Antiherpetic Agent Research Articles

Antiviral activity of Cleome rosea extracts from field-grown plants and tissue culture-derived materials against acyclovir-resistant Herpes simplex viruses type 1 (ACVr-HSV-1) and type 2 (ACVr-HSV-2)

Extracts from Cleome rosea were investigated for their activity against acyclovir-resistant strains of Herpes simplex type 1 (ACVr-HSV-1) and type 2 (ACVr-HSV-2). Methanolic and acidified (1% (v/v) HCl) methanolic extracts were prepared from field-grown plants and in vitro propagated plants, as well as from calli and cell suspension cultures. The extracts presented low cytotoxicity and caused virus titer reduction above 70%, with different mechanisms of action. Extracts from leaves of field-grown plants inhibited viral infection mainly by affecting the virus particle itself (virucidal effect), while extracts from calli acted mainly on cell receptors. On the other hand, all extracts evaluated affected the virus entry across the cell membrane and the intracellular viral replication at similar percentages, causing reduction on titers in the range of 68–90%. This study validated the potential use of in vitro materials as sources of antiherpetic agents from C. rosea.

Antiviral effect of arginine against herpes simplex virus type 1

We investigated the effects of arginine on the multiplication of herpes simplex virus type 1 (HSV-1) and the potential of arginine as an antiherpetic agent. Arginine suppressed the growth of HSV-1 concentration-dependently. Inhibition of HSV-1 by arginine leveled off at 50-60 mM, although the higher concentration was not suitable as an antiviral agent due to cytotoxicity. 'Time of addition' experiments revealed that arginine was particularly effective when added within 6 h post-infection (h p.i.), suggesting that the reagent sensitive step is in the early stages of the infection. A one-step growth curve of HSV-1 in the presence of 30 mM arginine revealed that: i) the latent period was significantly extended, ii) the rate of formation of progeny infectious virus decreased and iii) the final yield of progeny virus decreased to 1%. The addition of arginine at 8 h p.i., after the completion of viral DNA replication in the virus multiplication, allowed the normal formation of progeny virus in the subsequent 4 h, confirming that arginine does not directly interfere with the formation of progeny infectious virus. In addition, arginine also inhibits several RNA viruses.

Evaluation of Chikusetsusaponin IV a Isolated fromAlternanthera philoxeroidesfor Its Potency Against Viral Replication

Chikusetsusaponin IVa and calenduloside E were isolated from the whole plant of Alternanthera philoxeroides (Mart.) Griseb (Amaranthaceae) and evaluated for their antiviral activities. Chikusetsusaponin IVa showed antiviral activities against HSV-1, HSV-2, human cytomegalovirus, measles virus, and mumps virus with selectivity indices (CC (50)/IC (50)) of 29, 30, 73, 25, and 25, respectively. On the other hand, calenduloside E showed no antiviral effects against any of the viruses tested. The mode of HSV-2 action of chikusetsusaponin IVa was determined under different experimental conditions. The anti-HSV-2 target of the compound might be mainly related to direct inactivation of virus particles and to the inhibition of release of progeny viruses from infected cells, but it is not related to inhibition of viral attachment, cell penetration, and viral protein synthesis. This compound also provided in vivo efficacy in a mouse model of genital herpes caused by HSV-2. These results demonstrate that chikusetsusaponin IVa might be a candidate of antiherpetic agents.

ChemInform Abstract: Synthesis of Methyl‐Substituted Bicyclic Carbanucleoside Analogues as Potential Antiherpetic Agents.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of Methyl-substituted Bicyclic Carbanucleoside Analogs as Potential Antiherpetic Agents

Laboratory of Medicinal Chemistry, College of Pharmacy, Ewha Womans University, Seoul 120-750, KoreaReceived July 28, 2008Novel bicyclo[3.1.0]hexanyl purine nucleoside analogues were synthesized as potential antiherpetic agents viaa bicyclo[3.1.0]hexanol (±)- 8, which was prepared using a highly efficient carbenoid cycloaddition reaction. Ahighly diastereoselective reduction of ketone and a Mitsunobu reaction for the condensation of glycosyl donor(±)-12 with 6-chloropurine were employed. Key Words : Bicyclo[3.1.0]hexanone, Intramolecular carbenoid cycloaddition, Mitsunobu reaction, Diastereo-selective reduction, North conformationIntroductionSince the discovery of acyclovir

Synthesis of Novel Cyclopropyl Nucleoside Analogues as Potential Antiherpetic Agent

Synthesis of novel cyclopropyl pyrimidine and purine nucleoside derivatives was successfully achieved using one pot reactions including an alkylation, an oxirane-ring opening reaction and a lactonization and a hydroboration-oxidation as the key steps in order to find new antiherpetic agent.

