Homocysteine, an amino acid synthesized intracellularly by removal of the N-methyl group from the essential amino acid methionine. High plasma level of homocysteine is called hyperhomocysteinemia is a clinical biomarker for increased risk of cardiovascular disease, thromboembolic diseases, and myocardial infarction. It was shown, that hyperhomocysteinemia could be an independent risk factor for dementia and Alzheimer's disease. The falling of homocysteine concentrations in response to increasing B-group-vitamin status, have the hope that mental decline, or Alzheimer's disease, could be prevented by dietary modification or food fortification. Besides, homocysteine can behave as an anti-oxidant agent by increasing the antioxidant capacity of the tumor and endothelial cells.

Omaciclovir (previously known as H2G), a cyclic guanosine analog that is structurally similar to acyclovir and was in clinical development for the treatment of herpesvirus infections. This drug acted against varicella-zoster virus (VZV), by the formation of high concentrations of relatively stable H2G-triphosphate, which is a potent inhibitor of the viral DNA polymerases. However, further development of this drug was discontinued.

Valopicitabine is a nucleoside analog and the orally bioavailable prodrug of NM107 that competitively inhibits HCV NS5B polymerase, causing chain termination. Valopicitabine had been in phase II clinical trial for once-daily oral treatment of Hepatitis C virus infection. However, because of the overall risk/benefit profile of subjects undergoing clinical trials, further development of the drug has been temporarily placed on hold by the Swiss drug major Novartis and USA-based Idenix Pharmaceuticals company and the FDA.

Mafosfamide is a synthetic oxazaphosphorine derivative with antineoplastic properties. Mafosfamide alkylates DNA, forming DNA cross-links and inhibiting DNA synthesis. The effects of mafosfamide on various types of cancer cells were determined during preclinical investigations and clinical trials. Its development has been discontinued.

13-deoxyadriamycin hydrochloride (13-Deoxydoxorubicin hydrochloride, GPX-100) is an anthracycline similar to doxorubicin. GPX-100 is unique among anthracyclines because it is not converted to doxorubicinol during metabolism in the body. This metabolite has been shown to be a major cause of damage to the heart (cardiotoxicity) in laboratory studies. GPX-100 belongs to the class of reactive oxygen species stimulants; RNA synthesis inhibitors and Type II DNA topoisomerase inhibitors. It was in phase II clinical trial for the treatment of cancer.

Afeletecan (Bay 38-3441) is a camptothecin glycoconjugate which stabilizes the active lactone form of camptothecin and allows selective uptake into tumor cells. Afeletecan is a topoisomerase inhibitor. Afeletecan was in phase I clinical trials with Bayer for the treatment of cancer; however, development appears to have been discontinued.

Nitroarginine (LNNA), an analog of L-arginine, is a competitive inhibitor of nitric oxide synthase which has been shown to prevent glutamate toxicity. Nitroarginine has been experimentally tested for its ability to prevent ammonia toxicity and ammonia-induced alterations in brain energy and ammonia metabolites. The Kd value (k(off)/k(on)) of bovine brain cNOS for LNNA was 15 nM. In contrast to the potent and slow onset of LNNA inhibition of brain cNOS, LNNA inhibition of inducible mouse macrophage NOS (iNOS) was weaker (Ki = 4.4 uM) and rapidly reversible. Thus, LNNA was a 300-fold more potent inhibitor of bovine brain cNOS than mouse macrophage iNOS. By inhibiting nitric oxide synthase LNNA causes the selective reduction of blood flow to tumor cells. Despite the potential of LNNA to function as an adjuvant in cancer therapies, its poor solubility and stability have hindered the development of an injectable formulation of LNNA that is suitable for human administration.

Streptoniazid is a streptomycin derivative patented by Societe des usines chimiques de Rhone-Poulenc as antibiotic effective against tuberculosis.

Coumazoline is a vasoconstrictor developed as a nasal decongestant by a French corporation Labez. Intravenous administration of the compound to dogs lead to a marked and prolonged drop in the temperature of the gingival mucosa. In rats, coumazoline caused slowing of the dye diffusion on the surface of the skin. The compound did not influence the ciliary motility, as was measured on an isolated guinea pig trachea.

Carubicin (also known as Carminomycin) is an anthracycline antineoplastic antibiotic isolated from the bacterium Actinomadura carminata. Carubicin intercalates into DNA and interacts with topoisomerase II, thereby inhibiting DNA replication and repair and RNA and protein synthesis. The drug is active against a variety of experimental tumors. Pharmacology studies in animals revealed that the drug bound largely to serum proteins and that it was widely distributed. In clinical trials The main toxic effect was myelosuppression but gastrointestinal intolerance and alopecia were also reported. Objective partial responses were seen in two of seven previously untreated patients with non-small cell lung cancer and one of three patients with squamous cell carcinoma of the head and neck previously untreated with chemotherapy.