Design, synthesis and biological evaluation of chalcone analogues with novel dual antioxidant mechanisms as potential anti-ischemic stroke agents

The pathological mechanisms and potential therapeutic drugs for myocardial ischemia reperfusion injury

BACKGROUND

Cardiovascular disease is the main cause of death and disability, with myocardial ischemia being the predominant type that poses a significant threat to humans. Reperfusion, an essential therapeutic approach, promptly reinstates blood circulation to the ischemic myocardium and stands as the most efficacious clinical method for myocardial preservation. Nevertheless, the restoration of blood flow associated with this process can potentially induce myocardial ischemia-reperfusion injury (MIRI), thereby diminishing the effectiveness of reperfusion and impacting patient prognosis. Therefore, it is of great significance to prevent and treat MIRI.

PURPOSE

MIRI is an important factor affecting the prognosis of patients, and there is no specific in-clinic treatment plan. In this review, we have endeavored to summarize its pathological mechanisms and therapeutic drugs to provide more powerful evidence for clinical application.

METHODS

A comprehensive literature review was conducted using PubMed, Web of Science, Embase, Medline and Google Scholar with a core focus on the pathological mechanisms and potential therapeutic drugs of MIRI.

RESULTS

Accumulated evidence revealed that oxidative stress, calcium overload, mitochondrial dysfunction, energy metabolism disorder, ferroptosis, inflammatory reaction, endoplasmic reticulum stress, pyroptosis and autophagy regulation have been shown to participate in the process, and that the occurrence and development of MIRI are related to plenty of signaling pathways. Currently, a range of chemical drugs, natural products, and traditional Chinese medicine (TCM) preparations have demonstrated the ability to mitigate MIRI by targeting various mechanisms.

CONCLUSIONS

At present, most of the research focuses on animal and cell experiments, and the regulatory mechanisms of each signaling pathway are still unclear. The translation of experimental findings into clinical practice remains incomplete, necessitating further exploration through large-scale, multi-center randomized controlled trials. Given the absence of a specific drug for MIRI, the identification of therapeutic agents to reduce myocardial ischemia is of utmost significance. For the future, it is imperative to enhance our understanding of the pathological mechanism underlying MIRI, continuously investigate and develop novel pharmaceutical agents, expedite the clinical translation of these drugs, and foster innovative approaches that integrate TCM with Western medicine. These efforts will facilitate the emergence of fresh perspectives for the clinical management of MIRI.

Significance of Chalcone Scaffolds in Medicinal Chemistry

Chalcone is a simple naturally occurring α,β-unsaturated ketone with biological importance, which can also be easily synthesized in laboratories by reaction between two aromatic scaffolds. In plants, chalcones occur as polyphenolic compounds of different frameworks which are bioactive molecules that have been in traditional medicinal practice for many years. Chalcone-based lead molecules have been developed, possessing varied potentials such as antimicrobial, antiviral, anti-inflammatory, anticancer, anti-oxidant, antidiabetic, antihyperurecemic, and anti-ulcer effects. Chalcones contribute considerable fragments to give important heterocyclic molecules with therapeutic utilities targeting various diseases. These characteristic features have made chalcone a topic of interest among researchers and have attracted investigations into this widely applicable structure. This review highlights the extensive exploration carried out on the synthesis, biotransformations, chemical reactions, hybridization, and pharmacological potentials of chalcones, and aims to provide an extensive, thorough, and critical review of their importance, with emphasis on their properties, chemistry, and biomedical applications to boost future investigations into this potential scaffold in medicinal chemistry.

Evidence that a Novel Chalcone Derivative, Compound 27, Acts on the Epithelium Via the PI3K/AKT/Nrf2-Keap1 Signaling Pathway, to Mitigate LPS-Induced Acute Lung Injury in Mice

Acute lung injury (ALI) is a highly heterogeneous clinical syndrome and an important cause of mortality in critically ill patients, with limited treatment options currently available. Chalcone, an essential secondary metabolite found in edible or medicinal plants, exhibits good antioxidant activity and simple structure for easy synthesis. In our study, we synthesized a novel chalcone derivative, compound 27 (C27). We hypothesized that C27 could be a potential treatment for acute respiratory distress syndrome (ARDS). Therefore, the protective effects of C27 on lung epithelial cells during ALI and the underlying molecular mechanisms were investigated. In vivo, Intratracheal instillation of LPS (10 mg/kg) was used to induce acute lung injury in mice. In vitro, the bronchial epithelial cell line (Beas-2b) was treated with 30 μM tert-butyl hydroperoxide (t-BHP) to simulate oxidative stress. Our findings demonstrate that pretreatment with C27 reduces LPS-induced oxidative destruction and cellular apoptosis in lung tissues of mice. Furthermore, it significantly attenuates t-BHP-induced cellular reactive oxygen species (ROS) generation, mitochondrial damage, and apoptosis in vitro. Mechanistically, the signaling pathway involving Nrf2-Keap1 and the downstream antioxidative proteins were activated by C27 in vivo. Additionally, PI3K inhibitor LY294002 and Nrf2 inhibitor ML385 abolished the effect of C27 in vitro, indicating that the protective effect of C27 is mediated via the PI3K/AKT/Nrf2-Keap1 pathway. Our study provides evidence that C27 protects against LPS-induced ALI by mitigating oxidative stress via activation of the PI3K/AKT/Nrf2-Keap1 signaling pathway. Therefore, we hypothesize that C27 represents a viable alternative for ALI therapy.

Design, Synthesis, and Molecular Docking of Novel Miscellaneous Chalcones as p38α Mitogen-Activated Protein Kinase Inhibitors

New chalcones were synthesized and evaluated to serve as p38-α type of mitogen-activated protein kinase (MAPK) inhibitors. According to the National Cancer Institute, the findings indicated that at a 10 μM dosage, compounds 3a and 6 were the most active among all the compounds examined, with mean growth inhibition% of 94.83 and 58.49, respectively. In 5-dose testing, they showed anticancer activity in the micro-molar range with GI50 in the range of 1.41-46.1 and 2.07-31.3 μM, respectively. Besides, powerful activity, especially against the leukaemia cell lines and good selectivity to cancer cells compared to normal PCS-800-017 with a selectivity index=12.41 and 23.77, respectively. Compounds 3a and 6 inhibited p38α MAPK with IC50 values of 0.1462±0.0063 and 0.4356±0.0189 μM, correspondingly. 3a showed good inhibition for HL-60(TB) cells and induced cell cycle arrest in HL-60(TB) cells at the G2/M phase. Besides, it elevated the total apoptosis by 14.68-fold and increased the caspase-3 level by 3.52-fold compared with doxorubicin, which raised it by 4.30-fold, inducing apoptosis by acting as caspase-dependent inducers. These results suggest that 3a is a promising antiproliferative and p38α MAPK inhibitor, confirmed by molecular docking with high compatibility 3a with the p38α MAPK binding site.

Therapeutic effects of saffron and its components on neurodegenerative diseases

Due to an increase in the number of older people in recent years, neurodegenerative diseases as the most important age-related neurological disorders are considered as a great threat to human health. The treatment strategies for these disorders are symptomatic and there is no known definitive treatment; however, recently, several studies have investigated the effectiveness of some herbs and their components in limiting the progression and treatment of neurodegenerative disorders. In this study, we searched Medline (via PubMed), Scopus, Science Direct, and Google Scholar databases. The keywords used in the search were: saffron [title/abstract] or (saffron compound [title/abstract]) and (neurological disorders [title/abstract]), publication date range (2010-2023), and language (English). After applying inclusion and exclusion criteria, 30 articles remained. Of the 30 articles included in the study, six studies on the treatment of neurodegenerative disorders by saffron and its components were in the clinical trial phase, and 24 studies were in the preclinical phase. Saffron and its compounds can play an important role in inhibiting neuroinflammation and excitotoxic pathways, modulating autophagy and apoptosis, attenuating oxidative damage, and activating defensive antioxidant enzymes, resulting in neuroprotection against neurodegenerative diseases. Therefore, this study aimed to review the studies on the effects of saffron and its compounds on the treatment of neurodegenerative diseases.

Knockdown of Smox protects the integrity of the blood-brain barrier through antioxidant effect and Nrf2 pathway activation in stroke

Once an ischemic stroke occurs, reactive oxygen species (ROS) and oxidative stress degrade the tight connections between cerebral endothelial cells resulting in their damage. The expression of antioxidant genes may be enhanced, and ROS formation may be reduced following Nrf2 activation, which is associated with protection against ischemic stroke. Overexpression of spermine oxidase (Smox) in the neocortex led to increased H2O2 production. However, how Smox impacts the regulation of the blood-brain barrier (BBB) through antioxidants has not been examined yet. We conducted experiments both in the cell level and in the transient middle cerebral artery occlusion (tMCAO) model to evaluate the effect of Smox siRNA lentivirus (si-Smox) knockdown on BBB protection against ischemic stroke. Mice treated with si-Smox showed remarkably decreased BBB breakdown and reduced endothelial inflammation following stroke. The treatment with si-Smox significantly elevated the Bcl-2 to Bax ratio and decreased the production of cleaved caspase-3 in the tMCAO model. Further investigation revealed that the neuroprotective effect was the result of the antioxidant properties of si-Smox, which reduced oxidative stress and enhanced CD31+ cells in the peri-infarct cortical areas. Of significance, si-Smox activated Nrf2 in both bEnd.3 cells and tMCAO animals, and blocking Nrf2 with brusatol diminished the protective effects of si-Smox. The study findings suggest that si-Smox exerts neuroprotective effects and promotes angiogenesis by activating the Nrf2 pathway, thus decreasing oxidative stress and apoptosis caused by tMCAO. As a result, si-Smox may hold potential as a therapeutic candidate for preserving BBB integrity while treating ischemic stroke.

