Rheumatoid arthritis molecular targets and their importance to flavonoid-based therapy.

Rheumatoid arthritis (RA) is a progressive, chronic, autoimmune, inflammatory, and systemic condition that primarily affects the synovial joints and adjacent tissues, including bone, muscle, and tendons. The World Health Organization recognizes RA as one of the most prevalent chronic inflammatory diseases. In the last decade, there was an expansion on the available RA therapeutic options which aimed to improve patient's quality of life. Despite the extensive research and the emergence of new therapeutic approaches and drugs, there are still significant unwanted side effects associated to these drugs and still a vast number of patients that do not respond positively to the existing therapeutic strategies. Over the years, several references to the use of flavonoids in the quest for new treatments for RA have emerged. This review aimed to summarize the existing literature about the flavonoids' effects on the major pathogenic/molecular targets of RA and their potential use as lead compounds for the development of new effective molecules for RA treatment. It is demonstrated that flavonoids can modulate various players in synovial inflammation, regulate immune cell function, decrease synoviocytes proliferation and balance the apoptotic process, decrease angiogenesis, and stop/prevent bone and cartilage degradation, which are all dominant features of RA. Although further investigation is necessary to determine the effectiveness of flavonoids in humans, the available data from in vitro and in vivo models suggest their potential as new disease-modifying anti-rheumatic drugs. This review highlights the use of flavonoids as a promising avenue for future research in the treatment of RA.

Inflammation as common link to progressive neurological diseases.

Life expectancy has increased immensely over the past decades, bringing new challenges to the health systems as advanced age increases the predisposition for many diseases. One of those is the burden of neurologic disorders. While many hypotheses have been placed to explain aging mechanisms, it has been widely accepted that the increasing pro-inflammatory status with advanced age or "inflammaging" is a main determinant of biological aging. Furthermore, inflammaging is at the cornerstone of many age-related diseases and its involvement in neurologic disorders is an exciting hypothesis. Indeed, aging and neurologic disorders development in the elderly seem to share some basic pathways that fundamentally converge on inflammation. Peripheral inflammation significantly influences brain function and contributes to the development of neurological disorders, including Alzheimer's disease, Parkinson's disease, and multiple sclerosis. Understanding the role of inflammation in the pathogenesis of progressive neurological diseases is of crucial importance for developing effective treatments and interventions that can slow down or prevent disease progression, therefore, decreasing its social and economic burden.

Unravelling the Influence of Endocrine-Disrupting Chemicals on Obesity Pathophysiology Pathways.

Obesity represents a global health concern, affecting individuals of all age groups across the world. The prevalence of excess weight and obesity has escalated to pandemic proportions, leading to a substantial increase in the incidence of various comorbidities, such as cardiovascular diseases, type 2 diabetes, and cancer. This chapter seeks to provide a comprehensive exploration of the pathways through which endocrine-disrupting chemicals can influence the pathophysiology of obesity. These mechanisms encompass aspects such as the regulation of food intake and appetite, intestinal fat absorption, lipid metabolism, and the modulation of inflammation. This knowledge may help to elucidate the role of exogenous molecules in both the aetiology and progression of obesity.

The role of flavonoids in the regulation of epithelial-mesenchymal transition in cancer: A review on targeting signaling pathways and metastasis.

