Quassinoids isolated from Brucea javanica inhibit pepper mottle virus in pepper

•A green fluorescent protein tagged pepper mottle virus based antiviral assay can simply evaluate antiviral potential against PepMoV.•PepMoV-GFP based leaf-disc method led to the isolation of five quassinoids from Brucea javanica with antiviral activity.•All isolated compounds exhibited effective anti-PepMoV activity in systemic host plants.

A green fluorescent protein (GFP)-tagged pepper mottle virus (PepMoV) based leaf-disc method and systemic host method were developed to identify antiviral agents. Preliminary experiments using a PepMoV-GFP based leaf-disc method led to the isolation of five quassinoids, including brusatol (1), bruceantin (2), brucein A (3), bruceantinol (4), and brucein B (5), from the CH3OH extract of Brucea javanica. All isolated compounds exhibited inactivation effects in systemic host plants, and compounds 3 and 4 were potent, with a minimum inhibitory concentration of 10 μM. Furthermore, compound 3 was found to have a protective effect at the tested concentration of 40 μM.

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