RESUMO
BACKGROUND AND PURPOSE: Curcuma longa L. (CL), an Indian herb, has been used to treat many disorders because of its wide spectrum of pharmacological activities. It has been shown to exhibit anti-oxidant and anti-inflammatory properties, and is being used as herbal remedy since ancient times. Osteoarthritis of knee (KOA) is a chronic painful disorder in which prolong use of non-steroidal anti-inflammatory drugs (NSAIDs) or steroids may result into many serious side effects; hence, there is a need to develop herbal drugs, having good analgesia without side effects. Therefore, we planned to evaluate the efficacy of CL in KOA. METHODS: The study was designed as a randomized, double-blind, placebo-controlled trial in patients of KOA. After obtaining ethical clearance and written informed consent, a total of 160 patients of KOA were randomly enrolled into two groups to receive either CL extract or placebo along with the standard drug regimen. The patients were assessed on day 0, day 60, and day 120. On the days of their visit, the clinical prognosis was assessed by visual analog scale (VAS) and Western Ontario and McMaster Universities (WOMAC) Osteoarthritis index. On these days, the radiographs were also taken for Kellgren and Lawrence grading and blood samples were collected for assessing the changes in levels of IL-1ß and biomarkers of oxidative stress, such as reactive oxygen species and malondialdehyde (MDA). RESULTS: Over all significant improvement was observed in the patients of CL extract group as compared to placebo group. Clinically, the VAS and WOMAC scores became better, and simultaneously, the levels of biomarkers, viz., IL-1ß, ROS, and MDA, were also significantly (p < 0.05) improved. CONCLUSION: It may be concluded that on chronic administration, CL suppresses inflammation and brings clinical improvement in patients of KOA, which may be observed by decreased level of IL-1ß and VAS/WOMAC scores, respectively. At the same time, CL decreases the oxidative stress also.
Assuntos
Anti-Inflamatórios/uso terapêutico , Curcuma/química , Osteoartrite do Joelho/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/uso terapêutico , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/isolamento & purificação , Biomarcadores/sangue , Método Duplo-Cego , Feminino , Humanos , Interleucina-1beta/sangue , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Osteoartrite do Joelho/sangue , Osteoartrite do Joelho/imunologia , Medição da Dor/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/isolamento & purificação , Espécies Reativas de Oxigênio/sangue , Recuperação de Função FisiológicaRESUMO
BACKGROUND: Use of sedative agents for difficult to manage children during dental procedures has been indicated for years, but neither the agent nor the route has been found to be ideal. OBJECTIVES: The aim of the study was to evaluate and compare the efficacy and safety of oral dexmedetomidine (D) and ketamine (K) in producing moderate sedation among uncooperative pediatric dental patients. METHODS: This prospective, triple-blind, randomized comparative study included 112 ASA grade I children of both sexes aged 3-10 years, who satisfied all the inclusion criteria. They were randomly divided into four groups and ketamine 8 mg·kg(-1) (K) or dexmedetomidine 3 µg·kg(-1) (D1), 4 µg·kg(-1) (D2) and 5 µg·kg(-1) (D3) were given orally. Similar dental procedures were performed in these patients, and effects of these drugs were assessed in terms of changes in vital signs, onset and duration of sedation, analgesia, and amnesia. Secondary outcomes such as level of sedation, behavior, adverse effects, and overall success were also measured. RESULTS: The onset of sedation was significantly rapid with K and D3 as compared to D1 and D2. Recovery from sedation was fastest in group D1. Intra- and postoperative analgesia and anterograde amnesia were highest with K and least with D1, while D3 produced analgesia comparable to K. In K treated group, vomiting was observed in five patients and two patients exhibited emergence phenomenon. Overall, highest success rate was observed in D3 group. CONCLUSIONS: Given by oral route, the novel sedative dexmedetomidine provides dose-dependent effective analgo-sedation, comparable to ketamine, with less adverse effects.
Assuntos
Analgésicos não Narcóticos/uso terapêutico , Anestesia Dentária/métodos , Anestésicos Dissociativos/uso terapêutico , Dexmedetomidina/uso terapêutico , Hipnóticos e Sedativos/uso terapêutico , Ketamina/uso terapêutico , Administração Oral , Analgésicos não Narcóticos/efeitos adversos , Período de Recuperação da Anestesia , Anestésicos Dissociativos/efeitos adversos , Criança , Pré-Escolar , Sedação Consciente , Dexmedetomidina/efeitos adversos , Feminino , Humanos , Hipnóticos e Sedativos/efeitos adversos , Ketamina/efeitos adversos , Masculino , Estudos ProspectivosRESUMO
A highly efficient and practical route to 3,4-isopropylidene proline I, starting from (+)-3-carene, was developed. The three continuous stereocenters were constructed using the inherent chirality of the starting natural product 2. The overall yield for the 12-step synthesis is 34%. The optimized sequence leading to 1 has been successfully applied on a multigram scale, thereby establishing the practicality of this route.