One of the hallmarks of cancer is metastasis, a process that entails the spread of cancer cells to distant regions in the body, culminating in tumor formation in secondary organs. Importantly, the proinflammatory environment surrounding cancer cells further contributes to cancer cell transformation and extracellular matrix destruction. During metastasis, front-rear polarity and emergence of migratory and invasive features are manifestations of epithelial-mesenchymal transition (EMT). A variety of transcription factors (TFs) are implicated in the execution of EMT, the most prominent belonging to the Snail Family Transcriptional Repressor (SNAI) and Zinc Finger E-Box Binding Homeobox (ZEB) families of TFs. These TFs are regulated by interaction with specific microRNAs (miRNAs), as miR34 and miR200. Among the several secondary metabolites produced in plants, flavonoids constitute a major group of bioactive molecules, with several described effects including antioxidant, antiinflammatory, antidiabetic, antiobesogenic, and anticancer effects. This review scrutinizes the modulatory role of flavonoids on the activity of SNAI/ZEB TFs and on their regulatory miRNAs, miR-34, and miR-200. The modulatory role of flavonoids can attenuate mesenchymal features and stimulate epithelial features, thereby inhibiting and reversing EMT. Moreover, this modulation is concomitant with the attenuation of signaling pathways involved in diverse processes as cell proliferation, cell growth, cell cycle progression, apoptosis inhibition, morphogenesis, cell fate, cell migration, cell polarity, and wound healing. The antimetastatic potential of these versatile compounds is emerging and represents an opportunity for the synthesis of more specific and potent agents.

Silver nanoparticles exert toxic effects in human monocytes and macrophages associated with the disruption of Δψm and release of pro-inflammatory cytokines.

Silver nanoparticles (AgNP) are the most widely produced type of nanoparticles due to their antimicrobial and preservative properties. However, their systemic bioavailability may be considered a potential hazard. When AgNP reach the bloodstream, they interact with the immune cells, contributing to the onset and development of an inflammatory response. Monocytes and macrophages play a pivotal role in our defense system, but the interaction of AgNP with these cells is still not clear. Therefore, the main objective of this work was to assess the cytotoxic and pro-inflammatory effects induced by 5, 10, and 50 nm AgNP coated with polyvinylpyrrolidone (PVP) and citrate, in concentrations that could be attained in vivo (0-25 µg/mL), in human monocytes isolated from human blood and human macrophages derived from a monocytic cell line (THP-1). The effects of PVP and citrate-coated AgNP on cell viability, mitochondrial membrane potential, and cytokines release were evaluated. The results evidenced that AgNP exert strong harmful effects in both monocytes and macrophages, through the establishment of a strong pro-inflammatory response that culminates in cell death. The observed effects were dependent on the AgNP concentration, size and coating, being observed more pronounced cytotoxic effects with smaller PVP coated AgNP. The results showed that human monocytes seem to be more sensitive to AgNP exposure than human macrophages. Considering the increased daily use of AgNP, it is imperative to further explore the adverse outcomes and mechanistic pathways leading to AgNP-induced pro-inflammatory effects to deep insight into the molecular mechanism involved in this effect.

Biodistribution and intestinal inflammatory response following voluntary oral intake of silver nanoparticles by C57BL/6J mice.

Silver nanoparticles (AgNP) are among the most widely commercialized nanomaterials globally, with applications in medicine and the food industry. Consequently, the increased use of AgNP in the food industry has led to an unavoidable rise  in human exposure to these nanoparticles. Their widespread use raises concerns about potential hazards to human health, specifically their intestinal pro-inflammatory effects. Thus, the main objective of this study was to evaluate the biological effects of two subacute doses of 5 nm polyvinylpyrrolidone (PVP)-AgNP in C57BL/6J mice. One mg/kg body weight or 10 mg/kg bw was provided once a day for 14 days, using a new technology (HaPILLness) that allows voluntary, stress-free, and accurate oral dosing. It was observed that after oral ingestion, while AgNP is biodistributed throughout the entire organism, most of the ingested dose is excreted in the feces. The passage and accumulation of AgNP throughout the intestine instigated a prominent inflammatory response, marked by significant histological, vascular, and cellular transformations. This response was driven by the activation of the nuclear factor-кB (NF-кB) inflammatory pathway, ultimately leading to the generation of multiple cytokines and chemokines.

A Clinically Relevant Dosage of Mitoxantrone Disrupts the Glutathione and Lipid Metabolic Pathways of the CD-1 Mice Brain: A Metabolomics Study.

