The potential antiviral effect of adefovir, an acyclic nucleoside phosphonate analog of 2′-deoxyadenosine monophosphate, was first studied by Holý and De Clercq in 1980s. Adefovir is an acyclic nucleotide analog of adenosine monophosphate which is phosphorylated to the active metabolite adefovir diphosphate by cellular kinases. Adefovir diphosphate inhibits HBV DNA polymerase (reverse transcriptase) by competing with the natural substrate deoxyadenosine triphosphate and by causing DNA chain termination after its incorporation into viral DNA. Oral adefovir dipivoxil is effective and generally well tolerated in HBeAg-positive and -negative patients chronically infected with wild-type or lamivudine-resistant HBV.

Lamivudine is a reverse transcriptase inhibitor used alone or in combination with other classes of anti-human immunodeficiency virus (HIV) drugs in the treatment of HIV infection. This molecule has two stereo-centers, thus giving rise to four stereoisomers: (+/-)-cis-lamivudine and (+/-)-trans-lamivudine. The latter is considered to be impurity of the pharmaceutically active isomer, (-)-cis-lamivudine.

Cinobufotalin, the bufadienolide isolated from toad venom, has displayed antitumor activities in many in vitro systems. It has been shown that cinobufotalin induced significant apoptosis in cultured human lymphoma U-937 cells. It induced DNA fragmentation, mitochondrial membrane potential decrease, and reactive oxygen species (ROS) production in U-937 cells. Cinobufotalin induces cytotoxic effect in cultured lung cancer cells. Cinobufotalin (1/5 mg/kg, i.p. twice daily, for 7 days) significantly inhibited A549 xenograft growth in mice. Further, same cinobufotalin administration improved mice survival at week five. Cinobufotalin administration didn’t significantly affect mice body weight, indicating the relative safety of this regimen. Thus, cinobufotalin inhibits A549 xenograft growth in vivo and improves mice survival.

Vesatolimod, also known as GS-9620, is being developed in clinical studies for the treatment of chronic hepatitis B viral (HBV) infection, with the goal of inducing a liver-targeted antiviral effect without inducing the adverse effects associated with current systemic interferon-α (IFN-α) therapies. It is demonstrate interferon-stimulated gene induction without detectable serum interferon at low oral doses. GS-9620 is a potent and oral agonist of Toll-like receptor-7, a pattern-recognition receptor whose activation results in innate and adaptive immune stimulation

Telbivudine is an antiviral drug used in the treatment of hepatitis B infection. It is marketed by Swiss pharmaceutical company Novartis under the trade names Sebivo (Europe) and Tyzeka (United States). Clinical trials have shown it to be significantly more effective than lamivudine or adefovir, and less likely to cause resistance. Telbivudine is a synthetic thymidine nucleoside analogue; it is the L-isomer of thymidine. It is taken orally in a dose of 600 mg once daily with or without food. TYZEKA is the trade name for telbivudine, a synthetic thymidine nucleoside analogue with activity against hepatitis B virus (HBV). The chemical name for telbivudine is 1-((2S,4R,5S)-4-hydroxy-5-hydroxymethyltetrahydrofuran-2-y1)-5-methyl-1H-pyrimidine-2,4-dione, or 1-(2-deoxy-β-L-ribofuranosyl)-5-methyluracil. Telbivudine is a synthetic thymidine nucleoside analogue with activity against HBV DNA polymerase. It is phosphorylated by cellular kinases to the active triphosphate form, which has an intracellular half-life of 14 hours. Telbivudine 5'-triphosphate inhibits HBV DNA polymerase (reverse transcriptase) by competing with the natural substrate, thymidine 5'-triphosphate. Incorporation of telbivudine 5'-triphosphate into viral DNA causes DNA chain termination, resulting in inhibition of HBV replication. Telbivudine is an inhibitor of both HBV first strand (EC50 value = 1.3 ± 1.6 µM) and second strand synthesis (EC50 value = 0.2 ± 0.2 µM). Telbivudine 5'-triphosphate at concentrations up to 100 µM did not inhibit human cellular DNA polymerases α, β, or γ. No appreciable mitochondrial toxicity was observed in HepG2 cells treated with telbivudine at concentrations up to 10 µM.

Propagermanium, a newly introduced hydrophilic polymer of 3-oxygermanium propionic acid (3,3’-(1,3- dioxo-1,3-digermoxanediyl) bispropionic acid) has been reported to have antiinflammatory, antiviral and antineoplastic properties. In Japan propagermanium is approved for the treatment of HBe positive chronic hepatitis B. A postmarketing survey, however, revealed the occurrence of moderate to severe liver damage after the treatment in about 4% of patients. In most countries propagermanium falls under the regulations of dietary supplements. An import alert on germanium products was imposed by the U.S. FDA in 1988, because of possible injury to health. In Germany governmental institutions warned consumers of possibly fatal kidney damage.

Matrine is an active alkaloid, extracted from a traditional Chinese herbs of the Sophora family. Matrine has been reported for its anti-inflammatory and neuroprotective effects. It was demonstrated that the antinociceptive effects of ( )-matrine was mediated by mu- and kappa-opioid receptors. It could dose-dependently restore the balance of Th17/Treg cytokines and attenuate the cognitive impairment in Alzheimer's disease rats. Sophora flavescens and its bioactive compound, matrine alleviated caffeine-induced hyperactivity and promoted non-rapid eye movement sleep by activating ventrolateral preoptic nucleus neurons and modulating serotonergic transmission. Clinical trial results indicate, that intramuscular matrine may be an economical, efficacious, safe drug for the treatment of chronic hepatitis B. Matrine injection may be used to protect the liver function for patients with primary hepatic carcinoma after trans-artery chemo-embolization (TAE), to relieve the liver cells damage, and to improve the tolerance of TAE, so as to perform the next TAE in time.

Clevudine (also known as L-FMAU) is a nucleos(t)ide reverse transcriptase inhibitor, which inhibits the DNA synthesis activity of the hepatitis B virus polymerase. The drug was approved in Korea and Philippines and is being marketed under the names Levovir and Revovir. The drug is indicated in patients with chronic hepatitis B virus infection. Upon administration, clevudine is metabolized to the active metabolite, clevudine triphosphate, which is responsible for the inhibition of viral polymerase.

Oxymatrine is one of the key components extracted from Sophora flavescens, a leguminous plant grown in China, Japan, and some European countries. It has attracted much attention because of its low toxicity and side effects. Extensive research over the past decades have revealed various important pharmacological activities of oxymatrine under in vitro and in vivo conditions, including anti-inflammation, immunoregulatory, antihepatitis virus infection, antihepatic fibrosis, antianaphylaxis, and other immune regulation. Oxymatrine has been extensively studied for their cancer chemopreventive potential against various cancers, for instance, human pancreatic cancer, gastric cancer, breast cancer, lung cancer, osteosarcoma, and leukemia. However, the precise mechanisms underlying the anticancer activity of oxymatrine are largely unknown.

The potential antiviral effect of adefovir, an acyclic nucleoside phosphonate analog of 2′-deoxyadenosine monophosphate, was first studied by Holý and De Clercq in 1980s. Adefovir is an acyclic nucleotide analog of adenosine monophosphate which is phosphorylated to the active metabolite adefovir diphosphate by cellular kinases. Adefovir diphosphate inhibits HBV DNA polymerase (reverse transcriptase) by competing with the natural substrate deoxyadenosine triphosphate and by causing DNA chain termination after its incorporation into viral DNA. Oral adefovir dipivoxil is effective and generally well tolerated in HBeAg-positive and -negative patients chronically infected with wild-type or lamivudine-resistant HBV.