Nefiracetam is a cyclic derivative of gamma-aminobutyric acid (GABA). It is thought to act by normalising dysfunctional acetylcholine, GABA and possibly monoamine neurotransmitter systems, but it may also facilitate N/L-type calcium channel opening. Nefiracetam has received attention as a treatment for seizures, depression, and dementia. Nefiracetam was found to be extremely testicular toxic in both rats and dogs; it was found to significantly decrease the levels of testicular testosterone leading to atrophy and malformation of sperm.

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.

Colforsin (NKH477) is a water-soluble forskolin derivative. NKH477, like forskolin, showed adenylate cyclase stimulant activity in guinea pig ventricular membrane but did not inhibit Na+, K(+)-ATPase or phosphodiesterase (PDE) activity. The compound was developed by a Japanese company Nippon Kayaku. Colforsin daropate, a prodrug of colforsin, is marketed in Japan for the treatment of acute heart failure under tradename Adehl.

Antineoplaston A10 is a piperidinedione antineoplaston with potential antineoplastic activity. Antineoplaston A10 was originally isolated from human urine but is now synthetically derived. This agent intercalates into DNA, resulting in cell cycle arrest in G1 phase, reduction of mitosis, and decreased protein synthesis. Antineoplaston A10 may also inhibit ras-oncogene expression and activate tumor suppressor gene p53, leading to cell differentiation and apoptosis. Antineoplaston A10 has been used in trials studying the treatment of glioma, sarcoma, lymphoma, lung cancer, liver cancer, and kidney cancer, among others.

Tolimidone, Lyn protein-tyrosine kinase stimulant, is in phase II clinical by Melior Discovery and Bukwang for the treatment of type 2 diabetes. It is also in phase II clinical by Pfizer for the treatment of ulcer. However, this research has been discontinued.

FLUMECINOL, a benzhydrol derivative, is a hepatic microsomal drug-metabolizing enzyme inducer. It was in clinical development for the treatment of pruritus associated with primary biliary cirrhosis.

PGD2 (Prostaglandin D2) is a major cellular regulator, has been shown to bind different receptors: D prostanoid receptor (DP) and chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2). PGD2 reportedly inhibits platelet aggregation, the proliferation of cells, and activation of neutrophils. This compound is also a potent vasodilator that also relaxes smooth muscle but causes contraction of the bronchial airways. PGD2 promotes T cell migration via CRTH2 and aggravates asthma. In contrast, there have been some studies suggesting that PGD2 exerts anti-inflammatory effects via DP, such as inhibiting the migration and activation of neutrophils, basophils, dendritic cells and T cells. Elevated levels of prostaglandin D2 (PGD2) have been shown to be present in the bald scalp of androgenic alopecia (AGA) patients and was suggested the PGD(2)-GPR44 pathway as a potential target for treatment. Also was revealed, that PGD2 might be a new target for asthma therapy, PGD2 in serum and BALF were lower in the treated group than in the untreated group.

Harmine (aka telepathine) is a fluorescent harmala alkaloid belonging to the beta-carboline family of compounds. It is a naturally occurring metabolite in a number of plants, notably the Middle Eastern plant harmal or Syrian rue (Peganum harmala) and the South American vine Banisteriopsis caapi. Harmine is a reversible inhibitor of monoamine oxidase A (MAO-A), but not MAO-B. Harmine has been found to have potential anti-cancer and neuroprotective properties, and also promotes differentiation of osteoblasts and chondrocytes while inhibiting osteoclastogenesis. Harmine has also been used as a C-11 labeled probe in positron emission tomography.

Phorbol 12-myristate 13-acetate (PMA) also commonly known as 12-O-Tetradecanoylphorbol-13-acetate (TPA) is a phorbol ester that is commonly used to activate phospholipid-dependent protein kinase (protein kinase C). PMA/ TPA possesses potential antineoplastic effects and was studied in phase II clinical trials together with dexamethasone in patients with relapsed or refractory acute myeloid leukemia. In addition, PMA/ TPA participated in phase I trial for treating patients with hematologic cancer or bone marrow disorder that has not responded to previous treatment. Nevertheless, both clinical trials were terminated. Besides, PMA/ TPA was studied in patients with solid tumors, which had depressed white blood cell and neutrophil counts because of prior treatment with cytotoxic cancer chemotherapeutic drugs. It was shown, that the drug increased the low white blood cell and neutrophil counts toward the normal range.