Development of New PCR Protocols to Detect Genetic Diversity in the Metronidazole Metabolism Genes in Susceptible and Refractory Clinical Samples of Giardia duodenalis.

PURPOSE: Investigating the genetic variation in thioredoxin reductase (TrxR) and nitroreductase (NR) genes in both treatment-resistant and -sensitive Giardia duodenalis isolates can provide valuable information in identifying potential markers of resistance to metronidazole. The rapid increase in metronidazole treatment failures suggests the presence of genetic resistance mechanisms. By analyzing these genes, researchers can gain insights into the efficacy of metronidazole against G. duodenalis and potentially develop alternative treatment strategies. In this regard, four G. duodenalis isolates (two clinically sensitive and two clinically resistant to metronidazole) were collected from various hospitals of Shiraz, southwestern Iran. METHODS: Parasitological methods including sucrose flotation and microscopy were employed for the primary confirmation of G. duodenalis cysts in stool samples. Microscopy-positive samples were approved by SSU-PCR amplification of the parasite DNA. All four positive G. duodenalis specimens at SSU-PCR were afterward analyzed utilizing designed primers based on important metronidazole metabolism genes including TrxR, NR1, and NR2. RESULTS: Unlike TrxR gene, the results of NR1 and NR2 genes showed that there are non-synonymous variations between sequences of treatment-sensitive and -resistant samples compared to reference sequences. Furthermore, the outcomes of molecular docking revealed that there is an interaction between the protein sequence and spatial shape of treatment-resistant samples and metronidazole in the position of serine amino acid based on the NR1 gene. CONCLUSION: This issue can be one of the possible factors involved in the resistance of Giardia parasites to metronidazole. To reach more accurate results, a large sample size along with simulation and advanced molecular dynamics investigations are needed.

4-{3-[(Pyridin-4-ylmethyl)amino]-[1,2,4]triazolo[4,3-b][1,2,4]triazin-6-yl}phenol: An improved anticancer agent in hepatocellular carcinoma and a selective MDR1/MRP modulator.

Hepatocellular carcinoma is the most common type of primary liver cancer. However, multidrug resistance (MDR) is a major obstacle to the effective chemotherapy of cancer cells. This report documents the rational design, synthesis, and biological evaluation of a novel series of triazolotriazines substituted with CH2 NH-linked pyridine for use as dual c-Met/MDR inhibitors. Compound 12g with IC50 of 3.06 µM on HepG2 cells showed more potency than crizotinib (IC50 = 5.15 µM) in the MTT assay. In addition, 12g inhibited c-Met kinase at a low micromolar level (IC50 = 0.052 µM). 12g significantly inhibited P-gp and MRP1/2 efflux pumps in both cancerous HepG2 and BxPC3 cells starting from the lower concentrations of 3 and 0.3 µM, respectively. 12g did not inhibit MDR1 and MRP1/2 in noncancerous H69 cholangiocytes up to the concentration of 30 and 60 µM, respectively. Current results highlighted that cancerous cells were more susceptible to the effect of 12g than normal cells, in which the inhibition occurred only at the highest concentrations, suggesting a further interest in 12g as a selective anticancer agent. Overall, 12g, as a dual c-Met and P-gp/MRP inhibitor, is a promising lead compound for developing a new generation of anticancer agents.

Engineering and design of promising T-cell-based multi-epitope vaccine candidates against leishmaniasis.

