scholarly journals Fighting SARS-CoV-2 with green seaweed Ulva sp. extract: extraction protocol predetermines crude ulvan extract anti-SARS-CoV-2 inhibition properties in in vitro Vero-E6 cells assay

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12398
Author(s):  
Shai Shefer ◽  
Arthur Robin ◽  
Alexander Chemodanov ◽  
Mario Lebendiker ◽  
Robert Bostwick ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chemical Composition ◽  
Antiviral Activity ◽  
Cytopathic Effect ◽  
Average Molecular Weight ◽  
Ammonium Oxalate ◽  
Extraction Protocol ◽  
Reduction Assay ◽  
Green Seaweed

Due to the global COVID-19 pandemic, there is a need to screen for novel compounds with antiviral activity against SARS-COV-2. Here we compared chemical composition and the in vitro anti- SARS-COV-2 activity of two different Ulva sp. crude ulvan extracts: one obtained by an HCl-based and another one by ammonium oxalate-based (AOx) extraction protocols. The composition of the crude extracts was analyzed and their antiviral activity was assessed in a cytopathic effect reduction assay using Vero E6 cells. We show that the extraction protocols have a significant impact on the chemical composition, anti- SARS-COV-2 activity, and cytotoxicity of these ulvan extracts. The ulvan extract based on the AOx protocol had a higher average molecular weight, higher charge, and 11.3-fold higher antiviral activity than HCl-based extract. Our results strongly suggest that further bioassay-guided investigation into bioactivity of compounds found in Ulva sp. ulvan extracts could lead to the discovery of novel anti-SARS-CoV-2 antivirals.

scholarly journals Synthesis, characterization and evaluation of antidengue activity of enantiomeric Schiff bases derived from S-substituted dithiocarbazate

2020 ◽  
Vol 44 (5) ◽  
pp. 1395-1409
Author(s):  
Maqsood MARYAM ◽  
Sang Loon TAN ◽  
Karen Ann CROUSE ◽  
Mohamed Ibrahim MOHAMED TAHIR ◽  
Hui-Yee CHEE
Keyword(s):  
Antiviral Activity ◽  
Schiff Bases ◽  
Cytopathic Effect ◽  
Vero Cells ◽  
Enantiomerically Pure ◽  
Reduction Assay ◽  
Acid Catalyzed ◽  
Imine Bond ◽  
Unit Reduction

A series of Schiff bases have been successfully synthesized through the acid-catalyzed condensation of S-substituted dithiocarbazates and three enantiomerically pure monoterpenes, (1R)-(+)-camphor, (1S)-(-)-camphor, (1R)-(-)-camphorquinone, (1S)- (+)-camphorquinone, (R)-(-)-carvone and (S)-(+)-carvone. Spectroscopic results revealed that the Schiff bases containing camphor or carvone likely adopted an E-configuration along the characteristic imine bond while those containing camphorquinone assumed a Z-configuration. The antidengue potential of these compounds was evaluated based on DENV 2 caused cytopathic effect (CPE) reduction-based in vitro evaluation. The compounds were validated through secondary foci forming unit reduction assay (FFURA). Compounds were also tested for their cytotoxicity against Vero cells. The compounds showed variable degrees of antiviral activity with the camphor compounds displaying the highest antidengue potential. The enantiomers of the compounds behaved almost similarly during the antiviral evaluation.

scholarly journals Synthesis and Evaluation of Anti-Rhinovirus 1B Activity of Oxazolinyl-Isoflavans and -3(2H)-Isoflavenes

1992 ◽  
Vol 3 (4) ◽  
pp. 195-202 ◽  
Author(s):  
N. Desideri ◽  
C. Conti ◽  
I. Sestili ◽  
P. Tomao ◽  
M. L. Stein ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Antiviral Activity ◽  
Cytopathic Effect ◽  
Potent Inhibitor ◽  
Therapeutic Index ◽  
Intermediate Compound ◽  
Plaque Formation ◽  
Interesting Compound ◽  
Viral Cytopathic Effect