Exploring the Antioxidant Potency of New Naphthalene-Based Chalcone Derivatives: Design, Synthesis, Antioxidant Evaluation, Docking Study, DFT Calculations

Naphthalene-based chalcone derivative was successfully synthesized through the condensation of 2,4-dichlorobenzaldehyde with 2-acetylnaphthalene. This chalcone, denoted as compound 1, demonstrated a versatile reactivity upon treatment with both nitrogen and carbon nucleophiles, and yielded diverse heterocyclic scaffolds such as pyrazoline, thiazole, pyrimidine, pyran, and pyridine derivatives. The pyrazoline aldehyde derivative 7 was further derivatized to produce the hydrazide-hydrazone 13, namely, (1H-pyrazol-1-yl)methylene)acetohydrazide, which was exploited to synthesize derivatives of 2-oxo-2H-chromene-3-carbohydrazide 14, 2-(4-oxo-4,5-dihydrothiazol-2-yl)acetohydrazide 15, and 3-(4-nitrophenyl)acrylohydrazide 16. All the newly synthesized compounds were characterized by melting point, elemental analysis, as well as FT-IR, 1 H-NMR and mass spectroscopy. Furthermore, these heterocyclic derivatives were screened for their antioxidant capacities using the DPPH radical assay. The results showed that compounds 5 and 10 are the most potent antioxidants with IC50 values 178, 177(μM), respectively. comparable to that of ascorbic acid which has IC50 value 148. Meanwhile, compounds 2, 12, 13, 14, 15, and 16 exhibited moderate antioxidant activities with IC50 values ranged from 266 to 291(μM). Thus, these heterocycles could emerge as promising antioxidant drugs for the treatment of oxidative stress-related diseases. Finally, molecular docking was conducted to study the binding affinity for the most potent antioxidant compounds 5, 10, and ascorbic acid inside the active pocket of Human Peroxiredoxin 5 (1HD2). DFT calculations and global descriptors were calculated for the most potent compounds to correlate the relation between chemical structure and reactivity.

Recombinant human brain natriuretic peptide attenuates ischemic brain injury in mice by inhibiting oxidative stress and cell apoptosis via activation of PI3K/AKT/Nrf2/HO-1 pathway

Ischemic stroke followed by cerebral artery occlusion is a main cause of chronic disability worldwide. Recombinant human brain natriuretic peptide (rhBNP) has been reported to alleviate sepsis-induced cognitive dysfunction and brain I/R injury. However, the function and molecular mechanisms of rhBNP in ischemic brain injury have not been clarified. For establishment of an animal model of ischemic brain injury, C57BL/6 mice were treated with middle cerebral artery occlusion (MCAO) surgery for 1 h and reperfusion for 24 h. After subcutaneous injection of rhBNP into model mice, neurologic deficits were assessed by evaluating behavior of mice according to Longa scoring system, and TTC staining was utilized to determine the brain infarct size of mice. The levels of oxidative stress markers, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA), were detected in hippocampal tissues of mice by corresponding kits. Cell apoptosis in hippocampus tissues was examined by TUNEL staining. Protein levels of antioxidant enzymes (HO-1 and NQO1) in cerebral cortex, apoptotic markers (Bax, Bcl-2, and cleaved caspase), and PI3K/AKT pathway-associated factors in hippocampus were tested by western blot analysis. The results revealed that injection of rhBNP decreased neurologic deficit scores, the percent of brain water content, and infarct volume. Additionally, rhBNP downregulated MDA level, upregulated the levels of SOD, CAT, and GSH in hippocampus of mice, and increased protein levels of HO-1 and NQO1 in the cortex. Cell apoptosis in hippocampus tissues of model mice was inhibited by rhBNP which was shown as the reduced TUNEL-positive cells, the decreased Bax, cleaved caspase-3, and cleaved caspase-9 protein levels, and the enhanced Bcl-2 protein level. In addition, rhBNP treatment activated the PI3K/AKT signaling pathway and upregulated the protein levels of HO-1 and NRF2. Overall, rhBNP activates the PI3K/AKT/HO-1/NRF2 pathway to attenuate ischemic brain injury in mice after MCAO by suppression of cell apoptosis and oxidative stress.

Nanoparticle Formulations of Antioxidants for the Management of Oxidative Stress in Stroke: A Review

Stroke is currently one of the primary causes of morbidity and mortality worldwide. Unfortunately, there has been a lack of effective stroke treatment. Therefore, novel treatment strategies are needed to decrease stroke-induced morbidity and promote the patient's quality of life. Reactive oxygen species (ROS) have been recognized as one of the major causes of brain injury after ischemic stroke. Antioxidant therapy seems to be an effective treatment in the management of oxidative stress relevant to inflammatory disorders like stroke. However, the in vivo efficacy of traditional anti-oxidative substances is greatly limited due to their non-specific distribution and poor localization in the disease region. In recent years, antioxidant nanoparticles (NPs) have demonstrated a clinical breakthrough for stroke treatment. Some NPs have intrinsic antioxidant properties and act as antioxidants to scavenge ROS. Moreover, NPs provide protection to the antioxidant agents/enzymes while effectively delivering them into unreachable areas like the brain. Because of their nanoscale dimensions, NPs are able to efficiently pass through the BBB, and easily reach the damaged site. Here, we discuss the challenges, recent advances, and perspectives of antioxidant NPs in stroke treatment.

Molecular dynamics simulation approach of hybrid chalcone-thiazole complex derivatives for DNA gyrase B inhibition: lead generation

Compounds bearing thiazole and chalcone groups have been reported to be excellent leads for antibacterial, antitubercular and anticancer activities. In view of this, we performed quantitative structure-activity relationship studies using QSARINS for dataset preparation and for developing validated QSAR models that can predict novel series of thiazole-chalcone hybrids and further evaluate them for bioactivities. The molecular descriptors AATS8i, AVP-1, MoRSEE17 and GATSe7 were found to be active in predicting the structure-activity relationship. Molecular docking and dynamics simulation studies of the developed leads have shown insights into structural analysis. Furthermore, computational studies using AutoDock and Desmond predicted the key binding interactions responsible for the activity and the SwissADME tool computed the in silico drug likeliness properties. The lead compound 178 generated through this study creates a route for the optimization and development of novel drugs against tuberculosis infections. RMSD, RMSF, RoG, H-bond and SASA analysis confirmed the stable binding of compound 178 with the 6J90 structure. In addition, MM-PBSA and MM-GBSA also confirm the docking results. We propose the designed compound 178 as the best theoretical lead, which may further be experimentally studied for selective inhibition.

Dual Antioxidant DH-217 Mitigated Cerebral Ischemia-Reperfusion Injury by Targeting IKKβ/Nrf2/HO-1 Signal Axis

Antioxidants represent a potential therapy for cerebral ischemia-reperfusion injury (CIRI). Compounds which exhibit both direct and indirect antioxidative activity may potentially exert improved effects. Hence, we aimed to assess whether the dual antioxidant DH-217, a derivative of DHAP clinically used to treat coronary heart disease, can reduce oxidative stress damage and elucidate the underlying mechanism. Hydrogen peroxide (H₂O₂)-induced and Middle Cerebral Artery Occlusion (MCAO)-induced damages were used to imitate oxidative stress. The antioxidation of DH-217 was determined by MTT, ROS, colony and DPPH assay. Besides, immunofluorescence, Real-Time PCR Analyses, western blotting and si-RNA/Plasmid-induced protein expression were used for mechanism validation. DPPH scavenging assay evidenced DH-217 was a well free radical scavenger. Cell survival assay also showed that DH-217 had a significant cytoprotection through direct and indirect clearance mechanisms. Further, it clearly inhibited oxidative stress-induced IkappaB kinase beta (IKKβ) phosphorylation and increased heme oxygenase-1 (HO-1) expression. Significantly, these antioxidant beneficial effects were reversed by HO-1 inhibitor, si-nuclear erythroid 2-related factor 2 (Nrf2) and IKKβ plasmid. Meanwhile, DH-217 had a good neuroprotective effect on CIRI rats. The dual antioxidant DH-217 has potential reference value for drug development of CIRI. Furthermore, inhibition of IKKβ phosphorylation and activation of Nrf2/HO-1 could be a promising antioxidant pathway. Dual antioxidant DH-217 not only has the ability of directly scavenging ROS, but also can clear it by targeting IKKβ/Nrf2/HO-1 signal axis. Inhibition of IKKβ phosphorylation and activation of Nrf2/HO-1 may be a promising antioxidant pathway for CIRI.

