Novel plant-derived recombinant human interferons with broad spectrum antiviral activity

Type I interferons (IFNs) are potent mediators of the innate immune response to viral infection. IFNs released from infected cells bind to a receptor (IFNAR) on neighboring cells, triggering signaling cascades that limit further infection. Subtle variations in amino acids can alter IFNAR binding and signaling outcomes. We used a new gene crossbreeding method to generate hybrid, type I human IFNs with enhanced antiviral activity against four dissimilar, highly pathogenic viruses. Approximately 1400 novel IFN genes were expressed in plants, and the resultant IFN proteins were screened for antiviral activity. Comparing the gene sequences of a final set of 12 potent IFNs to those of parent genes revealed strong selection pressures at numerous amino acids. Using three-dimensional models based on a recently solved experimental structure of IFN bound to IFNAR, we show that many but not all of the amino acids that were highly selected for are predicted to improve receptor binding.     

Ribavirin--current status of a broad spectrum antiviral agent

Ribavirin is a very broad-spectrum virustatic antiviral agent, first synthesised in 1972. It is characterised by low toxicity apart from reversible anaemia, usually mild. Its multiple mechanisms of action mean that viral resistance rarely develops. It can be administered orally, intravenously, or via a nebuliser. It has shown varying degrees of clinical efficacy in a variety of human diseases including respiratory tract infections due to respiratory syncytial virus and influenza, measles, herpesvirus infections, HIV infection, Lassa fever, haemorrhagic fever with renal syndrome, and (in combination with IFN-alpha) chronic hepatitis C infection. It may well prove of value against other emerging exotic infections (e.g., West Nile virus, Nipah virus).     

Novel broad spectrum β-lactamase inhibitors

The proliferation of pathogens expressing β-lactamases with extended spectrum and increased expression, decreased permeability and the presence of multiple β-lactamases in Gram-negative pathogens has compromised the empirical use of many β-lactam antibiotics, especially cephalosporins and now carbapenems. Theoretically, existing β-lactamase inhibitors could be used in combination with appropriate β-lactams to overcome resistance mediated by extended spectrum β-lactamases, but new β-lactamase inhibitors with broader spectra, including activity against Class C β-lactamases, should prove useful in combination with β-lactams, particularly cephalosporins or carbapenems, against problematic strains. To design and optimize inhibitors with broad enzyme inhibitory activity that will be useful in therapy, drug design must encompass, along with measures of enzyme inhibition, concomitant assessment of these inhibitors in synergizing selected β-lactams in whole cell antibacterial assays.     

Fluorocyclopentenyl-cytosine with broad spectrum and potent antitumor activity

On the basis of the potent biological activity of cyclopentenyl-pyrimidines, fluorocyclopentenyl-pyrimidines were designed and synthesized from D-ribose. Among these, the cytosine derivative 5a showed highly potent antigrowth effects in a broad range of tumor cell lines and very potent antitumor activity in a nude mouse tumor xenograft model implanted with A549 human lung cancer cells. However, its 2'-deoxycytidine derivative 5b did not show any antigrowth effects, indicating that 2'-hydroxyl group is essential for the biological activity.     

Synthesis of new 3-methylthio-5-aryl-4-isothiazolecarbonitriles with broad antiviral spectrum

The isothiazole derivative 3-methylthio-5-(4-OBn-phenyl)-4-isothiazolecarbonitrile, coded IS-50, which in previous studies had exhibited a broad antipicornavirus spectrum of action, was selected as the model for the synthesis of a new series of 3-methylthio-5-aryl-4-isothiazolecarbonitriles. These compounds were prepared in good yield (from 66 to 82%) by alkylation of 3-methylthio-5-(4-hydroxyphenyl)-4-isothiazolecarbonitrile with suitable bromides in the presence of acetone; only the 4-cyanophenoxy derivatives were obtained in a yield of less than 30%. All the compounds were screened against a panel of 17 representative human rhinovirus (HRV) serotypes belonging to both A and B groups, enteroviruses polio 1, ECHO 9 and Coxsackie B1, cardiovirus EMC, measles virus, and herpes simplex virus type 1 (HSV-1). Our results demonstrate that HRV 86 (group A) and HRVs 39 and 89 (group B) are the rhinovirus serotypes more susceptible to the action of these compounds. Isothiazole derivatives with a longer intermediate alkyl chain exhibited good activity against polio 1 and ECHO 9. The compound bearing a butyl group between the two phenoxy rings showed the lowest IC(50) against Coxsackie B1 and measles viruses. No activity against HSV-1 was detected with any of the compounds screened.     