Assuntos
Compostos Alílicos/síntese química , Monoterpenos/química , Prolina/análogos & derivados , Prolina/síntese química , Compostos Alílicos/química , Monoterpenos Bicíclicos , Catálise , Cromatografia em Gel , Ciclização , Dados de Sequência Molecular , Estrutura Molecular , Prolina/química , EstereoisomerismoRESUMO
In the search for a second generation HCV protease inhibitor, molecular modeling studies of the X-ray crystal structure of Boceprevir1 bound to the NS3 protein suggest that expansion into the S4 pocket could provide additional hydrophobic Van der Waals interactions. Effective replacement of the P4 tert-butyl with a cyclohexylmethyl ligand led to inhibitor 2 with improved enzyme and replicon activities. Subsequent modeling and SAR studies led to the pyridine 38 and sulfone analogues 52 and 53 with vastly improved PK parameters in monkeys, forming a new foundation for further exploration.
Assuntos
Antivirais/química , Prolina/análogos & derivados , Inibidores de Proteases/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/farmacocinética , Antivirais/farmacologia , Área Sob a Curva , Disponibilidade Biológica , Cristalografia por Raios X , Haplorrinos , Modelos Moleculares , Prolina/química , Prolina/farmacocinética , Prolina/farmacologia , Inibidores de Proteases/farmacocinética , Inibidores de Proteases/farmacologia , Ratos , Relação Estrutura-AtividadeRESUMO
CONTEXT: The worldwide prevalence of rheumatoid arthritis (RA) is about 1%, whereas in India, it is approximately 0.75%. The current therapy for RA includes nonsteroidal anti-inflammatory drugs corticosteroids, disease-modifying anti-rheumatic drugs and some recently developed biologic agents, but all of these are associated with adverse effects. Some herbal drugs, such as Boswellia serrata, have been reported to possess anti-inflammatory activity. AIMS: The aim of this study is to evaluate the anti-arthritic activity of Boswellia serrata extract (BSE) in complete Freund's adjuvant (CFA)-induced arthritis in rats. MATERIALS AND METHODS: Thirty-six Wistar rats were divided into six equal groups. RA was induced by intradermal injection of 0.1 ml CFA in hind paw. Body weight, ankle diameter, paw volume, arthritic index, tumor necrosis factor-α (TNF-α), and histopathological examination were assessed. The experimental data were statistically assessed by one-way analysis of variance (ANOVA). STATISTICAL ANALYSIS USED: The recorded data were analyzed using paired t-test and ANOVA test using SPSS. The data were analyzed and represented as mean difference. Value of P < 0.05 was considered statistically significant. RESULTS: BSE at dose 180 mg/kg showed statistically significant improvement in body weight and decrease in ankle diameter and arthritic index (P < 0.05); however, there was insignificant change in paw volume (P = 0.056). This improvement was comparable with Indomethacin. The level of TNF-α did not show any statistically significant change (P = 0.076). Histopathological results also exhibited a reduction in inflammatory parameters. CONCLUSIONS: BSE might have usefulness as an adjunct to conventional therapy of RA.
RESUMO
An issue of clinical importance in the development of new antivirals for HCV is emergence of resistance. Several resistance loci to ketoamide inhibitors of the NS3/4A protease have been identified (residues V36, T54, R155, A156, and V170) by replicon and clinical studies. Using SCH 567312, a more potent protease inhibitor derived from SCH 503034 (boceprevir) series, we identified two new positions (Q41 and F43) that confer resistance to the ketoamide class. The catalytic efficiency of protease enzymes was not affected by most resistance mutations, whereas replicon fitness varied with specific mutations. SCH 503034 and another ketoamide inhibitor, VX-950 (telaprevir), showed moderate losses of activity against most resistance mutations (< or =10-fold); the highest resistance level was conferred by mutations at A156 locus. Although SCH 503034 and VX-950 bind similarly to the active site, differences in resistance level were observed with specific mutations. Changes at V36 and R155 had more severe impact on VX-950, whereas mutations at Q41, F43 and V170 conferred higher resistance to SCH 503034. Structural analysis of resistance mutations on inhibitor binding is discussed.