Different Strategies to Attenuate the Toxic Effects of Zinc Oxide Nanoparticles on Spermatogonia Cells

Zinc oxide nanoparticles (ZnO NPs) are one of the most used nanoparticles due to their unique physicochemical and biological properties. There is, however, a growing concern about their negative impact on male reproductive health. Therefore, in the present study, two different strategies were used to evaluate the recovery ability of spermatogonia cells from the first stage of spermatogenesis (GC-1 spg cell line) after being exposed to a cytotoxic concentration of ZnO NPs (20 µg/mL) for two different short time periods, 6 and 12 h. The first strategy was to let the GC-1 cells recover after ZnO NPs exposure in a ZnO NPs-free medium for 4 days. At this phase, cell viability assays were performed to evaluate whether this period was long enough to allow for cell recovery. Exposure to ZnO NPs for 6 h and 12 h induced a decrease in viability of 25% and 41%, respectively. However, the recovery period allowed for an increase in cell viability from 16% to 25% to values as high as 91% and 84%. These results strongly suggest that GC-1 cells recover, but not completely, given that the cell viability does not reach 100%. Additionally, the impact of a synthetic chalcone (E)-3-(2,6-dichlorophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (1) to counteract the reproductive toxicity of ZnO NPs was investigated. Different concentrations of chalcone 1 (0-12.5 µM) were used before and during exposure of GC-1 cells to ZnO NPs to mitigate the damage induced by NPs. The protective ability of this compound was evaluated through viability assays, levels of DNA damage, and cytoskeleton dynamics (evaluating the acetylated α-tubulin and β-actin protein levels). The results indicated that the tested concentrations of chalcone 1 can attenuate the genotoxicity induced by ZnO NPs for shorter exposure periods (6 h). Chalcone 1 supplementation also increased cell viability and stabilized the microtubules. However, the antioxidant potential of this compound remains to be elucidated. In conclusion, this work addressed the main cytotoxic effects of ZnO NPs on a spermatogonia cell line and analyzed two different strategies to mitigate this damage, which represent a significant contribution to the field of male fertility.

Neuroprotective Effect and Possible Mechanisms of Ginsenoside-Rd for Cerebral Ischemia/Reperfusion Damage in Experimental Animal: A Meta-Analysis and Systematic Review

Ischemic stroke, the most common type of stroke, can lead to a long-term disability with the limitation of effective therapeutic approaches. Ginsenoside-Rd (G-Rd) has been found as a neuroprotective agent. In order to investigate and discuss the neuroprotective function and underlying mechanism of G-Rd in experimental animal models following cerebral ischemic/reperfusion (I/R) injury, PubMed, Embase, SinoMed, and China National Knowledge Infrastructure were searched from their inception dates to May 2022, with no language restriction. Studies that G-Rd was used to treat cerebral I/R damage in vivo were selected. A total of 18 articles were included in this paper, and it was showed that after cerebral I/R damage, G-Rd administration could significantly attenuate infarct volume (19 studies, SMD = −1.75 [−2.21 to − 1.30], P < 0.00001). Subgroup analysis concluded that G-Rd at the moderate doses of >10- <50 mg/kg reduced the infarct volume to the greatest extent, and increasing the dose beyond 50 mg/kg did not produce better results. The neuroprotective effect of G-Rd was not affected by other factors, such as the animal species, the order of administration, and the ischemia time. In comparison with the control group, G-Rd administration could improve neurological recovery (lower score means better recovery: 14 studies, SMD = −1.50 [−2.00 to − 1.00], P < 0.00001; higher score means better recovery: 8 studies, SMD = 1.57 [0.93 to 2.21], P < 0.00001). In addition, this review suggested that G-Rd in vivo can antagonize the reduced oxidative stress, regulate Ca²⁺, and inhibit inflammatory, resistance to apoptosis, and antipyroptosis on cerebral I/R damage. Collectively, G-Rd is a promising natural neuroprotective agent on cerebral I/R injury with unique advantages and a clear mechanism of action. More clinical randomized, blind-controlled trials are also needed to confirm the neuroprotective effect of G-Rd on cerebral I/R injury.

Synthesis of Chalcones Derivatives and Their Biological Activities: A Review

Chalcone derivatives are considered valuable species because they possess a ketoethylenic moiety, CO-CH=CH-. Due to the presence of a reactive α,β-unsaturated carbonyl group, chalcones and their derivatives possess a wide spectrum of antiproliferative, antifungal, antibacterial, antiviral, antileishmanial, and antimalarial pharmacological properties. Recent developments in heterocyclic chemistry have led to the synthesis of chalcone derivatives, which had been biologically investigated toward certain disease targets. The major aspect of this review is to present the most recent synthesis of chalcones bearing N, O, and/or S heterocycles, revealing their biological potential during the past decade (2010-2021). Based on a review of the literature, many chalcone-heterocycle hybrids appear to exhibit promise as future drug candidates owing to their similar or superior activities compared to those of the standards. Thus, this review may prove to be beneficial for the development and design of new potent therapeutic drugs based on previously developed strategies.

An Overview of NRF2-Activating Compounds Bearing α,β-Unsaturated Moiety and Their Antioxidant Effects

The surge of scientific interest in the discovery of Nuclear Factor Erythroid 2 (NFE2)-Related Factor 2 (NRF2)-activating molecules underscores the importance of NRF2 as a therapeutic target especially for oxidative stress. The chemical reactivity and biological activities of several bioactive compounds have been linked to the presence of α,β-unsaturated structural systems. The α,β-unsaturated carbonyl, sulfonyl and sulfinyl functional groups are reportedly the major α,β-unsaturated moieties involved in the activation of the NRF2 signaling pathway. The carbonyl, sulfonyl and sulfinyl groups are generally electron-withdrawing groups, and the presence of the α,β-unsaturated structure qualifies them as suitable electrophiles for Michael addition reaction with nucleophilic thiols of cysteine residues within the proximal negative regulator of NRF2, Kelch-like ECH-associated protein 1 (KEAP1). The physicochemical property such as good lipophilicity of these moieties is also an advantage because it ensures solubility and membrane permeability required for the activation of the cytosolic NRF2/KEAP1 system. This review provides an overview of the reaction mechanism of α,β-unsaturated moiety-bearing compounds with the NRF2/KEAP1 complex, their pharmacological properties, structural activity-relationship and their effect on antioxidant and anti-inflammatory responses. As the first of its kind, this review article offers collective and comprehensive information on NRF2-activators containing α,β-unsaturated moiety with the aim of broadening their therapeutic prospects in a wide range of oxidative stress-related diseases.

Synthesis and biological evaluation of 1,2,4-triazole derivatives as potential Nrf2 activators for the treatment of cerebral ischemic injury

Acute ischemic stroke is a leading cause of disability and death. The development of neuroprotectants is an emerging strategy for the treatment of ischemic stroke. In this work, we designed and synthesized a series of 1,3,5-triaryl substituent triazole derivatives by introducing a phenolic group and phenyl ring to 3,5-diaryl substituents oxadiazole. Structure-activity relationship (SAR) analysis showed that compounds with alkyl groups or with substituents at the 3-position possessed better protective effects. Among the derivatives, 3,5-dimethyl substituted compound 24 exhibited the best neuroprotective effect with weak cytotoxicity. Compound 24 possessed a high plasma protein binding rate, moderate hERG inhibition, low acute toxicity, and suitable pharmacokinetic properties. In vivo experiments demonstrated that compound 24 exerted a protective effect by reducing cerebral infarction size, improving neurological behavior, and restoring redox balance in middle cerebral artery occlusion rats. Further investigation indicated that compound 24 exerted a protective effect against sodium nitroprusside (SNP) induced cell damage by scavenging intracellular reactive oxygen species and restoring mitochondrial membrane potential. Moreover, compound 24 induced the nuclear translocation of Nuclear factor erythroid 2-related factor (Nrf2) and promoted the generation of antioxidative proteins, including Heme oxygenase-1 (HO-1), NAD(P)H quinone dehydrogenase (NQO1), and glutamate-cysteine ligase catalytic (GCLC). Surface plasmon resonance (SPR) experiments indicated that compound 24 might activate the Nrf2 signaling pathway by interacting with the Keap1 Kelch domain. Taken together, these facts indicate that compound 24 might have potential in the treatment of ischemic stroke.

Cyclo-(Phe-Tyr) as a novel cyclic dipeptide compound alleviated ischemic stroke reperfusion brain injury via JUNB/JNK/NF-κB and SOX5/PI3K/AKT pathways

Ischemic stroke reperfusion (IR) can cause adverse reactions including apoptosis, oxidative stress, and inflammation, but the existing therapeutic strategies have been limited. Moreover, the regulation of microglia plays an important role in brain injury after reperfusion. Hence, it is imperative to find new and effective drugs for modulating microglia to treat IR brain injury. Cyclic peptide compound cyclo-(Phe-Tyr) (Sparganin C, SC) is a compound isolated from Sparganii Rhizoma. However, the protective effects of SC on the central nervous system are rather unclear. In an attempt to elucidate the protective effects and mechanism of SC on cerebral damage induced by the IR, we used a middle cerebral artery occlusion reperfusion (MCAO/R) model in rats and discovered that SC significantly decreased the size of cerebral infarcts, improved neurological scores, and blocked inflammatory and oxidative factor release. Using RNA-Seq and metabolomics association analyses, SC was shown to have a protective impact through the JUNB and SOX5-related pathways. Metabolomic analysis revealed twenty-eight differentially expressed biomarkers. In addition, the detection of SC content in brain tissue using LC/MS revealed that SC had blood-brain barrier penetration. To investigate the mechanism, we established an in vitro BV2 cell oxygen-glucose deprived re-oxygenation (OGD/R) model and used siRNA as well as an inhibitor. The protective effects of SC were dependent on the JUNB and SOX5 to inhibit inflammation and apoptosis in microglia. Our findings revealed for the first that SC against IR injury by reducing inflammation and apoptosis while simultaneously acting as potential therapeutic lead compound for ischemic stroke.