Long-term cognitive dysfunction, or "chemobrain", has been observed in cancer patients treated with chemotherapy. Mitoxantrone (MTX) is a topoisomerase II inhibitor that binds and intercalates with DNA, being used in the treatment of several cancers and multiple sclerosis. Although MTX can induce chemobrain, its neurotoxic mechanisms are poorly studied. This work aimed to identify the adverse outcome pathways (AOPs) activated in the brain upon the use of a clinically relevant cumulative dose of MTX. Three-month-old male CD-1 mice were given a biweekly intraperitoneal administration of MTX over the course of three weeks until reaching a total cumulative dose of 6 mg/kg. Controls were given sterile saline in the same schedule. Two weeks after the last administration, the mice were euthanized and their brains removed. The left brain hemisphere was used for targeted profiling of the metabolism of glutathione and the right hemisphere for an untargeted metabolomics approach. The obtained results revealed that MTX treatment reduced the availability of cysteine (Cys), cysteinylglycine (CysGly), and reduced glutathione (GSH) suggesting that MTX disrupts glutathione metabolism. The untargeted approach revealed metabolic circuits of phosphatidylethanolamine, catecholamines, unsaturated fatty acids biosynthesis, and glycerolipids as relevant players in AOPs of MTX in our in vivo model. As far as we know, our study was the first to perform such a broad profiling study on pathways that could put patients given MTX at risk of cognitive deficits.

Flavonoids as potential agents in the management of type 2 diabetes through the modulation of α-amylase and α-glucosidase activity: a review.

Type 2 diabetes (T2D) is one of the most prevalent metabolic diseases worldwide and is characterized by increased postprandial hyperglycemia (PPHG). α-Amylase and α-glucosidase inhibitors have been shown to slow the release of glucose from starch and oligosaccharides, resulting in a delay of glucose absorption and a reduction in postprandial blood glucose levels. Since current α-glucosidase inhibitors used in the management of T2D, such as acarbose, have been associated to strong gastrointestinal side effects, the search for novel and safer drugs is considered a hot topic of research. Flavonoids are phenolic compounds widely distributed in the Plant Kingdom and important components of the human diet. These compounds have shown promising antidiabetic activities, including the inhibition of α-amylase and α-glucosidase. The aim of this review is to provide an overview on the scientific literature concerning the structure-activity relationship of flavonoids in inhibiting α-amylase and α-glucosidase, including their type of inhibition and experimental procedures applied. For this purpose, a total of 500 compounds is covered in this review. Available data may be considered of high value for the design and development of novel flavonoid derivatives with effective and potent inhibitory activity against those carbohydrate-hydrolyzing enzymes, to be possibly used as safer alternatives for the regulation of PPHG in T2D.

A comprehensive review on the antidiabetic activity of flavonoids targeting PTP1B and DPP-4: a structure-activity relationship analysis.

Type 2 diabetes (T2D) is an expanding global health problem, resulting from defects in insulin secretion and/or insulin resistance. In the past few years, both protein tyrosine phosphatase 1B (PTP1B) and dipeptidyl peptidase-4 (DPP-4), as well as their role in T2D, have attracted the attention of the scientific community. PTP1B plays an important role in insulin resistance and is currently one of the most promising targets for the treatment of T2D, since no available PTP1B inhibitors were still approved. DPP-4 inhibitors are among the most recent agents used in the treatment of T2D (although its use has been associated with possible cardiovascular adverse events). The antidiabetic properties of flavonoids are well-recognized, and include inhibitory effects on the above enzymes, although hitherto not therapeutically explored. In the present study, a comprehensive review of the literature of both synthetic and natural isolated flavonoids as inhibitors of PTP1B and DPP-4 activities is made, including their type of inhibition and experimental conditions, and structure-activity relationship, covering a total of 351 compounds. We intend to provide the most favorable chemical features of flavonoids for the inhibition of PTP1B and DPP-4, gathering information for the future development of compounds with improved potential as T2D therapeutic agents.

Pro-inflammatory effects of silver nanoparticles in the intestine.

