Synthesis and anti-HCV activity evaluation of anilinoquinoline derivatives

Hepatitis C virus (HCV) infection is a main cause of chronic liver disease, leading to liver cirrhosis and hepatocellular carcinoma (HCC). The objective of our research was to develop effective agents against viral replication. Here, we have synthesized a series of anilinoquinoline derivatives. Based on a cell-based HCV replicon system, we observed that 2-(3'-nitroanilino)quinoline (18) exhibited anti-HCV activity with a 50% effective concentration (EC(50)) value of 7μM and a selective index (SI) value of 10. In addition, compound 18 possessed the inhibitory effect on HCV NS3/4A protease activity. Therefore, we concluded that the compound 18 possessed a potent activity against HCV replication and could provide as a new lead compound as anti-HCV inhibitor.     

Synthesis and anti-HCV activity of a new 2'-deoxy-2'-fluoro-2'-C-methyl nucleoside analogue

2'-Deoxy-2'-fluoro-2'-C-methyl nucleoside analogue 4 was designed and synthesized. Initial biological studies indicated that this compound showed promising activity against HCV replication.     

Synthesis,structure–activity relationships and biological evaluation of dehydroandrographolide and andrographolide derivatives as novel anti-hepatitis B virus agents

Dehydroandrographolide and andrographolide, two natural diterpenoids isolated from Andrographis paniculata possessed activity against HBV DNA replication with IC₅₀ values of 22.58 and 54.07 μM and low SI values of 8.7 and 3.7 in our random assay. Consequently, 48 derivatives of dehydroandrographolide and andrographolide were synthesized and evaluated for their anti-HBV properties to yield a series of active derivatives with lower cytotoxicity, including 14 derivatives against HBsAg secretion, 19 derivatives against HBeAg secretion and 38 derivatives against HBV DNA replication. Interestingly, compound 4e could inhibit not only HBsAg and HBeAg secretions but also HBV DNA replication with SI values of 20.3, 125.0 and 104.9. Furthermore, the most active compound 2c with SI value higher than 165.1 inhibiting HBV DNA replication was revealed with the optimal log P value of 1.78 and log D values. Structure–activity relationships (SARs) of the derivatives were disclosed for guiding the future research toward the discovery of new anti-HBV drugs.     

Inhibition of HIV-1 replication by a tricyclic coumarin GUT-70 in acutely and chronically infected cells

The anti-HIV-1 activity of GUT-70, a natural product derived from the stem bark of Chlophyllum brasiliense, was evaluated. GUT-70 inhibited HIV-1 replication in both acutely and chronically infected cells through suppression of NF-κB. Our results strengthen the idea that NF-κB pathway is one of the potential targets to control HIV-1 replication and that GUT-70 could serve as a lead compound to develop novel therapeutic agents against HIV-1 infection.     

Newer tetracycline derivatives: synthesis, anti-HIV, antimycobacterial activities and inhibition of HIV-1 integrase

A series of new tetracycline derivatives has been synthesized by reacting appropriate tetracyclines, formaldehyde and secondary amino (piperazino) function of fluoroquinolones using microwave irradiation with the yield ranging from 41 evaluated for its anti-HIV, antimycobacterial activities and HIV-1 integrase (IN) enzyme inhibition studies. Among the synthesized compounds, compound 10 was found to be the most promising compound active against HIV-1 replication with EC(50) of 5.2 microM and was nontoxic to the CEM cells until 200 microM, and MIC of 0.2 microg/mL against Mycobacterium tuberculosis, with moderate inhibition of both 3'-processing and strand transfer steps of HIV-1 IN.     