Oxazolinyl-isoflavans and −3(2H)-isoflavenes, substituted or not with a chlorine atom, were synthesized in order to compare their anti-rhinovirus activity with that of previously studied analogous compounds. The activity of the oxazolines and of the esters and acids, which are intermediates in the synthesis, was studied in vitro against rhinovirus serotype 1B infection in HeLa cells. The ability of various non cytotoxic concentrations to interfere with the development of the viral cytopathic effect and plaque formation was examined. All the tested compounds exerted a significant antiviral activity, and most of them were as active as some representative compounds of the oxazolinyl-phenoxyalkylisoxazole (WIN) series. 6-Oxazolinylisoflavan (VI) appeared to be the most interesting compound due to its high activity and therapeutic index. Among the substituted isoflavans and isoflavenes tested so far, the intermediate compound 6-chloro-3 (2H)-isoflavene-4′-carboxylic acid (XIX) was unexpectedly the most potent inhibitor of rhinovirus 1B plaque formation.

scholarly journals A Novel Substance Purified from Perilla Frutescens Britton Inhibits an Early Stage of HIV-1 Replication without Blocking Viral Adsorption

2002 ◽  
Vol 13 (5) ◽  
pp. 283-288 ◽  
Author(s):  
T Kawahata ◽  
T Otake ◽  
H Mori ◽  
Y Kojima ◽  
I Oishi ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Cytopathic Effect ◽  
Early Stage ◽  
Perilla Frutescens ◽  
Viral Strain ◽  
Viral Particles ◽  
Viral Adsorption ◽  
Hiv 1

Pf-gp6, a 6 kDa anti-degranulation glycoprotein purified from the extract of Perilla frutescens, was examined for its antiviral activity against HIV-1 and HIV-2 in vitro. HIV-1-induced cytopathic effect and proviral DNA synthesis were inhibited in the presence of Pf-gp6. The 50% inhibitory concentrations of Pf-gp6 for various HIV-1 strains, including clinical isolates and CCR5-using (R5) HIV-1, ranged between 1.3 and 71.0 μg/ml, depending on the combination of viral strain and host cell. Furthermore, Pf-gp6 did not directly inactivate infectious viral particles. A time-of-addition experiment revealed that Pf-gp6 lost its activity before zidovudine but after the CXCR-4 antagonist AMD3100 during the early stage of viral infection. Although the pinpoint target of Pf-gp6 remains to be elucidated, it may interfere with a step between viral entry and reverse transcription.

scholarly journals The Hydroalcoholic Extract of Uncaria tomentosa (Cat’s Claw) Inhibits the Infection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) In Vitro

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Andres F. Yepes-Perez ◽  
Oscar Herrera-Calderón ◽  
Cristian A. Oliveros ◽  
Lizdany Flórez-Álvarez ◽  
María I. Zapata-Cardona ◽  
...  
Keyword(s):  
Cytopathic Effect ◽  
Antiviral Effect ◽  
Stem Bark ◽  
Selectivity Index ◽  
Economic Losses ◽  
Uncaria Tomentosa ◽  
Hydroalcoholic Extract ◽  
Plaque Reduction Assay ◽  
Reduction Assay

The coronavirus disease 2019 (COVID-19) has become a serious problem for public health since it was identified in the province of Wuhan (China) and spread around the world producing high mortality rates and economic losses. Nowadays, the WHO recognizes traditional, complementary, and alternative medicine for treating COVID-19 symptoms. Therefore, we investigated the antiviral potential of the hydroalcoholic extract of Uncaria tomentosa stem bark from Peru against SARS-CoV-2 in vitro. The antiviral activity of U. tomentosa against SARS-CoV-2 in vitro was assessed in Vero E6 cells using cytopathic effect (CPE) and plaque reduction assay. After 48 h of treatment, U. tomentosa showed an inhibition of 92.7% of SARS-CoV-2 at 25.0 μg/mL ( p < 0.0001 ) by plaque reduction assay on Vero E6 cells. In addition, U. tomentosa induced a reduction of 98.6% ( p = 0.02 ) and 92.7% ( p = 0.03 ) in the CPE caused by SARS-CoV-2 on Vero E6 cells at 25 μg/mL and 12.5 μg/mL, respectively. The EC50 calculated for the U. tomentosa extract by plaque reduction assay was 6.6 μg/mL (4.89–8.85 μg/mL) for a selectivity index of 4.1. The EC50 calculated for the U. tomentosa extract by TCID50 assay was 2.57 μg/mL (1.05–3.75 μg/mL) for a selectivity index of 10.54. These results showed that U. tomentosa, known as cat's claw, has an antiviral effect against SARS-CoV-2, which was observed as a reduction in the viral titer and CPE after 48 h of treatment on Vero E6 cells. Therefore, we hypothesized that U. tomentosa stem bark could be promising in the development of new therapeutic strategies against SARS-CoV-2.