Assuntos
Antivirais/farmacologia , Farmacorresistência Viral , Hepacivirus/efeitos dos fármacos , Hepacivirus/genética , Mutação de Sentido Incorreto , Inibidores de Proteases/farmacologia , Proteínas de Transporte/metabolismo , Hepacivirus/fisiologia , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Modelos Moleculares , Estrutura Molecular , Oligopeptídeos/farmacologia , Prolina/análogos & derivados , Prolina/farmacologia , Inibidores de Proteases/química , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/metabolismo , Proteínas Virais/metabolismo , Replicação Viral/fisiologiaRESUMO
Posaconazole (SCH 56592) is a novel triazole antifungal drug that is marketed in Europe and the United States under the trade name 'Noxafil' for prophylaxis against invasive fungal infections. SCH 56592 was discovered as a possible active metabolite of SCH 51048, an earlier lead. Initial studies have shown that serum concentrations determined by a microbiological assay were higher than those determined by HPLC from animals dosed with SCH 51048. Subsequently, several animals species were dosed with (3)H-SCH 51048 and the serum was analyzed for total radioactivity, SCH 51048 concentration and antifungal activity. The antifungal activity was higher than that expected based on SCH 51048 serum concentrations, confirming the presence of active metabolite(s). Metabolite profiling of serum samples at selected time intervals pinpointed the peak that was suspected to be the active metabolite. Consequently, (3)H-SCH 51048 was administered to a large group of mice, the serum was harvested and the metabolite was isolated by extraction and semipreparative HPLC. LC-MS/MS analysis suggested that the active metabolite is a secondary alcohol with the hydroxyl group in the aliphatic side chain of SCH 51048. All corresponding monohydroxylated diastereomeric mixtures were synthesized and characterized. The HPLC retention time and LC-MS/MS spectra of the diastereomeric secondary alcohols of SCH 51048 were similar to those of the isolated active metabolite. Finally, all corresponding individual monohydroxylated diasteriomers were synthesized and evaluated for in vitro and in vivo antifungal potencies, as well as pharmacokinetics. SCH 56592 emerged as the candidate with the best overall profile.
Assuntos
Antifúngicos/análise , Antifúngicos/farmacocinética , Espectrometria de Massas , Triazóis/análise , Triazóis/farmacocinética , Animais , Antifúngicos/sangue , Cromatografia Líquida de Alta Pressão , Cães , Desenho de Fármacos , Macaca fascicularis , Masculino , Camundongos , Camundongos Endogâmicos , Coelhos , Triazóis/sangueRESUMO
OBJECTIVES: The objective of this study was to assess the safety and efficacy of intranasal and oral dexmedetomidine for procedural sedation in pediatric dental patients. MATERIALS AND METHODS: Forty-four uncooperative American Society of Anesthesiologists Grade-I children, requiring dental treatment were randomly divided into four groups who received different doses of dexmedetomidine through intranasal and oral routes. The vital signs were monitored continuously during each visit. RESULTS: In this study, significant (P < 0.05) differences were found in the onset of sedation, duration, and recovery time between intranasal and oral groups. All vital signs were within normal physiological limits with no significant adverse effects in either of the groups. CONCLUSION: Dexmedetomidine is a safe and effective agent for procedural sedation in pediatric dental patients with intranasal route having distinct advantages over oral route.
Assuntos
Dexmedetomidina/administração & dosagem , Administração Intranasal , Administração Oral , Criança , Pré-Escolar , Dexmedetomidina/efeitos adversos , Humanos , SegurançaRESUMO
The structures of both the native holo-HCV NS3/4A protease domain and the protease domain with a serine 139 to alanine (S139A) mutation were solved to high resolution. Subsequently, structures were determined for a series of ketoamide inhibitors in complex with the protease. The changes in the inhibitor potency were correlated with changes in the buried surface area upon binding the inhibitor to the active site. The largest contribution to the binding energy arises from the hydrophobic interactions of the P1 and P2 groups as they bind to the S1 and S2 pockets [the numbering of the subsites is as defined in Berger, A.; Schechter, I. Philos. Trans. R. Soc. London, Ser. B 1970, 257, 249-264]. This correlation of the changes in potency with increased buried surface area contributed directly to the design of a potent tripeptide inhibitor of the HCV NS3/4A protease that is currently in clinical trials.
