination of the concentration of AA present in two real samples (vitamin C tablet and vitamin C effervescent tablet) with recovery of 97.0 and 96.0%, respectively. Conclusions: A simple, sensitive and reliable modified electrode has been established and applied for the determination of AA. Highlights: The modified electrode represented a good performance in the analysis of the real sample.