Cutaneous leishmaniasis (CL) is a very common parasitic infection in subtropical areas worldwide. Throughout decades, there have been challenges in vaccine design and vaccination against CL. The present study introduced novel T-cell-based vaccine candidates containing IFN-γ Inducing epitopic fragments from Leishmania major (L. major) glycoprotein 46 (gp46), cathepsin L-like and B-like proteases, histone H2A, glucose-regulated protein 78 (grp78) and stress-inducible protein 1 (STI-1). For this aim, top-ranked human leukocyte antigen (HLA)-specific, IFN-γ Inducing, antigenic, CD4+ and CD8+ binders were highlighted. Four vaccine candidates were generated using different spacers (AAY, GPGPG, GDGDG) and adjuvants (RS-09 peptide, human IFN-γ, a combination of both, Mycobacterium tuberculosis Resuscitation promoting factor E (RpfE)). Based on the immune simulation profile, those with RS-09 peptide (Leish-App) and RpfE (Leish-Rpf) elicited robust immune responses and their tertiary structure were further refined. Also, molecular docking of the selected vaccine models with the human toll-like receptor 4 showed proper interactions, particularly for Leish-App, for which molecular dynamics simulations showed a stable connection with TLR-4. Upon codon optimization, both models were finally ligated into the pET28a( +) vector. In conclusion, two potent multi-epitope vaccine candidates were designed against CL and evaluated using comprehensive in silico methods, while further wet experiments are, also, recommended.

Benzoindolizidine Alkaloids Tylophorine and Lycorine and Their Analogues with Antiviral, Anti-Inflammatory, and Anticancer Properties: Promises and Challenges.

Ongoing viral research, essential for public health due to evolving viruses, gains significance owing to emerging viral infections such as the SARS-CoV-2 pandemic. Marine and plant alkaloids show promise as novel potential pharmacological strategies. In this narrative review, we elucidated the potential of tylophorine and lycorine, two naturally occurring plant-derived alkaloids with a shared benzoindolizidine scaffold, as antiviral agents to be potentially harnessed against respiratory viral infections. Possible structure-activity relationships have also been highlighted. The substances and their derivatives were found to be endowed with powerful and broad-spectrum antiviral properties; moreover, they were able to counteract inflammation, which often underpins the complications of viral diseases. At last, their anticancer properties hold promise not only for advancing cancer research but also for mitigating the oncogenic effects of viruses. This evidence suggests that tylophorine and lycorine could effectively counteract the pathogenesis of respiratory viral disease and its harmful effects. Although common issues about the pharmacologic development of natural substances remain to be addressed, the collected evidence highlights a possible interest in tylophorine and lycorine as antiviral and/or adjuvant strategies and encourages future more in-depth pre-clinical and clinical investigations to overcome their drawbacks and harness their power for therapeutic purposes.

An Overview on Anti-COVID-19 Drug Achievements and Challenges Ahead.

The appearance of several coronavirus pandemics/epidemics during the last two decades (SARS-CoV-1 in 2002, MERS-CoV in 2012, and SARS-CoV-2 in 2019) indicates that humanity will face increasing challenges from coronaviruses in the future. The emergence of new strains with similar transmission characteristics as SARS-CoV-2 and mortality rates similar to SARS-CoV-1 (∼10% mortality) or MERS-CoV (∼35% mortality) in the future is a terrifying possibility. Therefore, getting enough preparations to face such risks is an inevitable necessity. The present study aims to review the drug achievements and challenges in the fight against SARS-CoV-2 with a combined perspective derived from pharmacology, pharmacotherapy, and medicinal chemistry insights. Appreciating all the efforts made during the past few years, there is strong evidence that the desired results have not yet been achieved and research in this area should still be pursued seriously. By expressing some pessimistic possibilities and concluding that the drug discovery and pharmacotherapy of COVID-19 have not been successful so far, this short essay tries to draw the attention of responsible authorities to be more prepared against future coronavirus epidemics/pandemics.

Discovery of Chalcone-Based Hybrid Structures as High Affinity and Site-Specific Inhibitors against SARS-CoV-2: A Comprehensive Structural Analysis Based on Various Host-Based and Viral Targets.

