Quercetin, a flavonoid with anti-inflammatory activity, suppresses the development of abdominal aortic aneurysms in mice

The prognostic potential of long noncoding RNA XIST in cardiovascular diseases: a review

There is a significant mortality rate associated with cardiovascular disease despite advances in treatment. long Non-coding RNAs (lncRNAs) play a critical role in many biological processes and their dysregulation is associated with a wide range of diseases in which their downstream pathways are disrupted. A lncRNA X-inactive specific transcript (XIST) is well known as a factor that regulates the physiological process of chromosome dosage compensation for females. According to recent studies, lncRNA XIST is involved in a variety of cellular processes, including apoptosis, proliferation, invasion, metastasis, oxidative stress and inflammation, through molecular networks with microRNAs and their downstream targets in neoplastic and non-neoplastic diseases. Because these cellular processes play a role in the pathogenesis of cardiovascular diseases, we aim to investigate the role that lncRNA XIST plays in this process. Additionally, we wish to determine whether it is a prognostic factor or a potential therapeutic target in these diseases.

The Role of Inflammasome in Abdominal Aortic Aneurysm and Its Potential Drugs

Abdominal aortic aneurysm (AAA) has been recognized as a serious chronic inflammatory degenerative aortic disease in recent years. At present, there is no other effective intervention except surgical treatment for AAA. With the aging of the human population, its incidence is increasing year by year, posing a serious threat to human health. Modern studies suggest that vascular chronic inflammatory response is the core process in AAA occurrence and development. Inflammasome, a multiprotein complex located in the cytoplasm, mediates the expression of various inflammatory cytokines like interleukin (IL)-1β and IL-18, and thus plays a pivotal role in inflammation regulation. Therefore, inflammasome may exert a crucial influence on the progression of AAA. This article reviews some mechanism studies to investigate the role of inflammasome in AAA and then summarizes several potential drugs targeting inflammasome for the treatment of AAA, aiming to provide new ideas for the clinical prevention and treatment of AAA beyond surgical methods.

Oxidative Stress and the Pathogenesis of Aortic Aneurysms

Aortic aneurysms are responsible for significant morbidity and mortality. Despite their clinical significance, there remain critical knowledge gaps in the pathogenesis of aneurysm disease and the mechanisms involved in aortic rupture. Recent studies have drawn attention to the role of reactive oxygen species (ROS) and their down-stream effectors in chronic cardiovascular diseases and specifically in the pathogenesis of aortic aneurysm formation. This review will discuss current mechanisms of ROS in mediating aortic aneurysms, the failure of endogenous antioxidant systems in chronic vascular diseases, and their relation to the development of aortic aneurysms.

Evidence for a protective role of Protein Disulfide Isomerase-A1 against aortic dissection

BACKGROUND AND AIMS

Redox signaling is involved in the pathophysiology of aortic aneurysm/dissection. Protein Disulfide Isomerases and its prototype PDIA1 are thiol redox chaperones mainly from endoplasmic reticulum (ER), while PDIA1 cell surface pool redox-regulates thrombosis, cytoskeleton remodeling and integrin activation, which are mechanisms involved in aortic disease. Here we investigate the roles of PDIA1 in aortic dissection.

METHODS

Initially, we assessed the outcome of aortic aneurysm/dissection in transgenic PDIA1-overexpressing FVB mice using a model of 28-day exposure to lysyl oxidase inhibitor BAPN plus angiotensin-II infusion. In a second protocol, we assessed the effects of PDIA1 inhibitor isoquercetin (IQ) against aortic dissection in C57BL/6 mice exposed to BAPN for 28 days.

RESULTS

Transgenic PDIA1 overexpression associated with ca. 50% (p = 0.022) decrease (vs.wild-type) in mortality due to abdominal aortic rupture and protected against elastic fiber breaks in thoracic aorta. Conversely, exposure of mice to IQ increased thoracic aorta dissection-related mortality rates, from ca. 18%-50% within 28-days (p = 0.019); elastic fiber disruption and collagen deposition were also enhanced. The structurally-related compound diosmetin, which does not inhibit PDI, had negligible effects. In parallel, stretch-tension curves indicated that IQ amplified a ductile-type of biomechanical failure vs. control or BAPN-exposed mice aortas. IQ-induced effects seemed unassociated with nonspecific antioxidant effects or ER stress. In both models, echocardiographic analysis of surviving mice suggested that aortic rupture was dissociated from progressive dilatation.

CONCLUSIONS

Our data indicate a protective role of PDIA1 against aortic dissection/rupture and potentially uncovers a novel integrative mechanism coupling redox and biomechanical homeostasis in vascular remodeling.

The flavonoids induce the transcription of mRNA encoding erythropoietin in cultured embryonic stem cells via the accumulation of hypoxia-inducible factor-1α

Flavonoids are the most common phytochemicals in vegetables and herbal products. The beneficial functions of flavonoids in the brain and erythropoietic system have been proposed. Erythropoietin (EPO) is a potent protective agent in the brain; but which has difficulty to cross the blood brain barrier (BBB). Here, about 60 flavonoids were screened for their potential activation on the transcription of EPO mRNA in the neuronal embryonic stem cell lines, NT2/D1 and PC12. Amongst the screened flavonoids, formononetin, calycosin, ononin, chrysin, baicalein and apigenin showed robust up regulation of EPO production via enhancement of hypoxia response element (HRE) activity in cultured embryonic stem cells. In addition, the flavonoids showed activation of HRE activity by having increased accumulation of HIF-1α, but not on level of HIF-1β, in the cultures. The accumulation of HIF-1α was attributed to up regulation of HIF-1α mRNA and blockade of HIF-1α degradation upon treatment of the flavonoids. These results suggested a promising trend of developing commercial products of flavonoids as food supplements tailored for brain health.

Evaluation of anti-inflammatory, diuretic and oral glucose tolerance activities of phenolic compound-rich fractions of Hammada articulata in Albino Wistar rats

Hammada articulata is a plant widely used by the locals of the Algerian Sahara for multiple medicinal purposes. However, little was known about its chemical composition and the mechanisms of its bioactivity. For this purpose, the derived extracts [chloroform (CHCl₃), ethyl acetate (EtOAc) and n-butanol (n-BuOH)] of the 80% ethanol extract of its aerial parts, were evaluated for their anti-inflammatory, diuretic, and anti-hyperglycemic activities in vivo. A preliminary phytochemical screening of H. articulata extracts showed the presence of a variety of secondary metabolites. RP-HPLC/DAD was used to analyze some fractions obtained by fractionation of the three derived extracts, by column chromatography and chosen because of the abundance and simplicity of their chemical composition. The fractions obtained from EtOAc and n-BuOH extracts showed a particular richness in phenolic compounds mainly naringenin, quercetin, kaempferol, myricetin, and rutin, which were known for their many interesting biological activities. The three derived extracts from H. articulata were assessed for their anti-inflammatory activity in the carrageenan-induced edema model in rats and their diuretic activity using hydrochlorothiazide (HCTZ) as a diuretic reference. All extracts showed considerable anti-inflammatory activity; the highest was registered in the group treated with the n-BuOH extract. However, for the diuretic activity, only the chloroform extract was active, with a diuretic spectrum similar to that of the standard diuretic HCTZ. The anti-hyperglycemic effect was carried out on the three derived extracts administered orally at a dose of 200 mg/kg, using the glucose tolerance test after gavage with the extracts. The EtOAc and n-BuOH extracts showed significant anti-hyperglycemic activity, improving oral glucose tolerance in normal rats.