scholarly journals Astodrimer sodium, dendrimer antiviral, inhibits replication of SARS-CoV-2 in vitro

2020 ◽  
Author(s):  
Jeremy R.A. Paull ◽  
Alex Castellarnau ◽  
Carolyn A. Luscombe ◽  
Jacinth K. Fairley ◽  
Graham P. Heery
Keyword(s):  
Antiviral Activity ◽  
Host Cell ◽  
Cytopathic Effect ◽  
Limit Of Detection ◽  
Antiviral Agent ◽  
Effective Response ◽  
Enveloped Viruses ◽  
Host Cell Interactions

AbstractAn effective response to the ongoing coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will require a range of complementary preventive modalities. The current studies were conducted to evaluate the in vitro SARS-CoV-2 antiviral activity of astodrimer sodium, a dendrimer with broad spectrum antimicrobial activity, including against enveloped viruses in in vitro and in vivo models, that is marketed for antiviral and antibacterial applications. We report that astodrimer sodium inhibits replication of SARS-CoV-2 in Vero E6 cells when added to cells 1-hour prior to or 1-hour post infection, with 50% effective concentrations reducing virus-induced cytopathic effect (EC50) ranging from 0.090 to 0.742 μM (0.002 to 0.012 mg/mL). The selectivity index (SI) in these assays was as high as 2197. Astodrimer sodium was also effective in a virucidal evaluation when mixed with virus for 1 hour prior to infection of cells (EC50 1.83 μM [0.030 mg/mL]). Results from a time of addition study, which showed infectious virus was below the lower limit of detection at all time points tested, were consistent with the compound inhibiting early virus entry steps. The data were similar for all investigations and were consistent with the potent antiviral activity of astodrimer sodium being due to inhibition of virus-host cell interactions, as previously demonstrated for other viruses. Further studies will confirm if astodrimer sodium binds to SARS-CoV-2 spike protein and physically blocks initial association of the virus with heparan sulfate proteoglycans on the host cell. Given the in vitro effectiveness and significantly high SI, astodrimer sodium warrants further investigation for potential as a nasally administered or inhaled antiviral agent for SARS-CoV-2 prevention and treatment applications.

The molecular weight of ulvan affects the in vitro inflammatory response of a murine macrophage

2020 ◽  
Author(s):  
JT Kidgell ◽  
CRK Glasson ◽  
M Magnusson ◽  
G Vamvounis ◽  
Ian Sims ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Interleukin 10 ◽  
Sulfated Polysaccharide ◽  
Immunomodulatory Effect ◽  
Oligosaccharide Structure ◽  
1H And 13C Nmr ◽  
Signalling Molecules ◽  
Green Seaweed ◽  
Molecular Weight Fractions

© 2020 Elsevier B.V. Ulvan, a sulfated polysaccharide extracted from the green seaweed genus Ulva, has bioactive properties including an immunomodulating capacity. The immunomodulatory capacity of ulvan from Ulva ohnoi, however, has not been assessed in detail. We depolymerised purified ulvan from U. ohnoi to obtain a range of molecular weight fractions (Mw 7, 9, 13, 21, 209 kDa), which were characterised by constituent sugar analysis, SEC-MALLS, and NMR. Ulvan fractions contained 48.8–54.7 mol% rhamnose, 32.5–35.9 mol% glucuronic acid, 4.5–7.3 mol% iduronic acid, and 3.3–5.6 mol% xylose. 1H and 13C NMR was consistent with hydrolysis occurring at the anomeric centre without further modification to the oligosaccharide structure. The in vitro immunomodulatory effect of ulvan fractions was quantified by measuring levels of inflammatory-mediating signalling molecules released from LPS-stimulated RAW264.7 murine macrophages. All ulvan fractions showed no toxicity on RAW264.7 cells at concentrations below 100 μg mL−1 over 48 h. Secreted interleukin-10 and prostaglandin E2 demonstrated an anti-inflammatory effect by higher molecular weight ulvan fractions at 100 μg mL−1. To a lesser extent, these fractions also enhanced the LPS-induced inflammation through minor increases of IL-1β and IL-6. This study confirms that ulvan from U. ohnoi has a mild in vitro immunomodulatory effect.

