Antiviral compounds isolated from plants

Viruses are intracellular pathogens which utilize a number of host metabolic processes for virus replication in addition to proteins which are encoded for virus itself. Therefore, an effective antiviral drug must interfere with virus encoded proteins without affecting any cellular metabolic processes. Unfortunately, many antiviral drugs that have an inhibitory effect on virus replication, also have an inhibitory effect on molecular processes in infected, as well as uninfected, cells. There is currently no approved remedy for many viruses. Plants represent a large potential source of antiviral agents, such as: alkaloids, flavonoids, phenolic acids, phenylpropanoids, lignins, terpenoids, quinine, tannins, thiophenes, polyacetylenes or proteins. Some of them possess broad spectrum of antiviral activity.