3-Aminopropionitrile (beta-aminopropionitrile, BAPN) is a poisonous substance found in Lathyrus spp. (wild peas), for example, Lathyrus hirsutus (wild winter pea), sometimes sown with grasses to provide early-spring grazing. BAPN is a specific and irreversible inhibitor of LOX activity. It has been shown to reduce body weight gain and improve the metabolic profile in diet-induced obesity in rats. The administration of beta-aminopropionitrile has been proposed for pharmacological control of unwanted scar tissue in human beings. BAPN has been shown to have preventive effect in the development of fibrosis by decreasing tissue damage in an experimental model of corrosive esophagitis in rats. BAPN is FDA approved for the treatment of tendinitis of the superficial digital flexor tendon (SDFT) in horses where there is sonographic evidence of fiber tearing.

Pelitinib (EKB-569) is a 3-cyanoquinoline pan-ErbB tyrosine kinase inhibitor with potential antineoplastic activity. Pelitinib irreversibly binds covalently to epidermal growth factor receptors, thereby inhibiting receptor phosphorylation and signal transduction and resulting in apoptosis and suppression of proliferation in tumor cells that overexpress these receptors. Pelitinib had been in phase II clinical trials for the treatment of non-small cell lung cancer and colorectal cancer. Treatment-emergent adverse events were diarrhea, abdominal pain, gastrointestinal carcinoma, intestinal obstruction and vomiting.

Vinmegallate (also known as RGH-4417) was developed as a topical dermatological agent for the treatment of psoriasis. Vinmegallate is a phosphodiesterase inhibitor. However, information about the further development of this agent is not available.

Metoprine is a diaminopyrimidine folate antagonist with potential antineoplastic activity. Metoprine inhibits dihydrofolate reductase, resulting in decreased cellular folate metabolism and cell growth. Metoprine shows potent in vitro antitumor activity against several experimental tumors including methotrexate-resistant tumors. Metoprine inhibits the enzyme dihydrofolate reductase, much less effectively than methotrexate but it also inhibits histamine-N-methyltransferase, resulting in decreased histamine catabolism. S phase cells are most sensitive, whilst cells in G2 and M are least sensitive to the lethal effects of Metoprine, and a prolonged exposure to a high Metoprine concentration produces maximum cytotoxic effects. After oral administration, Metoprine has a widespread distribution and concentration in all tissues examined with the highest tissue/plasma ratios found in brain, lung, pancreas, and skin. Phase I and early Phase II clinical trials in various centers have shown activity in hypernephroma, epidermoid carcinoma arising in bronchus or head and neck, central nervous system leukemia, malignant melanoma, and mycosis fungicides. Metoprine had been in some phase II clinical trials but further studies were discontinued due to CNS and hematological toxicity.

Dazmegrel [UK 38485] is a thromboxane synthetase inhibitor which was undergoing development in the treatment of thrombosis, ischaemic heart disease, arrhythmias and asthma. Pfizer were conducting phase II studies in Denmark and the UK, phase I studies in Germany and Italy, and preclinical studies in France. Later this research was discontinued.

Emodin is a naturally occurring anthraquinone present in the roots of numerous plants and lichens and an active ingredient of various Chinese herbs. Emodin possesses various biological properties and serves as an anti-bacterial and anti-inflammatory agent. Emodin was studied as a potential anti-cancer agent: e.g., it was shown, that compound inhibits the invasion and migration of colon cancer cells in vitro and in vivo by blocking EMT, which is related with the inhibition of Wnt/β-catenin signaling pathway. Besides, emodin effectively ameliorates asthmatic airway inflammation and alternatively activated macrophages (AAMs) polarization, and thus can be a potential agent for the treatment of asthma. It is known that the Inhibition of AAMs is an alternative therapeutic strategy for treating asthma. Some experiments have revealed that emodin can be a beneficial dietary supplement in prolonging lifespan.

Picropodophyllin (also known as picropodophyllotoxin (PPP)), an orally active insulin-like growth factor 1 receptor (IGF1R) inhibitor that exhibits no activity at the insulin receptor, FGFR, PDGFR or EGFR. Picropodophyllin possesses antineoplastic activity. PPP is currently tested as an orally administrated single agent treatment in an open-label combined Phase I/II clinical study in advanced cancer patients with solid tumors which progress in spite of several lines of treatment. In addition, it effectively inhibits rhambodmyosarcomas tumor proliferation and metastasis in vitro and in an animal model.

Fiacitabine, also known as FIAC, is a pyrimidine nucleoside, which had been in phase II clinical trilas for the treatment Cytomegalovirus infections and Herpes simplex virus infections. However, these researches have been discontinued. It was also shown the inhibitor activity of FIAC against the DNA polymerase of hepadnaviruses.

Pyrazofurin (PF) (3,β-D-ribofuranosyl, 4-hydroxyprazole-5-carboxamide) is a C-nucleoside antibiotic, one in which the ribose joins the base-ring carbon instead of a base-ring nitrogen. Pyrazofurin potently inhibits orotidine 5'-monophosphate (OMP) decarboxylase, thereby interfering with de novo synthesis of uridine nucleotides and resulting in cytotoxicity. This agent also causes a rapid depletion of the pyrimidine deoxynucleotide pool, thereby inhibiting DNA synthesis and cell replication. PF was isolated from fermentation filtrate of Strepomyces candidus. This compound was initially found to have inhibitory activity against the vaccinia, herpes simplex, rhino and measles viruses in vitro and the vaccinia virus in vivo. More recently the antiviral spectrum has been extended to include the polio, Coxsackie, Sindbis and vesicular stomatitis viruses.

Cimoxatone is a fully reversible inhibitor selective for the A form of monoamine oxidase. Oral administration of Cimoxatone increased brain noradrenaline, dopamine, and serotonin and decreased DOPAC , 5-HIAA, and 3-methoxy-4-hydroxyphenylethylene glycol sulfate.