Previous studies indicated that natural-based chalcones have significant inhibitory effects on the coronavirus enzymes 3CLpro and PLpro as well as modulation of some host-based antiviral targets (HBATs). In this study, a comprehensive computational and structural study was performed to investigate the affinity of our compound library consisting of 757 chalcone-based structures (CHA-1 to CHA-757) for inhibiting the 3CLpro and PLpro enzymes and against twelve selected host-based targets. Our results indicated that CHA-12 (VUF 4819) is the most potent and multi-target inhibitor in our chemical library over all viral and host-based targets. Correspondingly, CHA-384 and its congeners containing ureide moieties were found to be potent and selective 3CLpro inhibitors, and benzotriazole moiety in CHA-37 was found to be a main fragment for inhibiting the 3CLpro and PLpro. Surprisingly, our results indicate that the ureide and sulfonamide moieties are integral fragments for the optimum 3CLpro inhibition while occupying the S1 and S3 subsites, which is fully consistent with recent reports on the site-specific 3CLpro inhibitors. Finding the multi-target inhibitor CHA-12, previously reported as an LTD4 antagonist for the treatment of inflammatory pulmonary diseases, prompted us to suggest it as a concomitant agent for relieving respiratory symptoms and suppressing COVID-19 infection.

Dual action anti-inflammatory/antiviral isoquinoline alkaloids as potent naturally occurring anti-SARS-CoV-2 agents: A combined pharmacological and medicinal chemistry perspective.

In the search for compounds that inhibit the SARS-CoV-2 after the onset of the COVID-19 pandemic, isoquinoline-containing alkaloids have been identified as compounds with high potential to fight the disease. In addition to having strong antiviral activities, most of these alkaloids have significant anti-inflammatory effects which are often manifested through the inhibition of a promising host-based anti-COVID-19 target, the p38 MAPK signaling pathway. In the present review, our pharmacological and medicinal chemistry evaluation resulted in highlighting the potential of anti-SARS-CoV-2 isoquinoline-based alkaloids for the treatment of COVID-19 patients. Considering critical parameters of the antiviral and anti-inflammatory activities, mechanism of action, as well as toxicity/safety profile, we introduce the alkaloids emetine, cephaeline, and papaverine as high-potential therapeutic agents for use in the treatment of COVID-19. Although preclinical studies confirm that some isoquinoline-based alkaloids reviewed in this study have a high potential to inhibit the SARS-CoV-2, their entry into drug regimens of COVID-19 patients requires further clinical trial studies and toxicity evaluation.

In silico design of a novel peptide-based vaccine against the ubiquitous apicomplexan Toxoplasma gondii using surface antigens.

Human toxoplasmosis is a global public health concern and a commercial vaccine is still lacking. The present in silico study was done to design a novel vaccine candidate using tachyzoite-specific SAG1-realted sequence (SRS) proteins. Overlapping B-cell and strictly-chosen human MHC-I binding epitopes were predicted and connected together using appropriate spacers. Moreover, a TLR4 agonist, human high mobility group box protein 1 (HMGB1), and His-tag were added to the N- and C-terminus of the vaccine sequence. The final vaccine had 442 residues and a molecular weight of 47.71 kDa. Physico-chemical evaluation showed a soluble, highly antigenic and non-allergen protein, with coils and helices as secondary structures. The vaccine 3D model was predicted by ITASSER server, subsequently refined and was shown to possess significant interactions with human TLR4. As well, potent stimulation of cellular and humoral immunity was demonstrated upon chimeric vaccine injection. Finally, the outputs showed that this vaccine model possesses top antigenicity, which could provoke significant cell-mediated immune profile including IFN-γ, and can be utilized towards prophylactic purposes. Supplementary Information: The online version contains supplementary material available at 10.1007/s40203-023-00140-w.

Synthesis and evaluation of 99mTc-labeled 1-(2-Pyridyl)piperazine derivatives as radioligands for 5HT7 receptors.