Through network pharmacology and molecular docking to explore the underlying mechanism of Artemisia annua L. treating in abdominal aortic aneurysm

Background: Abdominal aortic aneurysm (AAA) is a degenerative disease that causes health problems in humans. However, there are no effective drugs for the treatment of AAA. Artemisia annua L. (A. annua) is a traditional herbal that has been widely used in cardiovascular disease. Based on network pharmacology and molecular docking technology, this study predicted the practical components and potential mechanisms of A. annua inhibiting the occurrence and development of AAA.

Methods: The main active ingredients and targets of A. annua were screened through the TCMSP database; the GeneCards, OMIM, PharmGkb, and TTD databases were used to search for the targeted genes of AAA and map them to the targets of the active ingredients to obtain the active ingredient therapy of A. annua. The targets of AAA were to construct a protein interaction network through the STRING platform. R software was used to carry out the enrichment analysis of GO and KEGG for relevant targets, and Cytoscape was used to construct the active ingredient-target network prediction model of A. annua. Finally, AutoDock Vina was used to verify the results of the active ingredients and critical targets.

Results: The main active ingredients obtained from A. annua for the treatment of AAA include quercetin, luteolin, kaempferol, isorhamnetin, and artemetin, as well as 117 effective targets, including RELA, MAPK14, CCND1, MAPK1, AKT1, MYC, MAPK8, TP53, ESR1, FOS, and JUN. The 11 targeted genes might play a key role in disease treatment. Enriched in 2115 GO biological processes, 159 molecular functions, 56 cellular components, and 156 KEGG pathways, inferred that its mechanism of action might be related to PI3K-Akt signaling pathway, fluid shear stress, atherosclerosis, and AGE-RAGE signaling pathway. Molecular docking results showed that the top five active components of A. annua had a good affinity for core disease targets and played a central role in treating AAA. The low binding energy molecular docking results provided valuable information for the development of drugs to treat AAA.

Conclusion: Therefore, A. annua may have multiple components, multiple targets, and multiple signaling pathways to play a role in treating AAA. A. annua may have the potential to treat AAA.

Advances on nanoformulation approaches for delivering plant-derived antioxidants: A case of quercetin

Oxidative stress has been implicated in tumorigenic, cardiovascular, neuro-, and age-related degenerative changes. Antioxidants minimize the oxidative damage through neutralization of reactive oxygen species (ROS) and other causative agents. Ever since the emergence of COVID-19, plant-derived antioxidants have received enormous attention, particularly in the Indian subcontinent. Quercetin (QCT), a bio-flavonoid, exists in the glycosylated form in fruits, berries and vegetables. The antioxidant potential of QCT analogs relates to the number of free hydroxyl groups in their structure. Despite presence of these groups, QCT exhibits substantial hydrophobicity. Formulation scientists have tested nanotechnology-based approaches for its improved solubilization and delivery to the intended site of action. By the virtue of its hydrophobicity, QCT gets encapsulated in nanocarriers carrying hydrophobic domains. Apart from passive accumulation, active uptake of such formulations into the target cells can be facilitated through well-studied functionalization strategies. In this review, we have discussed the approaches of improving solubilization and bioavailability of QCT with the use of nanoformulations.

A Network-Biology led Computational Drug repurposing Strategy to prioritize therapeutic options for COVID-19

The alarming pandemic situation of novel Severe Acute Respiratory Syndrome Coronavirus 2 (nSARS-CoV-2) infection, high drug development cost and slow process of drug discovery have made repositioning of existing drugs for therapeutics a popular alternative. It involves the repurposing of existing safe compounds which results in low overall development costs and shorter development timeline. In the present study, a computational network-biology approach has been used for comparing three candidate drugs i.e. quercetin, N-acetyl cysteine (NAC), and 2-deoxy-glucose (2-DG) to be effectively repurposed against COVID-19. For this, the associations between these drugs and genes of Severe Acute Respiratory Syndrome (SARS) and the Middle East Respiratory Syndrome (MERS) diseases were retrieved and a directed drug-gene-gene-disease interaction network was constructed. Further, to quantify the associations between a target gene and a disease gene, the shortest paths from the target gene to the disease genes were identified. A vector DV was calculated to represent the extent to which a disease gene was influenced by these drugs. Quercetin was quantified as the best among the three drugs, suited for repurposing with DV of -70.19, followed by NAC with DV of -39.99 and 2-DG with DV of -13.71. The drugs were also assessed for their safety and efficacy balance (in terms of therapeutic index) using network properties. It was found that quercetin was a forerunner than other two drugs.

Effectiveness of a new rutin Cu(II) complex in the prevention of lipid peroxidation and hepatotoxicity in hypercholesterolemic rats

A new rutin copper(II) complex (R-Cu2) was prepared and characterized by spectroscopic methods and elemental analysis. The effects of rutin and R-Cu2 were evaluated on the prevention of hypercholesterolemia in animals feed with high-cholesterol diet (HCD) for 8 weeks. The animals (n = 5) were neither fed with HCD nor treated (control group), or were treated with vehicle, 10 mg/kg simvastatin, rutin (16 and 160 μmol/kg), and R-Cu2 (16 and 160 μmol/kg) administered orally. Total cholesterol (TC) levels were significantly increased (p < .01) in all HCD groups. In rutin and R-Cu2 groups, it was observed a discrete, but not significant, TC and LDL-induced increase inhibition compared with vehicle-treated group. R-Cu2 treatment significantly decreased (p < .05) plasma triglycerides compared with the vehicle-treated group. All groups receiving treatments maintained the malondialdehyde at normal levels. Serum NO levels were reduced in animals treated with rutin and R-Cu2 compared with the vehicle-treated group. In addition, the results also showed that the groups treated with rutin and R-Cu2 reduced significantly (p < .01), the number of neutrophils and prevented histological changes in all evaluated liver zones. R-Cu2 group maintained the ALT, AST, and ALP enzymes at normal levels. Thus, the effects of R-Cu2 in modulating inflammation and protecting liver damage were confirmed. PRACTICAL APPLICATIONS: Rutin, a plant-derived flavonoid, is one of phenolic compounds well known as a nutraceutical due to its antioxidant and anti-inflammatory properties. Findings of this study demonstrate the effects of both rutin and R-Cu2 in modulating inflammation and protecting liver damage in hypercholesterolemic rats. However, some effects analyzed became more evident in R-Cu2. Thereby, it was shown that the synthesis of a new flavonoid compound (R-Cu2) could be applied as a nutraceutical benefit option to prevent hypercholesterolemia condition.

