Phellodendron amurense Leaf Extract Inhibits Rhabdovirus Infection by Targeting Early Stages of Viral Entry.

Area of Science:

• Virology
• Natural Product Chemistry
• Drug Discovery

Background:

• RNA viruses mutate rapidly, requiring antivirals targeting conserved infection pathways.
• Viral hemorrhagic septicemia virus (VHSV) serves as a safe surrogate for high-throughput screening of potential antiviral agents.

Purpose of the Study:

• To identify novel antiviral compounds from natural sources using VHSV as a model.
• To investigate the mechanism of action of promising antiviral candidates.

Main Methods:

• High-throughput screening of 17,265 compounds, 2000 plant extracts, and 100 marine extracts against a recombinant VHSV.
• Cytotoxicity and antiviral activity assays, including dose-response, virucidal assays, and time-of-addition experiments.
• Fractionation of active extracts and analysis of lipophilic compound involvement.

Main Results:

• Phellodendron amurense (PL) leaf extract demonstrated significant antiviral activity with low cytotoxicity (selectivity index ≈ 10).
• The PL extract reduced viral infectivity and showed cross-activity against snakehead rhabdovirus.
• Mechanistic studies indicated the extract acts at early infection stages, likely by inactivating viral particles and interfering with attachment/entry.

Conclusions:

• Phellodendron amurense leaf extract is a potent antiviral agent targeting conserved entry mechanisms in enveloped RNA viruses.
• Lipophilic compounds in the n-hexane fraction are likely responsible for the observed antiviral effects.
• This extract represents a promising source for developing broad-spectrum antivirals.