Antiviral Activity of Dicarbonyls and Related Compounds in Embryonated Eggs

A variety of compounds containing a terminal α-ketoaldehyde or α-hydroxyaldehyde grouping showed marked activity against influenza A (PR-8) and Newcastle disease (NJ-KD) viruses in embryonated eggs. One of these compounds, β-ethoxy-α-ketobutyraldehyde hydrate (Kethoxal) appeared to be at least as active as any of the other compounds and the following results were obtained in detailed studies with this compound: Kethoxal was active in eggs when given 24 hr before experimental infection or 6 hr after infection with NJ-KD virus.Kethoxal at the maximum tolerated dose was able to protect eggs against as much as 4 × 106 LD50 of NJ-KD virus, and as little as 24 μg of Kethoxal were effective against low levels of virus.Kethoxal in eggs was active also against vaccinia virus, the GB strain of Newcastle, the London strain, of influenza A′, and against mumps virus.Kethoxal was a potent inactivating agent in vitro against NJ-KD and PR-8 viruses.The probable mode of antiviral activity in eggs was concluded to be through a direct virucidal action on extracellular virus.