Quercetin Reduces Hepatic Fibrogenesis by Inhibiting TGF-β/Smad3 Signaling Pathway in LX-2 Cell Line

Background: Liver fibrosis has become one of the leading causes of morbidity and mortality in the world. Liver fibrosis progresses to cirrhosis and can eventually lead to hepatocellular carcinoma (HCC). During fibrogenesis, the hepatic stellate cells (HSCs) remain active and continuously produce more extracellular matrix (ECM). Quercetin, one of the main flavonoids in vegetables, has shown hepatoprotective potential, but its effects on liver fibrosis are not apparent. Objectives: In this study, we investigated the antifibrotic activity of quercetin following stimulation of TGF-β in the LX-2 cell line (a type of HSC-derived cell line) and its underlying mechanism in vitro. Methods: The LX-2 cells were treated with TGF-β1 (2 ng/mL) for 24 h. Next, the cells were treated with quercetin for 24 h, and the mRNA expression of α-smooth muscle actin (α-SMA), collagen1α1, and p-Smad3 protein levels were measured. Results: The results showed that the expression of α-SMA, collagen 1α1 (COL1α1) genes, and also the level of p-Smad3 protein in the presence of TGF-β increased significantly compared to the control group. Moreover, quercetin in concentrations of 75 and 100 μM inhibited TGF-β1-induced expression of α-SMA and COL1α1 genes and the p-Smad3 protein in LX-2 cells. Conclusions: We conclude that quercetin inhibits further activation of HSCs by inhibiting the TGF-β/Smad3 signaling pathway and reduces ECM accumulation during liver fibrosis in vitro, and may prevent the progression of liver fibrosis. Thus, the use of quercetin is suggested as a potential therapeutic agent in the treatment of liver fibrosis.

Structural Characterization and Assessment of Anti-Inflammatory and Anti-Tyrosinase Activities of Polyphenols from Melastoma normale

Polyphenols, widely distributed in the genus Melastoma plants, possess extensive cellular protective effects such as anti-inflammatory, anti-tyrosinase, and anti-obesity, which makes it a potential anti-inflammatory drug or enzyme inhibitor. Therefore, the aim of this study is to screen for the anti-inflammatory and enzyme inhibitory activities of compounds from title plant. Using silica gel, MCI, ODS C18, and Sephadex LH-20 column chromatography, as well as semipreparative HPLC, the extract of Melastoma normale roots was separated. Four new ellagitannins, Whiskey tannin C (1), 1-O-(4-methoxygalloyl)-6-O-galloyl-2,3-O-(S)-hexahydroxydiphenoyl-β-d-glucose (2), 1-O-galloyl-6-O-(3-methoxygalloyl)-2,3-O-(S)-hexahydroxydiphenoyl-β-d-glucose (3), and 1-O-galloyl-6-O-vanilloyl-2,3-O-(S)-hexahydroxydiphenoyl-β-d-glucose (4), along with eight known polyphenols were firstly obtained from this plant. The structures of all isolates were elucidated by HRMS, NMR, and CD analyses. Using lipopolysaccharide (LPS)-stimulated RAW2 64.7 cells, we investigated the anti-inflammatory activities of compounds 1–4, unfortunately, none of them exhibit inhibit nitric oxide (NO) production, their IC₅₀ values are all > 50 μM. Anti-tyrosinase activity assays was done by tyrosinase inhibition activity screening model. Compound 1 showed weak tyrosinase inhibitory activity with IC₅₀ values of 426.02 ± 11.31 μM. Compounds 2–4 displayed moderate tyrosinase inhibitory activities with IC₅₀ values in the range of 124.74 ± 3.12–241.41 ± 6.23 μM. The structure–activity relationships indicate that hydroxylation at C-3′, C-4′, and C-3 in the flavones were key to their anti-tyrosinase activities. The successful isolation and structure identification of ellagitannin provide materials for the screening of anti-inflammatory drugs and enzyme inhibitors, and also contribute to the development and utilization of M. normale.

Therapeutic Potential of Quercetin to Alleviate Endothelial Dysfunction in Age-Related Cardiovascular Diseases

The vascular endothelium occupies a catalog of functions that contribute to the homeostasis of the cardiovascular system. It is a physically active barrier between circulating blood and tissue, a regulator of the vascular tone, a biochemical processor and a modulator of coagulation, inflammation, and immunity. Given these essential roles, it comes to no surprise that endothelial dysfunction is prodromal to chronic age-related diseases of the heart and arteries, globally termed cardiovascular diseases (CVD). An example would be ischemic heart disease (IHD), which is the main cause of death from CVD. We have made phenomenal advances in treating CVD, but the aging endothelium, as it senesces, always seems to out-run the benefits of medical and surgical therapies. Remarkably, many epidemiological studies have detected a correlation between a flavonoid-rich diet and a lower incidence of mortality from CVD. Quercetin, a member of the flavonoid class, is a natural compound ubiquitously found in various food sources such as fruits, vegetables, seeds, nuts, and wine. It has been reported to have a wide range of health promoting effects and has gained significant attention over the years. A growing body of evidence suggests quercetin could lower the risk of IHD by mitigating endothelial dysfunction and its risk factors, such as hypertension, atherosclerosis, accumulation of senescent endothelial cells, and endothelial-mesenchymal transition (EndoMT). In this review, we will explore these pathophysiological cascades and their interrelation with endothelial dysfunction. We will then present the scientific evidence to quercetin's anti-atherosclerotic, anti-hypertensive, senolytic, and anti-EndoMT effects. Finally, we will discuss the prospect for its clinical use in alleviating myocardial ischemic injuries in IHD.

Quercetin Downregulates Cyclooxygenase-2 Expression and HIF-1α/VEGF Signaling-Related Angiogenesis in a Mouse Model of Abdominal Aortic Aneurysm

Objective

Abdominal aortic aneurysm (AAA) development has been characterized by increased expression of vascular endothelial growth factor (VEGF), which contributes to angiogenesis via cyclooxygenase-2 (COX-2). Quercetin, one of the most common and well-researched flavonoids and abundant in vegetables and fruits, has beneficial effects in inhibiting angiogenesis. This study investigated the antiangiogenic effects of quercetin on experimental aneurysms.

Methods

We utilized the in vivo AAA mouse model induced by the periaortic application of CaCl₂ to examine the effectiveness of quercetin in blocking angiogenesis. Quercetin was administered at 60 mg/kg once daily on the day of the AAA induction and then continued for 6 weeks. Celecoxib, a selective COX-2 inhibitor, was used as the positive control.

Results

Our results demonstrated that quercetin significantly attenuated aneurysm growth in AAA mice and medial neovascularization. Accordingly, quercetin decreased the expression of proangiogenic mediators, including VEGF-A, intercellular adhesion molecule-1, vascular cell adhesion molecule 1, and vascular endothelial cadherin. Quercetin treatment also inhibited the expression of COX-2 and hypoxia-inducible factor 1α (HIF-1α). It was also found that quercetin-3-glucuronide, a major quercetin metabolite, downregulated the expression of COX-2, HIF-1α, VEGF-A, and matrix metalloproteinase activities in aortic vascular smooth muscle cells isolated from AAA mice.