Inhibiting Sphingosine 1-Phosphate Receptor Subtype 3 Attenuates Brain Damage During Ischemia-Reperfusion Injury by Regulating nNOS/NO and Oxidative Stress

Background

Ischemic stroke (IS) is a common disease endangering human life and health. Cerebral ischemia triggers a series of complex harmful events, including excitotoxicity, inflammation and cell death, as well as increased nitric oxide production through the activation of nitric oxide synthase (NOS). Oxidative stress plays a major role in cerebral ischemia and reperfusion. Sphingosine 1-phosphate receptor subtype 3 (S1PR3), a member of S1P’s G protein-coupled receptors S1PR1-S1PR5, is involved in a variety of biological effects in the body, and its role in regulating oxidative stress during cerebral ischemia and reperfusion is still unclear.

Methods

Transient middle cerebral artery occlusion (tMCAO) mice were selected as the brain ischemia–reperfusion (I/R) injury model. Male C57/BL6 mice were treated with or without a selective S1PR3 inhibition after tMCAO, and changes in infarct volume, Nissl staining, hematoxylin-eosin (H&E) staining and NOS protein, nitric oxide (NO), superoxide dismutase (SOD), and malondialdehyde (MDA) content after tMCAO were observed.

Results

In the cerebral ischemia–reperfusion model, inhibition of S1PR3 improved the infarct volume and neuronal damage in mice after tMCAO. Similarly, inhibition of S1PR3 can reduce the expression of NO synthase subtype neuronal NOS (nNOS) and reduce the production of NO after cerebral ischemia. After cerebral ischemia and reperfusion, the oxidative stress response was enhanced, and after the administration of the S1PR3 inhibitor, the SOD content increased and the MDA content decreased, indicating that S1PR3 plays an important role in regulating oxidative stress response.

Conclusion

Inhibiting S1PR3 attenuates brain damage during I/R injury by regulating nNOS/NO and oxidative stress, which provides a potential new therapeutic target and mechanism for the clinical treatment of IS.

Guide to tuning the chalcone molecular properties based on the push-pull effect energy scale created via the molecular tailoring approach

Using the molecular tailoring approach, a total energy scale for the push-pull effect in the range from -40 to 100 kcal/mol is created for the wide series of neutral, charged and doubly charged compounds on the chalcone platform. Taking into account similar energy scale for hydrogen bonds, the strength of the push-pull effect is ranked in the seven categories, ranging from negative (anti-push-pull) to very weak and very strong push-pull effect. It is demonstrated that the molecular properties of chalcone can be tuned prior synthesis due to the created energy scale for the push-pull effect. The single bonds of the π-spacer in the chalcones are shortened, the double ones are lengthened, and the C=O bond vibrations are red shifted when the push-pull effect is enhanced along the energy scale. The HOMO and LUMO energies change systematically while the HOMO-LUMO energy gap narrows as the strength of the push-pull effect increases.

Cellular and Molecular Targets for Non-Invasive, Non-Pharmacological Therapeutic/Rehabilitative Interventions in Acute Ischemic Stroke

BACKGROUND

Cerebral circulation delivers the blood flow to the brain through a dedicated network of sanguine vessels. A healthy human brain can regulate cerebral blood flow (CBF) according to any physiological or pathological challenges. The brain is protected by its self-regulatory mechanisms, which are dependent on neuronal and support cellular populations, including endothelial ones, as well as metabolic, and even myogenic factors.

OBJECTIVES

Accumulating data suggest that "non-pharmacological" approaches might provide new opportunities for stroke therapy, such as electro-/acupuncture, hyperbaric oxygen therapy, hypothermia/cooling, photobiomodulation, therapeutic gases, transcranial direct current stimulations, or transcranial magnetic stimulations. We reviewed the recent data on the mechanisms and clinical implications of these non-pharmaceutical treatments.

METHODS

To present the state-of-the-art for currently available non-invasive, non-pharmacological-related interventions in acute ischemic stroke, we accomplished this synthetic and systematic literature review based on the Preferred Reporting Items for Systematic Principles Reviews and Meta-Analyses (PRISMA).

RESULTS

The initial number of obtained articles was 313. After fulfilling the five steps in the filtering/selection methodology, 54 fully eligible papers were selected for synthetic review. We enhanced our documentation with other bibliographic resources connected to our subject, identified in the literature within a non-standardized search, to fill the knowledge gaps. Fifteen clinical trials were also identified.

DISCUSSION

Non-invasive, non-pharmacological therapeutic/rehabilitative interventions for acute ischemic stroke are mainly holistic therapies. Therefore, most of them are not yet routinely used in clinical practice, despite some possible beneficial effects, which have yet to be supplementarily proven in more related studies. Moreover, few of the identified clinical trials are already completed and most do not have final results.

CONCLUSIONS

This review synthesizes the current findings on acute ischemic stroke therapeutic/rehabilitative interventions, described as non-invasive and non-pharmacological.

Ubiquitin-Specific Protease 29 Exacerbates Cerebral Ischemia-Reperfusion Injury in Mice

Oxidative stress and apoptosis contribute to the progression of cerebral ischemia/reperfusion (I/R) injury. Ubiquitin-specific protease 29 (USP29) is abundantly expressed in the brain and plays critical roles in regulating oxidative stress and cell apoptosis. The purpose of the present study is to investigate the role and underlying mechanisms of USP29 in cerebral I/R injury. Neuron-specific USP29 knockout mice were generated and subjected to cerebral I/R surgery. For USP29 overexpression, mice were stereotactically injected with the adenoassociated virus serotype 9 vectors carrying USP29 for 4 weeks before cerebral I/R. And primary cortical neurons were isolated and exposed to oxygen glucose deprivation/reperfusion (OGD/R) stimulation to imitate cerebral I/R injury in vitro. USP29 expression was elevated in the brain and primary cortical neurons upon I/R injury. Neuron-specific USP29 knockout significantly diminished, whereas USP29 overexpression aggravated cerebral I/R-induced oxidative stress, apoptosis, and neurological dysfunction in mice. In addition, OGD/R-induced oxidative stress and neuronal apoptosis were also attenuated by USP29 silence but exacerbated by USP29 overexpression in vitro. Mechanistically, neuronal USP29 enhanced p53/miR-34a-mediated silent information regulator 1 downregulation and then promoted the acetylation and suppression of brain and muscle ARNT-like protein, thereby aggravating oxidative stress and apoptosis upon cerebral I/R injury. Our findings for the first time identify that USP29 upregulation during cerebral I/R may contribute to oxidative stress, neuronal apoptosis, and the progression of cerebral I/R injury and that inhibition of USP29 may help to develop novel therapeutic strategies to treat cerebral I/R injury.

Chalcones identify cTXNPx as a potential antileishmanial drug target

With current drug treatments failing due to toxicity, low efficacy and resistance; leishmaniasis is a major global health challenge that desperately needs new validated drug targets. Inspired by activity of the natural chalcone 2’,6’-dihydroxy-4’-methoxychalcone (DMC), the nitro-analogue, 3-nitro-2’,4’,6’- trimethoxychalcone (NAT22, 1c) was identified as potent broad spectrum antileishmanial drug lead. Structural modification provided an alkyne containing chemical probe that labelled a protein within the parasite that was confirmed as cytosolic tryparedoxin peroxidase (cTXNPx). Crucially, labelling is observed in both promastigote and intramacrophage amastigote life forms, with no evidence of host macrophage toxicity. Incubation of the chalcone in the parasite leads to ROS accumulation and parasite death. Deletion of cTXNPx, by CRISPR-Cas9, dramatically impacts upon the parasite phenotype and reduces the antileishmanial activity of the chalcone analogue. Molecular docking studies with a homology model of in-silico cTXNPx suggest that the chalcone is able to bind in the putative active site hindering access to the crucial cysteine residue. Collectively, this work identifies cTXNPx as an important target for antileishmanial chalcones.

Leishmaniasis is an insect vector-borne parasitic disease. With >350 million people world wide considered at risk, 12 million people currently infected and an economic cost that can be estimated in terms of >3.3 million working life years lost, leishmaniasis is a major global health challenge. The disease is of particular importance in Brazil. Current treatment of leishmaniasis is difficult requiring a long, costly course of drug treatment using old drugs with poor safety indications requiring close medical supervision. Moreover, resistance to current antileishmanials is growing, emphasising a major need for new drug targets. In earlier work we had identified a naturally inspired chalcone which had promising antileishmanial activity but with no known mode of action. In this work we use an analogue of this molecule as an activity based probe to identify a protein target of the chalcone. This protein, cTXNPx, has a major role in protecting the parasite against attack by reactive oxygen species in the host cell. By inhibiting this protein the parasite can no longer survive in the host. Collectively this work validates cTXNPx as a drug target with the chalcone as a lead structure for future drug discovery programmes.

