ABSTRACT
Abstract Background Hepatitis C virus (HCV) infection is a major worldwide health problem that can cause liver fibrosis and hepatocellular carcinoma (HCC). The clinical treatment of HCV infection mainly relies on the use of direct-acting antivirals (DAAs) that are usually expensive and have side effects. Therefore, achieving the discovery of more successful agents is always urgent. In this context, antiviral compounds that inhibit viral infections and disease progression with important therapeutic activities have been identified in animal venoms including arthropod toxins. This indicates that arthropod venoms represent a good natural source of promising candidates for new antivirals. Methods The antiviral activity of the wasp venom (WV), isolated from the Oriental hornet (Vespa orientalis), was assessed using cell culture technique with human hepatocellular carcinoma-derived cell line (Huh7it-1) and the recombinant strain of HCV genotype 2a (JFH1). Results The results revealed that WV inhibited HCV infectivity with 50% inhibitory concentration (IC50) of 10 ng/mL, while the 50% cytotoxic concentration (CC50) was 11,000 ng/mL. Time of addition experiment showed that the WV blocked HCV attachment/entry to the cells probably through virucidal effect. On the other hand, the venom showed no inhibitory effect on HCV replication. Conclusion WV can inhibit the entry stage of HCV infection at non-cytotoxic concentrations. Therefore, it could be considered a potential candidate for characterization of natural anti-HCV agents targeting the entry step.
ABSTRACT
Background Hepatitis C virus (HCV) infection is a major worldwide health problem that can cause liver fibrosis and hepatocellular carcinoma (HCC). The clinical treatment of HCV infection mainly relies on the use of direct-acting antivirals (DAAs) that are usually expensive and have side effects. Therefore, achieving the discovery of more successful agents is always urgent. In this context, antiviral compounds that inhibit viral infections and disease progression with important therapeutic activities have been identified in animal venoms including arthropod toxins. This indicates that arthropod venoms represent a good natural source of promising candidates for new antivirals. Methods The antiviral activity of the wasp venom (WV), isolated from the Oriental hornet (Vespa orientalis), was assessed using cell culture technique with human hepatocellular carcinoma-derived cell line (Huh7it-1) and the recombinant strain of HCV genotype 2a (JFH1). Results The results revealed that WV inhibited HCV infectivity with 50% inhibitory concentration (IC50) of 10 ng/mL, while the 50% cytotoxic concentration (CC50) was 11,000 ng/mL. Time of addition experiment showed that the WV blocked HCV attachment/entry to the cells probably through virucidal effect. On the other hand, the venom showed no inhibitory effect on HCV replication. Conclusion WV can inhibit the entry stage of HCV infection at non-cytotoxic concentrations. Therefore, it could be considered a potential candidate for characterization of natural anti-HCV agents targeting the entry step.(AU)
Subject(s)
Antiviral Agents , Wasp Venoms , Carcinoma, HepatocellularABSTRACT
Objective: To determine anti-viral activities of three Artocarpus species: Artocarpus altilis, Artocarpus camansi, and Artocarpus heterophyllus (A. heterophyllus) against Hepatitis C Virus (HCV). Methods: Antiviral activities of the crude extracts were examined by cell culture method using Huh7it-1 cells and HCV genotype 2a strain JFH1. The mode of action for anti-HCV activities was determined by time-of-addition experiments. The effect on HCV RNA replication and HCV accumulation in cells were analyzed by quantitative reverse transcription-PCR and western blotting, respectively. Results: The dichloromethane (DCM) extract of A. heterophyllus exhibited strong anti-HCV activity with an inhibitory concentration (IC50) value of (1.5 ± 0.6)μg/mL without obvious toxicity. The DCM extracts from Artocarpus altilis and Artocarpus camansi showed moderate anti-HCV activities with IC50 values being (6.5 ± 0.3) μg/mL and (9.7 ± 1.1) μg/mL, respectively. A time-of-addition studies showed that DCM extract from A. heterophyllus inhibited viral entry process though a direct virucidal activity and targeting host cells. HCV RNA replication and HCV protein expression were slightly reduced by the DCM treatment at high concentration. Conclusions: The DCM extract from A. heterophyllus is a good candidate to develop an antiviral agent to prevent HCV grant reinfection following liver transplantation.
ABSTRACT
Background: Loop-mediated isothermal amplification (LAMP) is a method already claimed as a simple technique to amplify DNA/ RNA using four to six primers as “a set” from conserved sequence of target gene. In this study we optimize the use of LAMP for detection of Mycobacterium tuberculosis in clinical isolates from Indonesia. Methods: Procedures to perform LAMP were optimized, then the method was applied to 122 archieved samples of DNA’s Mtb from clinical TB patients with Acid Fast Bacilli (AFB) smears positive. The samples were obtained in 2008 from 13 provinces in Indonesia for genotyping study, which then become collections of Center for Biomedical and Basic Technology of Health (CBBTH), NIHRD Indonesia. The optimization tests include sensitivity and specificity tests of several sets primers, which were evaluated using 10-fold serially diluted DNA of Mtb H37Rv and 12 species of Mycobacteria. Three equipments consisted of LAMP turbidimeter, heating block and water bath were compared for its ability in DNA amplification. Detection of M. tuberculosis from clinical isolates used set primers specific for gyrB gene, amplicon was detected with UV fluorescence system. Results: The results showed that the highest sensitivity was obtained using the set primers specific for 16S rRNA and gyrB which could detect 10.0 fg to 1.0 pg genomic DNA of Mtb H37Rv. The set primers specific for gyrB gene was the most specific primers. Application of LAMP using gyrB set primers on Indonesian clinical isolates showed 94.2% (114/121) positivity rate. Conclusion: LAMP method is potentially used in TB diagnosis in Indonesia.