Securinine is a plant-derived alkaloid from the Securinega plant that has been used clinically as a therapeutic for primarily neurological related diseases. Securinine is well-known GABAA antagonist and recently it was found that Securinine is able to up-regulate p53 protein and to modulate the related family member p73 protein in a p53-dependent fashion, inducing p73 in the HCT116 p53(-) cells and down-regulating it in the p53(+) cells. Securinine induces G1 phase cell cycle arrest, upregulates expression of p53 and Bax, and downregulates expression of Bcl-2, PI3K, mTOR, and p70s6k in breast cancer cells and promyelocytic leukemia cells. Securinine activates p38 MAPK, enhancing monocyte antibacterial activity in vitro as well. This compound also exhibits antimicrobial activity against Alternaria, Curvularia, and Helminthosporum. Additionally, securinine decreases AChE activity and suppresses amyloid-β (Aβ)-induced glial inflammatory responses in animal models of Alzheimer’s disease, improving cognitive deficits. Securinine’s activity as a GABA antagonist, likely explains its reported clinical success in limited studies for the treatment of neurological conditions such as amyotrophic lateral sclerosis (ALS), poliomyelitis and multiple sclerosis. Securinine has not been utilized in the United States, it has been used clinically in several other countries particularly China and Russia. In China, it is considered one of the 50 fundamental Chinese herbs and is used in Chinese herbal medicine.

Enpiprazole is a heterocyclic three-ringed pyrazolylalkyl piperazine derivative. Enpiprazole has a cataleptic action very similar to that of neuroleptics, and its effect on muscle relaxation is comparable with that of diazepam. Enpiprazole exerts anxiolytic properties in animals.

Nemifitide is a peptide analog of melanocyte-inhibiting factor (MIF) that has been reported to relieve depressive symptoms in a very short period. Tetragenex (formerly Innapharma) was developing nemifitide with potential in the treatment of depression. Clinical data obtained from two pilot clinical studies, double-blind, placebo-controlled, parallel-design, in-patient and outpatient, suggested that nemifitide may have the following advantages over current therapies: rapid onset of action (3–5 d), short period of administration (5–10 doses over a 1–2 wk period), and a relatively long duration of treatment effect (3–6 months). The mechanism of action of nemifitide was investigated by evaluating its in-vitro receptor binding and in-vivo localization in the rat brain as well as its interactions with psychoprobes indicative of specific neurotransmitter pathways in acute studies in rats. The results of these studies indicate that nemifitide readily crosses the blood–brain barrier and is localized mainly in the amygdala, hippocampus and frontal cortex of the rat brain. Its in-vitro binding to several receptors including 5-HT-2A, as well as its significant interaction with d-fenfluramine in the rat, suggest the participation of the serotonergic pathway in its mode of action in a different way than that observed with SSRI antidepressants.

Nicainoprol, also known as RU-42924, is calcium channel antagonist and a putative class I antiarrhythmic agent. Nicainoprol was shown to be useful in the prevention and treatment of arrhythmias associated with acute myocardial infarction. Nicainoprol had been in phase II clinical trials for the treatment of arrhythmia. However, this research has been discontinued.

Mofegiline (MDL 72,974A or (E)-2-(4-fluorophenethyl)-3-fluoroallylamine, hydrochloride), is a selective and irreversible inhibitor of monoamine oxidase type B (MAO-B) both in vitro and in vivo. In addition, mofegiline inhibits semicarbazide-sensitive amine oxidase activity from human serum and saphenous vein. In phase II studies, MDL 72,974A is proving to be a useful adjunct to conventional therapy of Parkinson's disease. It seems mofegiline development was discontinued.

Dextofisopam, a non-serotonergic agent currently being evaluated for the treatment of irritable bowel syndrome (IBS), is the R-enantiomer of racemic tofisopam, a molecule marketed and used safely outside the United States for over three decades for multiple indications including IBS. Dextofisopam represents a novel, first-in-class opportunity with a positive proof-of-concept study in an arena where there are few compounds with unique approaches or positive efficacy results. By structure, Dextofisopam is a member of the homophthalazine class; Dextofisopam binds to specific receptors in areas of the brain affecting autonomic function, including gastrointestinal (GI) function. Unlike the two 5-HT3 or 5-HT4 mediated IBS therapies currently available, both with significant safety concerns, Dextofisopam novel non-serotonergic activity offers a unique and innovative approach to IBS treatment. Recent studies have indicated that dextofisopam binds to a novel binding site within the central nervous system that may be responsible for mediating its actions. This receptor has been characterized as the 2,3-benzodiazepine receptor, which is distinct from the classical 1,4 or 1,5-benzodiazepine receptor. Dextofisopam has no significant binding at other receptors or ion channels

Cianopramine is a highly potent inhibitor of neuronal serotonin (5-HT) uptake developed by Hoffmann-La Roche for major depression treatment. In preclinical studies, acute and chronic treatment with Cianopramine shows clear behavioural effects Cianopramine increases neophobic reactions in the free exploration test, the avoidance reaction to a brightly illuminated chamber in the light/dark choice procedure as well as to open arms in the elevated plus-maze test. In a double-blind trial, Cianopramine effective in reducing scores on the Hamilton Psychiatric Rating Scale for Depression and on a global scale. Unfortunately, Cianopramine administrations were associated with significant adverse effects and future development was discontinued.

Methoxyphedrine (para-methoxymethcathinone, 4-methoxymethcathinone, bk-PMMA, PMMC, Methedrone, 4-MeOMC) is a phenethylamine, amphetamine, and cathinone derivative that acts as a triple reuptake/release/reversible monoamine oxidase inhibitor and used as a recreational drug. Methedrone has been found to be a potent serotonin transporter (SERT) and norepinephrine transporter (NET) inhibitor, but a weak dopamine transporter (DAT) inhibitor. Methedrone induces the transportation mediated release of NE, DA, and 5-HT from cells preloaded with monoamines making it a serotonin-norepinephrine-dopamine (SNDRA) releasing agent, also known as triple releasing agent (TRA), which is a common characteristic among drugs of abuse. The health risks associated with Methedrone are unknown but are expected to be similar to other cathinones. The deaths of two young men in southeast Sweden in 2009 were attributed to Methedrone overdose.

Tinabinol is a thiopyranobenzopyran derivative patented by Sharps Associates as tranquilizing agent. In preclinical modes Tinabinol shows good analgesic properties and causes ataxia in dogs at low doses.

Dabelotine is a cognitive-enhancing drug, developed by Servier. The drug has been shown to improve some aspects of cognitive processes, such as attention, curiosity, motivation, acquisition, and recall of memory. Dabelotine has also been shown to reduce the effect of an anticholinergic drug such as scopolamine. The drug increases the in vitro K+-induced norepinephrine release in rodent cerebral slices, and have no effect on noradrenergic and cholinergic receptor binding sites. Dabelotine was investigated in phase 2 clinical trials for the treatment of dementia, where it was demonstrated that 50-mg and 100-mg doses produced an improvement in reaction time and performance in memory tasks.