Glioblastoma multiform (GBM) is one of the most aggressive tumors of the central nervous system in humans. GBM overexpresses serotonin-7 receptors (5-HT7Rs); hence, this study aims to develop 5-HT7R targeted radiotracers. Aryl piperazine derivatives can act as ligands for 5-HT7R. Therefore, compounds 6 and 7 as 1-(3-nitropyridin-2-yl)piperazine derivatives were synthesized and radiolabeled with 99mTcN2+ core. Radiolabeled 6 and 7 (99mTcN-[6] and 99mTcN-[7]) were prepared with high radiochemical purity (RCP > 96%). They displayed high affinity toward U-87 MG cell line 5-HT7R. The calculated Ki for 99mTcN-[7] was lower than that of 99mTcN-[6] (14.85 ± 0.32 vs 22.57 ± 0.73 nM) which indicates the higher affinity of 99mTcN-[7] toward 5-HT7R. A molecular docking study also confirmed the binding of these radiotracers to 5-HT7R. The biodistribution study in normal mice revealed that 99mTcN-[7] has the highest brain accumulation at 30 min post-injection (0.54 ± 0.12 %ID/g) while the uptake of 99mTcN-[6] is much lower (0.14 ± 0.02 %ID/g). The biodistribution study in the xenograft model confirms that the radiotracers recognize the tumor site. 99mTcN-[6], and 99mTcN-[7] showed the highest tumor uptake at 1-hour post-injection (5.44 ± 0.58 vs 4.94 ± 1.65 %ID/g) and tumor-to-muscle ratios were (4.61 vs. 5.61). The injection of pimozide blocks the receptors and significantly reduces the tumor-to-muscle ratios at 1-hour post-injection to 0.81 and 0.31, respectively. In correlation with in vitro study, 99mTcN-[6] and 99mTcN-[7] visualize the tumor site in U-87 MG glioma xenografted nude mice and display the tumor-to-muscle ratios of 7.05 and 6.03.

Polyethyleneglycol-serine nanoparticles as a novel antidote for organophosphate poisoning: synthesis, characterization, in vitro and in vivo studies.

Acute organophosphate pesticide poisoning causes considerable worldwide mortality and morbidity. In this study, serine was attached to the polyethylene glycol-bisaldehyde (PEG) as a novel antidote for diazinon (DZ) poisoning. Serine and PEG were conjugated with a reductive amination reaction. PEG-serine NPs (PEG-NPs) were purified and their structure was analyzed by 1H NMR, 13 C NMR, IR, and particle size was determined via dynamic light scattering. In vitro studies, including hemolysis assay and cytotoxicity on SK-BR-3 and HFFF2 cell lines, were performed. In vivo studies of PEG-NPs were evaluated on DZ-exposed mice. PEG-NPs were administered (i.p.) 20 min after a single dose of DZ (LD50; 166 mg/kg). Atropine (20 mg/kg, i.p.) with pralidoxime (20 mg/kg, i.p.) was used as the standard therapy compared to PEG-NPs. NMR and IR data confirmed that the conjugation of PEG to serine occurred successfully. The average NP size was 22.1 ± 1.8 nm. The hemolysis of the PEG-NPs was calculated at 0.867%, 50% inhibitory concentration (IC50) was calculated 36 ± 4.5, and 41 ± 3.4 mg/mL on SK-BR-3 and HFFF2 cell lines, respectively. Percentage of surviving significantly improved by 12.5, 25, and 25% through the usage of PEG-NPs at doses of 100, 200, and 400 mg/kg, respectively, when compared with the DZ group. Cholinesterase enzyme activity, lipid peroxidation, and mitochondrial function significantly improved through PEG-NPs when compared with the DZ group. PEG conjugated serine is very biocompatible with low toxicity and can reduce the acute toxicity of DZ as a new combination therapy.

Application of emetine in SARS-CoV-2 treatment: regulation of p38 MAPK signaling pathway for preventing emetine-induced cardiac complications.

