Neuraminidase Inhibitory Activity Research Articles

Novel Anti-Viral Properties of the Herbal Extract of Davallia mariesii against Influenza A Virus.

Gu-Sui-Bu, the dried rhizome of Davallia mariesii, is a traditional Chinese herbal remedy with a significant history of treating osteoporosis and inflammatory conditions. However, its potential as an anti-influenza agent and its underlying mechanisms of action remain unexplored. To obtain a more potent extract from D. mariesii and gain insights into its mechanism of action against influenza A virus (IAV), we utilized a partitioning process involving organic solvents and water, resulting in the isolation of butanolic subfractions of the D. mariesii extract (DMBE). DMBE exhibited a broad anti-viral spectrum, effectively inhibiting IAV, with an EC50 of 24.32 ± 6.19 µg/mL and a selectivity index of 6.05. We subsequently conducted a series of in vitro assays to evaluate the antiviral effects of DMBE and to uncover its mechanisms of action. DMBE was found to inhibit IAV during the early stages of infection by hindering the attachment of the virus onto and its penetration into host cells. Importantly, DMBE was observed to hinder IAV-mediated cell-cell fusion. It also inhibited neuraminidase activity, plaque size, and the expression levels of phospho-AKT. In summary, this study provides evidence for the effectiveness of D. mariesii as a complementary and alternative herbal remedy against IAV. Specifically, our data highlight DMBE's capabilities in inhibiting viral entry and the release of virions.

Secondary Metabolites from the Coral-Derived Fungus Aspergillus austwickii SCSIO41227 with Pancreatic Lipase and Neuraminidase Inhibitory Activities.

The coral-derived fungus Aspergillus austwickii SCSIO41227 from Beibu Gulf yielded four previously uncharacterized compounds, namely asperpentenones B-E (1-4), along with twelve known compounds (5-16). Their structures were elucidated using HRESIMS and NMR (1H and 13C NMR, HSQC, HMBC), among which the stereo-structure of compounds 1-3 was determined by calculated ECD. Furthermore, compounds 1-16 were evaluated in terms of their enzyme (acetylcholinesterase (AChE), pancreatic lipase (PL), and neuraminidase (NA)) inhibitory activities. These bioassay results revealed that compounds 2 and 14 exerted noticeable NA inhibitory effects, with IC50 values of 31.28 and 73.64 μM, respectively. In addition, compound 3 exhibited a weak inhibitory effect against PL. Furthermore, these compounds showed the potential of inhibiting enzymes in silico docking analysis to demonstrate the interactions between compounds and proteins.

The neuraminidase activity of influenza A virus determines the strain-specific sensitivity to neutralization by respiratory mucus.

The respiratory tract of humans is constantly exposed to potentially harmful agents, such as small particles or pathogens, and thus requires protective measures. Respiratory mucus that lines the airway epithelia plays a major role in the prevention of viral infections by limiting the mobility of viruses, allowing subsequent mucociliary clearance. Understanding the interplay between respiratory mucus and viruses can help elucidate host and virus characteristics that enable the initiation of infection. Here, we tested a panel of primary influenza A viruses of avian or human origin for their sensitivity to mucus derived from primary human airway cultures and found that differences between virus strains can be mapped to viral neuraminidase activity. We also show that binding of influenza A viruses to decoy receptors on highly glycosylated mucus components constitutes the major inhibitory function of mucus against influenza A viruses.

Bisabolane-type sesquiterpenoids and bacillibactin from the marine-derived fungus Aspergillus sydowii SCSIO 41041 and their enzyme inhibiting activity

Twelve compounds, including eleven bisabolane-type sesquiterpenoids (1 − 11), and one bacillibactin (12) were identified from marine-derived fungus Aspergillus sydowii SCSIO 41041 isolated from Creseis acicula. The chemical structures were elucidated by the basis of spectroscopic evidences, including HRESIMS, NMR and optical rotation. Biologically, all compounds were evaluated for their acetyl cholin-esterase (AChE) enzyme, pancreatic lipase (PL) enzyme, neuraminidase (NA) and phosphodiesterase 4 (PDE4) inhibitory activities. Compound 12 displayed significant inhibitory activity against neuraminidase (NA) with an IC50 value of 24.0 μM, which was equivalent to the positive drug oseltamivir phosphate (IC50 value of 20.0 μM). And the NA inhibitory activity was confirmed by molecular docking analysis.