Nanotechnology is a promising technology of the twenty-first century, being a rapidly evolving field of research and industrial innovation widely applied in our everyday life. Silver nanoparticles (AgNP) are considered the most commercialized nanosystems worldwide, being applied in diverse sectors, from medicine to the food industry. Considering their unique physical, chemical and biological properties, AgNP have gained access into our daily life, with an exponential use in food industry, leading to an increased inevitable human oral exposure. With the growing use of AgNP, several concerns have been raised, in recent years, about their potential hazards to human health, more precisely their pro-inflammatory effects within the gastrointestinal system. Therefore a review of the literature has been undertaken to understand the pro-inflammatory potential of AgNP, after human oral exposure, in the intestine. Despite the paucity of information reported in the literature about this issue, existing studies indicate that AgNP exert a pro-inflammatory action, through generation of oxidative stress, accompanied by mitochondrial dysfunction, interference with transcription factors and production of cytokines. However, further studies are needed to elucidate the mechanistic pathways and molecular targets involved in the intestinal pro-inflammatory effects of AgNP.

Ecstasy metabolites and monoamine neurotransmitters upshift the Na+/K+ ATPase activity in mouse brain synaptosomes.

3,4-Methylenedioximethamphetamine (MDMA; "ecstasy") is a psychotropic drug with well-known neurotoxic effects mediated by hitherto not fully understood mechanisms. The Na+- and K+-activated adenosine 5'-triphosphatase (Na+/K+ ATPase), by maintaining the ion gradient across the cell membrane, regulates neuronal excitability. Thus, a perturbation of its function strongly impacts cell homeostasis, ultimately leading to neuronal dysfunction and death. Nevertheless, whether MDMA affects the Na+/K+ ATPase remains unknown. In this study, we used synaptosomes obtained from whole mouse brain to test the effects of MDMA, three of its major metabolites [α-methyldopamine, N-methyl-α-methyldopamine and 5-(glutathion-S-yl)-α-methyldopamine], serotonin (5-HT), dopamine, 3,4-dihydroxy-L-phenylalanine (L-Dopa) and 3,4-dihydroxyphenylacetic acid (DOPAC) on the Na+/K+ ATPase function. A concentration-dependent increase of Na+/K+ ATPase activity was observed in synaptosomes exposed to the tested compounds (concentrations ranging from 0.0625 to 200 µM). These effects were independent of protein kinases A and C activities. Nevertheless, a rescue of the compounds' effects was observed in synaptosomes pre-incubated with the antioxidant N-acetylcysteine (1 mM), suggesting a role for reactive species-regulated pathways on the Na+/K+ ATPase effects. In agreement with this hypothesis, a similar increase in the pump activity was found in synaptosomes exposed to the chemical generator of superoxide radicals, phenazine methosulfate (1-250 µM). This study demonstrates the ability of MDMA metabolites, monoamine neurotransmitters, L-Dopa and DOPAC to alter the Na+/K+ ATPase function. This could represent a yet unknown mechanism of action of MDMA and its metabolites in the brain.

Chemobrain: mitoxantrone-induced oxidative stress, apoptotic and autophagic neuronal death in adult CD-1 mice.

Mitoxantrone (MTX) is a topoisomerase II inhibitor used to treat a wide range of tumors and multiple sclerosis but associated with potential neurotoxic effects mediated by hitherto poorly understood mechanisms. In adult male CD-1 mice, the underlying neurotoxic pathways of a clinically relevant cumulative dose of 6 mg/kg MTX was evaluated after biweekly administration for 3 weeks and sacrifice 1 week after the last administration was undertaken. Oxidative stress, neuronal damage, apoptosis, and autophagy were analyzed in whole brain, while coronal brain sections were used for a closer look in the hippocampal formation (HF) and the prefrontal cortex (PFC), as these areas have been signaled out as the most affected in 'chemobrain'. In the whole brain, MTX-induced redox imbalance shown as increased endothelial nitric oxide synthase and reduced manganese superoxide dismutase expression, as well as a tendency to a decrease in glutathione levels. MTX also caused diminished ATP synthase ß expression, increased autophagic protein LC3 II and tended to decrease p62 expression. Postsynaptic density protein 95 expression decreased in the whole brain, while hyperphosphorylation of Tau was seen in PFC. A reduction in volume was observed in the dentate gyrus (DG) and CA1 region of the HF, while GFAP-ir astrocytes increased in all regions of the HF except in the DG. Apoptotic marker Bax increased in the PFC and in the CA3 region, whereas p53 decreased in all brain areas evaluated. MTX causes damage in the brain of adult CD-1 mice in a clinically relevant cumulative dose in areas involved in memory and cognition.

