ABSTRACT
Compared with the antibiotic therapy available for bacterial infections, there are still many viral diseases for which no effective drugs exist. Viruses are obligate intracellular parasites, so antiviral drugs should speci‰cally inhibit one or more steps of virus replication without causing unacceptable side effects. Since 1959, when the ‰rst antiviral drug idoxuridine (5-iodo-2′-deoxyuridine) was licensed for clinical use, about 50 drugs have been approved for the treatment of human virosis, half of which are used in human immunode‰ciency virus (HIV) infections (De Clercq 2010). Limitations of current antiviral compounds include a narrow antiviral spectrum, ineffectiveness against latent viruses, selection of drug-resistant mutants, and toxic side effects. To overcome these disadvantages, more effective compounds are being developed, and hundreds of virus inhibitors of different chemical structure are continuously being isolated from natural sources or laboratory synthesized. However, it has proved dif‰cult to ‰nd compounds that can selectively block viral replication without interference to the normal cellular processes and, thus, without signi‰cant toxicity to the host. In the last decades, the antiviral activity of natural and synthetic steroids has been reported (Castilla, Ramírez, and Coto 2010) and among the mammalian steroids tested, dehydroepiandrosterone (DHEA) exhibits inhibitory action against a broad range of viral infections.