银胶菊(Parthenium hysterophorus)中抗TMV活性成分的分离及活性测定

采用活性跟踪法从银胶菊中分离获得抗病毒活性物质,经质谱和核磁共振分析,确定该物质为小白菊内酯.采用半叶枯斑法和叶圆盘法测定了其对烟草花叶病毒(Tobacco mosaic virus,TMV)的抑制效果,结果表明:0.2 mg/mL的小白菊内酯在混合接种和药液浸泡两种处理中均表现出较好的体外抑制TMV活性,其抑制率分别为69.0%和72.1%;在离体条件下对烟草叶圆盘中的烟草花叶病毒复制也具有良好的抑制效果,抑制率为72.3%.     

A Novel Cell Cycle Inhibitor Stalls Replication Forks and Activates S Phase Checkpoint

DNA replication checkpoint is activated in response to replication stresses. It maintains the integrity of stalled replication forks and prevents premature segregation of largely unreplicated chromosomes. In budding yeast, Mec1 and Rad53 kinases (homologous to mammalian ATM/ATR and Chk2 kinases, respectively) are the main effectors of this checkpoint control. Using a yeast based screen, we have identified acompound (named here ENA) which inhibits DNA replication and activatesMec1/Rad53 checkpoint. A brief exposure to this compound stops fork progression at or near replication origin and renders the forks incompetent to resume replication despite the presence of a functional checkpoint. ENA also inhibits DNA synthesis in mammalian cells leading to the activation of ATM/ATR pathway and the induction of apoptosis in a p53 independent manner. Interestingly, ENA acts as an effective antiproliferative agent against a subset of cancer cell lines and as an anti-tumor agent against human xenografts in mice. Thus, ENA is a potent cell cycle inhibitor with conceivable therapeutic potential.     

女贞子提取物主要活性组分及其抗丙型肝炎病毒复制活性分析

中药女贞子(Ligustrum lucidum,LL)具有肝保护和抗炎症作用.本研究分析女贞子提取物对丙型肝炎病毒(hepatitis C virus, HCV)复制的影响及其活性成分. 薄层层析法分离女贞子水提取物,获得5个分离组分. Real-time RT-PCR 和Western印迹发现,分离组分1和2 抑制HCV JFH1细胞感染模型中的JFH1病毒复制. 分离组分的高效液相色谱(high-performance liquid chromatography,HPLC)分析表明,熊果酸和齐墩果酸可能是组分1 和 2的抗病毒活性成分. 熊果酸和齐墩果酸抗病毒实验发现,熊果酸和齐墩果酸抑制HCV JFH1的复制,它们的选择指数 (SI) 分别为 6.7 和30.8. 这些研究结果表明,女贞子及其化学成分熊果酸和齐墩果酸具有潜在的丙型肝炎治疗价值.     

Novel 1,2,4-triazole and imidazole derivatives of L-ascorbic and imino-ascorbic acid: synthesis, anti-HCV and antitumor activity evaluations

Several novel 1,2,4-triazole and imidazole L-ascorbic acid (1, 2, 3, 5, 6 and 9) and imino-ascorbic acid (4, 7 and 8) derivatives were prepared and evaluated for their inhibitory activity against hepatitis C virus (HCV) replication and human tumour cell proliferation. Compounds 6 and 9 exerted the most pronounced cytostatic effects in all tumour cell lines tested, and were highly selective for human T-cell acute lymphoblastic leukaemia cells (CEM/0) with IC(50)s of 10 ± 4 and 7.3 ± 0.1 μM, respectively. Unlike compound 9, compound 6 showed no toxicity in human diploid fibroblasts. One of the possible mechanisms of action of compound 6 accounting for observed cytostatic activity towards haematological malignancies might be inhibition of inosine monophosphate dehydrogenase (IMPDH) activity, a key enzyme of de novo purine nucleotide biosynthesis providing the cells with precursors for DNA and RNA synthesis indispensable for cell growth and division, which has emerged as an important target for antileukemic therapy. In addition, this compound proved to be the most potent inhibitor of the hepatitis C virus replication as well. However, observed antiviral effect was most likely associated with the effect that the compound exerted on the host cell rather than with selective effect on the replication of the virus itself. In conclusion, results of this study put forward compound 6 as a potential novel antitumor agent (IMPDH inhibitor) for treating leukaemia. Its significant biological activity and low toxicity in human diploid fibroblasts encourage further development of this compound as a lead.     

