Synthesis of glycoporphyrin derivatives and their antiviral activity against herpes simplex virus types 1 and 2

Studies on the synthesis, structural elucidation, and antiviral evaluation of several carbohydrate-substituted meso-tetraarylporphyrins against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are described. The potential of those photosensitizers, and of their precursors, on the photoinactivation of HSV-1 and HSV-2 was examined in Vero cells. Their virucidal and viral replication effects were assessed under white light, at their maximum noncytotoxic concentrations. The highest inhibitory effects on viral replication, for both viruses, were obtained with the glycoporphyrins where the sugar moiety bears unprotected hydroxyl groups. Strong inhibition of virus yield was observed even at concentrations much lower than their maximum noncytotoxic concentrations. These compounds can be postulated to be useful as potential drugs for the treatment of herpes simplex viruses infections.     

Synthesis of cationic beta-vinyl substituted meso-tetraphenylporphyrins and their in vitro activity against herpes simplex virus type 1

An easy route to cationic beta-vinyl substituted meso-tetraphenylporphyrin derivatives is described. Two novel compounds were tested in vitro for their antiviral photoactivity against herpes simplex virus type 1. One of these compounds exhibited a significant activity, reaching 99% of virus inactivation after 15 min of photoactivation.     

Synthesis of purine modified 2'-C-methyl nucleosides as potential anti-HCV agents

Based on the anti-hepatitis C activity of 2′-C-methyl-adenosine and 2′-C-methyl-guanosine, a series of new modified purine 2′-C-methyl nucleosides was prepared as potential anti-hepatitis C virus agents. Herein, we report the synthesis of both 6-modified and 2-modified purine 2′-C-methyl-nucleosides along with their anti-HCV replication activity and cytotoxicity in different cells.     

Synthesis and antiviral activity of 2'-deoxy-2'-fluoro-2'-C-methyl-7-deazapurine nucleosides, their phosphoramidate prodrugs and 5'-triphosphates

Thirty novel α- and β-d-2'-deoxy-2'-fluoro-2'-C-methyl-7-deazapurine nucleoside analogs were synthesized and evaluated for in vitro antiviral activity. Several α- and β-7-deazapurine nucleoside analogs exhibited modest anti-HCV activity and cytotoxicity. Four synthesized 7-deazapurine nucleoside phosphoramidate prodrugs (18-21) showed no anti-HCV activity, whereas the nucleoside triphosphates (22-24) demonstrated potent inhibitory effects against both wild-type and S282T mutant HCV polymerases. Cellular pharmacology studies in Huh-7 cells revealed that the 5'-triphosphates were not formed at significant levels from either the nucleoside or the phosphoramidate prodrugs, indicating that insufficient phosphorylation was responsible for the lack of anti-HCV activity. Evaluation of anti-HIV-1 activity revealed that an unusual α-form of 7-carbomethoxyvinyl substituted nucleoside (10) had good anti-HIV-1 activity (EC(50)=0.71±0.25 μM; EC(90)=9.5±3.3 μM) with no observed cytotoxicity up to 100 μM in four different cell lines.     

Antiviral activity of Lactobacillus brevis towards herpes simplex virus type 2: role of cell wall associated components

The aim of this research was to study the mechanisms of Lactobacillus brevis antiviral activity towards HSV-2 and to identify the bacterial components responsible for the inhibiting effect. Bacterial extract and cell walls were prepared by lysozyme digestion of L. brevis cells untreated or treated with LiCl to remove S-layer proteins. Bacterial extract and cell wall fragments showed a dose dependent inhibitory effect on HSV-2 multiplication. In order to characterize the inhibitory activity of L. brevis, the bacterial extract was subjected to different physical and chemical treatments. The inhibitory activity was resistant to high temperature and proteases digestion and appeared to be associated with compounds with a molecular weight higher than 10 kDa. DNA, RNA and lipids isolated from bacterial cells were devoid of inhibitory effect. The antiviral activity of both bacterial extract and cell wall fragments obtained from L. brevis cells after the S-layer removal was significantly reduced compared to untreated cells suggesting that the inhibitory activity is likely due to a heat-resistant non-protein cell surface bacterial component.     