Anticancer Activity of Natural and Synthetic Chalcones

Cancer is a condition caused by many mechanisms (genetic, immune, oxidation, and inflammatory). Anticancer therapy aims to destroy or stop the growth of cancer cells. Resistance to treatment is theleading cause of the inefficiency of current standard therapies. Targeted therapies are the most effective due to the low number of side effects and low resistance. Among the small molecule natural compounds, flavonoids are of particular interest for theidentification of new anticancer agents. Chalcones are precursors to all flavonoids and have many biological activities. The anticancer activity of chalcones is due to the ability of these compounds to act on many targets. Natural chalcones, such as licochalcones, xanthohumol (XN), panduretin (PA), and loncocarpine, have been extensively studied and modulated. Modification of the basic structure of chalcones in order to obtain compounds with superior cytotoxic properties has been performed by modulating the aromatic residues, replacing aromatic residues with heterocycles, and obtaining hybrid molecules. A huge number of chalcone derivatives with residues such as diaryl ether, sulfonamide, and amine have been obtained, their presence being favorable for anticancer activity. Modification of the amino group in the structure of aminochalconesis always favorable for antitumor activity. This is why hybrid molecules of chalcones with different nitrogen hetercycles in the molecule have been obtained. From these, azoles (imidazole, oxazoles, tetrazoles, thiazoles, 1,2,3-triazoles, and 1,2,4-triazoles) are of particular importance for the identification of new anticancer agents.

Thymus quinquecostatus Celak. ameliorates cerebral ischemia-reperfusion injury via dual antioxidant actions: Activating Keap1/Nrf2/HO-1 signaling pathway and directly scavenging ROS

BACKGROUND

Thymus quinquecostatus Celak. has been widely used as a spice and a folk medicine for relieving exterior syndrome and alleviating pain in China.

PURPOSE

To explore the protective effects and the underlying mechanism against cerebral ischemia-reperfusion injury (CIRI) of the T. quinquecostatus combining with its chemical composition.

STUDY DESIGN AND METHODS

High-polar extract (HPE) was extracted from T. quinquecostatus and polyphenols in HPE were enriched to obtain polyphenol-rich fraction (PRF) using Macroporous resin. The free radicals and zebrafish embryos were used to compare the antioxidant activities of HPE and PRF in vitro and in vivo. Then, the transient middle cerebral artery occlusion (tMCAO) model was established in rats. Neurological deficit score, infarction rate, morphology and apoptosis of neurons were examined to investigate the protective effects of PRF on CIRI. The mRNA and protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) and the activities of downstream antioxidant enzymes in ischemia tissues were determined to clarify the underlying mechanisms. Also, reactive oxygen species (ROS) level in zebrafish embryos were detected after incubation with PRF for a short time (2 h) to investigate whether PRF could directly eliminate free radicals. Finally, chemical composition of PRF were analyzed to investigate the material basis for antioxidant activity and anti-CIRI effect.

RESULTS

Compared with HPE, PRF showed stronger antioxidant activities. PRF exhibited obvious protective effects including ameliorating neurological deficit, lowering infarction rate, and improving the cellular morphology in hippocampus CA1 and cortex after tMCAO. TUNEL staining suggested PRF dose-dependently improved the apoptosis of the neurons in ischemic cortex. RT-qPCR and Western Blot results suggested that PRF regulated oxidative stress (OS) via activating the Keap1/Nrf2/HO-1 signaling pathway. Also, PRF could directly scavenge excessive ROS in zebrafish embryos after a short-time PRF incubation. The anti-CIRI effect might be primarily attributed to the abundant polyphenols in PRF, including flavonoids, polymethoxylated flavonoids, flavonoid glycosides, and phenolic acids.

CONCLUSION

T. quinquecostatus contains abundant polyphenols and exhibited a good protective effect against CIRI via dual antioxidant mechanisms, providing a reference for further research and application for this plant.

MicroRNA-23a-5p Is Involved in the Regulation of Lipopolysaccharide-Induced Acute Lung Injury by Targeting HSP20/ASK1

Inflammation and oxidative stress contribute to the progression of acute lung injury (ALI). MicroRNA-23a-5p (miR-23a-5p) has been reported to regulate inflammation and oxidative stress; however, its role in ALI is still poorly elucidated. Mice were intravenously treated with the miR-23a-5p antagomir, agomir, or the negative controls for 3 consecutive days and then received a single intratracheal injection of lipopolysaccharide (LPS, 5 mg/kg) to induce ALI. Pulmonary function, bronchoalveolar lavage fluids (BALFs), arterial blood gas, and molecular biomarkers associated with inflammation and oxidative stress were analyzed. In addition, murine peritoneal macrophages were isolated and treated with LPS to verify the role of miR-23a-5p in vitro. We detected an elevation of miR-23a-5p expression in the lungs from ALI mice. The miR-23a-5p antagomir was prevented, whereas the miR-23a-5p agomir aggravated inflammation, oxidative stress, lung tissue injury, and pulmonary dysfunction in LPS-treated mice. Besides, the miR-23a-5p antagomir also reduced the productions of proinflammatory cytokines and free radicals in LPS-treated primary macrophages, which were further augmented in cells following the miR-23a-5p agomir treatment. Additional findings demonstrated that the miR-23a-5p agomir exacerbated LPS-induced ALI via activating apoptosis signal-regulating kinase 1 (ASK1), and that pharmacological or genetic inhibition of ASK1 significantly repressed the deleterious effects of the miR-23a-5p agomir. Moreover, we proved that the miR-23a-5p agomir activated ASK1 via directly reducing heat shock protein 20 (HSP20) expression. miR-23a-5p is involved in the regulation of LPS-induced inflammation, oxidative stress, lung tissue injury, and pulmonary dysfunction by targeting HSP20/ASK1, and it is a valuable therapeutic candidate for the treatment of ALI.

Chalcones: Synthetic Chemistry Follows Where Nature Leads

Chalcones belong to the flavonoid class of phenolic compounds. They form one of the largest groups of bioactive natural products. The potential anticancer, anti-inflammatory, antimicrobial, antioxidant, and antiparasitic properties of naturally occurring chalcones, and their unique chemical structural features inspired the synthesis of numerous chalcone derivatives. In fact, structural features of chalcones are easy to construct from simple aromatic compounds, and it is convenient to perform structural modifications to generate functionalized chalcone derivatives. Many of these synthetic analogs were shown to possess similar bioactivities as their natural counterparts, but often with an enhanced potency and reduced toxicity. This review article aims to demonstrate how bioinspired synthesis of chalcone derivatives can potentially introduce a new chemical space for exploitation for new drug discovery, justifying the title of this article. However, the focus remains on critical appraisal of synthesized chalcones and their derivatives for their bioactivities, linking to their interactions at the biomolecular level where appropriate, and revealing their possible mechanisms of action.

Thiazole-based Chalcone Derivatives as Potential Anti-inflammatory Agents: Biological Evaluation and Molecular Modelling

BACKGROUND

Inflammation is a multifactorial process reflecting the response of the organism to various stimuli and is associated with a number of disorders such as arthritis, asthma and psoriasis, which require long-lasting or repeated treatment.

OBJECTIVE

The aim of this paper is to evaluate the anti-inflammatory activity of previous synthesized thiazole-based chalcone derivatives.

METHODS

Chalcones were synthesized via Cliazen-Schmidt condensation1-(4-methyl-2- alkylamino)thiazol-5-yl) ethanone with a corresponding aromatic aldehyde. For the evaluation of possible anti-inflammatory activity, carrageenan mouse paw edema was used.

RESULTS

Eight out of thirteen tested chalcones showed anti-inflammatory activity in a range of 51- 55%. Prediction of toxicity revealed that these compounds are not toxic.

CONCLUSION

In general, it can be concluded that these compounds can be used for further modifications in order to develop more active and safe agents.

A novel PGAM5 inhibitor LFHP-1c protects blood-brain barrier integrity in ischemic stroke

Blood–brain barrier (BBB) damage after ischemia significantly influences stroke outcome. Compound LFHP-1c was previously discovered with neuroprotective role in stroke model, but its mechanism of action on protection of BBB disruption after stroke remains unknown. Here, we show that LFHP-1c, as a direct PGAM5 inhibitor, prevented BBB disruption after transient middle cerebral artery occlusion (tMCAO) in rats. Mechanistically, LFHP-1c binding with endothelial PGAM5 not only inhibited the PGAM5 phosphatase activity, but also reduced the interaction of PGAM5 with NRF2, which facilitated nuclear translocation of NRF2 to prevent BBB disruption from ischemia. Furthermore, LFHP-1c administration by targeting PGAM5 shows a trend toward reduced infarct volume, brain edema and neurological deficits in nonhuman primate Macaca fascicularis model with tMCAO. Thus, our study identifies compound LFHP-1c as a firstly direct PGAM5 inhibitor showing amelioration of ischemia-induced BBB disruption in vitro and in vivo, and provides a potentially therapeutics for brain ischemic stroke.