Comparative Molecular Field Analysis (CoMFA), Molecular Docking and ADMET Study on Thiazolidine-4-carboxylic acid Derivatives as New Neuraminidase Inhibitors

The objective of this research was to create a 3D-QSAR CoMFA model for a set of twenty-five neuraminidase inhibitors containing thiazolidine-4-carboxylic acid derivatives and to identify a new potent neuraminidase inhibitor for the treatment of influenza. The statistical parameters of the generated model are excellent: Q2 = 0.708, R2 = 0.997. The external validation results were (r2 0 = 0.922, K= 1.016, R2 pred = 0.674, r2 m= 0.778) indicating that the constructed model has good predictive power. Based on the contour map of the CoMFA model, we were able to propose six novel compounds with higher neuraminidase inhibitory activity than the most active compound. The six proposed molecules were submitted to molecular docking to analyse the bindings formed between the newly designed molecules and the neuraminidase. All of the proposed molecules were found to be more stable on the active site of neuraminidase than the reference molecule (1SJ). SwissADME was used to estimate the pharmacokinetic properties of each proposed molecule, while ProToxII and VEGA QSAR were used to investigate any potential toxicity. Finally, a reaction mechanism for synthesizing the six proposed compounds was described, which could potentially be explored further in the search for novel neuraminidase inhibitors. In conclusion, this study has identified potential candidates for the development of more effective neuraminidase inhibitors for the treatment of influenza.

Human anti-N1 monoclonal antibodies elicited by pandemic H1N1 virus infection broadly inhibit HxN1 viruses in vitro and in vivo

Neuraminidase (NA) is one of the two influenza virus surface glycoproteins, and antibodies that target it are an independent correlate of protection. However, our current understanding of NA antigenicity is incomplete. Here, we describe human monoclonal antibodies (mAbs) from a patient with a pandemic H1N1 virus infection in 2009. Two mAbs exhibited broad reactivity and inhibited NA enzyme activity of seasonal H1N1 viruses circulating before and after 2009, as well as viruses with avian or swine N1s. The mAbs provided robust protection from lethal challenge with human H1N1 and avian H5N1 viruses in mice, and both target an epitope on the lateral face of NA. In summary, we identified two broadly protective NA antibodies that share a novel epitope, inhibited NA activity, and provide protection against virus challenge in mice. Our work reaffirms that NA should be included as a target in future broadly protective or universal influenza virus vaccines.

Zanamivir infusion improves endothelial function and reduces arterial stiffness in diabetic mice

Endothelial dysfunction and arterial stiffening are consistently manifested in type 2 diabetes (T2D) and contribute to the development of cardiovascular disease. Consequently, there is an urgent need to identify novel therapies that improve endothelial function and reduce arterial stiffness in T2D. Endothelial dysfunction is characterized by a reduced capacity of the endothelium to induce vasodilation. Physiologically, this is evident as an impairment in flow-mediated dilation, a process in which the endothelial glycocalyx participates in the mechanosensation and mechanotransduction of shear that leads to the production of the vasodilator nitric oxide. Nitric oxide, in turn, has also been shown to be a potent regulator of vascular wall homeostasis, including arterial stiffness. In T2D, circulating neuraminidase activity is increased and implicated in glycocalyx degradation and endothelial dysfunction. Accordingly, we hypothesized that inhibition of neuraminidase activity would enhance endothelial function and reduce arterial stiffness in T2D. We tested this hypothesis in diabetic db/db mice infused with zanamivir (n=10) or vehicle control (n=10) for 4 weeks via subcutaneously implanted osmotic mini pumps. We chose to use the FDA approved neuraminidase inhibitor zanamivir to increase the translatability of our study. Treatment with zanamivir did not affect body weight or blood pressure. Nonetheless, it improved flow-mediated dilation in isolated mesenteric arteries assessed using pressure myography, with no associated changes in endothelium-independent vasodilation. Zanamivir also reduced stiffness in isolated mesenteric and femoral arteries, as well as aortic stiffness as assessed in vivo via pulse wave velocity and ex vivo via atomic force microscopy. These results indicate that zanamivir is a potential therapeutic to ameliorate vascular dysfunction in T2D. National Institutes of Health grant: R01HL153264 to LM-L and JP This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Structure-based drug design, molecular dynamics simulation, ADMET, and quantum chemical studies of some thiazolinones targeting influenza neuraminidase