Emetine is one of the most highly potent anti-SARS-CoV-2 agents ever identified. In addition to having strong anti-SARS-CoV-2 activities, emetine has other valuable therapeutic effects such as strong anti-inflammatory and anti-arterial pulmonary hypertension (APH) properties, which are suitable for the treatment of COVID-19. Its proper concomitant therapeutic effect has led researchers to test this compound in clinical trials to combat COVID-19. However, due to the risks of cardiac complications, very low doses of emetine have been used in different studies, which may not have significant therapeutic effects. The p38 MAPK signaling pathway is strongly highlighted as an important operator in cardiac cellular damages such as disruption of cardiac fibroblast function and myopathy/cardiomyopathy. Inhibition of this pathway by appropriate inhibitors has also been considered by scientists as a promising strategy for the treatment of fatal host-related hyper-inflammatory immune responses following SARS-CoV-2 infection. Although remarkable stimulatory effects of emetine on activation of the p38 MAPK pathway have been reported in recent studies and strong evidence suggests that this pathway plays an effective role in the emetine's toxicities, it has not been discussed yet that emetine induced cellular cardiac complications may be due to the activation of this critical pathway. Considering these points could lead to the finding of strategies for applying the valuable potential of emetine in the treatment of COVID-19 at low risks.

Towards the First Multiepitope Vaccine Candidate against Neospora caninum in Mouse Model: Immunoinformatic Standpoint.

Neospora caninum is an economically significant parasite among livestock, particularly in dairy cattle herds, causing storm abortions. Vaccination seems necessary to limit the infection and its harsh consequences. This is the first steps towards developing a multiepitope vaccine candidate against N. caninum using in silico approaches. High-ranked mouse MHC-binding and shared linear B-cell epitopes from six proteins (SRS2, MIC3, MIC6, GRA1, IMP-1, and profilin) as well as IFN-γ-inducing epitopes (from SAG1) were predicted, screened, and connected together through appropriate linkers. Finally, RS-09 protein (TLR4 agonist) and histidine tag were added to N- and C-terminal of the vaccine sequence, yielding 486 residues in length. Physicochemical properties showed a stable (instability index: 27.23), highly soluble, antigenic (VaxiJen score: 0.9554), and nonallergenic candidate. Secondary structure of the multiepitope protein included 58.85% random coil, 20.99% extended strand, and 20.16% alpha helix. Also, the tertiary structure was predicted, and further analyses validated a stable interaction between the vaccine model and mouse TLR4 (binding score: -1261.6). Virtual simulation of immune profile demonstrated potently stimulated humoral (IgG+IgM) and cell-mediated (IFN-γ) responses upon multiepitope vaccine injection. Altogether, a potentially immunogenic vaccine candidate was developed using several N. caninum proteins, with the capability to elicit IFN-γ upsurge and other components of cellular immunity, and can be used in prophylactic purposes against neosporosis.

Novel Molecular Targets and Mechanisms for Neuroprotective Modulation in Neurodegenerative Disorders.

BACKGROUND: Neuronal death underlies the symptoms of several human neurological disorders, including Alzheimer's, Parkinson's and Huntington's diseases, and amyotrophic lateral sclerosis and their precise pathophysiology have not yet been elucidated. According to various studies, the prohibition is the best therapy with neuroprotective approaches, which are advanced and safe methods. METHODS: This review summarizes some of the already-known and newly emerged neuroprotective targets and strategies and their experimental effects have also been reported. Accordingly, literature was studied from 2000 to 2021, and appropriate articles were searched in Google Scholar and Scopus with the keywords given in the keywords section of the current review. RESULTS: Lewy bodies are the histopathologic characteristics of neurodegenerative disorders and are protein-rich intracellular deposits in which Alpha-synuclein is its major protein. Alphasynuclein's toxic potential provides a compelling rationale for therapeutic strategies aimed at decreasing its burden in neuronal cells through numerous pathways, including ubiquitin-proteasome system and autophagy-lysosome pathway, proteolytic breakdown via cathepsin D, kallikrein-6 (neurosin), calpain-1 or MMP9, heat shock proteins, and proteolysis targeting chimera which consists of a target protein-ligand and an E3 ubiquitin ligase (E3) followed by target protein ubiquitination (PROTACs). Other targets that have been noticed recently are the mutant huntingtin, tau proteins and glycogen synthase kinase 3ß; their accumulation proceeds extensive neuronal damage and up to the minute approach such as proteolysis targeting chimera promotes its degradation in cells. Various studies demonstrated that Mendelian gene mutations can result in neurodegenerative diseases. An additional target that has gained much interest is epigenetics, such as mutation, phosphodiesterase, RNA binding proteins and Nuclear respiratory factor 1. CONCLUSION: The novel molecular targets and new strategies compiled and introduced here can be used by scientists to design and discover more efficient small molecule drugs against neurodegenerative diseases. And also, the genes in which their mutations can lead to the α-synuclein aggregation or accumulation have been discussed and considered a valuable information on epigenetics in dementia.