In vitro synthesis of glycogen: the structure, properties, and physiological function of enzymatically-synthesized glycogen

Biologia ◽  
2011 ◽  
Vol 66 (3) ◽  
Author(s):  
Hideki Kajiura ◽  
Hiroki Takata ◽  
Tsunehisa Akiyama ◽  
Ryo Kakutani ◽  
Takashi Furuyashiki ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chain Length ◽  
Large Scale ◽  
Glycogen Synthesis ◽  
Average Molecular Weight ◽  
Spherical Particles ◽  
Average Chain Length ◽  
Scale Production ◽  
In Vitro Synthesis

AbstractThis review describes a new enzymatic method for in vitro glycogen synthesis and its structure and properties. In this method, short-chain amylose is used as the substrate for branching enzymes (BE, EC 2.4.1.18). Although a kidney bean BE and Bacillus cereus BE could not synthesize high-molecular weight glucan, BEs from 6 other bacterial sources produced enzymatically synthesized glycogen (ESG). The BE from Aquifex aeolicus was the most suitable for the production of glycogen with a weight-average molecular weight (M w) of 3,000–30,000 k. The molecular weight of the ESG is controllable by changing the concentration of the substrate amylose. Furthermore, the addition of amylomaltase (AM, EC 2.4.1.25) significantly enhanced the efficiency of this process, and the yield of ESG reached approximately 65%. Typical preparations of ESG obtained by this method were subjected to structural analyses. The average chain length, interior chain length, and exterior chain length of the ESGs were 8.2–11.6, 2.0–3.3, and 4.2–7.6, respectively. Transmission electron microscopy and intrinsic viscosity measurement showed that the ESG molecules formed spherical particles. Unlike starch, the ESGs were barely degraded by pullulanase. Solutions of ESG were opalescent (milky-white and slightly bluish), and gave a reddishbrown color on the addition of iodine. These analyses revealed that ESG shares similar molecular shapes and solution properties with natural-source glycogen. Moreover, ESG had macrophage-stimulating activity and its activity depends on the molecular weight of ESG. We successfully achieved large scale production of ESG. ESG could lead to new industrial applications, such as in the food, chemical, and pharmaceutical fields.

scholarly journals Selection of Water-Soluble Chitosan by Microwave-Assisted Degradation and pH-Controlled Precipitation

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1274 ◽  
Author(s):  
Céline M. A. Journot ◽  
Laura Nicolle ◽  
Yann Lavanchy ◽  
Sandrine Gerber-Lemaire
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Aqueous Media ◽  
Phase Changes ◽  
Water Soluble ◽  
In Vivo Evaluation ◽  
Microwave Assisted ◽  
Selection Of

In the field of gene therapy, chitosan (CS) gained interest for its promise as a non-viral DNA vector. However, commercial sources of CS lack precise characterization and do not generally reach sufficient solubility in aqueous media for in vitro and in vivo evaluation. As low molecular weight CS showed improved solubility, we investigated the process of CS depolymerization by acidic hydrolysis, using either long time heating at 80 °C or short time microwave-enhanced heating. The resulting depolymerized chitosan (dCS) were analyzed by gel permeation chromatography (GPC) and 1H nuclear magnetic resonance (NMR) to determine their average molecular weight (Mn, Mp and Mw), polydispersity index (PD) and degree of deacetylation (DD). We emphasized the production of water-soluble CS (solubility > 5 mg/mL), obtained in reproducible yield and characteristics, and suitable for downstream functionalization. Optimal microwave-assisted conditions provided dCS with a molecular weight (MW) = 12.6 ± 0.6 kDa, PD = 1.41 ± 0.05 and DD = 85%. While almost never discussed in the literature, we observed the partial post-production aggregation of dCS when exposed to phase changes (from liquid to solid). Repeated cycles of freezing/thawing allowed the selection of dCS fractions which were exempt of crystalline particles formation upon solubilization from frozen samples.

