Angelicin (isopsoralen), is a furocoumarin, occuring in a number of plants belonging to the Umbelliferae family. It acts as a photosensitizer by forming DNA monoadducts. Angelicin is able to inhibit monoamine oxidase (MAO) activities in rat brain mitochondria. Angelicin exerts antineoplastic and antidiabetic properties in animal models.

Rosmarinic acid (α-o-caffeoyl-3,4-dihydroxyphenyllactic acid; RA) is a naturally occurring hydroxylated compound commonly found in species of the subfamily Nepetoideae of the Lamiaceae and Boraginaceae, such as Rosmarinus officinalis, Salvia officinalis, and Perilla frutescens. RA is biosynthesized from the amino acids L-phenylalanine and L-tyrosine by eight enzymes that include phenylalanine ammonia lyase and cinnamic acid 4-hydroxylase. Recently, RA and its derivatives have attracted interest for their biological activities, which include anti-inflammatory, anti-oxidant, anti-angiogenic, anti-tumor, and anti-microbial functions. Clinically, RA attenuates T cell receptor-mediated signaling, attenuates allergic diseases like allergic rhinitis and asthma, and 2,4-dinitrofluorobenzene-induced atopic dermatitis-like symptoms, protects from neurotoxicity, and slows the development of Alzheimer's disease. Rosmarinic Acid seems to be able to suppress 5-lipoxygenase and 5-HETE synthesis (a pro-inflammatory compound in the omega-6 metabolic chain). Rosmarinic acid appeared to be effective in suppressing allergies in a dose-dependent manner, with 30% of the placebo group reporting symptom relief compared to 55.6% of the 50mg group and 70% of the 200mg group.

Ethyl Ferulate is an ester type of Ferulic Acid and has powerful antioxidant, free radical scavenging and UV adsorption properties. Ethyl Ferulate can be incorporated into various cosmetic formulations including aqueous, ethanolic and emulsion-based creams, sun creams or moisturizers. Ethyl ferulate demonstrated the cytoprotective effects against oxidative damage in neuronal cells. Ethyl ferulate has also been widely studied and some recent findings include its anticholinesterase activity; inhibition of nuclear factor-kappa B (NF-κB) activity in LPS-stimulated RAW 264.7 macrophages; inhibition of inducible nitric oxide synthase (iNOS) induction in UV-induced oxidative stress in melanocytes; induction of heme oxygenase (HO-1) activity in rat astrocytes and neurons, which is a putative pathway against oxidative stress that underline neurodegenerative diseases; and cytoprotective effect against reactive oxygen species (ROS)-induced damage through the stimulation of dermal fibroblasts stress response.

Indeloxazine is a neuroleptic, originally developed and marketed in Japan. It is indicated to allay autonomic hyperactivity following cerebral infarction, cerebral haemorrhage or atherosclerosis. It was found to be a weak inhibitor of both type A and type B monoamine oxidases. Indeloxazine-induced facilitation of acetylcholine release in frontal cortex is mediated by endogenous 5-HT and involves at least in part cortical 5-HT4 receptors. As a potential teratogen, Indeloxazine must not be consumed or handled by pregnant or nursing women, or by women who might become pregnant. It was removed from the market reportedly for lack of effectiveness.

Bifemelane is a psychotropic drug, was found to inhibit monoamine oxidase (MAO). It inhibited type A MAO (MAO-A) competitively and type B (MAO-B) noncompetitively and it was a more potent inhibitor of MAO-A than of MAO-B. Bifemelane is an antidepressant and cerebral activator that is used in Japan for the treatment of cerebral infarction patients with depressive symptoms, and in the treatment of senile dementia as well. It also appears to be useful in the treatment of glaucoma.

Lazabemide is a reversible and selective inhibitor of monoamine oxidase B (MAO-B) that was under clinical development against Parkinson's disease, Alzheimer's disease and as an aid to smoking cessation. The development of the drug was discontinued due to liver toxicity.

Debrisoquin is an antihypertensive drug having guanethidine-like properties, which inhibits monoamine oxidase (MAO) and does not enter the brain. Debrisoquine was used for the treatment of hypertension. Debrisoquine hydroxylation phenotype has been the most used test in humans to evaluate CYP2D6 activity. Two debrisoquine hydroxylation phenotypes have been described: poor and extensive metabolizers. A group with a very low debrisoquine metabolic ratio within the extensive metabolizers, named ultrarapid metabolizers, has also been distinguished. This CYP2D6 variability can be for a large part alternatively determined by genotyping, which appears to be of clinical importance given CYP2D6 involvement in the metabolism of a large number of commonly prescribed drugs.

Safinamide (FCE 26743, NW 1015, PNU 151774, PNU 151774E, trade name Xadago) combines potent, selective, and reversible inhibition of MAO-B with blockade of voltage-dependent Na+ and Ca2+ channels and inhibition of glutamate release. Safinamide is under development with Newron, Zambon and Meiji Seika Pharma for the treatment of Parkinson's disease. Safinamide has been launched in the EU, Iceland and Liechtenstein. Safinamide was well tolerated and safe in the clinical development program that demonstrated the amelioration of motor symptoms and OFF phenomena by safinamide when combined with dopamine agonists or levodopa.

Safinamide (FCE 26743, NW 1015, PNU 151774, PNU 151774E, trade name Xadago) combines potent, selective, and reversible inhibition of MAO-B with blockade of voltage-dependent Na+ and Ca2+ channels and inhibition of glutamate release. Safinamide is under development with Newron, Zambon and Meiji Seika Pharma for the treatment of Parkinson's disease. Safinamide has been launched in the EU, Iceland and Liechtenstein. Safinamide was well tolerated and safe in the clinical development program that demonstrated the amelioration of motor symptoms and OFF phenomena by safinamide when combined with dopamine agonists or levodopa.

Rasagiline (N-propargyl-1-(R)-aminoindan) is a selective, irreversible monoamine oxidase B (MAO B) inhibitor, which has been developed as an anti-Parkinson drug and was sold as a mesylate salt under brand name AZILECT. AZILECT is indicated for the treatment of the signs and symptoms of idiopathic Parkinson’s disease (PD) as initial monotherapy and as adjunct therapy to levodopa. The effectiveness of AZILECT was demonstrated in patients with early Parkinson’s disease who were receiving AZILECT as monotherapy and who were not receiving any concomitant dopaminergic therapy. The effectiveness of AZILECT as adjunct therapy was demonstrated in patients with Parkinson’s disease who were treated with levodopa. PD is a progressive neurodegenerative, dopamine deficiency disorder. The main therapeutic strategies for PD treatment relies on dopamine precursors (levodopa), inhibition of dopamine metabolism (monoamine oxidase [MAO] B and catechol-O-methyl transferase inhibitors), and dopamine receptor agonists. In contrast to selegiline, rasagiline is not metabolized to potentially toxic amphetamine metabolites. The precise mechanisms of action of rasagiline is unknown. One mechanism is believed to be related to its MAO-B inhibitory activity, which causes an increase in extracellular levels of dopamine in the striatum.