Antiviral activity of gilvocarcin V plus UVA radiation.

Gilvocarcin V (GV), a coumarin, is a nucleic acid photosensitizer that is phototoxic to bacteria and mammalian cells at picomolar levels in the presence of near-UV radiation (UVA). We evaluated the effectiveness of GV plus UVA for inactivation of several viruses, including herpes simplex virus, type 1 (HSV) and the bacterial viruses phi X174, T7, PRD1 and phi 6. Some inactivation of the bacterial viruses was observed with UVA radiation alone (4-50% survival at 26 kJ/m2). Additional photosensitized inactivation was observed only with T7 and phi 6 at 2.0 microM GV. On the other hand, HSV was photoinactivated with concentrations of GV three orders of magnitude lower (1.0 nM). Similar to the case with UV (254 nm) inactivation, the GV-UVA survival curve for HSV indicated multicomponent inactivation kinetics, which could not be explained by photobleaching of GV. The wide range of photosensitivities of these viruses to GV cannot be adequately explained by models based only on viral nucleic acid content or presence of lipid envelopes.