• Bulletin of the Korean Chemical Society
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• v.29 no.11
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• pp.2221-2226
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• 2008

• Journal of Integrative Natural Science
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• v.4 no.4
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• pp.273-277
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• 2011

It's a threat for the public health that H1N1 (Influenza virus A) causes disease and transmits among humans. WHO (world health organization) declared that the infections caused by the new strain had reached pandemic proportions. The approved neuraminidase inhibitors (Zanamivir and Oseltamivir) and related investigative drug (BCX-1812) are potent, specific inhibitors of influenza A and B viruses. These drugs are highly effective to prevent influenza A and B infections. Early therapeutic use reduces illness duration and respiratory complications. Recently, we found one of the potent inhibitor of erystagallin A ($IC_{50}$ of 2.04 ${\mu}M$) for neuraminidase target, this inhibitor shows most similar structure to its natural substrate, sialic acid. Therefore, we chose 1l7f to get the receptor structure for docking study among many crystal structures. A docking study has been performed in Surflex-Dock module in SYBYL 8.1. In the present study, we attempt to compare the docking studies of pterocarpin and erystagallin A with neuraminidase receptor structure. In the previous report, the methoxy group of pterocarpin had H-bonding with Arg residues. The present docking results for erystagallin A showed the backbone of hydroxyl group shows significant H-bonding interactions with Arg152 and Arg292. The results showed that erystagallin A interacts more favorably with distinctive binding site rather than original active site. Therefore, we tried to reveal plausible binding mode and important amino acid for this inhibitor using docking and site id search calculations of Sybyl. The results obtained from this work may be utilized to design novel inhibitors for neuraminidase.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.1-6
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• 2023

Dendranthema zawadskii is a one of the popular plants as native in South Korea. In this study, linarin was isolated and purified using silica-gel, Diaion, and Sephadex LH-20 from the aerial parts of D. zawadskii. The chemical structure was completely identified through spectroscopic data including 1D, 2D nucleic magnetic resonance, and HRFABMS. Furthermore, linarin inhibited the bacterial neuraminidase (BNA) activity with 13.5 μM of IC₅₀ dose-dependently. Through the enzyme kinetic experiments, linarin as BNA inhibitor exhibited a typical noncompetitive inhibition mode which K_m was contestant and V_max decreased as the concentration of the inhibitor increased. It was further identified that the inhibition constant was 16.0 μM. Linarin was the most abundance metabolite in the aerial part of D. zawadskii extract by UHPLC-TOF/MS analysis. Therefore, D. zawadskii and its main component are expected that it can be effectively used for the infection and inflammation caused by bacteria.

• Mycobiology
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• v.40 no.2
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• pp.142-144
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• 2012

During the search for neuraminidase inhibitors from medicinal fungi, we found that the culture broth of Phellinus linteus exhibited potent inhibitory activity. Solvent partition, Sephadex LH-20 column chromatography, and high-performance liquid chromatography (HPLC) were performed for purification of two active substances from the culture broth. According to $^1H$ NMR measurements and comparison of HPLC retention times with those of authentic compounds, their chemical structures were identified as hispidin and hypholomine B. Compounds (hispidin) 1 and 2 (hypholomine B) inhibited neuraminidase, with $IC_{50}$ values of 13.1 and 0.03 ${\mu}M$, respectively.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.212-216
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• 2015

Oseltamivir, also known as Tamifu, is an inhibitor of neuraminidase protein which plays an essential role in proliferation and replication of influenza virus. Binding to the active site of neuraminidase, the oseltamivir prevents the protein from enzyme reaction. Conformational change of the protein(neuraminidase) should be accompanied by the enzyme reaction, but the drug inhibits the protein to deform. In this study, we examine the influence of oseltamivir on protein's conformational change in the structural and mechanical point of view. Finite element analysis of the protein can be an useful approach to investigate the influence of oseltamivir on the deformation of a protein. We suggest the finite element based protein model, and then perform the linear static analysis with the displacement loading condition based on the first two largest motion which can be obtained from the normal mode analysis. The results show that it takes more energy to change shape of the protein with an oseltamivir attached than the protein without an oseltamivir.

