Evaluation on antiviral activity of a novel arctigenin derivative against multiple rhabdoviruses in aquaculture.

Rhabdoviruses cause devastating diseases in aquaculture, resulting in enormous economic losses. Our previous studies indicated that imidazole arctigenin derivatives possessed antiviral activities against aquatic rhabdoviruses. Based on the data of structure-activity relationship, a new imidazole arctigenin derivative, 4-(8-(2-bromoimidazole)octyloxy)-arctigenin (BOA), was designed and synthesized. And its antiviral activities against aquatic rhabdoviruses (SVCV, IHNV and MSRV) were evaluated in vitro. By comparing inhibitory concentration at half-maximal activity (IC 50), we found that BOA (IC50 = 1.11 μM) possessed a higher anti-IHNV activity than the antiviral imidazole arctigenin derivatives which were found in our previous study. Besides, BOA could cause profound inhibition of SVCV and MSRV replication. By the reduction assays on cytopathic effect, BOA exhibited a protective effect on two host cell lines. As a typical rhabdovirus, SVCV was chosen as a model to illuminate the anti-rhabdovirus mechanism of BOA. BOA was discovered to not impact directly on viral particles or interfere with SVCV adsorption. And it worked within the 2-6 h of the early phase of virus replication. In addition, after repression of cell cycle S phase and recovery of caspase-3/8/9 activities activated by SVCV, BOA inhibited SVCV-induced apoptosis and then reduced the release of viral particles at the late stage of virus replication. Altogether, BOA was expected to be a highly efficient antiviral agent against multiple rhabdoviruses in the field of aquaculture.