Conclusion

Quercetin attenuates neovascularization during AAA growth, and this effect is mediated via the inhibition of COX-2, which decreases HIF-1α/VEGF signaling-related angiogenesis.

Natural antidotes and management of metal toxicity

The global burden of heavy metal especially mercury, arsenic, lead, and cadmium toxicities remains a significant public health challenge. Developing nations are particularly at high risk and carry the highest burden of this hazard. Chelation therapy has been the mainstay for treatment of heavy metal poisoning where the chelating agent binds metal ions to form complex ring-like structures called "chelates" to enhance their elimination from the body. Metal chelators have some drawbacks such as redistribution of some heavy metals from other tissues to the brain thereby increasing its neurotoxicity, causing loss of essential metals such as copper and zinc as well as some serious adverse effects, e.g., hepatotoxicity. The use of natural antidotes, which are easily available, affordable, and with little or no side effects compared to the classic metal chelators, is the focus of this review and suggested as cheaper options for developing nations in the treatment of heavy metal poisoning.

Phytochemical analysis and anti-inflammatory effects of Filipendula vulgaris Moench extracts

Filipendula vulgaris Moench (dropwort) is used in traditional medicine for relieving various inflammation-related diseases. In the present study, the phytochemical profile of F. vulgaris aerial part (FVA) and root (FVR) methanolic extracts was evaluated by LC-DAD-HRMS analysis. Furthermore, their in vitro and in vivo anti-inflammatory effects, as well as their potential cytotoxicity, were assessed. Results showed that the extracts mainly contain phenolics like flavonoids, hydrolyzable tannins, procyanidins, and phenolic acid derivatives, including gaultherin. No in vitro cytotoxicity was found at the highest concentration (50 μg/mL). FVA extract (50 μg/mL) significantly inhibited cyclooxygenase-1 and -2 (COX-1 and COX-2) activities in vitro (>50% inhibition), and FVR extract considerably inhibited COX-2 activity (52.5 ± 2.7%) without affecting COX-2 gene expression in LPS-stimulated THP-1 cells. The extracts demonstrated prominent in vivo anti-inflammatory potential upon oral administration in rats. Especially FVA extract at 100 and 200 mg/kg significantly inhibited carrageenan-induced edema formation. From these results, it can be concluded that F. vulgaris extracts possess interesting anti-inflammatory properties.

A diet enriched with tree nuts reduces severity of atherosclerosis but not abdominal aneurysm in angiotensin II-infused apolipoprotein E deficient mice

BACKGROUND AND AIMS

Diets enriched with tree nuts have been demonstrated to reduce the risk of atherosclerosis-related cardiovascular events. Abdominal aortic aneurysm (AAA) shares common risk factors with atherosclerosis and AAA patients commonly have atherosclerosis related cardiovascular events. AAA has some distinct pathological and clinical characteristics to those of atherosclerosis. No previous study has examined the effect of a diet enriched with tree nuts on experimental or clinical AAA. This study investigated the effect of a diet enriched with tree nuts on the development and severity of AAA within an experimental rodent model.

METHODS

Male apolipoprotein E deficient mice were allocated to a diet enriched with tree nuts or control diet for 56 days (n = 17 per group). After 28 days, all mice were infused with angiotensin II whilst being maintained on their respective diets. The primary outcome was AAA severity assessed by the supra-renal aortic diameter, measured by ultrasound and ex vivo morphometric analysis. The severity of atherosclerosis was assessed by computer-aided analysis of Sudan IV stained aortic arches and sections of brachiocephalic arteries prepared with Van Gieson's stain.

RESULTS

The diet enriched with tree nuts did not influence aortic diameter or aortic rupture incidence. Mice receiving the diet enriched with tree nuts had significantly less atherosclerosis within the brachiocephalic artery (p = 0.033) but not in the aortic arch.

CONCLUSIONS

This experimental study suggests that a diet enriched with tree nuts does not reduce the severity of AAA, but does reduce the severity of atherosclerosis within the brachiocephalic artery. The study was not powered to identify a moderate effect of the diet on the primary outcome and therefore this cannot be excluded.

Quercetin induces the selective uptake of HDL-cholesterol via promoting SR-BI expression and the activation of the PPARγ/LXRα pathway

Reverse cholesterol transport (RCT) is the process to deliver cholesterol to the liver for further excretion and involves scavenger receptor class B type I (SR-BI)-mediated selective lipid uptake (SLU) from high-density lipoprotein cholesterol (HDL-C). The up-regulation of hepatic SR-BI expression accelerates HDL-C clearance in circulation and impedes the development of atherosclerosis (AS). In the present study, we explored the modulation of hepatic SR-BI expression and SR-BI-mediated SLU by quercetin, a natural flavonoid compound in the diet with a favorable role in cardiovascular disorders. We found that quercetin significantly increased the expression level of SR-BI in HepG2 cells in a concentration- and time-dependent manner. Besides, quercetin had stimulatory effects on the binding of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil)-labeled HDL to hepatocytes and ¹²⁵I/³H-CE-HDL association. Treatment with small interfering RNA (siRNA) or SR-BI specific inhibitor, BLT-1, inhibited quercetin-induced Dil-HDL binding and selective HDL-C uptake. Treatment with quercetin increased both proliferator-activated receptor γ (PPARγ) and liver X receptor α (LXRα) levels. Additionally, the quercetin-induced expression of SR-BI, Dil-HDL binding and the selective uptake of HDL-C were significantly attenuated by treatment with PPARγ siRNA, LXRα siRNA, and their antagonists, respectively. In C57BL/6 mice, quercetin administration potently increased SR-BI, PPARγ and LXRα levels and lipid accumulation in the liver. Altogether, our results suggest that quercetin-induced up-regulation of SR-BI and subsequent lipid uptake in hepatocytes might contribute to its beneficial effects on cholesterol homeostasis and atherogenesis.

Chinese Herbal Medicine as a Potential Treatment of Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is an irreversible condition where the abdominal aorta is dilated leading to potentially fatal consequence of aortic rupture. Multiple mechanisms are involved in the development and progression of AAA, including chronic inflammation, oxidative stress, vascular smooth muscle (VSMC) apoptosis, immune cell infiltration and extracellular matrix (ECM) degradation. Currently surgical therapies, including minimally invasive endovascular aneurysm repair (EVAR), are the only viable interventions for AAAs. However, these treatments are not appropriate for the majority of AAAs, which measure <50 mm. Substantial effort has been invested to identify and develop pharmaceutical treatments such as statins and doxycycline for this potentially lethal condition but these interventions failed to offer a cure or to retard the progression of AAA. Chinese herbal medicine (CHM) has been used for the management of cardiovascular diseases for thousands of years in China and other Asian countries. The unique multi-component and multi-target property of CHMs makes it a potentially ideal therapy for multifactorial diseases such as AAA. In this review, we review the current scientific evidence to support the use of CHMs for the treatment of AAA. Mechanisms of action underlying the effects of CHMs on AAA are also discussed.