Sequence changes in the human adenovirus type 5 DNA polymerase associated with resistance to the broad spectrum antiviral cidofovir

Although there is currently no FDA approved antiviral treatment for adenovirus (Ad) infections, the broad spectrum antiviral cidofovir (CDV) has demonstrated potent inhibitory activity against many Ad serotypes in vitro and in an in vivo ocular replication model. The clinical potential of CDV prompted the assessment for the emergence of CDV resistance in Ad5. Serial passage of Ad5 in increasing concentrations of CDV resulted in derivation of four different Ad5 variants with increased resistance to CDV. CDV resistance was demonstrated by ability to replicate viral DNA in infected cells at CDV concentrations that inhibit the parental virus, by ability to form plaques in CDV concentrations of >20 microg/ml and by increased progeny release following infection and growth in media containing CDV. Using marker rescue, the loci for CDV resistance in variant R1 was shown to be mediated by one residue change L741S, one of two mutations within the R1 encoded DNA polymerase. The CDV-resistant variants R4, R5 and R6 also contained mutations in their respective DNA polymerase sequences, but these were different from R1; variant R4 contained two changes (F740I and V180I), whereas both R5 and R6 variants contained the non-conserved mutation A359E. R6 contained additional alterations L554F and V817L. The location of the R1 change is close to a region of the DNA polymerase which is conserved with other polymerases that is predicted to involve nucleotide binding.     

Lipoproteins account for part of the broad non-specific antiviral activity of human serum.

Several antiviral substances have been detected in human serum but few have been shown to possess broad antiviral activity. These broadly active antiviral molecules could be of significance as innate defense mechanisms. We have previously identified and characterized a broadly antiviral glycoprotein, UTI3, which accounts for 50 antiviral units/ml of human and mammalian sera. In addition there are reports of antiviral activity of human serum apolipoprotein A-1 (apo A-1), an important constituent of high density lipoprotein (HDL), against human immunodeficiency virus (HIV) and herpesvirus. Therefore we investigated (1) whether HDL is broadly antiviral, (2) how much of the broad antiviral activity of serum is due to HDL, and (3) the mechanism(s) of HDL's antiviral action. In this paper we report that (1) HDL does have broad antiviral activity, (2) HDL accounts for a modest but significant portion of the antiviral activity of serum, and (3) HDL acts by preventing virus penetration. Overall, HDL may be one of the broadly antiviral defences in the bloodstream.     

广谱抗病毒抗生素17997体内外抗病毒活性研究

从我国云南省土壤中分离到１株放线菌，基们生的抗生素１７９９７具有广谱抗病毒作用在细菌培养内对单纯疱疹病毒１型，单纯疱疹病毒２型，人免疫缺陷病毒１型，水疱性口炎病毒及柯萨奇病毒Ｂ３均有显著抑制活性，ＩＣ５０在μｍｏｌ／Ｌ水平。其在小鼠体内对单纯疱疹病毒１型及２型所致疱疹性脑炎有确切治疗效果，对死亡保护率平均生存日与对照组相比有统计意义的显著差别。     

Potentiation of interferon action by mixtures of recombinant DNA-derived human interferons

Natural and essentially pure recombinant DNA-derived HuIFN-alpha and HuIFN-gamma were examined for their relative abilities to potentiate interferon action. Potentiation of human interferon's antiviral and antiproliferative activities were studied. The essentially pure recombinant DNA-derived human interferons were found to be as effective in their potentiating interactions as their natural counterparts. The results demonstrate that it is the human interferons themselves which interact to potentiate human interferon's varied activities.     

