Marine natural seaweed products as potential antiviral drugs against Bovine viral diarrhea virus

Bovine viral diarrhea virus (BVDV) is an etiologic agent that causes important economic losses in the world. It is endemic in cattle herds in most parts of the world. The purpose of this study was to evaluate the in vitro cytotoxic effect and antiviral properties of several marine natural products obtained from seaweeds: the indole alkaloid caulerpin (CAV, 1) and three diterpenes: 6-hydroxydichotoma-3,14-diene-1,17-dial (DA, 2), 10,18-diacetoxy-8-hydroxy-2,6-dolabelladiene (DB1, 3) and 8,10,18-trihydroxy-2,6-dolabelladiene (DB3, 4). The screening to evaluate the cytotoxicity of compounds did not show toxic effects to MDBK cells. The antiviral activity of the compounds was measured by the inhibition of the cytopathic effect on infected cells by plaque assay (PA) and EC50 values were calculated for CAV (EC=2,0+/-5.8), DA (EC 2,8+/- 7.7), DB1 (EC 2,0+/-9.7), and DB3 (EC 2,3+/-7.4). Acyclovir (EC50 322+/- 5.9) was used in all experiments as the control standard. Although the results of the antiviral activity suggest that all compounds are promising as antiviral agents against BVDV, the Selectivity Index suggests that DB1 is the safest of the compounds tested.