Quercetin treatment regulates the Na+,K+-ATPase activity, peripheral cholinergic enzymes, and oxidative stress in a rat model of demyelination

Quercetin is reported to exert a plethora of health benefits through many different mechanisms of action. This versatility and presence in the human diet has attracted the attention of the scientific community, resulting in a huge output of in vitro and in vivo (preclinical) studies. Therefore, we hypothesized that quercetin can protect Na⁺,K⁺-ATPase activity in the central nervous system, reestablish the peripheral cholinesterases activities, and reduce oxidative stress during demyelination events in rats. In line with this expectation, our study aims to find out how quercetin acts on the Na⁺,K⁺-ATPase activity in the central nervous system, peripheral cholinesterases, and stress oxidative markers in an experimental model of demyelinating disease. Wistar rats were divided into 4 groups: vehicle, quercetin, ethidium bromide (EB), and EB plus quercetin groups. The animals were treated once a day with vehicle (ethanol 20%) or quercetin 50 mg/kg for 7 (demyelination phase, by gavage) or 21 days (remyelination phase) after EB (0.1%, 10 μL) injection (intrapontine).The encephalon was removed, and the pons, hypothalamus, cerebral cortex, hippocampus, striatum, and cerebellum were dissected to verify the Na⁺,K⁺-ATPase activity. Our results showed that quercetin protected against reduction in Na⁺,K⁺-ATPase in the pons and cerebellum in the demyelination phase, and it increased the activity of this enzyme in the remyelination phase. During the demyelination, quercetin promoted the increase in acetylcholinesterase activity in whole blood and lymphocytes induced by EB, and it reduced the increase in acetylcholinesterase activity in lymphocytes in the remyelination phase. On day 7, EB increased the superoxide dismutase and decreased catalase activities, as well as increased the thiobarbituric acid-reactive substance levels. Taken together, these results indicated that quercetin regulates the Na⁺,K⁺-ATPase activity, affects the alterations of redox state, and participates in the reestablishment of peripheral cholinergic activity during demyelinating and remyelination events.

Tephrosin attenuates sepsis induced acute lung injury in rats by impeding expression of ICAM-1 and MIP-2

Acute lung injury (ALI), a devastating form of respiratory infections, is characterized by increased edema, release of cytokines, weakened arterial oxygenation and infiltration of neutrophils and lymphocytes. The objective of the research envisaged was to reveal protective effects of tephrosin (TP) in ALI. In the present investigation, sepsis was triggered in rats by cecal ligation and puncture (CLP) method, and TP was administered intraperitonially. Five groups - Group A (control), Group B (Sham group) Group C (infected and untreated), and Group D and E (infected and treated with 25 and 50 mg/kg TP respectively) - of ten rats each, were used for the investigation. Evaluation parameters included measurement of arterial oxygenation, lung water content, protein determination, cytokine determination, neutrophil and lymphocyte count in the bronchoalveolar lavage fluid (BALF). As indicated by histopathological examination, the lung injury score was maximum in group C, but indicated reduction in group D and E. Intracellular adhesion molecule (ICAM)-1 and macrophage inflammatory protein-2 (MIP-2) are known to be important mediators responsible for ALI. Reduction in the ICAM-1 and MIP-2 expression was found to reduce after treatment with TP. In comparison to group D, group E reflected higher magnitude of ICAM-1 and MIP-2 suppression due to administration of higher TP dose. Compared to Group A and B, Group E indicated slightly higher expression of ICAM-1 and MIP-2. The research envisaged thus supports that TP attenuates ICAM-1 and MIP-2 expression in sepsis induced ALI rat model.

miR-195 suppresses abdominal aortic aneurysm through the TNF-α/NF-κB and VEGF/PI3K/Akt pathway

In the present study, the function of microRNA (miR)‑195 on abdominal aortic aneurysm (AAA) and its possible mechanism were investigated. Reverse transcription‑quantitative polymerase chain reaction analysis was used to detect the expression of miR‑195 in patients with AAA. The expression levels of miR‑195 in patients with AAA were effectively increased. The present study also used miR‑195 mimics to increase the expression of miR‑195, and ELISA kits and western blot analysis were used to analyze the levels of interleukin (IL)‑1β and IL‑6, and the protein expression levels of matrix metalloproteinase (MMP)‑2, MMP‑9, tumor necrosis factor (TNF)‑α, nuclear factor (NF)‑κB, vascular endothelial growth factor (VEGF), phosphoinositide 3‑kinase (PI3K) and phosphorylated (p‑)Akt. The overexpression of miR‑195 promoted the levels of IL‑1β and IL‑6, induced the protein expression of MMP‑2 and MMP‑9, upregulated the protein expression of TNF‑α and NF‑κB, and suppressed the protein expression levels of VEGF, PI3K and p‑Akt in angiotensin II‑vascular smooth muscle cells. In addition, TNF‑α promoted the pre‑inflammatory effect of miR‑195 on the protein expression levels of TNF‑α and NF‑κB, levels of IL‑1β and IL‑6, and protein expression levels of MMP‑2 and MMP‑9 in the angiotensin II‑vascular smooth muscle cells. Suppression of PI3K promoted the pre‑inflammatory effect of miR‑195 on the protein expression of PI3K, p‑Akt and VEGF, the levels of IL‑1β and IL‑6, and the protein expression of MMP‑2 and MMP‑9 in angiotensin II‑vascular smooth muscle cells. Combined, these results suggested that miR‑195 suppressed AAA inflammation through the TNF‑α/NF‑κB and VEGF/PI3K/Akt pathways.

Profiling of Polyphenol Composition and Antiradical Capacity of Erica cinerea

The aim of the current study was to determine the profile and content of polyphenols present in Erica cinerea, an important plant species from Northern Portuguese flora and often reported as having anti-inflammatory, antioxidant, and anti-radical activity. The analysis of polyphenols was performed by HPLC-DAD/UV-Vis, and the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) method was used to evaluate its radical scavenging activity. HPLC analysis showed that both plants presented a great diversity of compounds, with 33% flavones, 28% flavanols, and 26% hydroxycinnamic acids. The antiradical activity was dose-dependent, and the IC₅₀ values were 0.251 mg mL^-1. Based on our study, E. cinerea presented interesting bioactive compounds and it can be used to extract and purify bioactive polyphenols to be used in pharmaceutical or agro-food industries.