Amphipathic DNA Polymers Exhibit Antiherpetic Activity In Vitro and In Vivo

Phosphorothioated oligonucleotides have a sequence-independent antiviral activity as amphipathic polymers (APs). The activity of these agents against herpesvirus infections in vitro and in vivo was investigated. The previously established sequence-independent, phosphorothioation-dependent antiviral activity of APs was confirmed in vitro by showing that a variety of equivalently sized homo- and heteropolymeric AP sequences were similarly active against herpes simplex virus type 1 (HSV-1) infection in vitro compared to the 40mer degenerate parent compound (REP 9), while the absence of phosphorothioation resulted in the loss of antiviral activity. In addition, REP 9 demonstrated in vitro activity against a broad spectrum of other herpesviruses: HSV-2 (50% effective concentration [EC(50)], 0.02 to 0.06 microM), human cytomegalovirus (EC(50), 0.02 to 0.13 microM), varicella zoster virus (EC(50), <0.02 microM), Epstein-Barr virus (EC(50), 14.7 microM) and human herpesvirus types 6A/B (EC(50), 2.9 to 10.2 microM). The murine microbicide model of genital HSV-2 was then used to evaluate in vivo activity. REP 9 (275 mg/ml) protected 75% of animals from disease and infection when provided 5 or 30 min prior to vaginal challenge. When an acid-stable analog (REP 9C) was used, 75% of mice were protected when treated with 240 mg/ml 5 min prior to infection (P < 0.001), while a lower dose (100 mg/ml) protected 100% of the mice (P < 0.001). The acid stable REP 9C formulation also provided protection at 30 min (83%, P < 0.001) and 60 min (50%, P = 0.07) against disease. These observations suggest that APs may have microbicidal activity and potential as broad-spectrum antiherpetic agents and represent a novel class of agents that should be studied further.

Klüver Bucy syndrome, unusual consequence of excessively rapid correction of severe hyponatremia

Features of Klüver-Bucy syndrome (KBS) include hypersexuality, hyperorality, placidity, visual agnosia, amnesia, hypermetamorphosis, and emotional and nutritional behavior changes. It is a clinical presentation of bitemporal disorders with limbic system abnormalities. The most common cause of KBS is herpes encephalitis. An otherwise healthy 61-year-old woman presented with mental status changes (MMSE-0) after 6 days of severe vomiting. Extracellular dehydration, hyponatremia (107 mmol/L), low levels of natriuresis, and mild hypokalemia were noted. The initial computed tomography (CT) of the brain was normal. Over 36 hours of hospitalization in a district hospital she developed unusual neuropsychiatric disorders: hypersexuality, hyperorality, absence, visual agnosia, sensory aphasia, amnesia, and depression typical of KBS. She was then transferred to a neurology department. Clear improvement was visible 3 months later: MMSE-22, moderation of hypersexuality and hyperorality, partial correction of amnesia and aphasia, regression of visual agnosia. But the prosopagnosia (face blindness) persisted, and the patient remained unable to differentiate positive and negative facial expressions. Intracranial mass, epilepsy, neuromeningeal infection and head trauma were all ruled out. Antiepileptic and antiherpetic agents were tested without success. There was no evidence of adrenal insufficiency or inappropriate vasopressin secretion. Only severe vomiting, corrected by water intake, could explain the hyponatremia. The first MRI showed bitemporal edema; 3 months later it showed large bitemporal lesions, both internal and external, with atrophy of the hippocampus and limbic system. These MRI findings are characteristic of KBS. To our knowledge, this is the only the second case of KBS with bitemporal myelinolysis reported related to excessively rapid correction of hyponatremia (increase of 30 mmol/L over 36 h), which leads more usually to central pontine myelinolysis.