Synthesis and antiviral activity of coumarin derivatives against infectious hematopoietic necrosis virus

Infectious hematopoietic necrosis virus (IHNV) is a highly contagious disease of juvenile salmonid species. However, robust anti-IHNV drugs currently are extremely scarce. For the purpose of seeking out anti-IHNV drugs, here a total of 24 coumarin derivatives are designed, synthesized and evaluated for their anti-viral activities. By comparing the half maximal inhibitory concentrations (IC₅₀) of the 12 screened candidate drugs in epithelioma papulosum cyprini (EPC) cells infected with IHNV, the imidazole coumarin derivative C4 is selected for additional validation studies, with an IC₅₀ of 2.53 μM at 72 h on IHNV glycoprotein. Further experiments revealed that C4 could significantly inhibit apoptosis and cellular morphological damage induced by IHNV. On account of these findings, derivative C4 could be a viable way of controlling IHNV and considered as a promising lead compound for the development of commercial drugs.     

Chemical structure and antiviral activity of carrageenans from Meristiella gelidium against herpes simplex and dengue virus

Chemical and spectroscopic methods showed that the major KCl-precipitated galactans from Meristiella gelidium (Solieriaceae) are iota/kappa/nu-hybrid carrageenans with the former one in higher proportion. These carrageenans showed, by HPSEC-MALLS analysis, unimodal symmetrical peaks with MW of 425.6–956.7 kDa. The effectiveness of the crude extracts from M. gelidium against HSV-2 was higher than the corresponding extract from G. griffithsiae, previously determined. However, when considering the homogeneous carrageenans, the fractions obtained from both seaweeds showed the same level of activity. The extracts and carrageenan derived from M. gelidium were more effective inhibitors of DENV-2 if compared with G. griffithsiae samples and reference polysaccharides. The most active fraction obtained from M. gelidium showed a selectivity index against HSV-2 of 25,000, a value high enough to consider this carrageenan as a promising agent to be evaluated for the treatment of genital HSV-2 infections.     

Antiviral activity of Basidiomycete mycelia against influenza type A(serotype H1N1) and herpes simplex virus type 2 in cell culture

In this study, we investigated the in vitro antiviral activity of the mycelia of higher mushrooms against influenza virus type A(serotype H1N1) and herpes simplex virus type 2(HSV-2), strain BH. All 10 investigated mushroom species inhibited the reproduction of influenza virus strain A/FM/1/47(H1N1) in MDCK cells reducing the infectious titer by 2.0–6.0 lg ID50. Four species, Pleurotus ostreatus, Fomes fomentarius, Auriporia aurea, and Trametes versicolor, were also determined to be effective against HSV-2 strain BH in RK-13 cells, with similar levels of inhibition as for influenza. For some of the investigated mushroom species—Pleurotus eryngii, Lyophyllum shimeji, and Flammulina velutipes—this is the first report of an anti-influenza effect. This study also reports the first data on the medicinal properties of A. aurea, including anti-influenza and antiherpetic activities. T. versicolor 353 mycelium was found to have a high therapeutic index(324.67), and may be a promising material for the pharmaceutical industry as an anti-influenza and antiherpetic agent with low toxicity. Mycelia with antiviral activity were obtained in our investigation by bioconversion of agricultural wastes(amaranth flour after CO2 extraction), which would reduce the cost of the final product and solve some ecological problems.     

Antiviral activity of Basidiomycete mycelia against influenza type A (serotype H1N1) and herpes simplex virus type 2 in cell culture

In this study, we investigated the in vitro antiviral activity of the mycelia of higher mushrooms against influenza virus type A(serotype H1N1) and herpes simplex virus type 2(HSV-2), strain BH. All 10 investigated mushroom species inhibited the reproduction of influenza virus strain A/FM/1/47(H1N1) in MDCK cells reducing the infectious titer by 2.0–6.0 lg ID50. Four species, Pleurotus ostreatus, Fomes fomentarius, Auriporia aurea, and Trametes versicolor, were also determined to be effective against HSV-2 strain BH in RK-13 cells, with similar levels of inhibition as for influenza. For some of the investigated mushroom species—Pleurotus eryngii, Lyophyllum shimeji, and Flammulina velutipes—this is the first report of an anti-influenza effect. This study also reports the first data on the medicinal properties of A. aurea, including anti-influenza and antiherpetic activities. T. versicolor 353 mycelium was found to have a high therapeutic index(324.67), and may be a promising material for the pharmaceutical industry as an anti-influenza and antiherpetic agent with low toxicity. Mycelia with antiviral activity were obtained in our investigation by bioconversion of agricultural wastes(amaranth flour after CO2 extraction), which would reduce the cost of the final product and solve some ecological problems.     

Analysis of toxic and mutagenic activities of antiherpesvirus nucleosides against HeLa cells and herpes simplex virus type 1.