The genetic mutability of the influenza virus leads to the existence of drug-resistant strains which is dangerous, particularly with the lingering coronavirus disease (COVID-19). This necessitated the need for the search and discovery of more potential anti-influenza agents to avert future outbreaks. In furtherance of our previous in-silico studies on 5-benzyl-4-thiazolinones as anti-influenza neuraminidase (NA) inhibitors, molecule 11 was selected as the template scaffold for the structure-based drug design due to its good binding, pharmacokinetic profiling, and better NA inhibitory activity. As such, eighteen (18) new molecules (11a-r) were designed with better MolDock scores as compared with the template scaffold and the zanamivir reference drug. However, the dynamic stability of molecule 11a in the binding cavity of the NA target (3TI5) showed water-mediated hydrogen and hydrophobic bondings with the active residues such as Arg118, Ile149, Arg152, Ile222, Trp403, and Ile427 after the MD simulation for 100 ns. The drug-likeness and ADMET assessment of all designed molecules predicted non-violation of the stipulated thresholds of Lipinski’s rule and good pharmacokinetic properties respectively. In addition, the quantum chemical calculations also suggested the significant chemical reactivity of molecules with their smaller band energy gap, high electrophilicity, high softness, and low hardness. The results obtained in this study proposed a reliable in-silico viewpoint for anti-influenza drug discovery and development.Communicated by Ramaswamy H. Sarma

Ferulic Acid: A Review of Pharmacology, Toxicology, and Therapeutic Effects on Pulmonary Diseases.

Ferulic acid (FA), a prevalent dietary phytochemical, has many pharmacological effects, including anti-oxidation and anti-inflammation effects, and has been widely used in the pharmaceutical, food, and cosmetics industries. Many studies have shown that FA can significantly downregulate the expression of reactive oxygen species and activate nuclear factor erythroid-2-related factor-2/heme oxygenase-1 signaling, exerting anti-oxidative effects. The anti-inflammatory effect of FA is mainly related to the p38 mitogen-activated protein kinase and nuclear factor-kappaB signaling pathways. FA has demonstrated potential clinical applications in the treatment of pulmonary diseases. The transforming growth factor-β1/small mothers against decapentaplegic 3 signaling pathway can be blocked by FA, thereby alleviating pulmonary fibrosis. Moreover, in the context of asthma, the T helper cell 1/2 imbalance is restored by FA. Furthermore, FA ameliorates acute lung injury by inhibiting nuclear factor-kappaB and mitogen-activated protein kinase pathways via toll-like receptor 4, consequently decreasing the expression of downstream inflammatory mediators. Additionally, there is a moderate neuraminidase inhibitory activity showing a tendency to reduce the interleukin-8 level in response to influenza virus infections. Although the application of FA has broad prospects, more preclinical mechanism-based research should be carried out to test these applications in clinical settings. This review not only covers the literature on the pharmacological effects and mechanisms of FA, but also discusses the therapeutic role and toxicology of FA in several pulmonary diseases.

Design, synthesis and neuraminidase inhibitory activity of 4-methyl-5-(3-phenylacryloyl) thiazoles.

A series of 4-methyl-5-(3-phenylacryloyl)thiazoles based on chalcones were designed, synthesized and evaluated for their influenza neuraminidase (NA) inhibitory activity in vitro. A preliminary structure-activity relationship (SAR) analysis showed that thiazoles bearing amide had greater potency. It also showed that mono-hydroxyl group at 4-position on phenyl ring was more effective than other electron-releasing groups or electron-withdraw groups. Compounds A2 and A26 were more potent against NA with IC50 values of 8.2 ± 0.5μg/mL and 6.2 ± 1.4μg/mL, respectively. Molecular docking study demonstrated that thiazoles skeleton was benefit for the NA inhibitory activity.

