MPEP (2-methyl-6-(phenylethynyl)pyridine) was one of the first compounds found to act a selective antagonist for the metabotropic glutamate receptor subtype mGluR5. It was under development by Novartis in the late 1990's. MPEP was found to produce neuroprotective effects following acute brain injury in animals. MPEP was also found to have positive effects on animal models of depression, anxiety and morphine withdrawl.

3-Indolepropionic acid (IN-OX1; Indole-3-propionic acid; OX-1; Oxigon; SHP 22; SHP-622; VP-20629), an endogenous substance produced by bacteria in the intestine, is a deamination product of Tryptophan (T947200) that protects the hippocampus (studied in gerbils) from ischemic damage and oxidative stress. It’s ability to protect the neurons in this way is attributed to its potent antioxidative effects. 3-Indolepropionic acid is also hypothesized to have protective effects on the thyroid gland. 3-Indolepropionic acid is being studied for therapeutic use in Alzheimer's disease. 3-Indolepropionic acid (IPA) completely protected primary neurons and neuroblastoma cells against oxidative damage and death caused by exposure to Abeta, by inhibition of superoxide dismutase, or by treatment with hydrogen peroxide. In kinetic competition experiments using free radical-trapping agents, the capacity of IPA to scavenge hydroxyl radicals exceeded that of melatonin, an indoleamine considered to be the most potent naturally occurring scavenger of free radicals. In contrast with other antioxidants, IPA was not converted to reactive intermediates with pro-oxidant activity. In 2011, Intellect redirected the focus of the OX1 program from Alzheimer's disease to FA (Friedreich's Ataxia). Research suggests that the symptoms associated with FA are the result of oxidative stress caused by the abnormal accumulation of iron. OX1's ability to neutralize ROS could be an effective agent to reduce oxidative stress in FA, thereby eliminating the symptoms of FA and increasing both quality of life and longevity in affected individuals.

Avelestat, also known as AZD9668, is a novel, oral inhibitor of neutrophil elastase (NE), an enzyme implicated in the signs, symptoms, and disease progression in NE-driven respiratory diseases such as bronchiectasis, Cystic Fibrosis and chronic obstructive pulmonary disease via its role in the inflammatory process, mucus overproduction, and lung tissue damage. Its development was discontinued due to unknown reasons. Nevertheless, this drug in the phase II of clinical trial as adjunctive therapy in improving insulin sensitivity of insulin-resistant type 2 diabetic subjects. The drug's clinical profile suggests that it will be well tolerated with few, if any, side effects, and the existence of simple methods that can indirectly measure its activity in vivo.

Iodophthalein was used as an iodine-containing X-ray contrast agent in icteric subjects. There is also existed mention, that iodophthalein has also been used as a wound treatment, and for the treatment of intestinal catarrhs. But nowadays more modern drugs are being used.

Prodolic acid is an indole derivative patented by American Home Products Corp. as antiinflammatory agent. Prodolic acid acts as non-steroidal anti-inflammatory compound and inhibits bradykinin-induced bronchoconstriction but did not affects histamine-induced bronchoconstriction in the guinea pig. In preclinical studies, Prodolic acid exhibits potent anti-inflammatory activity in adjuvant arthritic rats.

Midesteine (previously known as MR 889), a thiolactic acid derivative was developed as an inhibitor of the chymotrypsin and elastolytic activity of leukocyte elastase. Midesteine participated in clinical trials for patients with chronic obstructive pulmonary disease. The drug is also studied to treat asthma, cystic fibrosis, and emphysema. However, all these studies were discontinued.

Tridecanoic acid is a 13-carbon saturated fatty acid found in dairy products and also as a product of anaerobic biodegradation of n-hexadecane. It has been identified as a substrate of phospholipase A2. Saturated fatty acids with carbon chain lengths of C12 to C14 activated the alpha-, beta-, gamma-, and epsilon-subspecies of the protein kinase C, and this activation was synergistic with that by diacylglycerol. Tridecanoic acid(C13) was most effective among the saturated fatty acids examined.

Sodium sulfanilate is a salt of sulphanilic acid and has been used to monitor the degree of renal dysfunction in dogs.

Arctigenin is a plant lignan extracted from Arctium lappa that has been shown to have estrogenic properties. In ER-positive MCF-7 cells, arctigenin efficiently inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cell migration and invasion. Arctigenin confers anti-metastatic effects by inhibiting MMP-9 and uPA via the Akt, NF-κB and MAPK signaling pathways on breast cancer, regardless of ER expression. Intake of arctigenin could be an effective supplement for breast cancer patients. Arctigenin is a phenylpropanoid dibenzylbutyrolactone lignan compound possessing antitumor, anti-inflammatory, anti-influenza, antioxidant, antibacterial, and hypoglycaemic activities. Arctigenin exhibited significant antiproliferative activity against CCRF-CEM cells after 72 h treatment with IC50 values of 1.21 ± 0.15 um. It arrested CCRF-CEM cells in the S phase. It induced apoptosis in CCRF-CEM cells in a concentration- and time-dependent manner. Arctigenin is a good candidate for the development of novel agents against T-cell lymphoma. Arctigenin has been found to act as an agonist of adiponectin receptor 1 (AdipoR1). Arctigenin is an antagonist of MR and effectively decreases the Na/K-ATPase 1 gene expression, thus highlighting its potential as an anti-hypertensive drug lead compound.