Antiphytoviral activity of alkaloids from Cephalotaxus sinensis

•C. sinensis extract was effective against tobacco mosaic virus in the lab & field.•Eight alkaloids from C. sinensis extract were isolated and identified.•Drupacine and cephalotaxine were the main active constituents in the extract.•Drupacine and cephalotaxine inactivated TMV and inhibited replication.•This is the first report of the antiviral activities of C. sinensis alkaloids.