Assuntos
Antivirais/síntese química , Proteínas de Transporte/antagonistas & inibidores , Proteínas de Transporte/química , Hepacivirus/enzimologia , Prolina/análogos & derivados , Inibidores de Serina Proteinase/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas não Estruturais Virais/química , Proteínas Virais/antagonistas & inibidores , Proteínas Virais/química , Antivirais/química , Sítios de Ligação , Cristalografia por Raios X , Peptídeos e Proteínas de Sinalização Intracelular , Modelos Moleculares , Prolina/síntese química , Prolina/química , Conformação Proteica , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Background:To study the prescription behavior of oral contraceptive pills (OCPs) by physicians, gynecologists, and alternative medicine practitioners (AMPs). Materials and Methods?Close-ended questionnaire-based cross-section study was performed between 1st September 2012 and 28th February 2014 in three groups of responders, i.e., AMP, general medical practitioners (GMPs), and obstetricians and gynecologists (ObGy). A stratified random cluster sample was used. Data of 400 subjects in all three groups were obtained using both univariate and multi-variate sophisticated statistical analyses for analyzing attitude and practices and were recorded on an ordinal scale using appropriate non-parametric test. Results?Of the 1,237 subjects surveyed, 400 completed questionnaires were received from each of the three groups viz; AMPs, GMPs, and ObGy. Remaining 37 incomplete questionnaires were not included in the final analysis. Conclusion?There are equal misconceptions regarding OCPs among users and prescribing physicians. Preference for OCPs in married and unmarried women is also equally low. OCP usage and their prescription practices can be improved by removing potential barriers, developing public–private partnership, and training promoters.
RESUMO
Introduction of various modified prolines at P(2) and optimization of the P(1) side chain led to the discovery of SCH6 (24, Table 2), a potent ketoamide inhibitor of the HCV NS3 serine protease. In addition to excellent enzyme potency (K(i)*= 3.8 nM), 24 was also found to be a potent inhibitor of HCV subgenomic RNA replication with IC(50) and IC(90) of 40 and 100 nM, respectively. Recently, antiviral activity of 24 was demonstrated with inhibition of the full-length genotype 2a HCV genome. In addition, 24 was found to restore the responsiveness of the interferon regulatory factor 3 (IRF-3) in cells containing HCV RNA replicons.
Assuntos
Amidas/química , Amidas/farmacologia , Genoma Viral/genética , Hepacivirus/efeitos dos fármacos , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Serina Endopeptidases/metabolismo , Animais , Haplorrinos , Hepacivirus/enzimologia , Hepacivirus/genética , Modelos Moleculares , Estrutura Molecular , RNA Viral/genética , Ratos , Serina Endopeptidases/química , Inibidores de Serina Proteinase/química , Inibidores de Serina Proteinase/farmacologia , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/metabolismoRESUMO
Hepatitis C virus (HCV) infection is the major cause of chronic liver disease, leading to cirrhosis and hepatocellular carcinoma, which affects more than 170 million people worldwide. Currently the only therapeutic regimens are subcutaneous interferon-alpha or polyethylene glycol (PEG)-interferon-alpha alone or in combination with oral ribavirin. Although combination therapy is reasonably successful with the majority of genotypes, its efficacy against the predominant genotype (genotype 1) is moderate at best, with only about 40% of the patients showing sustained virological response. Herein, the SAR leading to the discovery of 70 (SCH 503034), a novel, potent, selective, orally bioavailable NS3 protease inhibitor that has been advanced to clinical trials in human beings for the treatment of hepatitis C viral infections is described. X-ray structure of inhibitor 70 complexed with the NS3 protease and biological data are also discussed.