Papaverine, a promising therapeutic agent for the treatment of COVID-19 patients with underlying cardiovascular diseases (CVDs).

The causative agent of coronavirus disease-2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), enters the host cells via an angiotensin-converting enzyme 2 (ACE2)-mediated endocytosis-dependent manner. Because ACE2 is highly expressed in the heart, SARS-CoV-2 can severely infect heart tissue and arteries, causing acute and chronic damage to the cardiovascular system. Therefore, special attention should be paid to finding appropriate agents to protect this vital system during COVID-19 treatment. Papaverine is a unique vasodilator alkaloid that is clinically used in the treatment of vasospasm. Interestingly, this compound has potent and direct effects on a wide range of viruses, and could also prevent viral exploitation mechanisms of the host cell facilities by inhibiting some cellular signaling pathways such as p38 MAPK. This pathway was recently introduced as a promising target for the treatment of COVID-19. Papaverine also has anti-inflammatory effects which is useful in combating the hyper-inflammatory phase of the COVID-19. Unlike some medications that have severe dosage-restrictions in the treatment of COVID-19 due to cardiac side effects, papaverine is recommended for use in many heart disorders. The ability of papaverine to treat COVID-19 has become more promising when the results of some extensive screenings showed the strong ability of this compound to inhibit the cytopathic effects of SARS-CoV-2 with EC50 of 1.1 µM. Having several therapeutic effects along with desired safety profile raises this hypothesis that papaverine could be a promising compound for the suppression of SARS-CoV-2 and prevention of ischemia/vasoconstriction-related complications in COVID-19 disease, especially in patients with underlying cardiovascular diseases (CVDs).

Designing a novel multiepitope peptide vaccine against melanoma using immunoinformatics approach.

Malignant melanoma is the most aggressive and life-threaten skin cancer. Nowadays, the prevention and treatment of melanoma are challenging areas for researchers and physicians. Therefore, we implemented an in silico-based approach to design a multi-epitope peptide vaccine for melanoma. This approach consists of immunoinformatics, molecular docking, and dynamic stimulation assessments to identify potent targets. Three most immunogenic melanoma proteins; NEYSO-1, gp-100, and MART-1were considered to predict immunodominant B and T cell epitopes. The prioritized epitopes had significant potential to induce strong humoral and cellular immunity and INF-γ responses without the possibility of allergenicity. To enhance the immunogenic properties of the vaccine, we used adjuvants HBHA, the helper epitope of PADRE, and three segments of the helper epitope from TTFrC. To design the final vaccine construct, appropriate linkers are used to join immunogenicscreened-epitopes and also the adjuvants. The physicochemical and immunological properties of the vaccine were evaluated.The designed-vaccine construct was docked to TLR4 to visualize the complex affinity and then conformational dynamics simulation was used to analyze time-dependent interaction behavior. In silico cloning demonstrated that the vaccine can be efficiently expressed in E.coli. Therefore, the designed vaccine might have the ability to induce humoral and cellular immune responses against melanoma cancer antigens. This vaccine has a high-quality structure and suitable characteristics such as high stability, solubility, and a high potential for expression in a prokaryotic system. However, these results need the experimental study to ensure the immunogenicity and safety profile of the melanoma candidate vaccine construct.