Evaluation of Chalcone Derivatives as Photosynthesis and Plant Growth Inhibitors

We report the evaluation of chalcone derivatives as photosystem II (PSII) and plant growth inhibitors. Chalcone derivatives were evaluated as PSII inhibitors through Chl a fluorescence measurement. (E)-Chalcone (6a) and (E)-3-(4-bromophenyl)-1-(4-fluorophenyl)prop-2-en-1-one (6j) showed the best results, reducing the performance index on absorption basis parameter (PI_abs ) by 70 %. Additionally, the decrease of TR₀ /RC and ET₀ /RC parameters indicates that the chalcone derivatives limited the number of active PSII reaction centers and the amount of trapped energy within them. Compounds 6a and 6j both act as post-emergent herbicides at 50 μM, reducing the root biomass of the Ipomoea grandifolia weed by 72 % and 83 %, respectively, corroborating the fluorescence results. The selectivity against weeds as compared to valuable crops by compounds 6a and 6j were evaluated employing Zea mays and Phaseolus vulgaris plants. In these, our newly synthesized compounds showed no effects on biomass accumulation of roots and aerial parts when compared to the control, providing valuable evidence for the role of these compounds as selective inhibitors of the growth of undesired weeds.

Design, green synthesis, antioxidant activity screening, and evaluation of protective effect on cerebral ischemia reperfusion injury of novel monoenone monocarbonyl curcumin analogs

Antioxidants with high efficacy and low toxicity have the potential to treat cerebral ischemia reperfusion injury (CIRI). Dienone monocarbonyl curcumin analogs (DMCA) capable of overcoming the instability and pharmacokinetic defects of curcumin possess notable antioxidant activity but are found to be significantly toxic. In this study, a novel skeleton of the monoenone monocarbonyl curcumin analogue sAc possessing reduced toxicity and improved stability was designed on the basis of the DMCA skeleton. Moreover, 32 sAc analogs were obtained by applying a green, simple, and economical synthetic method. Multiple sAc analogs with an antioxidant protective effect in PC12 cells were screened using an H₂O₂-induced oxidative stress damage model, and quantitative evaluation of structure-activity relationship (QSAR) model with regression coefficient of R² = 0.918921 was built through random forest algorithm (RF). Among these compounds, the optimally active compound sAc15 elicited a potent protective effect on cell growth of PC12 cells by effectively eliminating ROS generation in response to oxidative stress injury by activating the Nrf2/HO-1 antioxidant signaling pathway. In addition, sAc15 exhibited good protection against CIRI in the mice middle cerebral artery occlusion (MCAO) model. In this paper, we provide a novel class of antioxidants and a potential compound for stroke treatment.

Analogs of imine resveratrol alleviate oxidative stress-induced neurotoxicity in PC12 cells via activation of Nrf2

Oxidative stress is closely associated with neurodegenerative, cardiovascular and metabolic diseases. Resveratrol and related compounds have shown great potential as antioxidants via either direct scavenging of abundant reactive oxygen species (ROS) or activation of the Kelch-like ECH-associated protein 1-nuclear factor (erythroid-derived 2)-like 2-antioxidant response elements pathway. In the present study, we evaluated imine resveratrol analogs (IRAs) for their neuroprotective effects against ROS in PC12 cells, which are a commonly employed model system for studies of neuronal development and function. We identified that IRA-3 (4-[[(4-hydroxyphenyl)methylene]amino]-phenol) was more potent than resveratrol at rescuing PC12 cells from H₂ O₂ -induced oxidative damage, exhibiting a recovery percentage of 60.4% at 50 μm. Our findings suggest that the neuroprotective effect of IRA-3 was achieved via multiple routes, including direct scavenging of ROS, rescue of endogenous antioxidants and activation of the Kelch-like ECH-associated protein 1-nuclear factor (erythroid-derived 2)-like 2-antioxidant response elements pathway. Our results suggest that IRA-3 may have potential for development into a possible treatment for neurodegenerative diseases.

Thiazole-Chalcone Hybrids as Prospective Antitubercular and Antiproliferative Agents: Design, Synthesis, Biological, Molecular Docking Studies and In Silico ADME Evaluation

Compounds bearing thiazole and chalcone pharmacophores have been reported to possess excellent antitubercular and anticancer activities. In view of this, we designed, synthesized and characterized a novel series of thiazole-chalcone hybrids (1-20) and further evaluated them for antitubercular and antiproliferative activities by employing standard protocols. Among the twenty compounds, chalcones 12 and 7, containing 2,4-difluorophenyl and 2,4-dichlorophenyl groups, showed potential antitubercular activity higher than the standard pyrazinamide (MIC = 25.34 µM) with MICs of 2.43 and 4.41 µM, respectively. Chalcone 20 containing heteroaryl 2-thiazolyl moiety exhibited promising antiproliferative activity against the prostate cancer cell line (DU-145), higher than the standard methotrexate (IC50 = 11 ± 1 µM) with an IC50 value of 6.86 ± 1 µM. Furthermore, cytotoxicity studies of these compounds against normal human liver cell lines (L02) revealed that the target molecules were comparatively less selective against L02. Additional computational studies using AutoDock predicted the key binding interactions responsible for the activity and the SwissADME tool computed the in silico drug likeliness properties. The lead compounds generated through this study, create a way for the optimization and development of novel drugs against tuberculosis infections and prostate cancer.

Neuroprotective Effect of a New Free Radical Scavenger HL-008 in an Ischemia-Reperfusion Injury Rat Model

Oxidative stress plays a critical role in cerebral ischemia-reperfusion injury. We have previously developed a powerful antioxidant, HL-008. This study aimed to investigate the neuroprotective function of HL-008. HL-008 efficacy in vitro and in vivo was evaluated using a PC-12 cell oxidative stress model induced by hydrogen peroxide and a rat model of middle cerebral artery occlusion, respectively. The MTT assay was used to analyze cell viability. 2,3,5-Triphenyltetrazolium chloride and Hematoxylin and Eosin staining, immunofluorescence, western blot, and proteomics were used to evaluate the infarction volume, brain tissue morphology, apoptosis, inflammation, and related pathways. Indicators related to oxidative levels were also detected. HL-008 significantly reduced the cerebral infarction volume induced by ischemia-reperfusion, improved the neurological score, alleviated oxidative stress and inflammation in the brain tissue, reduced glial cell activation, inhibited brain tissue apoptosis by influencing multiple signaling pathways, and had a neuroprotective effect. If HL-008 is successfully developed, it could significantly improve stroke patients' quality of life.

Overexpression of microRNA-202-3p in bone marrow mesenchymal stem cells improves cerebral ischemia-reperfusion injury by promoting angiogenesis and inhibiting inflammation

BACKGROUND

Cerebral ischemia-reperfusion injury (CIRI) can cause brain tissue inflammation, neuronal degeneration, and apoptosis. There is increasing evidence that microRNAs (miRNA) exert neuroprotective effects by regulating the inflammatory process during cerebral ischemia-reperfusion injury. Additionally, it is increasingly acknowledged that neuroinflammation is regulated by Toll-like receptor 4 (TLR4). However, it is unclear whether miRNA can exert its neuroprotective effects by regulating TLR4-mediated inflammation.

METHODS

The effects of BMSCs over-expressing miR-202-3p on CIRI, angiogenesis in midbrain tissue, and the release of inflammatory factors (IFs) in the serum were measured using in vivo rat models. We also used SH-SY5Y cells to establish an ischemia-reperfusion in vitro cell model. The interaction between miR-202-3p and TLR4 was analyzed by overexpressing miR-202-3p and knocking down TLR4. Knockdown of TLR4 was performed using siRNA.

RESULTS

Overexpression of miR-202-3p in BMSCs could significantly improve brain function and reduce brain damage. Simultaneously, miR-202-3p could significantly promote angiogenesis, increase the expression of vWF and VEGF, and reduce the expression of IFs. When the expression of TLR4 was significantly reduced in SH-SY5Y cells, the expression of IFs increased. Therefore, miRNA-202-3p may interact with TLR4 to modulate inflammation.

CONCLUSION

Our data indicated that miR-202-3p potentially exerts its neuroprotective effects and protects against CIRI by regulating TLR4-mediated inflammation.

Activation of Nrf2 signaling pathway by natural and synthetic chalcones: a therapeutic road map for oxidative stress

Introduction:Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway plays a key role in diverse gene expressions responsible for protection against oxidative stress and xenobiotics. Chalcones with a common chemical scaffold of 1,3-diaryl-2- propen-1-one, are abundantly present in nature with a wide variety of pharmacological properties. This review will discuss the interactions of natural and synthetic chalcones with Nrf2 signaling.Areas covered:Chalcones are reportedly found to activate Nrf2 signaling pathway, expression of Nrf2-regulated antioxidant genes, induce cytoprotective proteins and upregulate multidrug resistance-associated proteins. Chalcones being soft electrophiles are less prone to hostile off-target effects and unlikely to induce carcinogenicity and mutagenicity. Furthermore, their low toxicity, structural diversity, feasibility in structural reorganization and the presence of α,β-unsaturated carbonyl group which makes them suitable drug candidates targeting Nrf2-dependent diseases.Expert opinion:Nrf2-Keap1 signaling pathway plays a central role in redox signaling. However, available therapeutic agents for Nrf2 activation have limited practical applications due to their associated risks, relatively low efficacy and bioavailability. The designing and fabrication of new chemical entities with chalcone scaffold-based Michael acceptor mechanism should be aimed as potential therapeutic Nrf2 activators to target oxidative stress and inflammation-mediated diseases such as atherosclerosis, Parkinson's disease and many more.

