Identification of an indol-based derivative as potent and selective varicella zoster virus (VZV) inhibitor

Musella, Simona; di Sarno, Veronica; Ciaglia, Tania; Sala, Marina; Spensiero, Antonia; Scala, Maria Carmina; Ostacolo, Carmine; Andrei, Graciela; Balzarini, Jan; Snoeck, Robert; Novellino, Ettore; Campiglia, Pietro; Bertamino, Alessia; Gomez-Monterrey, Isabel M.

We report the synthesis and antiviral activity of a new family of non-nucleoside antivirals, derived from the indole nucleus. Modifications of this template through Mannich and Friedel-Crafts reactions, coupled with nucleophilic displacement and reductive aminations led to 23 final derivatives, which were pharmacologically tested. Tryptamine derivative 17a was found to have a selective inhibitory activity against human varicella zoster virus (VZV) replication in vitro, being inactive against a variety of other DNA and RNA viruses. A structure-activity relationship (SAR) study showed that the presence of a biphenyl ethyl moiety and the acetylation at the amino group of tryptamine are a prerequisite for anti-VZV activity. The novel compound shows the same activity against thymidine kinase (TK)-competent (TK(+)) and TK-deficient (TK(−)) VZV strains, pointing to a novel mechanism of antiviral action.