Frequency of acyclovir‐resistant herpes simplex viruses isolated from the general immunocompetent population and patients with acquired immunodeficiency syndrome

Herpes simplex virus (HSV) infections are usually chronically recurrent in the normal population and represent a significant cause of morbidity in immunocompromised patients. Acyclovir (ACV) is widely used for the treatment and prophylaxis of HSV infections. The emergence of ACV-resistant strains has been frequently reported as a result of long-term ACV therapy. Despite the widespread use of ACV, there are no data available in our area on the frequency of ACV-resistant HSVs. The purpose of this study was to evaluate the susceptibility of HSV isolated from normal subjects and patients with acquired immunodeficiency syndrome (AIDS) to ACV. HSVs were isolated from the orofacial region of normal individuals and patients with AIDS. The susceptibility of isolated HSV strains to various concentrations of ACV was determined by plaque reduction assay. The sensitivity of the viral strains was expressed as IC(50) (the concentration of drug reducing the viral plaque by 50%). One hundred and thirty-three isolates from 102 normal subjects and 31 patients with AIDS were tested. One HSV-1 isolate from normal individuals had intermediate susceptibility. Two ACV-resistant isolates (one HSV-1 and one HSV-2), with IC(50) > or = 2 to < or = 3 microg/mL, and one highly resistant HSV-2 isolate, with IC(50) > or = 5 microg/mL, were detected in patients with AIDS. Our data show that the prevalence of ACV-resistant strains is very low in the general immunocompetent population; however, in patients with AIDS, the prevalence of ACV-resistant strains is remarkable (P = 0.001). Alternative antiherpetic agents should be employed to control and reduce the emergence of ACV-resistant strains in patients with AIDS.

Advances in the antiviral therapy of herpes virus infection in children

Herpes viruses are ubiquitous, and primary infection with many of these viruses is common during childhood. In general, children tolerate primary infection well, with only mild symptoms, but in the immunocompromised, including the newborn, infection can be associated with serious morbidity and mortality. Drug treatment for many of the herpes infections is available but is often associated with serious side effects. In the pediatric age group, treatment is further hindered by a lack of information on suitable dosing regimes, unavailability of oral solutions and a lack of clinical trials specifically investigating response to treatment in this group of patients. This article will review current evidence regarding the pharmacokinetics and dosing of the most commonly used antiherpetic agents and will look specifically at the treatment of the more common herpes virus infections in children.

Antiviral activity of diverse classes of broad-acting agents and natural compounds in HHV-6-infected lymphoblasts

Background HHV-6 replication requires complex and poorly understood interactions between viral and cellular factors. Objectives Several natural compounds or broad-acting pharmacological agents were studied in an attempt to discover new targets for anti-HHV-6 therapy. Study design The antiviral activity was determined in human T-lymphoblasts, using HHV-6A (GS)-infected HSB-2 cells, HHV-6B (Z29)-infected MOLT-3 cells and HHV- 6B (HST)-infected MT4 cells. Virus replication was measured by CPE and qPCR assay. Foscarnet was included as the reference compound. Results Among the 15 natural compounds tested, only ‘red marine algae’ (an extract rich in sulfated polysaccharides) exhibited strong activity when added during virus adsorption. Among the broad-acting pharmacological agents, chloroquine, artemisinin, hypericin, ribavirin, resveratrol and glycyrrhizic acid were all inactive. Amantadine produced a reproducible inhibition of HHV-6 replication, albeit at relatively high concentrations. Except for lamotrigine, which was moderately active against HHV-6B, several antiepileptic drugs were shown to have no activity. We included several compounds which we previously described as potent HHV-6 inhibitors, i.e., the non-nucleoside inhibitor CMV423 and the acyclic nucleoside phosphonate analogues cidofovir and 9-( S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-3-deazaadenine. The latter compound exhibited remarkable anti-HHV-6 activity. Conclusion Further optimization of compounds belonging to diverse classes of antiherpetic agents, for their specific action against HHV-6, is warranted.

