Human cytomegalovirus: Drug resistance and new treatment options using natural products.

Human cytomegalovirus (HCMV), a member of the β-herpesvirus family, is a cause of high morbidity and mortality rates among immunosuppressed individuals and patients with acquired immunodeficiency syndrome (AIDS). Despite the availability of approved antiviral drugs, treatment of HCMV infections remains difficult. Antiviral therapies are in part limited by the small number of available drugs showing satisfactory clinical results. Other factors, such as low potency, poor oral bioavailability and the emergence of drug resistance, also contribute significantly to the obstacles confronting current therapies for HCMV infection. In search of new drugs for the treatment of HCMV infection, researchers have turned their attention to natural products. Unfortunately, not many natural compounds have proven to be efficacious against HCMV. Those that have shown good results in vitro are reviewed here, and their molecular targets and mechanisms of action are discussed along with those of established antiviral agents.