Adenine 9-beta-D-arabinofuranoside (ara-A) is a synthetically produced purine nucleoside that is used in cell signaling research. It has commonly been used in anti-viral research with hepadnaviridae and herpes simplex viruses. The nucleoside ara-A interferes with viral DNA synthesis, but only in its active phosphorylated form. Active ara-ATP inhibits synthesis by incorporating into viral DNA and preventing phosphodiester bridge formation.

The compound ara-A is a precursor of adenine 9-beta-D-arabinofuranoside 5’monophosphate (ara-AMP). In vivo rat experiments of ara-AMP have shown a higher solubility and affinity for some proteins, both of which facilitate ara-AMP movement. Isolated human hepatocytes have also been shown to specifically endocytose the albumin/ara-AMP conjugate.

Asunaprevir is a potent inhibitor of the enzyme serine protease NS3 in hepatitis C viruses (HCV) and is currently in phase III clinical trials. This enzyme’s C terminal functions as a helicase for host DNA allowing access for viral manipulation. Asunaprevir is used in tandem with ribavirin and other direct or indirect acting antiviral compounds results in a thorough eradication of HCV.

Cidofovir dihydrate is an acyclic analog of deoxycytidine monophosphate that is used as an antiviral. It targets a wide range of DNA viruses including, Poxviridae, Papillomaviridae and a high degree of activity against cytomegaloviruses.

Cidofovir dihydrate interrupts viral proliferation by inhibiting viral DNA synthesis. Host cell protein kinases phosphorylate cidofovir dihydrate to its active form cidofovir diphosphate. The active metabolite competes with deoxycytidine triphosphate for the viral DNA polymerase. Incorporation of Cidofovir diphosphate into the DNA strand halts synthesis and viral replication.

Ganciclovir is a synthetic analogue of 2’-deoxy-guanosine used as an antiviral agent. It works by inhibiting viral DNA synthesis by competitive inhibition of viral DNA polymerases eventually resulting in termination. Most commonly, it is used against cytomegalovirus (CMV) infections. Ganciclovir has also been used to perform selective removal of undifferentiated embryonic stem cells from cultures along with HSV1 thymidine kinase.

Ribavirin is broad-spectrum antiviral nucleoside active against HIV, RSV, HCV, and adenovirus. It functions as a precursor to diphosphates and triphosphates, which inhibit viral RNA-dependent RNA polymerases. Ribavirin is an inhibitor of purine biosynthesis. Additionally, a metabolite of ribavirin, ribavirin 5’-phosphate, is an inhibitor of inosine monophosphate dehydrogenase.