Design, Synthesis, and Antiviral Evaluation of Sialic Acid Derivatives as Inhibitors of Newcastle Disease Virus Hemagglutinin-Neuraminidase: A Translational Study on Human Parainfluenza Viruses.

Global infections with viruses belonging to the Paramyxoviridae, such as Newcastle disease virus (NDV) or human parainfluenza viruses (hPIVs), pose a serious threat to animal and human health. NDV-HN and hPIVs-HN (HN hemagglutinin-neuraminidase) share a high degree of similarity in catalytic site structures; therefore, the development of an efficient experimental NDV host model (chicken) may be informative for evaluating the efficacy of hPIVs-HN inhibitors. As part of the broad research in pursuit of this goal and as an extension of our published work on antiviral drug development, we report here the biological results obtained with some newly synthesized C4- and C5-substituted 2,3-unsaturated sialic acid derivatives against NDV. All developed compounds showed high neuraminidase inhibitory activity (IC50 0.03-13 μM). Four molecules (9, 10, 23, 24) confirmed their high in vitro inhibitory activity, which caused a significant reduction of NDV infection in Vero cells, accompanied by very low toxicity.

Study on the Interaction between Silibinin and Neuraminidase.

Neuraminidase is a pathogenic protein of the avian influenza virus. Previous studies have shown that silibinin has the potential to inhibit neuraminidase activity. This study aims to explore the interaction between silibinin and neuraminidase and the effect of silibinin on the structure and activity of neuraminidase. In this study, two-dimensional fluorescence spectrum, three-dimensional fluorescence spectrometry, Uv-vis spectroscopy, and circular dichroism analysis were used. Silibinin alters the secondary structure of neuraminidase and inhibits the activity of neuraminidase. Silibinin can interact with neuraminidase and inhibit its activity.

Rapid detection of traditional Chinese medicine with neuraminidase inhibitory activities based on high-throughput and virtual screening strategy

BackgroundOseltamivir, a neuraminidase inhibitor (NAI), is the primary and first-line anti-influenza drug. In recent years, more and more oseltamivir resistant strains appeared frequently. PurposeTo identify anti-influenza candidates to overcome oseltamivir resistance from traditional Chinese medicine. MethodsHigh-throughput screening platform was used to screen candidates with oseltamivir sensitive and resistant neuraminidase (NA) inhibitory activities from traditional Chinese medicine (TCM) and in validation of potential active components in vitro. Molecular docking is used for virtual screening of TCM compound libraries and analysis of the molecular mechanism of active compounds. ResultsSix out of 188 TCM formula granules were screened out with good inhibitory activities in oseltamivir sensitive (H5N1) and resistant NA (H274Y mutant). A compound library containing 679 candidates in the above six plants were docked into binding pockets of H5N1 NA and its H274Y mutant. The results indicated that diverse structural types, including flavonoids glycosides, alkaloids, caffeoylquinic acid derivatives, etc. showed good docking scores on the two NAs. Furthermore, 10 representative compounds tested in vitro showed inhibitory activities in both oseltamivir sensitive and resistant NA. The docking simulations revealed that natural TCM molecules bind with NA in an absolute different mode compared with oseltamivir, which occupy the extra cavities adjacent to the active site of NA, thus might make them non-susceptible to be influenced by mutation around the active sites. ConclusionsThe combination of high-throughput screening and molecular docking can efficiently screen out candidates that have the potential to overcome oseltamivir resistance from TCM.