In Vitro Antioxidant Activities and the Therapeutic Potential of Some Newly Synthesized Chalcones Against 4-Acetaminophenol Induced Hepatotoxicity in Rats

The lack of safety and efficacy of existing hepatoprotective agents urge the need to explore novel hepatoprotective agents. The research work was planned to study the therapeutic potential of some newly synthesized chalcones against 4-acetaminophenol induced hepatotoxicity in rats. Male albino rats (N = 30) were divided into 6 groups of 5 animals each i.e. group I; Toxic control (4-acetaminophenol), group II; normal control (Normal saline), group III; Positive control (silymarin; 50 mg/kg bw) and groups IV-VI (test groups) treated with 3 chalcone analogues i-e 3a, 3f & 3 g (100, 150, 150 mg/kg bw, respectively). All the study group animals were administered with 4-acetaminophenol to induce hepatotoxicity except normal control. Following hepatotoxicity induction, test group animals were administered with selected doses of test compounds and toxic group animals left untreated. Liver enzymes including ALT, AST, ALP and serum bilirubin were determined photometrically. Antioxidant activities of test compounds were also determined. Histopathological examination of liver biopsies was also carried out through H & E staining. The test chalcones (3a, 3f & 3 g) significantly decreased the levels of liver enzymes and serum bilirubin toward normal and the pattern of results in the test group animals were comparable to silymarin administered animals indicating the hepatoprotective potential of test compounds. Moreover, the test chalcones (3a, 3f & 3 g) antagonized the effect of 4-acetaminophenol and thus, raised the catalase (CAT) and superoxide dismutase (SOD) while decreased the malondialdehyde (MDA) in experimental animals. The test chalcones (3a, 3f & 3 g) on histological examination of liver showed improvement of tissue morphology. The study concluded that the tested compounds have antioxidant potential and may act as hepatoprotective agent. However, in-depth studies are required to validate their safety and to elucidate the exact mechanism of action.

Targeting redox-altered plasticity to reactivate synaptic function: A novel therapeutic strategy for cognitive disorder

Redox-altered plasticity refers to redox-dependent reversible changes in synaptic plasticity via altering functions of key proteins, such as N-methyl-d-aspartate receptor (NMDAR). Age-related cognitive disorders includes Alzheimer's disease (AD), vascular dementia (VD), and age-associated memory impairment (AAMI). Based on the critical role of NMDAR-dependent long-term potentiation (LTP) in memory, the increase of reactive oxygen species in cognitive disorders, and the sensitivity of NMDAR to the redox status, converging lines have suggested the redox-altered NMDAR-dependent plasticity might underlie the synaptic dysfunctions associated with cognitive disorders. In this review, we summarize the involvement of redox-altered plasticity in cognitive disorders by presenting the available evidence. According to reports from our laboratory and other groups, this "redox-altered plasticity" is more similar to functional changes rather than organic injuries, and strategies targeting redox-altered plasticity using pharmacological agents might reverse synaptic dysfunctions and memory abnormalities in the early stage of cognitive disorders. Targeting redox modifications for NMDARs may serve as a novel therapeutic strategy for memory deficits.

Discovery of novel JAK2 and EGFR inhibitors from a series of thiazole-based chalcone derivatives

The Janus kinase (JAK) and epidermal growth factor receptor (EGFR) have been considered as potential targets for cancer therapy due to their role in regulating proliferation and survival of cancer cells. In the present study, the aromatic alkyl-amino analogs of thiazole-based chalcone were selected to experimentally and theoretically investigate their inhibitory activity against JAK2 and EGFR proteins as well as their anti-cancer effects on human cancer cell lines expressing JAK2 (TF1 and HEL) and EGFR (A549 and A431). In vitro cytotoxicity screening results demonstrated that the HEL erythroleukemia cell line was susceptible to compounds 11 and 12, whereas the A431 lung cancer cell line was vulnerable to compound 25. However, TF1 and A549 cells were not sensitive to our thiazole derivatives. From kinase inhibition assay results, compound 25 was found to be a dual inhibitor against JAK2 and EGFR, whereas compounds 11 and 12 selectively inhibited the JAK2 protein. According to the molecular docking analysis, compounds 11, 12 and 25 formed hydrogen bonds with the hinge region residues Lys857, Leu932 and Glu930 and hydrophobically came into contact with Leu983 at the catalytic site of JAK2, while compound 25 formed a hydrogen bond with Met769 at the hinge region, Lys721 near a glycine loop, and Asp831 at the activation loop of EGFR. Altogether, these potent thiazole derivatives, following Lipinski's rule of five, could likely be developed as a promising JAK2/EGFR targeted drug(s) for cancer therapy.

A novel SIRT6 activator ameliorates neuroinflammation and ischemic brain injury via EZH2/FOXC1 axis

Ischemic stroke is the second leading cause of death worldwide with limited medications and neuroinflammation was recognized as a critical player in the progression of stroke, but how to control the overactive neuroinflammation is still a long-standing challenge. Here, we designed a novel SIRT6 activator MDL-811 which remarkably inhibited inflammatory response in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and primary mouse microglia, which were abolished by silencing SIRT6. RNA-seq screening identified the forkhead box C1 (Foxc1) is a key gene evoked by MDL-811 stimulation and is required for the anti-inflammatory effects of MDL-811. We found MDL-811-activated SIRT6 directly interacted with enhancer of zeste homolog 2 (EZH2) and promoted deacetylation of EZH2 which could bind to the promoter of Foxc1 and upregulate its expression to modulate inflammation. Moreover, our data demonstrated that MDL-811 not only ameliorated sickness behaviors in neuroinflammatory mice induced by LPS, but also markedly reduced the brain injury in ischemic stroke mice in addition to promoting long-term functional recovery. Importantly, MDL-811 also exhibited strong anti-inflammatory effects in human monocytes isolated from ischemic stroke patients, underlying an interesting translational perspective. Taken together, MDL-811 could be an alternative therapeutic candidate for ischemic stroke and other brain disorders associated with neuroinflammation.

Growth differentiation factor 11 mitigates cardiac radiotoxicity via activating AMPKα

Cardiac radiotoxicity largely impedes the therapeutic benefits of radiotherapy to malignancies. Growth differentiation factor 11 (GDF11) is implicated in the pathogenesis of cardiac diseases under different pathological conditions. This study aims to investigate the role and underlying mechanisms of GDF11 on cardiac radiotoxicity. Mice were injected with cardiotropic adeno-associated virus 9 carrying the full-length mouse GDF11 gene or negative control under a cTnT promoter from the tail vein, and then received a single dose of 20 Gray (Gy) whole-heart irradiation (WHI) for 16 weeks to imitate cardiac radiotoxicity. Compound C (CC, 20 mg/kg) was intraperitoneally injected every two days at 1 week before WHI stimulation to inhibit 5' AMP-activated protein kinase α (AMPKα). Cardiac GDF11 expression was significantly suppressed at both the protein and mRNA levels. GDF11 overexpression decreased oxidative stress, apoptosis, and fibrosis in radiated hearts, thereby mitigating cardiac radiotoxicity, and dysfunction. Further detection revealed that GDF11 activated AMPKα to reduce radiation-induced oxidative damage and that AMPKα inhibition by CC offset the cardioprotective effects by GDF11. GDF11 mitigates cardiac radiotoxicity via activating AMPKα and it is a promising candidate to treat cardiac radiotoxicity.

A synthetic chalcone derivative, compound 39, alleviates lipopolysaccharide-induced acute lung injury in mice

Our research group has previously synthesized various chalcone analogues. Of these analogues, compound 39 has been shown to exhibit potent antioxidative activities but its anti-inflammatory and anti-apoptosis effects remain unclear. Thus, the present study investigated the in vivo and in vitro effects and mechanisms of compound 39 in lipopolysaccharide (LPS)-induced acute lung injury (ALI). To induce ALI, the mice received LPS via a tracheal instillation 6 h after intragastric administration of compound 39 or vehicle. Histological changes, the lung wet/dry weight ratio, and the amounts of protein and inflammatory cells in the broncho-alveolar lavage (BAL) fluid were assessed after 24 h. Additionally, to determine its underlying mechanisms, Western blot and immunofluorescence analyses were used. Moreover, the in vitro effects of compound 39 were also investigated. In the in vivo experiment, compound 39 markedly alleviated histopathological alterations, lung edema, and protein leakage, and exhibited potent anti-inflammatory effects. In the in vitro experiments, compound 39 dose-dependently reduced the levels of pro-inflammatory cytokines and reactive oxygen species. The results suggested that the anti-inflammatory effects of compound 39 were due to suppression of the mitogen-activated protein kinase (MAPK)/nuclear factor κB (NF-κB) pathway. Compound 39 also enhanced the protein levels of Bcl-2 and reduced the protein levels of Bax and cleaved caspase-3. The present study confirmed the anti-inflammatory, oxy-radical prohibitive, and anti-apoptosis activities of compound 39 against LPS-induced tissue and cell damage, and revealed the mechanisms underlying those processes.

