In Vitro Anti-HIV-1 Activity Of Novel Heteropolyacid And Cordyceps Sinensis

Currently, AIDS(Acquired Immunodeficiency Syndrom, AIDS) is still spreading rapidly in the global scope and is still a serious threat to human health and life safety. Therefore, to find new anti-viral drug is the research emphasis and direction for the treatment of HIV infection. This study had analyzed the anti-HIV-1 activity and mechanism of heteropolyacid compound KA-1 and the extracts of cordyceps sinensis.Firstly, the cytotoxicity and in vitro anti-HIV acitivity of KA-1 were evaluated by CCK-8 method and in vitro infection model. It was found that KA-1 had dose-dependent antiviral effect and its IC50 was 0.073 ± 0.045 ?g/m L. In the experimental concentrations, KA-1 had inhibition rate of 80% or more for R3 A wild strains of HIV-1. The combination of KA-1 and the zidovudine(AZT) showed that KA-1 and AZT had a synergistic effect, and synergistic/antagonistic capacity of KA-1 and AZT is 71.46/-39.69 nM2%. The surface plasma resonance(SPR) technology was used to detect the binding affinity of KA-1 with HIV-1 Vpu, Vif, reverse transcriptase, integrase and gp41. It was found that KA-1 had high affinity with Vif, integrase and gp41. In vitro reverse transcriptase, integrase, protease activity test determinate the effect of KA-1 on these three enzymes, which had obvious inhibitory effect on integrase. Fluorescent staining and Western blot showed that KA-1 reduced the expression of exogenous Vpu protein but it had no influence on Vif protein expression; virus-cell fusion experiment, it was proved that KA-1 specifically targeted on envelope protein and can inhibit the formation of gp41 protein 6-helix bundle.Later, the cytotoxicity and in vitro anti-HIV acitivity of five extracts from Cordyceps sinensis were determined by CCK-8 method and in vitro infection model. It was found that they all had dose-dependent antiviral effect. Then SPR and enzyme activity test were used to detect the binding affinity of the extracts of Cordyceps sinensis with HIV-1 Vif protein and reverse transcriptase and it was found that they had a good affinity; enzyme activity test in vitro proved that the extract had inhibitory effect on reverse transcriptase. Compared with the dry caterpillar fungus, fresh caterpillar fungus had a more significant inhibitory activity. Lastly, the acitive ingredient cordycepin were inverstigated using CCK-8 method and in vitro infection model. It was found that they had dose-dependent antiviral effect. Then SPR, Western blot, retroviral enzyme activity test were used to detect the effect of cordycepin on Vif protein and reverse transcriptase and it was found that cordycepin had a good affinity. Cordycepin inhibited the degradation of A3 G protein induced by Vif protein, but it had no significant effect on the expression of the Vif protein. Inhibition of enzyme activity test in vitro proved that cordycepin had the antiretroviral enzyme activity.In summary, the data showed that KA-1 exerted potent anti-viral activity mainly through inhibiting HIV-1 integrase activity and the formation of gp41 protein core structure. The anti-viral effect of cordyceps sinensis extracts and cordycepin were mediated via inhibiting reverse transcriptase, integrase and Vif protein. Finally, the study identified the potent in vitro anti-vrial effect and possible mechanism of KA-1 and cordyceps sinensis. More studies are needed to further elucidate these mechanisims.