Engineering a multi-epitope vaccine candidate against Leishmania infantum using comprehensive Immunoinformatics methods.

Visceral leishmaniasis (VL) is a severe disease with particular endemicity in over 80 countries worldwide. There is no approved human vaccine against VL in the market. This study was aimed at designing and evaluation of a multimeric vaccine candidate against Leishmania infantum through utilization of helper T lymphocyte (HTL) and cytotoxic T lymphocyte (CTL) immunodominant proteins from histone H1, KMP11, LACK and LeIF antigens. Top-ranked mouse MHC-I, MHC-II binders and CTL epitopes were predicted and joined together via spacers. Also, a TLR-4 agonist (RS-09 synthetic protein) and His-tag were added to the N- and C-terminal of the vaccine sequence, respectively. The final chimeric vaccine had a length of 184 amino acids with a molecular weight of 18.99 kDa. Physico-chemical features showed a soluble, highly-antigenic and non-allergenic candidate. Secondary and tertiary structures were predicted, and subsequent analyses confirmed the construct stability that was capable to properly interact with TLR-4/MD2 receptor. Immunoinformatics simulation displayed potent stimulation of T cell immune responses, with particular rise in IFN-γ, upon vaccination with the proposed multi-epitope candidate. In conclusion, immunoinformatics data demonstrated a highly antigenic vaccine candidate in mouse, which could develop considerable levels clearance mechanisms and other components of cellular immune profile, and can be directed for VL prophylactic purposes. Supplementary Information: The online version contains supplementary material available at 10.1007/s11756-021-00934-3.

Therapeutic potential of chelerythrine as a multi-purpose adjuvant for the treatment of COVID-19.

Multifunctional nature of phytochemicals and their chemical diversity has attracted attention to develop leads originated from nature to fight COVID-19. Pharmacological activities of chelerythrine and its congeners have been studied and reported in the literature. This compound simultaneously has two key therapeutic effects for the treatment of COVID-19, antiviral and anti-inflammatory activities. Chelerythrine can prevent hyper-inflammatory immune response through regulating critical signaling pathways involved in SARS-CoV-2 infection, such as alteration in Nrf2, NF-κB, and p38 MAPK activities. In addition, chelerythrine has a strong protein kinase C-α/-ß inhibitory activity suitable for cerebral vasospasm prevention and eryptosis reduction, as well as beneficial effects in suppressing pulmonary inflammation and fibrosis. In terms of antiviral activity, chelerythrine can fight with SARS-CoV-2 through various mechanisms, such as direct-acting mechanism, viral RNA-intercalation, and regulation of host-based antiviral targets. Although chelerythrine is toxic in vitro, the in vivo toxicity is significantly reduced due to its structural conversion to alkanolamine. Its multifunctional action makes chelerythrine a prominent compound for the treatment of COVID-19. Considering precautions related to the toxicity at higher doses, it is expected that this compound is useful in combination with proper antivirals to reduce the severity of COVID-19 symptoms.

Design, synthesis and biological evaluation of naphthalene-derived (arylalkyl)azoles containing heterocyclic linkers as new anticonvulsants: A comprehensive in silico, in vitro, and in vivo study.

