Inhibition of human cytomegalovirus immediate-early gene expression and replication by the ethyl acetate (EtOAc) fraction of Elaeocarpus sylvestris in vitro

BACKGROUND In immunocompromised patients, human cytomegalovirus (HCMV) infection can lead to severe, life-threatening diseases, such as pneumonitis, hepatitis, gastrointestinal tract disease, and retinitis. We previously reported that a 70% ethanol extract of Elaeocarpus sylvestris leaves (ESE) inhibits human cytomegalovirus (HCMV) replication in vitro. In the present study, we determined the solvent fraction of ESE that inhibits HCMV replication using activity-guided fractionation. METHODS Activity-guided fractionation of ESE was performed to determine the solvent fraction that inhibits HCMV replication. Effects of solvent fractions on HCMV lytic gene expression and major immediate-early (MIE) enhancer/promoter activity were further investigated. RESULTS Among the solvent fractions tested, the EtOAc fraction of ESE markedly reduced HCMV lytic gene expression and viral replication in vitro without exerting significant cytotoxic effects against human foreskin fibroblasts (HFF). Furthermore, the EtOAc fraction negatively affected HCMV MIE enhancer/promoter activity. CONCLUSION Our data collectively indicate that the EtOAc fraction of ESE contains active constituents that inhibit HCMV MIE enhancer/promoter activity and viral replication. The EtOAc fraction of ESE is a good source of novel drug candidates for treatment of HCMV-associated diseases.