Assuntos
Antivirais/síntese química , Hepacivirus/enzimologia , Prolina/análogos & derivados , Proteínas não Estruturais Virais/antagonistas & inibidores , Administração Oral , Animais , Antivirais/química , Antivirais/farmacocinética , Área Sob a Curva , Sítios de Ligação , Disponibilidade Biológica , Cristalografia por Raios X , Cães , Haplorrinos , Estrutura Molecular , Prolina/síntese química , Prolina/química , Prolina/farmacocinética , Ratos , Relação Estrutura-Atividade , Distribuição Tecidual , Proteínas não Estruturais Virais/químicaRESUMO
Electrospray ionization (ESI) quadrupole ion-trap tandem mass spectrometry (MS/MS) was utilized to characterize a class of complex oligosaccharide antibiotics (everninomicins) that include SCH 27899, everninomicin-D, amino everninomicin (SCH 27900), and SCH 49088 (containing a hydroxylamino-ether sugar). The addition of sodium chloride (approximately 1 microg/mL) facilitates the formation of abundant metal complex ions, and this was used because protonation does not readily occur for most of these compounds. The multiple-stage mass analysis (MS(n)) of the sodiated species provides an important series of fragment ions that are specific for sugar sequence and for some sugar-ring opening. These data suggest a general charge-remote fragmentation pattern with the sodium cation residing in a specific, central location of the sugar chain and fragmentation occurring to trim the end of the molecule. For protonated everninomicin (SCH 27900), however, the proton appears to be mobile during the collisional activation process, opening different fragmentation pathways depending on the proton location. The use of water and acetonitrile with 0.1% acetic acid as the solvent in ESI-MS promotes rapid hydrolysis of the central ortho ester, resulting in the formation of abundant sodiated products that are hydrated. These product ions of the hydrated molecules are likely formed by the same charge-remote fragmentation processes as those that occur for the unhydrolyzed precursor.
Assuntos
Aminoglicosídeos , Antibacterianos/análise , Oligossacarídeos/análise , Cromatografia Gasosa-Espectrometria de Massas , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Background: Rheumatoid arthritis (RA) is an immune-mediated arthropathy, so for the treatment disease modifying antirheumatoid drugs are required. In this study we are evaluating the immunomodulatory property of Boswellia serrata extract (BSE) as an alternative medicine.Methods: Complete Freund’s adjuvant (CFA), 0.1ml was injected intradermally in the footpad of left hind paw in 36 Wistar rats to induce RA. Animals were divided into 6 groups. BSE in the doses of 45mg/kg, 90mg/kg and 180mg/kg was administered and cyclophosphamide as standard drug. Various parameters as body weight, paw thickness, ankle diameter, paw volume, arthritis index, TNF- ? and histopathological changes were analyzed.Results: Marked reduction in paw thickness, ankle diameter, paw volume, arthritis index and an improved body weight was found in high dose BSE (180mg/kg) group but the effect was lesser than standard drug Cyclophosphamide.Conclusions: BSE has significant potential as an alternative medicine for treatment of autoimmune diseases like rheumatoid arthritis.
RESUMO
Boceprevir (SCH 503034), 1, a novel HCV NS3 serine protease inhibitor discovered in our laboratories, is currently undergoing phase III clinical trials. Detailed investigations toward a second generation protease inhibitor culminated in the discovery of narlaprevir (SCH 900518), 37, with improved potency (â¼10-fold over 1), pharmacokinetic profile and physicochemical characteristics, currently in phase II human trials. Exploration of synthetic sequence for preparation of 37 resulted in a route that required no silica gel purification for the entire synthesis.
RESUMO
Hepatitis C virus (HCV) infection is a global health crisis leading to liver cirrhosis, hepatocellular carcinoma, and liver failure in humans. Recently, we disclosed the discovery of Boceprevir, SCH 503034 (1), a novel, potent, selective, orally bioavailable NS3 protease inhibitor that is currently undergoing phase III clinical trials. Our efforts toward a second generation HCV NS3 serine protease inhibitor were directed at improving the overall profile of the inhibitor. This article will elaborate on our studies leading to the discovery of new P4 modified inhibitors with enhanced potency and improved oral bioavailability. Thus, introduction of ether and carbamate-derived P4 moieties resulted in improving the replicon potency significantly. Incorporation of the P' secondary amide residue afforded significant improvement in pharmacokinetic properties. Combining the preferred moieties, identified from comprehensive SAR studies, resulted in inhibitors that displayed superior potency and very good oral as well as target organ exposure in rats.
Assuntos
Descoberta de Drogas , Hepacivirus/enzimologia , Inibidores de Proteases/farmacologia , Inibidores de Proteases/farmacocinética , Proteínas não Estruturais Virais/antagonistas & inibidores , Amidas/química , Animais , Modelos Moleculares , Conformação Molecular , Inibidores de Proteases/síntese química , Inibidores de Proteases/química , Ratos , Relação Estrutura-AtividadeRESUMO
Hepatitis C is the most prevalent liver disease. Viral hepatitis C (HCV), a small (+)-RNA virus, infects chronically an estimated 300 million people worldwide. Results of Phase I clinical studies with our first generation HCV inhibitor Boceprevir, SCH 503034 (1), presented at the 56th Annual Meeting of the American Association for the Study of Liver Diseases (AASLD) were encouraging, and thus, additional human clinical studies are underway. In view of the positive data from our first generation compound, further work aimed at optimizing its overall profile was undertaken. Herein, we report that extension of our earlier inhibitor to the P(4) pocket and optimization of the P(1)' capping led to the discovery of new ketoamide inhibitors of the HCV NS3 serine protease with improved in vitro potency. In addition to being potent inhibitors of HCV subgenomic RNA replication, some of the new P(4)-capped inhibitors were also found to have improved PK profile.