Quercetin ameliorates imiquimod-induced psoriasis-like skin inflammation in mice via the NF-κB pathway

Quercetin (QC) is a dietary flavonoid abundant in many natural plants. A series of studies have shown that it has been shown to exhibit several biological properties, including anti-inflammatory, anti-oxidant, cardio-protective, vasodilatory, liver-protective and anti-cancer activities. However, so far the possible therapeutic effect of QC on psoriasis has not been reported. The present study was undertaken to evaluate the potential beneficial effect of QC in psoriasis using a generated imiquimod (IMQ)-induced psoriasis-like mouse model, and to further elucidate its underlying mechanisms of action. Effects of QC on PASI scores, back temperature, histopathological changes, oxidative/anti-oxidative indexes, pro-inflammatory cytokines and NF-κB pathway in IMQ-induced mice were investigated. Our results showed that QC could significantly reduce the PASI scores, decrease the temperature of the psoriasis-like lesions, and ameliorate the deteriorating histopathology in IMQ-induced mice. Moreover, QC effectively attenuated levels of TNF-α, IL-6 and IL-17 in serum, increased activities of GSH, CAT and SOD, and decreased the accumulation of MDA in skin tissue induced by IMQ in mice. The mechanism may be associated with the down-regulation of NF-κB, IKKα, NIK and RelB expression and up-regulation of TRAF3, which were critically involved in the non-canonical NF-κB pathway. In conclusion, our present study demonstrated that QC had appreciable anti-psoriasis effects in IMQ-induced mice, and the underlying mechanism may involve the improvement of antioxidant and anti-inflammatory status and inhibition on the activation of the NF-κB signaling. Hence, QC, a naturally occurring flavone with potent anti-psoriatic effects, has the potential for further development as a candidate for psoriasis treatment.

Protective role of quercetin against hematotoxic and immunotoxic effects of furan in rats

Furan (Fu) is a liver carcinogen produced during heating process of food and concerns a public health problem. The current study was undertaken to evaluate the protective role of quercetin (Que) on Fu-induced hematological, immunological, and histopathological alterations in rats. Fifty male Sprague Dawley rats were divided into five equal groups. Group I (Cont) received distilled water, group II (CO) received corn oil, group III (Que) received Que at 50 mg/kg BW, group IV (Fu) received Fu at 16 mg/kg BW, and group V received Que + Fu simultaneously; all groups gavaged daily for 30 days. Our results revealed that Fu administration significantly elevated RBCs, Hb, PCV, WBCs, lymphocytes, and granulocytes and reduced phagocytic percent (Ph%) and index (PhI). Fu decreased the serum total protein, albumin, globulin, IgM, IgG, and IL4, with a significant increase in the TNFα and 8-OHdG. Moreover, it decreased the GSH content and GST activity and increased the MDA levels in the splenic tissue. Histopathologically, Fu led to a moderate depletion in the lymphoid cells and weak immunostaining of CD20 antigen of few lymphocytes appeared in the spleen. Meanwhile, Que co-administration ameliorated the altered hematological parameters and improved the Ph% and PhI. It modulated the serum biochemical parameters and immunoglobulins. Moreover, it decreased lipid peroxidation and enhanced antioxidant status in the spleen. The results indicated that Que possesses antioxidant protective activity against Fu-induced oxidative damage and stimulates the immune function.

In vitro and in vivo assessment of meadowsweet (Filipendula ulmaria) as anti-inflammatory agent

ETHNOPHARMACOLOGICAL RELEVANCE

Meadowsweet (Filipendula ulmaria (L.) Maxim, Rosaceae) has been traditionally used in most European countries for the treatment of inflammatory diseases due to its antipyretic, analgesic, astringent, and anti-rheumatic properties. However, there is little scientific evidence on F. ulmaria anti-inflammatory effects regarding its impact on cyclooxygenases enzymatic activity and in vivo assessment of anti-inflammatory potential. This study aims to reveal the anti-inflammatory activity of methanolic extracts from the aerial parts (FUA) and roots (FUR) of F. ulmaria, both in in vitro and in vivo conditions.

MATERIALS AND METHODS

The characteristic phenolic compounds in F. ulmaria extracts were monitored via high performance thin layer chromatography (HPTLC). The in vitro anti-inflammatory activity of F. ulmaria extracts was evaluated using cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzyme assays, and an assay for determining COX-2 gene expression. The in vivo anti-inflammatory effect of F. ulmaria extracts was determined in two doses (100 and 200 mg/kg b.w.) with hot plate test and carrageenan-induced paw edema test in rats. Inflammation was also evaluated by histopathological and immunohistochemical analysis.

RESULTS

FUA extract showed the presence of rutoside, spiraeoside, and isoquercitrin. Both F. ulmaria extracts at a concentration of 50μg/mL were able to inhibit COX-1 and -2 enzyme activities, whereby FUA extract (62.84% and 46.43% inhibition, respectively) was double as effective as the root extract (32.11% and 20.20%, respectively). Extracts hardly inhibited the level of COX-2 gene expression in THP-1 cells at a concentration of 25μg/mL (10.19% inhibition by FUA and 8.54% by FUR). In the hot plate test, both extracts in two doses (100 and 200mg/kg b.w.), exhibited an increase in latency time when compared with the control group (p<0.05). In the carrageenan-induced acute inflammation test, FUA at doses of 100 and 200mg/kg b.w., and FUR at 200mg/kg, were able to significantly reduce the mean maximal swelling of rat paw until 6h of treatment. Indomethacin, FUA, and FUR extracts significantly decreased inflammation score and this effect was more pronounced after 24h, compared to the control group (p<0.05).

CONCLUSIONS

The observed results of in vitro and, for the first time, in vivo anti-inflammatory activity of meadowsweet extracts, provide support of the traditional use of this plant in the treatment of different inflammatory conditions. Further investigation of the anti-inflammatory compounds could reveal the mechanism of anti-inflammatory action of these extracts.

Anti-Inflammatory Activity of Citrus bergamia Derivatives: Where Do We Stand?

Inflammatory diseases affect a large portion of the worldwide population, and chronic inflammation is a major risk factor for several dangerous pathologies. To limit the side effects of both synthetic and biological anti-inflammatory drugs, the use of herbal medicines, nutraceuticals and food supplements has increased tremendously as alternative and/or complementary medicine to treat several pathologies, including inflammation. During the last decades, the biological properties of Citrus bergamia (bergamot) derivatives have obtained important scientific achievements, and it has been suggested their use in a context of a multitarget pharmacological strategy. Here, we present an overview of the anti-inflammatory properties of bergamot extracts that could represent the scientific basis for develop novel and alternative strategies to improve health status and attenuate inflammatory conditions.

An update on the role of nutrigenomic modulations in mediating the cardiovascular protective effect of fruit polyphenols

Polyphenols are plant food microconstituents that are widely distributed in the human diet, with fruits and fruit-derived products as one of the main dietary sources. Epidemiological studies have shown an inverse relationship between the intake of different classes of polyphenols and the risk of myocardial infarction or cardiovascular disease (CVD) mortality. These compounds have been associated with the promotion of cardiovascular health as evidenced by clinical studies reporting beneficial effects of polyphenol-rich fruit consumption on intermediate markers of cardiovascular diseases. Additionally, animal and in vitro studies have indicated positive roles of polyphenols in preventing dysfunctions associated with the development of cardiovascular diseases. However, the mechanisms of action underlying their beneficial effects appear complex and are not fully understood. This review aims to provide an update on the nutrigenomic effects of different groups of polyphenols from fruits and especially focuses on their cardiovascular protective effects in cell and animal studies.