In continuation of our research to find strong and safe anticonvulsant agents, a number of (arylalkyl)azoles (AAAs) containing naphthylthiazole and naphthyloxazole scaffolds were designed and synthesized. The in vivo anticonvulsant evaluations in BALB/c mice revealed that some of them had significant anticonvulsant activity in both maximal electroshock (MES) and pentylenetetrazole (PTZ) models of epilepsy. The best profile of activity was observed with compounds containing imidazole and triazole rings (C1, C6, G1, and G6). In particular, imidazolylmethyl-thiazole C1 with median effective dose (ED50)= 7.9 mg/kg in the MES test, ED50= 27.9 mg/kg in PTZ test, and without any sign of neurotoxicity (in the rotarod test, 100 mg/kg) was the most promising compound. The patch-clamp recording was performed to study the mechanism of action of the representative compound C1 on hippocampal dentate gyrus (DG) cells. The results did not confirm any modulatory effect of C1 on the voltage-gated ion channels (VGICs) or GABAA agonism, but suggested a significant reduction of excitatory postsynaptic currents (EPSCs) frequency on hippocampal DG neurons. Sub-acute toxicity studies revealed that administration of the most active compounds (C1, C6, G1, and G6) at 100 mg/kg bw/day for two weeks did not result in any mortality or significant toxicity as evaluated by assessment of biochemical markers such as lipid peroxidation, intracellular glutathione, total antioxidant capacity, histopathological changes, and mitochondrial functions. Other pharmacological aspects of compounds including mechanistic and ADME properties were investigated computationally and/or experimentally. Molecular docking on the NMDA and AMPA targets suggested that the introduction of the heterocyclic ring in the middle of AAAs significantly affects the affinity of the compounds. The obtained results totally demonstrated that the prototype compound C1 can be considered as a new lead for the development of anticonvulsant agents.

Synthesis, in silico, in vitro and in vivo evaluations of isatin aroylhydrazones as highly potent anticonvulsant agents.

In this study, a series of new isatin aroylhydrazones (5a-e and 6a-e) was synthesized and evaluated for their anticonvulsant activities. The (Z)-configuration of compounds was confirmed by 1H NMR. In vivo studies using maximal electroshock (MES) and pentylenetetrazole (PTZ) models of epilepsy in mice revealed that while most of compounds had no effect on chemically-induced seizures at the higher dose of 100 mg/kg but showed significant protection against electrically-induced seizures at the lower dose of 5 mg/kg. Certainly, N-methyl analogs 6a and 6e were found to be the most effective compounds, displaying 100% protection at the dose of 5 mg/kg. Protein binding and lipophilicity(logP) of the selected compounds (6a and 6e) were also determined experimentally. In silico evaluations of title compounds showed acceptable ADME parameters, and drug-likeness properties. Distance mapping and docking of the selected compounds with different targets proposed the possible action of them on VGSCs and GABAA receptors. The cytotoxicity evaluation of 6a and 6e against SH-SY5Y and Hep-G2 cell lines indicated safety profile of compounds on the neuronal and hepatic cells.

Development of a chimeric vaccine candidate based on Toxoplasma gondii major surface antigen 1 and apicoplast proteins using comprehensive immunoinformatics approaches.

This study was aimed at designing and evaluation of a multimeric vaccine construct against Toxoplasma gondii via utilization of SAG1 along with apicoplast ribosomal proteins (S2, S5 and L11). Top-ranked MHC-I and MHC-II binding as well as shared, immunodominant linear B-cell epitopes were predicted and joined together via appropriate linkers. Also, TLR-4 agonist (RS-09 synthetic protein) and His-tag were added to the N- and C-terminal of the vaccine sequence. The finally-engineered chimeric vaccine had a length of 291 amino acids with a molecular weight of 31.46 kDa. Physico-chemical features showed a soluble, highly-antigenic and non-allergenic candidate. Secondary and tertiary structures were predicted, and subsequent analyses confirmed the construct stability that was capable to properly interact with human TLR-4. Immunoinformatics-based simulation displayed potent stimulation of T- and B-cell mediated immune responses upon vaccination with the proposed multi-epitope candidate. In conclusion, obtained information demonstrated a highly antigenic vaccine candidate, which could develop high levels of IFN-γ and other components of cellular immune profile, and can be directed for toxoplasmosis prophylactic purposes.