Metvan: a novel oxovanadium(IV) complex with broad spectrum anticancer activity

Among the 25 bis(cyclopentadienyl)vanadium(IV) and 14 oxovanadium(IV) compounds synthesised and evaluated for anticancer activity, bis(4,7-dimethyl-1,10-phenanthroline) sulfatooxovanadium(IV) (metvan) was identified as the most promising multitargeted anticancer vanadium complex with apoptosis-inducing activity. At nanomolar and low micromolar concentrations, metvan induces apoptosis in human leukaemia cells, multiple myeloma cells and solid tumour cells derived from breast cancer, glioblastoma, ovarian, prostate and testicular cancer patients. It is highly effective against cisplatin-resistant ovarian cancer and testicular cancer cell lines. Metvan is much more effective than the standard chemotherapeutic agents dexamethasone and vincristine in inducing apoptosis in primary leukaemia cells from patients with acute lymphoblastic leukaemia, acute myeloid leukaemia or chronic acute myeloid leukaemia. Metvan-induced apoptosis is associated with a loss of mitochondrial transmembrane potential, the generation of reactive oxygen species and depletion of glutathione. Treatment of leukaemia cells from acute lymphoblastic leukaemia, acute myeloid leukaemia and chronic acute myeloid leukaemia patients with metvan inhibits the constitutive expression as well as the gelatinolytic activities of matrix metalloproteinase-9 and -2. Treatment of human malignant glioblastoma and breast cancer cells with metvan at concentrations > 1 microM is associated with a nearly complete loss of the adhesive, migratory and invasive properties of the treated cancer cell populations. Metvan shows favourable pharmacokinetics in mice and does not cause acute or subacute toxicity at the dose levels tested (12.5 - 50 mg/kg). Therapeutic plasma concentrations > or = 5 microM, which are highly cytotoxic against human cancer cells, can be rapidly achieved and maintained in mice for at least 24 h after intraperitoneal bolus injection of a single 10 mg/kg non-toxic dose of metvan. Metvan exhibits significant antitumour activity, delays tumour progression and prolongs survival time in severe combined immunodeficient mouse xenograft models of human malignant glioblastoma and breast cancer. The broad spectrum anticancer activity of metvan together with favourable pharmacodynamic features and lack of toxicity warrants further development of this oxovanadium compound as a new anticancer agent. Metvan could represent the first vanadium complex as an alternative to platinum-based chemotherapy.     

Triazolam is more efficacious than diazepam in a broad spectrum of recombinant GABAA receptors

Benzodiazepine-induced modifications of GABA (γ-aminobutyric acid) activated Cl⁻ currents were studied in native GABA_A receptors expressed in neonatal rat brain cortical neurons in primary cultures and in recombinant GABA_A receptors expressed in transformed human embryonic kidney cells (293) after a transient transfection with cDNAs encoding for different molecular forms of α, β, and γ subunits of GABA_A receptors. The efficacy of triazolam in cortical neurons was higher than that of diazepam. In transfected cells, triazolam showed a greater efficacy as a positive modulator of GABA-elicited Cl⁻ currents in α1β1γ1, α1β1γ2, α1β1γ3, α6β1γ2 and α1β3γ2 receptors than diazepam, except in α3β1γ2 receptors where diazepam was more efficacious. When triazolam and diazepam were applied together to GABA_A receptors assembled by transfecting cDNAs encoding for α1β1γ1 subunits, the action of triazolam was curtailed in a manner related to the dose of diazepam. In recombinant receptors assembled with α1β1γ1 receptors, maximally active doses of triazolam were more efficacious than those of clonazepam, alpidem, zolpidem, diazepam or bretazenil.     