Flavonoids as antiobesity agents: A review.

Obesity is a global health problem that affects all age groups in both developing and developed countries. In recent years, the prevalence of overweight and obesity has reached pandemic levels, resulting in a dramatic increase in the incidence of various comorbidities, such as cardiovascular diseases, type 2 diabetes, and cancer, consequently leading to massive health and socioeconomic burdens. Together with lifestyle changes, antiobesity pharmacotherapy is gaining momentum as an adjunctive treatment. However, the available pharmacological approaches have limited use owing to either significant adverse effects or low efficacy. Over the years, natural products have been an important source of lead compounds for drug discovery. Among these, flavonoids are associated with important biological effects and health-promoting activities. In this review, we discuss the modulatory effects of flavonoids on obesity and their potential mechanisms of action. The literature strongly suggests that most common flavonoids demonstrate a pronounced effect on obesity as shown by their ability to lower body weight, fat mass, and plasma triglycerides/cholesterol, both in in vitro and in vivo models. The impact of flavonoids on obesity can be observed through different mechanisms: reducing food intake and fat absorption, increasing energy expenditure, modulating lipid metabolism, or regulating gut microbiota profile. A better understanding of the known antiobesity mechanisms of flavonoids will enable their potential use to treat this medical condition. Therefore, this review focuses on the putative biological mechanisms through which flavonoids may prevent or treat obesity and highlights new perspectives on future pharmacological use.

Global, Regional, and National Burden of Calcific Aortic Valve and Degenerative Mitral Valve Diseases, 1990-2017.

BACKGROUND: Nonrheumatic valvular diseases are common; however, no studies have estimated their global or national burden. As part of the Global Burden of Disease Study 2017, mortality, prevalence, and disability-adjusted life-years (DALYs) for calcific aortic valve disease (CAVD), degenerative mitral valve disease, and other nonrheumatic valvular diseases were estimated for 195 countries and territories from 1990 to 2017. METHODS: Vital registration data, epidemiologic survey data, and administrative hospital data were used to estimate disease burden using the Global Burden of Disease Study modeling framework, which ensures comparability across locations. Geospatial statistical methods were used to estimate disease for all countries, because data on nonrheumatic valvular diseases are extremely limited for some regions of the world, such as Sub-Saharan Africa and South Asia. Results accounted for estimated level of disease severity as well as the estimated availability of valve repair or replacement procedures. DALYs and other measures of health-related burden were generated for both sexes and each 5-year age group, location, and year from 1990 to 2017. RESULTS: Globally, CAVD and degenerative mitral valve disease caused 102 700 (95% uncertainty interval [UI], 82 700-107 900) and 35 700 (95% UI, 30 500-42 500) deaths, and 12.6 million (95% UI, 11.4 million-13.8 million) and 18.1 million (95% UI, 17.6 million-18.6 million) prevalent cases existed in 2017, respectively. A total of 2.5 million (95% UI, 2.3 million-2.8 million) DALYs were estimated as caused by nonrheumatic valvular diseases globally, representing 0.10% (95% UI, 0.09%-0.11%) of total lost health from all diseases in 2017. The number of DALYs increased for CAVD and degenerative mitral valve disease between 1990 and 2017 by 101% (95% UI, 79%-117%) and 35% (95% UI, 23%-47%), respectively. There is significant geographic variation in the prevalence, mortality rate, and overall burden of these diseases, with highest age-standardized DALY rates of CAVD estimated for high-income countries. CONCLUSIONS: These global and national estimates demonstrate that CAVD and degenerative mitral valve disease are important causes of disease burden among older adults. Efforts to clarify modifiable risk factors and improve access to valve interventions are necessary if progress is to be made toward reducing, and eventually eliminating, the burden of these highly treatable diseases.