Mechanisms by which acyclovir reduces the oxidative neurotoxicity and biosynthesis of quinolinic acid

The concentration of the endogenous neurotoxin quinolinic acid (QA) is increased in the central nervous system of mice with herpes simplex encephalitis. We have previously shown that the antiherpetic agent acyclovir (AC) has the ability to reduce QA-induced neuronal damage in rat brain, by attenuating lipid peroxidation. The mechanism by which QA induces lipid peroxidation includes the enhancement of the iron (Fe)-mediated Fenton reaction and the generation of free radicals, such as the superoxide anion (O 2 − ). Thus, the present study determined whether AC has the ability to reduce Fe 2+-induced lipid peroxidation, O 2 − generation and QA-induced superoxide anion generation, and to bind free Fe. O 2 − and Fe 2+ are also cofactors of the enzymes, indoleamine-2,3-dioxygenase (IDO) and 3-hydroxyanthranilate-3,4-dioxygenase (3-HAO) respectively. These enzymes catalyse steps in the biosynthesis of QA; thus, the effect of AC on their activity was also investigated. AC significantly attenuates Fe 2+-induced lipid peroxidation and O 2 − generation. AC reduces O 2 − generation in the presence of QA and strongly binds Fe 2+ and Fe 3+. It also reduces the activity of both IDO and 3-HAO, which could be attributed to the superoxide anion scavenging and iron binding properties, respectively, of this drug.

Tricyclic nucleoside analogues as antiherpes agents

Tricyclic (T) guanine analogues are a class of compounds in which the N1 and N 2 atoms of the guanine system are linked by etheno bridge to form the 3,9-dihydro-9-oxo-5H-imidazo[1,2-a]purine system. Almost 70 tricyclic derivatives of guanine-type potent antiherpetic agents acyclovir (ACV), ganciclovir (GCV) and 9-{[cis-1′,2′-bis(hydroxymethyl)cycloprop-1′-yl]methyl}guanine were synthesized and evaluated for activity against viruses of the herpes family. Here, we review the most successful compounds in terms of their antiviral activity and physico-chemical properties. These features are modulated by the kind and position of additional substituents present in the appended third ring of aglycone. The best antiherpetic activity–fluorescence combinations as well as activity of compounds in comparison to parent congeners are summarized. The data presented indicate that compounds of the 6-(4-RPh) family are of particular importance because of their advantageous antiviral potency, increased lipophilicity and good or moderate fluorescence properties.

Synthesis and biological activity of tricyclic analogues of 9-{[ cis-1′,2′-bis(hydroxymethyl)cycloprop-1′-yl]methyl}guanine

The base moiety of the potent antiherpetic agent 9-{[ cis-1′,2′-bis(hydroxymethyl)cycloprop-1′-yl]methyl}guanine 3 was transformed into that of the tricyclic 3,9-dihydro-9-oxo-6- R-5 H-imidazo[1,2- a]purine system. The tricyclic analogues 5a– d were evaluated for their activity against herpes viruses as well as for cytostatic activity against HSV-1 thymidine kinase (TK) gene-transduced human osteosarcoma tumor cells. Marked activity was found against VZV. The 6-phenyl-substituted fluorescent analogues 5c and d were comparable to that of parent 3 in activity against the VZV strain YS and were 3-fold less active against the VZV strain OKA. The compounds 5a– d also showed marked activity against HSV-1 (KOS) and HSV-2 (G)—against the former generally approximately comparable to that of acyclovir 1a and one order of magnitude lower than 3; against the latter comparable to that of 1a and approximately 6- to 30-fold lower than that of 3. The most pronounced cytostatic activity (5-fold lower than that of 3) was exhibited by compounds 5c and d. Tricyclic analogues with pseudosugar moieties are intrinsically bio-active.

Extracts and molecules from medicinal plants against herpes simplex viruses

Herpes simplex viruses (HSV-1 and -2) are important pathogens for humans, especially in the case of highly susceptible adults. Moreover, HSV-2 has been reported to be a high risk factor for HIV infection. Therefore, the discovery of novel anti-HSV drugs deserves great efforts. In this paper, we review anti-HSV substances from natural sources, including both extracts and pure compounds from herbal medicines, reported in studies from several laboratories. The role of traditional medicine for the development of anti-HSV compounds is also discussed. Interestingly, it was found that traditional medicines, like Ayurvedic, traditional Chinese (TCM), Chakma medicines, are good and potential sources for promising anti-HSV drugs. A second objective of this review is to discuss several anti-HSV compounds with respect to their structure–activity relationship (SAR). A large number of small molecules, like phenolics, polyphenols, terpenes (e.g., mono-, di-, tri-), flavonoids, sugar-containing compounds, were found to be promising anti-herpetic agents. Our major conclusion is that natural products from medicinal plant extracts are very important source of anti-HSV agents.