Important Flavonoids and Their Role as a Therapeutic Agent

Flavonoids are phytochemical compounds present in many plants, fruits, vegetables, and leaves, with potential applications in medicinal chemistry. Flavonoids possess a number of medicinal benefits, including anticancer, antioxidant, anti-inflammatory, and antiviral properties. They also have neuroprotective and cardio-protective effects. These biological activities depend upon the type of flavonoid, its (possible) mode of action, and its bioavailability. These cost-effective medicinal components have significant biological activities, and their effectiveness has been proved for a variety of diseases. The most recent work is focused on their isolation, synthesis of their analogs, and their effects on human health using a variety of techniques and animal models. Thousands of flavonoids have been successfully isolated, and this number increases steadily. We have therefore made an effort to summarize the isolated flavonoids with useful activities in order to gain a better understanding of their effects on human health.

Synthesis of Novel Aryloxyethylamine Derivatives and Evaluation of Their in Vitro and in Vivo Neuroprotective Activities

A series of aryloxyethylamine derivatives were designed, synthesized and evaluated for their biological activity. Their structures were confirmed by ¹ H-NMR, ¹³ C-NMR, FT-IR and HR-ESI-MS. The preliminary screening of neuroprotection of compounds in vitro was detected by MTT, and the anti-ischemic activity in vivo was tested using bilateral common carotid artery occlusion in mice. Most of these compounds showed potential neuroprotective effects against the glutamate-induced cell death in differentiated rat pheochromocytoma cells (PC12 cells), especially for (4-fluorophenyl){1-[2-(4-methoxyphenoxy)ethyl]piperidin-4-yl}methanone, {1-[2-(4-methoxyphenoxy)ethyl]piperidin-4-yl}(4-methoxyphenyl)methanone, (4-bromophenyl){1-[2-(4-methoxyphenoxy)ethyl]piperidin-4-yl}methanone, {1-[2-(4-chlorophenoxy)ethyl]piperidin-4-yl}(4-chlorophenyl)methanone, (4-chlorophenyl)(1-{2-[(naphthalen-2-yl)oxy]ethyl}piperidin-4-yl)methanone, (4-chlorophenyl){1-[2-(4-methoxyphenoxy)ethyl]piperidin-4-yl}methanone and {1-[2-(4-bromophenoxy)ethyl]piperidin-4-yl}(4-chlorophenyl)methanone, which exhibited potent protection of PC12 cells at three doses (0.1, 1.0, 10 μM). Compounds (4-fluorophenyl){1-[2-(4-methoxyphenoxy)ethyl]piperidin-4-yl}methanone, (4-fluorophenyl){1-[2-(naphthalen-2-yloxy)ethyl]piperidin-4-yl}methanone, {1-[2-(4-methoxyphenoxy)ethyl]piperidin-4-yl}(4-methoxyphenyl)methanone and {1-[2-(4-chlorophenoxy)ethyl]piperidin-4-yl}(4-chlorophenyl)methanone possessed the significant prolongation of the survival time of mice subjected to acute cerebral ischemia and decreased the mortality rate at all five doses tested (200, 100, 50, 25, 12.5 mg/kg) and had significant neuroprotective activity. In addition, (4-fluorophenyl){1-[2-(4-methoxyphenoxy)ethyl]piperidin-4-yl}methanone, {1-[2-(4-methoxyphenoxy)ethyl]piperidin-4-yl}(4-methoxyphenyl)methanone and {1-[2-(4-chlorophenoxy)ethyl]piperidin-4-yl}(4-chlorophenyl)methanone possessed outstanding neuroprotection in vitro and in vivo. These compounds can be used as a promising neuroprotective agents for future development of new anti-ischemic stroke agents. Basic structure-activity relationships are also presented.

Curcumin-laden exosomes target ischemic brain tissue and alleviate cerebral ischemia-reperfusion injury by inhibiting ROS-mediated mitochondrial apoptosis

The pathogenesis of ischemic cerebrovascular disease has revealed that ischemia-reperfusion (I/R) injury often leads to aggravation of metabolic oxidative stress and blood-brain barrier (BBB) destruction, eventually causing secondary brain tissue damage. Accumulated reactive oxygen species (ROS) in focal ischemia activate mitochondria-mediated apoptosis and damage the BBB by degrading tight junction proteins (TJPs). Herein, we report macrophage-derived exosomes (Ex) loaded with curcumin (cur) as a multifunctional biomimetic delivery vehicle (Ex-cur) for targeting ischemic brain tissue and alleviating cerebral I/R injury by inhibiting ROS-mediated mitochondrial apoptosis in a transient cerebral ischemia rat model. The design principle relies on unique features of macrophage-derived exosomes and the natural ingredient cur. Specifically, cur can be entrapped within exosomes when incubated with murine macrophage RAW264.7 cells, and its stability is subsequently significantly improved. The resultant Ex-cur can target ischemic regions by leveraging the targeting migration capability of Ex driven by inflammation. Accumulated Ex-cur in ischemic regions is experimentally proven to be highly effective at reducing ROS accumulation by virtue of the antioxidant properties of cur. Using Ex-cur to down-regulate ROS accumulation in lesions, we alleviate BBB damage and suppress mitochondria-mediated neuronal apoptosis, which is confirmed by a series of relevant protein analysis. These findings demonstrate good therapeutic efficacy of Ex-cur for treating I/R injury, providing experimental evidence for the potential clinical benefits of Ex-cur for other modes of neuroprotection.

Design, Facile Synthesis and Characterization of Dichloro Substituted Chalcones and Dihydropyrazole Derivatives for Their Antifungal, Antitubercular and Antiproliferative Activities

Infectious diseases caused by fungi and mycobacteria pose an important problem for humankind. Similarly, cancer is one of the leading causes of death globally. Therefore, there is an urgent need for the development of novel agents to combat the deadly problems of cancer, tuberculosis, and also fungal infections. Hence, in the present study, we designed, synthesized, and characterized 30 compounds including 15 chalcones (2–16) and 15 dihydropyrazoles (17–31) containing dichlorophenyl moiety and also screened these compounds for their antifungal, antitubercular, and antiproliferative activities. Among these compounds, the dihydropyrazoles showed excellent antifungal and antitubercular activities whereas the chalcones exhibited promising antiproliferative activity. Among the dihydropyrazoles, compound 31 containing 2-thienyl moiety showed promising antifungal activity (MIC 5.35 µM), whereas compounds 22 and 24 containing 2,4-difluorophenyl and 4-trifluoromethyl scaffolds revealed significant antitubercular activity with the MICs of 3.96 and 3.67 µM, respectively. Compound 16 containing 2-thienyl moiety in the chalcone series showed the highest anti-proliferative activity with an IC₅₀ value of 17 ± 1 µM. The most active compounds identified through this study could be considered as starting points in the development of drugs with potential antifungal, antitubercular, and antiproliferative activities.

Plasma exosomes protect against cerebral ischemia/reperfusion injury via exosomal HSP70 mediated suppression of ROS

AIMS

Ischemic stroke is the leading cause of severe disability and death worldwide. As the pathogenesis of stroke has not been clearly elucidated and the ability of current therapeutic drugs on crossing the blood-brain barrier (BBB) is extremely low, there is no effective strategy to treat stroke. We aim at investigating the specific advantages of using plasma exosomes (Pla-Exo) for targeting ischemic brain and exploring its underlying mechanism in neuroprotection.

MAIN METHODS

Pla-Exo was obtained by a gradient ultracentrifugation of fresh plasma. The quantification of penetrated Pla-Exo through BBB was investigated in vitro BBB model, furthermore, the effects of Pla-Exo and exosomal HSP70 on cerebral ischemia/reperfusion injury were evaluated.

KEY FINDINGS

Pla-Exo enhanced BBB crossing by specific interaction between Pla-Exo inherited heat shock protein 70 (HSP70) and endothelial Toll-like receptor 4 (TLR4). As expected, Pla-Exo increased HSP70 expression in the ischemic region through the transfer of HSP70, and led to HSP70 mediated suppression of ROS, thus alleviating cerebral ischemia/reperfusion (I/R) injury by attenuating the deterioration of BBB and preventing mitochondria damage.

SIGNIFICANCE

These findings indicated that Pla-Exo can provide protection against ischemia-reperfusion injury via the regulation of HSP70 and it should be further studied as a potential candidate for protection against ischemic injury.

Identification and optimization of piperine analogues as neuroprotective agents for the treatment of Parkinson's disease via the activation of Nrf2/keap1 pathway

Parkinson's disease (PD) is a slowly progressive and complex neurodegenerative disorder. Up to date, there are no approved drugs that could slow or reverse the neurodegenerative process of PD. Here, we reported the synthesis of series of piperine analogues and the evaluation of their neuroprotective effects against hydrogen peroxide (H₂O₂) induced damage in the neuron-like PC12 cells. Among these analogues, 3b exhibited the most potent protection effect and its underlying mechanism was further investigated. Further results indicated that the ROS scavenging and cytoprotection effect of 3b might be related to the Nrf2 activation and upregulation of related phase II antioxidant enzymes, such as HO-1 and NQO1. In in vivo study, oral administration (100 mg/kg) of 3b significantly attenuated PD-associated behavioral deficits in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD and protected tyrosine hydroxylase-immunopositive dopaminergic neurons. Our results provided evidence that 3b might be a promising candidate for Parkinson's disease treatment.