Nano-based drug delivery systems used as vehicles to enhance polyphenols therapeutic effect for diabetes mellitus treatment.

Diabetes mellitus is one of the biggest health emergencies of the 21st century worldwide, characterized by deficiency in insulin secretion and/or action, leading to hyperglycemia. Despite the currently available antidiabetic therapeutic options, 4.2 million people died in 2019 due to diabetes. Thus, new effective interventions are required. Polyphenols are plant secondary metabolites and have been recognized for their vast number of biological activities, including potential antidiabetic effects. However, the poor bioavailability and high metabolization of polyphenols restrict their biological effects in vivo. Nanotechnology is a promising area of research to improve the therapeutic effect of several compounds. Therefore, this review provides an overview of the literature about the utility of nano-based drug delivery systems as vehicles of polyphenols in diabetes treatment. It was possible to conclude that, in general, nano-based drug delivery systems can potentiate the beneficial antidiabetic properties of polyphenols, when compared with the free compounds, opening a new field of research in diabetology.

Optimization and Validation of an In Vitro Standardized Glycogen Phosphorylase Activity Assay.

Glycogen phosphorylase (GP) is a key enzyme in the glycogenolysis pathway and a potential therapeutic target in the management of type 2 diabetes. It catalyzes a reversible reaction: the release of the terminal glucosyl residue from glycogen as glucose 1-phosphate; or the transfer of glucose from glucose 1-phosphate to glycogen. A colorimetric method to follow in vitro the activity of GP with usefulness in structure-activity relationship studies and high-throughput screening capability is herein described. The obtained results allowed the choice of the optimal concentration of enzyme of 0.38 U/mL, 0.25 mM glucose 1-phosphate, 0.25 mg/mL glycogen, and temperature of 37 °C. Three known GP inhibitors, CP-91149, a synthetic inhibitor, caffeine, an alkaloid, and ellagic acid, a polyphenol, were used to validate the method, CP-91149 being the most active inhibitor. The effect of glucose on the IC50 value of CP-91149 was also investigated, which decreased when the concentration of glucose increased. The assay parameters for a high-throughput screening method for discovery of new potential GP inhibitors were optimized and standardized, which is desirable for the reproducibility and comparison of results in the literature. The optimized method can be applied to the study of a panel of synthetic and/or natural compounds, such as polyphenols.

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

Silver nanoparticles (AgNP) have been increasingly incorporated into food-related and hygiene products for their unique antimicrobial and preservative properties. The consequent oral exposure may then result in unpredicted harmful effects in the gastrointestinal tract (GIT), which should be considered in the risk assessment and risk management of these materials. In the present study, the toxic effects of polyethyleneimine (PEI)-coated AgNP (4 and 19 nm) were evaluated in GIT-relevant cells (Caco-2 cell line as a model of human intestinal cells, and neutrophils as a model of the intestinal inflammatory response). This study also evaluated the putative protective action of dietary flavonoids against such harmful effects. The obtained results showed that AgNP of 4 and 19 nm effectively induced Caco-2 cell death by apoptosis with concomitant production of nitric oxide, irrespective of the size. It was also observed that AgNP induced human neutrophil oxidative burst. Interestingly, some flavonoids, namely quercetin and quercetagetin, prevented the deleterious effects of AgNP in both cell types. Overall, the data of the present study provide a first insight into the promising protective role of flavonoids against the potentially toxic effects of AgNP at the intestinal level.

3,4-Methylenedioxymethamphetamine Hepatotoxicity under the Heat Stress Condition: Novel Insights from in Vitro Metabolomic Studies.