Structurally various p-terphenyls with neuraminidase inhibitory from a sponge derived fungus Aspergillus sp. SCSIO41315

Guided by Global Natural Products Social molecular networking, 14 new p-terphenyl derivatives, asperterphenyls A–N (1–14), together with 20 known p-terphenyl derivatives (15–34), were obtained from a sponge derived fungus Aspergillus sp. SCSIO41315. Among them, new compounds 2–8 and 15–17 were ten pairs of enantiomers. Comprehensive methods such as chiral-phase HPLC analysis, ECD calculations and X-ray diffraction analysis were applied to determine the absolute configurations. Asperterphenyls B (2) and C (3) represented the first reported natural p-terphenyl derivatives possessing a dicarboxylic acid system. Asperterphenyl A (1) displayed neuraminidase inhibitory activity with an IC50 value of 1.77 ± 0.53 µM and could efficiently inhibit infection of multiple strains of H1N1 with IC50 values from 0.67 ± 0.28 to 1.48 ± 0.60 µM through decreasing viral plaque formation in a dose-dependent manner, which suggested that asperterphenyl A (1) might be exploited as a potential antiviral compound in the pharmaceutical fields.

Rapid screening of neuraminidase inhibitors using an at-line nanofractionation platform involving parallel oseltamivir-sensitive/resistant neuraminidase bioassays

In this study, an advanced at-line nanofractionation based screening platform was developed to screen potential neuraminidase inhibitors (NAIs) from Lonicera japonica Thunb by involving two parallel bioassays, for determining both oseltamivir-sensitive neuraminidase (NAS) and oseltamivir-resistant neuraminidase (NAR) inhibitory activities. 20 potential NAIs with both NAS and NAR inhibitory effects were screened from Lonicera japonica Thunb and identified by mass spectrometer, including 11 phenolic acids, 8 flavonoids and one iridoid glycoside. The proposed at-line nanofractionation based screening platform for NAIs was also used to rapidly screen nine batches of water extracts of Lonicera japonica Thunb or its similar species. Clear differences in the number and content of active components were easily observed, demonstrating that the proposed method possesses great potential for the quality control of herb medicines.

Diapin®: A food supplement with diverse therapeutic potentials

Background and Aims: For many centuries herbs and spices have traditionally been used to treat or manage a variety of diseases. The formulation of food supplements containing single or multiple herbs or spices is now popular. These formulations provide biochemical, pharmacological and medicinal benefits due to their diverse phytochemical constituents. Methods: In the present study, Diapin® – a food supplement containing Olea europaea L. leaves extract, Cinnamomum cassia (L.) J. Presl stem extract, Nigella sativa L. seed oil, Cocos nucifera L. oil and vitamin D3 – dissolved in absolute ethanol was evaluated for α-amylase, α-glucosidase, acetylcholinesterase, elastase, neuraminidase, adenosine deaminase and arginase inhibitory activity. Results: The supplement strongly inhibited neuraminidase (IC50 = 0.272 ± 0.007 mg/mL), while adenosine deaminase, acetylcholinesterase, elastase and arginase were moderately inhibited (with an IC50 of 4.562 ± 0.052, 5.396 ± 0.563, 5.783 ± 0.058 and 6.800 ± 0.067 mg/mL respectively). The less inhibition activity was on α-amylase and α-glucosidase (IC50 = 9.593 ± 0.582 and 14.010 ± 2.280 mg/mL respectively). Conclusion: The pharmacological activities of Diapin® can be attributed to its opulent phytochemical composition. The present findings support the folkloric claim of Diapin® supplement having antidiabetic, anticancer, anti-inflammatory, antimicrobial, anti-ageing, and immune bolstering properties, in addition to the mitigation of Alzheimer’s disease and the alleviation of neurological dysfunction.

In vitro antiviral, antioxidant and in vivo antipyretic activity of three South Africa medicinal plants crude extracts

This study investigated anti-viral, antioxidant activity and anti-pyretic of crude extract from Artemisia afra, Artemisia absinthium and Pittiosporum viridflorum leaves. The crude extracts were prepared by maceration using aqueous, methanol and dichloromethane respectively. Antiviral studies were evaluated with influenza virus using Fluorescence based -Neuraminidase inhibitors. Antioxidant activities determined with DPPH, Nitric oxide, hydroxyl and super oxide anion radicals’ Anti-pyretic activities were evaluated using rats with yeast induced pyrexia. Total phenol, flavonoids, and pro-anthocyanin contents of the plants samples were evaluated using standard protocols. The crude extracts exhibited neuraminidase inhibitory activity against the influenza virus at different thresholds. Artemisia absinthium aqueous extract showed the best activity against A/Sydney/5/97. Whereas Artemisia afra methanol crude extract displayed highest antioxidant potential against the tested antioxidant parameters. All the crude extracts significantly reversed yeast induced pyrexia in rats, similar to paracetamol. Thus, they could serve as natural remedy for respiratory diseases such as Influenza.