Oxidative stress and abdominal aortic aneurysm: potential treatment targets

Abdominal aortic aneurysm (AAA) is a significant cause of mortality in older adults. A key mechanism implicated in AAA pathogenesis is inflammation and the associated production of reactive oxygen species (ROS) and oxidative stress. These have been suggested to promote degradation of the extracellular matrix (ECM) and vascular smooth muscle apoptosis. Experimental and human association studies suggest that ROS can be favourably modified to limit AAA formation and progression. In the present review, we discuss mechanisms potentially linking ROS to AAA pathogenesis and highlight potential treatment strategies targeting ROS. Currently, none of these strategies has been shown to be effective in clinical practice.

Quercetin-loaded nanomicelles to circumvent human castration-resistant prostate cancer in vitro and in vivo

Prostate cancer is highly prevalent and has become the second leading cause of cancer-related death in men. Its treatment remains a challenge in the clinic, particularly in patients who have advanced to "castration-resistant prostate cancer" (CRPC). Thus, more effective therapeutic strategies are required. Quercetin (QCT) is a natural flavonoid compound that has attracted increasing interest due to its anticancer activity. However, the clinical application of quercetin is largely hampered by its poor water solubility and low bioavailability. The objective of this study was to evaluate the therapeutic potential of novel QCT-loaded nanomicelles (M-QCTs) assembled from DSPE-PEG2000 for prostate cancer treatment. Our results indicated that QCT was efficiently encapsulated into micelles up to 1 mg mL(-1), which corresponds to a 450-fold increase of its water solubility. In vitro studies showed that the half-maximal inhibitory concentration (IC50) value (20.2 μM) of M-QCTs was much lower than free QCT (>200 μM). Thus, M-QCTs were considerably more effective than free QCT in proliferation inhibition and apoptosis induction of human androgen-independent PC-3 cells. Furthermore, M-QCTs showed superior antitumor efficacy and the tumor proliferation rate reduced by 52.03% compared to the control group in the PC-3 xenograft mouse model, possibly due to increased accumulation of M-QCTs at the tumor site by the enhanced permeability and retention (EPR) effect. Collectively, our studies demonstrated that M-QCTs significantly increase drug accumulation at the tumor site and exhibit superior anticancer activity in prostate cancer. Thus, our nanomicelle-based drug delivery system constitutes a promising and effective therapeutic strategy for clinical treatment.

Chemical and pharmaceutical evaluation of the relationship between triazole linkers and pore size on cyclodextrin–calixarene nanosponges used as carriers for natural drugs

Nanosponges based nanocarriers with three different cavities were used to encapsulate and release bioactive compounds.

Proinflammatory Pathways: The Modulation by Flavonoids

Inflammation is a natural, carefully orchestrated response of the organism to tissue damage, involving various signaling systems and the recruitment of inflammatory cells. These cells are stimulated to release a myriad of mediators that amplify the inflammatory response and recruit additional cells. These mediators present numerous redundancies of functions, allowing a broad and effective inflammatory response, but simultaneously make the understanding of inflammation pathways much difficult. The extent of the inflammatory response is usually self-limited, although it depends on the balance between the pro- and anti-inflammatory signals. When that equilibrium is dislocated, a more widespread inflammatory response may take place. Flavonoids have been shown to be possible alternatives to the traditionally molecules used as anti-inflammatory agents. In fact, the biological activities of flavonoids include the modulation of the diverse phases of inflammatory processes, from the gene transcription and expression to the inhibition of the enzymatic activities and the scavenging of the reactive species. In the present review, the inflammatory network is widely revised and the flavonoids' broad spectrum of action in many of the analyzed inflammatory pathways is revised. This kind of integrated revision is original in the field, providing the reader the simultaneous comprehension of the inflammatory process and the potential beneficial activities of flavonoids.

Evaluation of anti-inflammatory and mechanism of action of extract of Macrosiphonia longiflora (Desf.) Müll. Arg

ETHNOPHARMACOLOGICAL RELEVANCE

Macrosiphonia longiflora (Desf.) Müll. Arg (Apocynaceae), popularly known as 'velame' and 'velame branco', is a native subshrub that grows in the Brazilian Cerrado. This plant is widely used in traditional medicine in the form of decoction and infusion, particularly as anti-inflammatory, depurative, anti-rheumatic, antisyphilitic and antiulcer remedy. There is no available information in the literature that has addressed its pharmacological activity and phytochemical analysis.

AIM OF THE STUDY

This study aimed to evaluate the anti-inflammatory pharmacological profile of the hydroethanolic extract of Macrosiphonia longiflora, using in vivo and in vitro acute inflammation experimental models, as well as investigate the roles of cytokines and nitric oxide in its mechanism of action, and including phytochemical analysis constitution of its hydroethanolic extract.

MATERIALS AND METHODS

Hydroethanolic (70%) extract of Macrosiphonia longiflora (HEMl) was prepared by maceration. The preliminary phytochemical analysis was performed according to procedures described in the literature. Selected secondary metabolites detected were quantified by spectrophotometry and high performance liquid chromatography (HPLC). Its cytotoxic potential in Chinese hamster ovary (CHO-k1) epithelial cell lines was evaluated using Alamar Blue. in vivo anti-inflammatory activity was evaluated with carrageenan- and dextran-induced paw edemas, carrageenan-induced pleurisy in rats and lipopolysaccharide (LPS)-induced peritonitis in mice. The in vitro anti-inflammatory activity was evaluated using RAW 264.7 cells stimulated with LPS and interferon (INF)-γ. Effects of HEMl on the inflammatory cytokines (IL-1β, IL-10, IL-17, INF-γ and TNF-α) concentrations in the peritoneal lavage were evaluated using commercial ELISA kits, while the Griess method was employed to determine nitric oxide (NO) concentrations in the peritoneal lavage, as well as in the supernatants of RAW 264.7 cells.

RESULTS

Preliminary phytochemical analysis, revealed the presence of phenolics compounds, terpenoids, alkaloids and flavonoids. Spectrophotometric analysis revealed the presence of relatively high content of phenolics and flavonoids in HEMl. HPLC analysis confirmed the presence of the quantified compounds and demonstrated the presence of ellagic acid in the detected matrix of compounds. HEMl appeared to be non-cytotoxic. It effectively inhibited (p<0.05) paw edema induced by carrageenan and dextran. Furthermore, HEMl also significantly reduced exudates volume and leukocyte migration in the carrageenan-induced pleurisy and LPS-induced peritonitis, neutrophils counts in LPS-induced peritonitis. HEMl also acts by effectively inhibiting the following inflammatory cytokines: IL-1β and IL-10 levels in the peritoneal lavage, but had no effect on IL-17 level in the peritonitis model. In addition, HEMl had no effect on the levels of tumor necrosis factor alpha (TNF-α) present in the peritoneal lavage and cells supernatants. The concentration of NO, as assessed by measurement of nitrite (NO2(-)), showed that pretreatment with HEMl reduced NO significantly in the peritoneal lavage and in RAW 264.7 cells co-stimulated with LPS and INF-γ.