Assuntos
Amidas/farmacologia , Descoberta de Drogas , Prolina/análogos & derivados , Inibidores de Serina Proteinase/farmacologia , Inibidores de Serina Proteinase/farmacocinética , Proteínas não Estruturais Virais/antagonistas & inibidores , Amidas/síntese química , Amidas/química , Animais , Sítios de Ligação , Genoma Viral/efeitos dos fármacos , Hepacivirus/efeitos dos fármacos , Hepacivirus/enzimologia , Hepacivirus/genética , Modelos Moleculares , Conformação Molecular , Prolina/química , Prolina/farmacologia , RNA Viral/efeitos dos fármacos , Ratos , Inibidores de Serina Proteinase/síntese química , Inibidores de Serina Proteinase/química , Estereoisomerismo , Relação Estrutura-Atividade , Replicação Viral/efeitos dos fármacosRESUMO
The structures of both native and S139A holo-HCV NS3/4A protease domain were solved to high resolution. Subsequently, structures were determined for a series of ketoamide inhibitors in complex with the protease. The changes in the inhibitor potency were correlated with changes in the buried surface area upon binding the inhibitor to the active site. The largest contributions to the binding energy arise from the hydrophobic interactions of the P1 and P2 groups as they bind to the S1 and S2 pockets. This correlation of the changes in potency with increased buried surface area contributed directly to the design of a potent tripeptide inhibitor of the HCV NS3/4A protease, which is currently in clinical trials.
Assuntos
Hepacivirus/enzimologia , Prolina/análogos & derivados , Inibidores de Proteases/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Modelos Moleculares , Estrutura Molecular , Prolina/químicaRESUMO
BACKGROUND: Current hepatitis C virus (HCV) therapies may cure approximately 60% of infections. They are often contraindicated or poorly tolerated, underscoring the need for safer and more effective drugs. A novel, alpha-ketoamide-derived, substrate-based inhibitor of the HCV serine protease (SCH446211) was developed. Compared with earlier reported inhibitors of similar chemical class, it has a P1'-P2' extension which provides extended interaction with the protease active site. The aim of this study was to evaluate the in vitro antiviral activity of SCH446211. METHODS: Binding constant of SCH446211 to HCV NS3 protease was measured with the chromogenic substrate in vitro cleavage assay. Cell-based activity of SCH446211 was evaluated in replicon cells, which are Huh-7 hepatoma cells stably transfected with a subgenomic HCV RNA as reported previously. After 72 h of incubation with SCH446211, viral transcription and protein expression were measured by real-time RT-PCR (TaqMan), quantitative in situ hybridization, immunoblot and indirect immunofluorescence. RESULTS: The binding constant of SCH446211 to HCV NS3 protease was 3.8 +/- 0.4 nM. HCV replication and protein expression were inhibited by SCH446211 in replicon cells as consistently shown by four techniques. In particular, based on quantitative real-time RT-PCR measurements, the IC50 and IC90 of SCH446211 were estimated to be 40 +/- 20 and 100 +/- 20 nM (n = 17), respectively. Long-term culture of replicon cells with SCH446211 reduced replicon RNA to <0.1 copy per cell. SCH446211 did not show cellular toxicity at concentrations up to 50 microM. CONCLUSIONS: SCH446211 is a potent inhibitor of HCV protease in vitro. Its extended interaction with the HCV NS3 protease active site is associated with potent in vitro antiviral activity. This observation is potentially a useful guide for development of future potent inhibitors against HCV NS3 protease.
Assuntos
Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Oligopeptídeos/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Hepacivirus/genética , RNA Viral/análise , RepliconRESUMO
Depeptidization efforts of the P(3)-P(2) region of P(3) capped alpha-ketoamide inhibitor of HCV NS3 serine protease 1 are reported. We clearly established that N-methylation of the P(2) nitrogen and modification of the P(2)' carboxylic acid terminus were essential for activity in the replicon assay.