Inhibition of virus multiplication and alteration of cyclic AMP level in cell cultures by flavonoids.

The inhibitory effect of four flavonoid compounds on virus multiplication and their influence on the intracellular cyclic AMP (cAMP) level were studied in cell cultures. Quercetin and quercitrin reduced the yields of Human (alpha) herpesvirus 1 (HSV-1) and Suid (alpha) herpesvirus 1 (pseudorabies virus), but hesperidin and rutin had no effect. Further, quercetin and quercitrin elevated the intracellular level of cAMP, whereas hesperidin and rutin did not alter the cAMP level. Both antiviral activity and cAMP-enhancing effect were dependent on the concentrations of the flavonoids, and these effects turned out to be parallel. This study suggests that a relation exists between the antiviral effect and the cAMP-enhancing activity of flavonoids.