scholarly journals PROPERTIES OF NATIVE PROTEIN-CONTAINING ANTIGENS OF STREPTOCOCCUS PNEUMONIAE

2019 ◽  
Vol 1 (1) ◽  
pp. 22-28
Author(s):  
D. S. Vorobyev ◽  
I. B. Semenova ◽  
Yu. V. Volokh ◽  
E. E. Romanenko ◽  
A. P. Baturo ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chemical Composition ◽  
Immune Serum ◽  
Rabbit Serum ◽  
Protective Activity ◽  
Native Protein ◽  
In Vivo Experiments ◽  
Sds Electrophoresis

Aim. The study of immunochemical and immunobiological properties of native protein-containing antigens of pneumococcus. Materials and methods. The study was carried out on the strains of the Collective Usage Center «Collection of Mechnikov Res. Inst. for Vaccine and Sera». In the work studied the chemical composition, the molecular weight of the obtained antigens in SDS-electrophoresis and antibody titers in ELISA. Protective activity of protein-containing antigens of pneumococcus was determined in experiments of active protection of mice. Results. Protein-containing antigens of pneumococcus were isolated from S. pneumoniae serotypes 3, 6B, 10A, 14, 19F, 23F and 36. The chemical composition of the preparations contained from 16 to 35% protein. In SDS-electrophoresis in polyacrylamide gel it was established that the molecular weight of protein-containing antigens of pneumococcus ranged from 14 to 116 kDa. Using ELISA shows the cross-activity of native antigens. Virtually all drugs reacted with antimicrobial rabbit serum obtained to serotype 19F (p≤0.05). Serotype serum 14 was less active and only protein-containing pneumococcal antigens obtained from 14 and 19F serotypes (p≤0.05) interacted with it. In the precipitation test according to Ouchterlony it was confirmed that preparations of serotypes 3, 6B, 14, 19F and 36 reacted with rabbit immune serum obtained for S. pneumoniae 19F serotype. In immunoblotting it was found that protein-containing antigens of pneumococcus isolated from serotypes 3, 6B, 10A, 14, 19F and 36 were associated with monoclonal antibodies to pneumococcal protein — pneumolysin. In vivo experiments it was shown that protein-containing antigens of pneumococcus protected animals from intraperitoneal infection of S. pneumoniae in homologous and heterologous systems (p≤0.05). Conclusion. The revealed immunochemical and cross-protective activity of protein-containing antigens of pneumococcus in vitro and in vivo experiments allows to select drugs derived from serotypes 6B, 10A, 19F and 36, as the most promising for further study of the intraspecific protective activity of individual native proteins of pneumococcus. 

scholarly journals Degradation of 3D-Printed Porous Polylactic Acid Scaffolds Under Mechanical Stimulus

2021 ◽  
Vol 9 ◽  
Author(s):  
Heming Chen ◽  
Quan Shi ◽  
Hengtao Shui ◽  
Peng Wang ◽  
Qiang Chen ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Numerical Model ◽  
Young’S Modulus ◽  
Polylactic Acid ◽  
Young's Modulus ◽  
Average Molecular Weight ◽  
Mechanical Stimulus ◽  
Number Average Molecular Weight ◽  
3D Printed

Polylactic acid (PLA) is a biodegradable polymer commonly used as a scaffold material to repair tissue defects, and its degradation is associated with mechanical stimulus. In this study, the effect of mechanical stimulus on the degradation of 3D-printed PLA scaffolds was investigated by in vitro experiments and an author-developed numerical model. Forty-five samples with porosity 64.8% were printed to carry out the degradation experiment within 90 days. Statistical analyses of the mass, volume fraction, Young’s modulus, and number average molecular weight were made, and the in vitro experiments were further used to verify the proposed numerical model of the scaffold degradation. The results indicated that the mechanical stimulus accelerated the degradation of the PLA scaffold, and the higher mechanical stimulus led to a faster degradation of the scaffolds at the late stage of the degradation process. In addition, the Young’s modulus and the normalized number average molecular weight of the PLA scaffolds between the experiments and the numerical simulations were comparable, especially for the number average molecular weight. The present study could be helpful in the design of the biodegradable PLA scaffolds.

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