CONCLUSION

The results obtained in this study indicate that HEMl possesses very low cytotoxic potential. In addition, it demonstrated a potent anti-inflammatory activity in both the in vivo and in vitro models of acute inflammation. The anti-inflammatory effect is partly related to the inhibition of IL-1β, IL-10, and nitric oxide releases, but independent of TNF-α and IL-17 modulation. Phytochemical analysis revealed the predominant presence of the flavonoids (naringin, rutin, myricetin, morin, quercetin, (±)-naringenin, and luteolin) and phenols (ellagic acid), which are possibly involved in the anti-inflammatory effect of HEMl. The current study provided supportive evidence for the popular use of HEMl in the treatment of inflammatory conditions, and shed more light on the possible roles of the inflammatory cytokines in its mechanisms of action as anti-inflammatory agent.

Protective effect of quercetin on lipopolysaccharide-induced acute lung injury in mice by inhibiting inflammatory cell influx

Sepsis may result in lung injury through a complex cascade of events including interstitium infiltration of inflammatory cells. Quercetin, the most abundant dietary flavonoid found in various plants and food products, possesses potent anti-inflammatory and antioxidative properties. The purpose of this study was to investigate whether preventive administration of quercetin could exert beneficial effects on experimental septic acute lung injury induced by lipopolysaccharide (LPS). C57/BL6 mice were challenged with LPS and survival time was monitored from 0–96 h after LPS treatment. Quercetin markedly rescued lethality, improved survival time, and inhibited serum necrosis factor α, interleukin 1β, and interleukin 6, and nitric oxide (NO), and increased IL-10 secretion. Moreover, quercetin decreased lung pathological changes, myeloperoxidase activity, and malondialdehyde levels. Quercetin also reduced the lung permeability changes and neutrophil and macrophage recruitment to the bronchoalveolar lavage fluid compared to the vehicle. Additionally, quercetin significantly reduced COX-2, HMGB1, iNOS expression, and NF-κB p65 phosphorylation. These results suggest that treatment with quercetin in septic mice improved survival time and lung injury. Quercetin may be a promising potential therapeutic reagent for LPS-induced acute lung injury.

Post-column mobile phase adjustment: a strategy to eliminate the contradiction between liquid chromatography and mass spectrometry in the determination of flavonoids in rat plasma

Flavonoids are a group of important naturally occurring polyphenolic compounds with a wide range of biological effects. In this study, a sensitive liquid chromatography tandem mass spectrometry method was developed to simultaneously determine multiple active flavonoids, including quercetin (Que), kaempferol (Kae), apigenin (Api), isorhamnetin (Iso), luteolin (Lut), and naringenin (Nar), in rat plasma. To achieve a satisfied peak shape and LC separation, formic acid with the concentration between 0.05 and 0.2%, or in some case 5%, was generally used to acidify the LC mobile phase in reported studies. Here we found that even 0.05% formic acid could lead to strong mass signal suppression, and the absence of formic acid could reverse the signal suppression but cause serious peak tailing. There is an irreconcilable contradiction between liquid chromatography (LC) and mass spectrometry (MS). In order to simultaneously satisfy LC and MS, LC mobile phase with 0.00075% formic acid and post column mobile phase adjustment with 0.0677% ammonium solution in isopropanol were applied. Compared with the conventional method with mobile phase containing 0.05% formic acid, the mass signal response of Que, Kae, Api, Iso, Lut, Nar, and Oka increased 26.2, 18.6, 13.6, 23.5, 17.5, 15.6 and 15.4 fold, respectively. In addition, the post column mobile phase addition exhibited the better peak shape for the reduction of analytes longitudinal diffusion. The method has been fully validated according to FDA guidelines within the linear range between 0.328 ng mL⁻¹ and 168 ng mL⁻¹, and successfully applied to a pilot pharmacokinetic study of rats after administering 5.43 g kg⁻¹ Pollen of Brassica campestris.

Matrix metalloproteinase enzymes and their naturally derived inhibitors: novel targets in photocarcinoma therapy

The continuous exposure of skin to ultraviolet radiations generates reactive oxygen species leading to photoaging in which degradation of dermal collagen and degeneration of elastic fibers occurs. Matrix metalloproteinase [MMP] enzymes are the proteolytic enzymes which have significant potentiality of cleaving extracellular matrix [ECM] against Ultraviolet [UV] radiation. The important MMPs are MMP1, MMP2 and MMP7 which promote skin cancer when irradiated by UV rays. In lieu of this, the investigation of MMPs and their inhibitors are constantly being studied for successive results. Recent researches have focused on some traditionally used bioactive moieties as natural matrix metalloproteinases inhibitors (MMPIs) and emphasized on the need of more extensive and specific studies on MMPIs, so that a good combination of natural or synthetic MMPIs with the conventional drugs can be evolved for cancer chemotherapy. In this review, we discuss the current view on the feasibility of MMPs as targets for therapeutic intervention in cancer. This review also summarizes the role of small molecular weight natural MMPIs and a clinical update of those natural MMPIs that are under clinical trial stage.

Quercetin reduces oxidative stress and inhibits activation of c‑Jun N‑terminal kinase/activator protein‑1 signaling in an experimental mouse model of abdominal aortic aneurysm

Oxidative stress is becoming increasingly linked to the pathogenesis of abdominal aortic aneurysms (AAAs). The antioxidant activity of flavonoids has attracted attention for their possible role in the prevention of cardiovascular diseases. The purpose of this study was to determine whether an antioxidant mechanism is involved in the aneurysm formation inhibitory effect afforded by quercetin. Male C57/BL6 mice received quercetin continuously from 2 weeks prior to and 6 weeks following the AAA induction with extraluminal CaCl2. Quercetin treatment decreased AAA incidence and inhibited the reactive oxygen species generation, nitrotyrosine formation and lipid peroxidation production in the aortic tissue during AAA development. In addition, quercetin‑treated mice exhibited significantly lower expression of the p47phox subunit of nicotinamide adenine dinucleotide phosphate oxidase and inducible nitric oxide synthase, as well as coordinated downregulation of manganese‑superoxide dismutase activities and glutathione peroxidase (GPx)‑1 and GPx‑3 expression. Quercetin also blunted the expression of c‑Jun N‑terminal kinase (JNK) and phospho‑JNK and, in addition, diminished activation of the activator protein (AP)‑1 transcription factor. Gelatin zymography showed that quercetin eliminated matrix metalloproteinase (MMP)‑2 and MMP‑9 activation during AAA formation. In conclusion, the inhibitory effects of quercetin on oxidative stress and MMP activation, through modulation of JNK/AP‑1 signaling, may partly account for its benefit in CaCl2‑induced AAA.