In vitro antimicrobial activity of cefpirome, a new cephalosporin with a broad antimicrobial spectrum

The in vitro activity of cefpirome (HR 810), a new cephalosporin antibiotic having a 2,3-cyclopentenopyridine group in the 3-position side chain, was compared with in vitro activities of 5 other cephalosporins. HR 810 showed a broad spectrum of antimicrobial activity against Gram-positive and Gram-negative bacteria when tested using 71 standard strains and 876 clinical isolates. HR 810 inhibited 70% of the clinically isolated Staphylococcus aureus and Staphylococcus epidermidis strains when used at 0.59-0.84 microgram/ml, 2- to 25-fold lower than values of reference antibiotics, and the compound was also highly effective against Enterococcus faecalis which is relatively resistant to most of the existing cephem antibiotics. The activity of HR 810 against Enterobacteriaceae members (11 species), based on its minimal inhibitory concentrations inhibiting 90% of bacterial growth (MIC90S), was the highest among the cephalosporins used. Especially against Enterobacter species and Citrobacter freundii, the MIC90S of the compound were 4- to 64-fold lower than the values of the other antibiotics. Against Pseudomonas aeruginosa, HR 810 was as active as cefoperazone, an antipseudomonal agent. The minimal bactericidal concentrations (MBCs) of HR 810 were equal to or only 2-fold greater than the MICs for most of 12 standard strains tested. The compound markedly decreased viable bacterial counts at its MICs, thus showing strong bactericidal activities. The in vitro activity of HR 810 was not affected by pH or human serum content of agar media, but the activity against Gram-negative bacteria was lowered as the inoculum size increased.     

Pregabalin may represent a novel class of anxiolytic agents with a broad spectrum of activity

The present study examines the effect of pregabalin (previously S-Isobutylgaba and CI-1008) in two distinct rat models of anxiety. Pregabalin binds with high affinity and selectivity to the alpha(2)delta subunit of voltage dependent calcium channels (VDCC). Its corresponding R-enantiomer (R-isobutylgaba) is approximately 10 fold weaker. Pregabalin dose-dependently induced anxiolytic-like effects in both the rat conflict test and elevated X-maze with respective minimum effective doses (MED) of 3 and 10 mg kg(-1). In contrast, R-isobutylgaba only showed activity at the highest dose of 100 mg kg(-1) in the conflict test. These data indicate that pregabalin may possess clinical utility as a novel anxiolytic agent and demonstrates the importance of the alpha(2)delta subunit of VDCC in the mediation of anxiety related behaviours.     

抗分枝杆菌植物天然产物研究进展

由分枝杆菌引起的感染是人类健康的巨大威胁。目前,多种结核分枝杆菌和非结核分枝杆菌对临床抗分枝杆菌药物具有较高的耐药性。中药治疗分枝杆菌感染具有悠久历史。例如,中药材狼毒已应用于抗结核分枝杆菌的治疗。非中药来源的植物中,也蕴含丰富的抗分枝杆菌成分。这些植物来源的天然产物具有较好的结构多样性,是开发抗分枝杆菌药物的潜在来源。本文综述了近年来在中药和其他非中药来源植物中发现的,具有良好抗分枝杆菌活性的化合物或提取物,并介绍了它们的作用机制。这些活性植物天然产物为新抗分枝杆菌药物的发现提供了化合物库。同时,这些植物天然产物结构与现有抗分枝杆菌药物具有显著的差别,研究其作用机制,也可发现新的抗分枝杆菌靶标。     

Novel potential agents for human cytomegalovirus infection: synthesis and antiviral activity evaluation of benzothiadiazine dioxide acyclonucleosides

The first acyclonucleosides based on the benzothiadiazine dioxide system were synthesized following the silylation procedure. Several acyclic moieties, including acetoxyethoxymethyl, benzyloxymethyl, and propargyloxymethyl groups, were introduced. Two synthetic strategies were designed to selectively obtain the N-1 or N-3 derivatives. Lipase-mediated deacylation was used for the deprotection of the acyclonucleosides. Some of the benzothiadiazine dioxide acyclonucleosides, in particular 16, proved active against human cytomegalovirus (CMV) at concentrations slightly higher than that found for ganciclovir [50% inhibitory concentration (IC50) = 3. 5-3.7 micrograms/mL, cytotoxicity (CC50) >/= 40 micrograms/mL, MCC = 20 micrograms/mL]. Additionally, compound 16 inhibited the replication of human immunodeficiency virus type 1 (HIV-1) and HIV-2 in CEM cells at concentrations that were 5-fold lower than its cytotoxic concentration.