Antiviral activity of berberine against dengue and Zika viruses

PICCINI LE; GIANNONE DA; CASTILLA V

CABA

Congreso; Drug Discovery for Neglected Diseases International Congress 2018. 4th Scientific Meeting of Research Network of Natural Products against Neglected Diseases; 2018

Dengue (DENV) and Zika (ZIKV) viruses are both arthropod-borne viral human pathogens, belonging to the Flaviviridaefamily. In spite of their increasing global incidence, no specific antiviral therapy is available [1].In recent years, it has been reported that berberine, an isoquinoline alkaloid, exhibits antiviral activity against severalviruses, such as enterovirus 71, Chikungunya virus and respiratory syncytial virus [2, 3, 4]. In this study, the antiviral activityof berberine against DENV and ZIKV in Vero cell cultures was investigated.First, the effect of berberine on cell viability was determined by the MTT colorimetric method. The compoundconcentration required to reduce cell viability by 50% (CC50) was >187,5 μM. On the other hand, antiviral activitywas determined by a viral yield inhibition assay using different non-cytotoxic concentrations of berberine in cellsinfected with ZIKV or DENV. Quantification of viral production was performed by the plaque formation method and thecompound concentration required to inhibit virus yield by 50% (EC50) was calculated. EC50 values were 5,7 μM, 9,1 μM,2,4 μM, 11,6 μM and 6,3 μM for ZIKV, DENV-1, DENV-2, DENV-3 and DENV-4, respectively.Treatment with berberine (40 μM) caused a strong decrease in the number of cells expressing the viral glycoproteinE, assessed by immunofluorescence assay. A reduction of 93,4% (for ZIKV) and 82,8% (for DENV-2) in the numberof infected cells was achieved in berberine treated cultures compare to control ones. Furthermore, the presence ofberberine (40 μM) either between 1 and 8 h post-infection (p.i.) or between 8 and 24 h p.i. produced a significantinhibition (> 90%) of ZIKV and DENV-2 infectious titers. This inhibitory effect was also verified by western blot analysisof E glycoprotein expression.Finally, to determine whether berberine exerts a direct inactivating effect on viral particles, aliquots of DENV-2 or ZIKVstocks were incubated with different concentrations of berberine for 2h at 37°C. Residual infectivity was quantifiedby the method of plaque formation and the compound concentration required to inactivate virus by 50% (IC50) wascalculated. The IC50 values were 12,2 μM for ZIKV and 37,8 μM for DENV-2.In conclusion, different methodological approaches allowed us to demonstrate that berberine exerts a significant anddose-dependent inhibition of ZIKV and DENV multiplication in Vero cells, either when the compound was present atearly or late stages of infection. In addition, berberine displays a direct inactivating effect on viral particles.