The toxic and mutagenic activities of five antiherpesvirus agents to HeLa cells and herpes simplex virus type 1 (HSV-1) were investigated. 5-Iodo-2'-deoxyuridine (IDU) and 9-beta-D-arabinofuranosyl-adenine (araA) showed very potent inhibitory effects on cell growth and the cloning efficiency of HeLa cells, whereas 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil (BV-araU), E-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) and 9-(2-hydroxyethoxymethyl)guanine (ACV) showed less inhibitory effect. 50% inhibitory doses of BV-araU and BVDU for cell growth were 657 and 253 micrograms/ml, respectively. Although the growth inhibitory activity of BVDU was very weak, as above, the mutagenic activity of this drug to the cells, estimated by induction of colchicine-resistant mutants, was observed to be 4 micrograms/ml, which was a markedly smaller dose than the inhibitory dose for cell growth, and the highest frequency of mutation of the cells was shown at 100 micrograms/ml of BVDU. This activity was more potent than that of IDU. No mutagenic activity of BV-araU, araA and ACV to cells was observed within the concentration range of 1-800 micrograms/ml. IDU showed high mutagenic activity to HSV-1 growing in human embryo lung fibroblasts, and IDU-resistant mutants were induced at a high frequency. BVDU also induced a small amount of BVDU-resistant mutant virus, although this drug induced many mutant cells. No mutagenic activity of BV-araU, araA and ACV to HSV-1 was observed.     

Synthesis and biological evaluation of novel imidazole nucleosides as potential anti-dengue virus agents

In this work, we developed imidazole nucleoside derivatives with anti-dengue virus (DENV) activity was examined. First, compounds in a nucleosides library were screened to find lead compounds which inhibit replication of DENV. As a result, 5-ethynyl-(1-β-d-ribofuranosyl)imidazole-4-carboxamide (1; EICAR) and its 4-carbonitrile derivative EICNR (2) were selected as promising antiviral compounds. However, both of them also exhibited cytotoxicity. In order to develop an effective and less toxic compound, 4′-thio and 4′-seleno derivatives of EICAR and EICNR 3–6 were prepared. The resulting 4′-thioEICAR and 4′-thioEICNR showed inhibitory effect on DENV replication without cytotoxicity as potent as ribavirin, a positive control.     

Antiviral activities against herpes simplex virus type 1 by HPH derivatives and their structure-activity relationships

The compound named Histidine-pyridine-histidine (HPH) is an oxygen-activating ligand derived from the structure of bleomycin. We synthesized HPH derivatives, namely HPH-1 to -8, and investigated their antiviral activities against herpes simplex virus type 1. HPH-8 showed potent antiviral activity with an EC50 of 15 microM, and relatively high cytotoxicity with a CC50 of 37 microM. In contrast, HPH-4 indicated a weaker antiviral activity with an EC50 of 79 microM, but exhibited a far more less cytotoxicity (CC50 500 microM). Other HPH derivatives showed no effects against antiviral activities and cytotoxicities.     

Synthesis and evaluation of 2′-dihalo ribonucleotide prodrugs with activity against hepatitis C virus

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Hepatitis C virus (HCV) nucleoside inhibitors have been a key focus of nearly 2 decades of HCV drug research due to a high barrier to drug resistance and pan-genotypic activity profile provided by molecules in this drug class. Our investigations focused on several potent 2′-halogenated uridine-based HCV polymerase inhibitors, resulting in the discovery of novel 2′-deoxy-2′-dihalo-uridine analogs that are potent inhibitors in replicon assays for all genotypes. Further studies to improve in vivo performance of these nucleoside inhibitors identified aminoisobutyric acid ethyl ester (AIBEE) phosphoramidate prodrugs 18a and 18c, which provide high levels of the active triphosphate in dog liver. AIBEE prodrug 18c was compared with sofosbuvir (1) by co-dosing both compounds by oral administration in dog (5 mg/kg each) and measuring liver concentrations of the active triphosphate metabolite at both 4 and 24 h post dosing. In this study, 18c provided liver triphosphate concentrations that were 6-fold higher than sofosbuvir (1) at both biopsy time points, suggesting that 18c could be a highly effective agent for treating HCV infected patients in the clinic.     

Synthesis and anti-HCMV activity of novel cyclopropyl phosphonic acid nucleosides

A simple synthetic route for novel acyclic phosphonate nucleosides is described. The characteristic cyclopropyl moiety 8 was constructed employing the Simmons-Smith reaction as key step starting from simple acyclic 2-butene-1,4-diol. The condensation of the mesylate 11 with natural nucleosidic bases (A,C,T,U) under nucleophilic substitution conditions (K₂CO₃, 18-Crown-6, DMF) and hydrolysis afforded the target nucleosides 16, 17, 18, and 19. In addition, the antiviral evaluations against various viruses were performed.     