3,28-Di-O-(dimethylsuccinyl)-betulin isomers as anti-HIV agents

Four isomers of 3,28-di-O-(dimethylsuccinyl)-betulin were prepared and evaluated for anti-HIV activity against HIV-1 replication in H9 lymphocyte cells. 3-O-(3',3'-Dimethylsuccinyl)-28-O-(2", 2"-dimethvlsuccinyl)-betulin (11) was the most potent anti-HIV compound with an EC5, value of 0.00087 microM and a TI value of 42,400.     

Discovery of a hepatitis C target and its pharmacological inhibitors by microfluidic affinity analysis

More effective therapies are urgently needed against hepatitis C virus (HCV), a major cause of viral hepatitis. We used in vitro protein expression and microfluidic affinity analysis to study RNA binding by the HCV transmembrane protein NS4B, which plays an essential role in HCV RNA replication. We show that HCV NS4B binds RNA and that this binding is specific for the 3' terminus of the negative strand of the viral genome with a dissociation constant (Kd) of approximately 3.4 nM. A high-throughput microfluidic screen of a compound library identified 18 compounds that substantially inhibited binding of RNA by NS4B. One of these compounds, clemizole hydrochloride, was found to inhibit HCV RNA replication in cell culture that was mediated by its suppression of NS4B's RNA binding, with little toxicity for the host cell. These results yield new insight into the HCV life cycle and provide a candidate compound for pharmaceutical development.     

Curcumin inhibits hepatitis C virus replication via suppressing the Akt-SREBP-1 pathway

A polyphenolic compound from the curry spice turmeric, curcumin, is known to show anti-viral activity against the influenza virus, adenovirus, coxsackievirus, and the human immunodeficiency virus. However, it remains to be determined whether curcumin can inhibit the replication of hepatitis C virus (HCV). In this study, we showed that curcumin decreases HCV gene expression via suppression of the Akt-SREBP-1 activation, not by NF-κB pathway. The combination of curcumin and IFNα exerted profound inhibitory effects on HCV replication. Collectively, our results indicate that curcumin can suppress HCV replication in vitro and may be potentially useful as novel anti-HCV reagents.     

Discovery of a Novel Compound with Anti-Venezuelan Equine Encephalitis Virus Activity That Targets the Nonstructural Protein 2

Alphaviruses present serious health threats as emerging and re-emerging viruses. Venezuelan equine encephalitis virus (VEEV), a New World alphavirus, can cause encephalitis in humans and horses, but there are no therapeutics for treatment. To date, compounds reported as anti-VEEV or anti-alphavirus inhibitors have shown moderate activity. To discover new classes of anti-VEEV inhibitors with novel viral targets, we used a high-throughput screen based on the measurement of cell protection from live VEEV TC-83-induced cytopathic effect to screen a 340,000 compound library. Of those, we identified five novel anti-VEEV compounds and chose a quinazolinone compound, CID15997213 (IC₅₀ = 0.84 µM), for further characterization. The antiviral effect of CID15997213 was alphavirus-specific, inhibiting VEEV and Western equine encephalitis virus, but not Eastern equine encephalitis virus. In vitro assays confirmed inhibition of viral RNA, protein, and progeny synthesis. No antiviral activity was detected against a select group of RNA viruses. We found mutations conferring the resistance to the compound in the N-terminal domain of nsP2 and confirmed the target residues using a reverse genetic approach. Time of addition studies showed that the compound inhibits the middle stage of replication when viral genome replication is most active. In mice, the compound showed complete protection from lethal VEEV disease at 50 mg/kg/day. Collectively, these results reveal a potent anti-VEEV compound that uniquely targets the viral nsP2 N-terminal domain. While the function of nsP2 has yet to be characterized, our studies suggest that the protein might play a critical role in viral replication, and further, may represent an innovative opportunity to develop therapeutic interventions for alphavirus infection.     