Insecticidal activity of the pyrimidine nucleoside analogue (E)‐5‐(2‐bromovinyl)‐2′‐deoxyuridine (BVDU)

The insecticidal activity of the antiherpetic agent (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) was assessed in in vivo assays against the fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera, Noctuidae). BVDU, mixed into an artificial diet, caused a variety of effects, depending on the concentration used. Compared with controls, food intake was lower, larval growth was retarded and larval development was prolonged. The treated larvae formed smaller pupae and the hatching moths often showed morphogenetic defects. A higher mortality could be found in larval and pupal stages and was generally caused by moult disruption. A choice assay showed that BVDU has very slight feeding-deterrent properties, which only partly explain the toxic effects. The agent most probably acts through its cytostatic activity that has been described previously using cell lines of different insect species.

Construction of recombinant herpes simplex virus type I expressing green fluorescent protein without loss of any viral genes

For use in various applications in research on herpes simplex virus type 1, we attempted to generate recombinant HSV-1 expressing green fluorescent protein (GFP) without any loss of viral genes. Our results were as follows. (i) A recombinant HSV-1 (YK333), in which a GFP expression cassette driven by the Egr-1 promoter was inserted into the intergenic region between UL3 and UL4, was constructed. (ii) YK333 replicated as well as wild-type HSV-1 F strain in Vero cells. (iii) As one application of the recombinant YK333 for research on HSV-1, we developed a system to detect anti-herpetic activity, termed a fluorescence-based anti-viral assay. The 50% inhibitory concentration of ganciclovir for YK333 determined using our newly developed assay was comparable to that determined using a plaque reduction assay. YK333 will be a convenient tool for herpes simplex virus research, including such applications as monitoring of viral replication in vitro and in vivo, and rapid screening of potential anti-herpetic agents.

Novel Benzthiodiazepinones as Antiherpetic Agents: SAR Improvement of Therapeutic Index by Alterations of the Seven‐Membered Ring.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Novel Benzthiodiazepinones as antiherpetic agents: SAR improvement of therapeutic index by alterations of the seven-membered ring

A series of novel benzthiodiazepinones was studied as antiherpetic agents. Significant improvements in potency and therapeutic index in a viral replication assay were realized over the starting molecule. The role of stereospecific substitution on the diazepine ring and optimal nitrogen substitution were investigated.

Dimethyl sulfoxide blocks herpes simplex virus-1 productive infection in vitro acting at different stages with positive cooperativity. Application of micro-array analysis.

BackgroundDimethyl sulfoxide (DMSO) is frequently used at a concentration of up to 95% in the formulation of antiherpetic agents because of its properties as a skin penetration enhancer. Here, we have analyzed the effect of DMSO on several parameters of Herpes Simplex Virus replication.MethodsProductive infection levels of HSV-1 were determined by plaque assay or by reporter gene activity, and its DNA replication was estimated by PCR. Transcript levels were evaluated with HSV-specific DNA micro-arrays.ResultsDMSO blocks productive infection in vitro in different cell types with a 50% inhibitory concentration (IC50) from 0.7 to 2% depending upon the multiplicity of infection. The concentration dependence exhibits a Hill coefficient greater than 1, indicating that DMSO blocks productive infection by acting at multiple different points (mechanisms of action) with positive cooperativity. Consistently, we identified at least three distinct temporal target mechanisms for inhibition of virus growth by DMSO. At late stages of infection, DMSO reduces virion infectivity, and markedly inhibits viral DNA replication. A third mode of action was revealed using an oligonucleotide-based DNA microarray system for HSV. These experiments showed that DMSO reduced the transcript levels of many HSV-1 genes; including several genes coding for proteins involved in forming and assembling the virion. Also, DMSO markedly inhibited some but not all early transcripts indicating a previously unknown mode for inhibiting the early phase of HSV transcription-replication cycle.ConclusionThese observations suggest that DMSO itself may have a role in the anti-herpetic activity of formulations utilizing it as a dispersant.