Affinity ultrafiltration and UPLC-HR-Orbitrap-MS based screening of neuraminidase inhibitors from Angelica pubescens

Traditional Chinese medicine is a rich source of natural products and has a long history of use because of its remarkable clinical efficacy. In the present study, the chemical constitutes of Angelica pubescens were studied by ultra high performance liquid chromatography and high-resolution Orbitrap mass spectrometry (UPLC-HR-Orbitrap-MS). A total of 78 compounds were identified and the main composition were coumarins and phenolic acids. Then, the neuraminidase was incubated with extract of Angelica pubescens to screen the neuraminidase inhibitors by affinity ultrafiltration methods. As a result, 13 small molecules were discovered to interact with neuraminidase for the first time. In vitro neuraminidase inhibitory activity of the screened compounds and extract of Angelica pubescens was tested, and isochlorogenic acid C, isochlorogenic acid B, osthole, chlorogenic acid, xanthotoxin, phellopterin and imperatorin were proved to have this activity. In addition, molecular docking analysis was conducted to predict the potential docking position. This study may provide a reference for the medical substance basis in Angelica and the clinical usage of this drug.

New dihydrobenzoxanthone derivatives with bacterial neuraminidase inhibitory activity isolated from Artocarpus elasticus

Artocarpus elasticus is a popular fruit tree in the tropical regions. Primary screenings of methanol extracts of the root bark confirmed its potent inhibition of bacterial neuraminidase (BNA), which plays an essential role in the pathogenesis of many microbial diseases. Assessments of the responsible phytochemicals were conducted by isolating eight compounds (1–8) and two of them (6 and 8) were identified as new compounds. Among the isolates, the dihydrobenzoxanthones attained the highest BNA inhibition with IC50 values of 0.5 ∼ 3.9 µM. Further investigation of the inhibitory mechanism by Lineweaver-Burk plots revealed the phytochemicals to function as reversible noncompetitive inhibitors. Fluorescence quenching showed their binding affinities were highly correlated with their inhibitory potential dose-dependently. Molecular docking experiments suggested the dihydrobenzoxanthones (4 and 6) as noncompetitive inhibitors of BNA with unique interaction with Tyr435 of BNA in comparison with the mother flavonoid (7).

Multiple Neuraminidase Containing Influenza Virus-like Particle Vaccines Protect Mice from Avian and Human Influenza Virus Infection.

Avian influenza virus remains a threat for humans, and vaccines preventing both avian and human influenza virus infections are needed. Since virus-like particles (VLPs) expressing single neuraminidase (NA) subtype elicited limited heterosubtypic protection, VLPs expressing multiple NA subtypes would enhance the extent of heterosubtypic immunity. Here, we generated avian influenza VLP vaccines displaying H5 hemagglutinin (HA) antigen with or without avian NA subtypes (N1, N6, N8) in different combinations. BALB/c mice were intramuscularly immunized with the VLPs to evaluate the resulting homologous and heterosubtypic immunity upon challenge infections with the avian and human influenza viruses (A/H5N1, A/H3N2, A/H1N1). VLPs expressing H5 alone conferred homologous protection but not heterosubtypic protection, whereas VLPs co-expressing H5 and NA subtypes elicited both homologous and heterosubtypic protection against human influenza viruses in mice. We observed that VLP induced neuraminidase inhibitory activities (NAI), virus-neutralizing activity, and virus-specific antibody (IgG, IgA) responses were strongly correlated with the number of different NA subtype expressions on the VLPs. VLPs expressing all 3 NA subtypes resulted in the highest protection, indicated by the lowest lung titer, negligible body weight changes, and survival in immunized mice. These results suggest that expressing multiple neuraminidases in avian HA VLPs is a promising approach for developing a universal influenza A vaccine against avian and human influenza virus infections.