Influenza virus proton channels.

The M2 ion channel proteins of influenza A and B viruses are essential to viral replication. The two ion channels share a common motif, HXXXW, that is responsible for proton selectivity and activation. The ion channel for the influenza A virus, but not influenza B virus, is inhibited by the antiviral drug amantadine and amantadine-resistant escape mutants form in treated influenza A patients. The studies reviewed suggest that an antiviral compound directed against the conserved motif would be more useful than amantadine in inhibiting viral replication.     

Protective Effects of Caffeine on Chikungunya and Zika Virus Infections: An in Vitro and in Silico Study

Infection by viruses Chikungunya (CHIKV) and Zika (ZIKV) continue to be serious problems in tropical and subtropical areas of the world. Here, we evaluated the antiviral and virucidal activity of caffeine against CHIKV and ZIKV in Vero, A549, and Huh-7 cell lines. Results showed that caffeine displays antiviral properties against both viruses. By pre-and post-infection treatment, caffeine significantly inhibited CHIKV and ZIKV replication in a dose-dependent manner. Furthermore, caffeine showed a virucidal effect against ZIKV. Molecular docking suggests the possible binding of caffeine with envelope protein and RNA-dependent RNA polymerase of CHIKV and ZIKV. This is the first study that showed an antiviral effect of caffeine against CHIKV and ZIKV. Although further studies are needed to better understand the mechanism of caffeine-mediated repression of viral replication, caffeine appears to be a promising compound that could be used for in vivo studies, perhaps in synergy with other compounds present in daily beverages.     

N'-[2-(2-thiophene)ethyl]-N'-[2-(5-bromopyridyl)] thiourea as a potent inhibitor of NNI-resistant and multidrug-resistant human immunodeficiency virus-1

The thiophene-ethyl thiourea (TET) compound N′-[2-(2-thiophene)ethyl]-N′-[2-(5-bromopyridyl)]-thiourea (compound HI-443) was five times more potent than trovirdine, 1250 times more potent than nevirapine, 100 times more potent than delavirdine, 75 times more potent than MKC-442, and 50 times more potent than AZT against the multidrug resistant HIV-1 strain RT-MDR with a V106A mutation. HI-443 was almost as potent against the NNI-resistant HIV-1 strain A17 with a Y181C mutation as it was against HTLV_IIIB. The activity of HI-443 against A17 was ten times more potent than that of trovirdine, 2083 times more potent than that of nevirapine, and 1042 times more potent than that of delavirdine. HI-443 inhibited the replication of the NNI-resistant HIV-1 strain A17 variant with Y181C plus K103N mutations in RT with an IC₅₀ value of 3.3 μM, whereas the IC₅₀ values of trovirdine, nevirapine, and delavirdine were all >100 μM. These findings establish the novel thiophene containing thiourea compound HI-443 as a novel NNI with potent antiviral activity against NNI-sensitive, NNI-resistant and multidrug-resistant strains of HIV-1.     

Synthesis and biological evaluation of a class of quinolone triazoles as potential antimicrobial agents and their interactions with calf thymus DNA

A novel series of quinolone triazoles were synthesized and characterized by IR, NMR, MS and HRMS spectra. All the newly prepared compounds were screened for their antimicrobial activities against seven bacteria and four fungi. Bioactive assay manifested that most of new compounds exhibited good or even stronger antibacterial and antifungal activities against the tested strains including multi-drug resistant MRSA in comparison with reference drugs Norfloxacin, Chloromycin and Fluconazole. The preliminary interactive investigations of compound 6b with calf thymus DNA by fluorescence and UV–vis spectroscopic methods revealed that compound 6b could effectively intercalate DNA to form compound 6b–DNA complex which might block DNA replication and thus exert its antimicrobial activities.