Physical mapping of the herpes simplex virus type 2 nuc- lesion affecting alkaline exonuclease activity by using herpes simplex virus type 1 deletion clones

The nuc- lesion affecting alkaline exonuclease activity in the herpes simplex virus type 2 (HSV-2) mutant ts1348 had previously been mapped to the EcoRI-D restriction enzyme fragment of HSV-1. Eight clones with deletions representing most of HSV-1 EcoRI fragment D were selected with lambda gtWES hybrids. These clones were tested for their ability to rescue the alkaline exonuclease activity of HSV-2 nuc- ts1348 virus. The sequences colinear with the HSV-2 nuc- lesion were found to map between 0.169 and 0.174 map units on the HSV-1 Patton genome, representing an 0.8-kilobase-pair region that is 12.9 to 13.7 kilobase pairs from the left end of HSV-1 EcoRI fragment D.     

Properties of herpes simplex virus type 1 and type 2 DNA polymerase

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) DNA polymerases were highly purified from infected HeLa BU cells by DEAE cellulose, phosphocellulose and DNA cellulose column chromatography. DNA exonuclease activity but not endonuclease activity was found associated with both types of DNA polymerase. Both DNA polymerase activities could be activated by salt in a similar fashion with the optimal activity in the range of ionic strength between 0.22 and 0.29 alpha. At an ionic strength of 0.14, spermidine and putrescine in the concentration range (0--5 mM) studied could mimic the action of KCI in stimulating DNA polymerase activity. Spermine, in the same concentration range, had a biphasic effect. At an ionic strength of 0.29 all three polyamines were inhibitory. HSV-1 and HSV-2 DNA polymerase are similar in their column chromatographic behavior, sedimentation rate in sucrose gradient centrifugation, and activation energy, but they differ in their heat stability at 45 degrees C with the HSV-2 enzyme more stable than the HSV-1 enzyme. Kinetic behavior of both enzymes is similar, with Km values for deoxyribonucleoside triphosphates in the range of 5 . 10(-7) to 1.8 . 10(-8) M. IdUTP and dUTP served as apparent competitive inhibitors with respect to dTTP, and AraATP acted as an apparent competitive inhibitor with respect to dATP. AraATP could not replace dATP in the DNA polymerization reaction; in contrast, IdUTP could replace TTP. Phosphonoformic acid behaved as an uncompetitive inhibitor with respect to DNA. The ID(50) value estimated was foind to be dependent on the purity of the DNA polymerase used and the ionic strength of the assay condition. Each DNA-polymerase associated DNA exonuclease had the same stability at 45 degrees C as its DNA polymerase. The associated DNAase activity was inhibited by phosphonoformic acid and high ionic strength of the assay condition.     

Synthesis and in vitro antileishmanial activity of 5-substituted-2'-deoxyuridine derivatives

We report herein the synthesis and the in vitro antileishmanial evaluation of 5-substituted-2'-deoxyuridine nucleosides. The most active compound against Leishmania donovani promastigotes was Thia-dU (3a) with an IC50 =3 microM. This compound exhibited the same activity as zidovudine (3'-azido-2'-deoxythymidine) used as nucleoside reference compound. Considering the cytotoxicity of synthetic compounds on peritoneal murine macrophages, the most toxic compound was MeThio-dU (3d) with a MTC at 10 microM. Only Methia-dU (3b) was active against intramacrophagic amastigotes with an IC50 =6.5 microM. This latter can now be evaluated in vivo, for further investigations through structure-based drug design.     

Metal complexes of bovine lactoferrin inhibit in vitro replication of herpes simplex virus type 1 and 2

The inhibitory effect of bovine lactoferrin (BLf) saturated with ferric, manganese or zinc ions, on the infection of Vero cells by human herpes simplex virus type 1 (HSV1) and 2 (HSV2) was investigated. Viral infectivity determined by intracellular antigen synthesis and plaque formation was efficiently inhibited by metal saturated lactoferrins in a dose-dependent manner. Effective BLf concentrations which reduced the infection by 50% ranged from 5.2 to 31 mug ml and were far below the cytotoxicity threshold. Fe BLf and Mn BLf exhibited selectivity indexes higher than Zn BLf and apoBLf for both viruses and the effect was mainly directed towards the early steps of infection. The slight viral inhibition shown by the citrate complexes of the different metals could indicate that the antiviral effect was not significantly influenced by Fe , Mn or Zn ions delivered by BLf into the cells. © Rapid Science 1998