• Mycobiology
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• v.42 no.2
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• pp.189-192
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• 2014

During a search for neuraminidase inhibitors derived from medicinal fungi, we found that the fermentation broth of Phellinus linteus exhibited potent neuraminidase inhibitory activity. Through bioassay-guided fractionation, two active compounds were purified from the ethyl acetate-soluble portion of the fermentation broth of P. linteus. These structures were identified as inotilone (1) and 4-(3,4-dihydroxyphenyl)-3-buten-2-one (2) by spectroscopic methods. Compounds 1 and 2 inhibited H1N1 neuraminidase activity with $IC_{50}$ values of 29.1 and 125.6 $125.6{\mu}M$, respectively, in a dose-dependent manner. They also exhibited an antiviral effect in a viral cytopathic effect reduction assay using MDCK cells. These results suggest that compounds 1 and 2 from the culture broth of P. linteus would be good candidates for the prevention and therapeutic strategies towards viral infections.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1575-1577
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• 2004

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.778-782
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• 2003

In the course of screening anti-influenza agents from natural products, four neuraminidase inhibitors were isolated from the methanol extract of mushroom Microphorus affinis by purification using solvent partition, silica gel column chromatography, Sephadex LH-20, and semi-preparative HPLC. The chemical structures of these compounds were identified as ${\alpha}-lupeol$, methyl linoleate, methyl palmitate, and methyl oleate by means of spectral data including GC-MS, $^1H-,\;and\;^{13}C-NMR\;with\;IC_{50}$ values of 5.65, 7.07, 7.12, and $7.52\;\mu\textrm{M}$, respectively. They did not inhibit other glycosidases such as glucosidase, mannosidase, and galactosidase, indicating that they were relatively specific inhibitors of neuraminidase. The relationship between the fatty acid structure and inhibitory activity was investigated. The result showed that, in the case of an aliphatic linear hydrocarbon skeleton, at least one carboxyl (presumably any carbonyl) moiety and sixteen carbons were the necessary requirements for potent inhibition, whereas saturated, unsaturated, free, and ester forms did not have any significant effect on the activity.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.367-374
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• 2003

In the course of screening neuraminidase inhibitors from herbal medicines, Reynoutria elliptica exhibited high inhibitory activity. Four active compounds were isolated from the ethyl acetate soluble fraction by consecutive purification using sillica gel, Sephadex LH-20 chromatography, and recrystallization. The chemical structures of these compounds were identified as 1,3,8-trihydroxy-6-methylanthraquinone (emodin) 1,8-dihydroxy-3-methoxy-6-methylanthraquinone (emodin 3-methyl ether; physcion), 1,3,8-trihydroxy-6-hydoxymethylanthraquinone ($\omega$-hydroxyemodin), and 3,5,4 -trihydroxystilbene (trans-resvertrol) by spectral data including MS, $^1 H-, and ^{13}C-NMR. The IC_{50}$ values of emodin, emodin 3-methyl ether, $\omega$-hydroxyemodin, and trans-resvertrol were 2.81, 74.07, 10.49, and 8.77 $\mu$M, respectively. They did not inhibit other glycosidase such as glucosidase, mannosidase, and galactosidase, indicating that they were relatively specific inhibitors of neuraminidase.

• Mycobiology
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• v.47 no.2
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• pp.256-260
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• 2019

Neuraminidase (NA) cleaves the glycosidic bond linkages of sialic acids to release the mature virions from infected cells and has been an attractive therapeutic target for anti-influenza agents. In our ongoing investigation of NA inhibitors in mushroom extracts, we found that the extract the fruiting body of Glaziella splendens potently inhibited neuraminidase. The fruiting bodies of G. splendens were extracted and partitioned successively with hexane, ethyl acetate, and butanol. The ethyl acetate soluble-layer was subjected to silica gel and Sephadex LH-20 column chromatographies, and MPLC to obtain five compounds (1-5). Their structures were determined by spectroscopic methods. NA inhibitory activity of these compounds was evaluated using NAs from recombinant rvH1N1, H3N2, and H5N1 influenza A viruses. One compound (1) was elucidated as a new azaphilone derivative, and four compounds (2-5) were identified as entonaemin A, comazaphilone D, rubiginosin A, and entonaemin B, respectively. Compounds 3 and 4 showed considerable inhibitory activity against three types of neuraminidases with the $IC_{50}$ values of 30.9, 41.8, and $35.7{\mu}M$ for 3 and 46.5, 50.4, and $29.9{\mu}M$ for 4, respectively. This study reveals that the fruiting bodies of G. splendens possess azaphilone derivatives with the NA inhibitory activity. This is the first report on the isolation of neuraminidase inhibitors from the fruiting bodies of G. splendens.