Hyperthermia has been extensively reported as a life-threatening consequence of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) abuse. In this work, we used a sensitive untargeted metabolomic approach based on gas chromatography-mass spectrometry to evaluate the impact of hyperthermia on the hepatic metabolic changes caused by MDMA. For this purpose, primary mouse hepatocytes were exposed to subtoxic (LC01 and LC10) and toxic (LC30) concentrations of MDMA for 24 h, at 37 or 40.5 °C (simulating body temperature increase after MDMA consumption), and alterations on both intracellular metabolome and extracellular volatilome were evaluated. Multivariate analysis showed that metabolic patterns clearly discriminate MDMA treated cells from control cells, both in normothermic and hyperthermic conditions. The metabolic signature was found to be largely common to MDMA subtoxic and toxic concentrations, although with evident differences in the magnitude of response, with metabolic changes significantly more pronounced at 40.5 °C. Discriminant metabolites associated with MDMA-induced hepatotoxicity are mostly involved in the amino acid metabolism, aminoacyl tRNA biosynthesis, glutathione metabolism, tricarboxylic acid cycle, and pyruvate metabolism. Moreover, our metabolomic findings were corroborated by classical toxicity parameters, demonstrating the high sensitivity of this omic approach to assess molecular-level effects. Overall, this study indicates that MDMA triggers significant metabolic alterations on hepatic cells, even at low concentrations, that are clearly exacerbated at high temperatures. These findings provide new metabolic pieces to solve the puzzle of MDMA's hepatotoxicity mechanism and emphasize the increased risks of MDMA abuse due to the thermogenic action of the drug.

Chalcones as Modulators of Neutrophil Oxidative Burst under Physiological and High Glucose Conditions.

Several epidemiological studies indicate that neutrophils, under hyperglycemic conditions, are involved in the perpetuation of the inflammatory status, a characteristic of diabetes mellitus, leading to the production of prodigious quantities of reactive species and the release of neutrophil extracellular traps (NETs). Accordingly, our aim was to study the ability of a panel of 25 structurally related chalcones to modulate human neutrophil oxidative burst and the production of NETs under physiological and high glucose conditions. In general, all chalcones presented similar effects under physiological and high glucose conditions. 2',4-Dihydroxy-3-methoxychalcone (3), here studied for the first time, was the most active (IC50 ≤ 5 µM) on the inhibition of neutrophil oxidative burst, showing the importance of the presence of hydroxy substituents at the C-2' and C-4 positions of the A and B rings, respectively, and a 3-methoxy substituent at B ring of the chalcone scaffold. In the present experimental conditions, NETs release only occurred under high glucose levels. The pentahydroxylated chalcone 1 was the only one that was able to modulate the NETs release. This study provided important considerations about the chalcones' scaffold and their modulatory effect on human neutrophil activities at physiological and high glucose conditions, evidencing their potential use as complementary antidiabetic agents.

Structural Specificity of Flavonoids in the Inhibition of Human Fructose 1,6-Bisphosphatase.

Liver fructose 1,6-bisphosphatase (FBPase) is a recognized regulatory enzyme of the gluconeogenesis pathway, which has emerged as a valid target to control gluconeogenesis-mediated overproduction of glucose. As such, the management of diabetes with FBPase inhibitors represents a potential alternative for the currently used antidiabetic agents. In this study, the FBPase inhibition of a panel of 55 structurally related flavonoids was tested, through a microanalysis screening system. Then, a subset of seven active inhibitors and their close chemical relatives were further evaluated by molecular dynamics (MD) simulations using a linear interaction energy (LIE) approach. The results obtained showed that D14 (herbacetin) was the most potent inhibitor, suggesting that the presence of -OH groups at the C-3, C-4', C-5, C-7, and C-8 positions, as well as the double bond between C-2 and C-3 and the 4-oxo function at the pyrone ring, are favorable for the intended effect. Furthermore, D14 (herbacetin) is stabilized by a strong interaction with the Glu30 side chain and the Thr24 backbone of FBPase. This is the first investigation studying the in vitro inhibitory effect of a panel of flavonoids against human liver FBPase, thus representing a potentially important step for the search and design of novel inhibitors of this enzyme.