Derivatives of benzo(c)fluorene. VI. Antiviral and interferon-inducing activities of three benzo(c)fluorenone derivatives in mice.

The antiviral effect of 3 derivatives of benzo(c)fluorenone against encephalomyocarditis (EMC) and vaccinia viruses in mice was compared with that of tilorone hydrochloride (THCl). All 3 derivatives were effective against either virus following single-dose oral application as well as after 4-times repeated subcutaneous (s.c.) treatment, but following oral administration only the VUFB 14162 derivative exerted an antiviral effect corresponding to that of THCl. After s.c. application, however, VUFB 14162 derivative was less toxic than THCl. Two benzo(c)fluorenone derivatives, namely VUFB 14162 and 13431, induced in mouse sera the levels of interferon (IFN), which production kinetics and hyporeactivity phenomenon were comparable with those induced by THCl. Because no IFN was found following administration of the third VUFB 13371 derivative, its antiviral effect consisted probably in an other than IFN-inducing mechanism.