Shikonin is a major naphthoquinone compound found in the roots of Lithospermum erythrorhizon and exhibits powerful anticancer activities for various cancer cells. Shikonin and its derivatives are characterized by a wide spectrum of antibacterial activities: high antibacterial activity towards Gram-positive bacteria (Staphylococcus aureus et al.), a stable fungicidal effect towards Candida and Trichosporon fungi. Shikonin normalizes the production of the key mediators of inflammation IL-1 and IL-2, IFN-γ, reduces vascular permeability in the focus of inflammation, exhibiting a marked anti-inflammatory effect. Combined therapy with applications of a bio-polymeric film with shikonin and its esters (naphthoquinone derivatives) led to an obvious improvement of the clinical parameters and reduced the morphological signs of the buccal mucosal lesions. The drug was well tolerated by all patients and no side effects were recorded. Shikonin, as a naturally occurring, low-molecular-weight pan-chemokine receptor inhibitor, constitutes a basis for the development of novel anti-HIV therapeutic agents.

PK-11195 is a selective antagonist of the Translocator Protein (TSPO). The C11 radiolabeled isotope of PK-11195 ([11C]-(R)-PK-11195) has been used effectively for diagnostic PET imaging in a number of CNS conditions where imaging of TSPO is informative (the S- enantiomer is not used). Applicable conditions including Schizophrenia, Multiple Sclerosis, and Traumatic Brain Injuries where it has been particularly useful for detection of increased microglial activation. It has also been investigated as means to monitor the role of Toll-Like Receptor-4 (TLR-4) after cerebral ischemia in mice. It should be noted that the unlabeled PK-11195 had been investigated for a number of potential therapeutic uses but did not progress beyond animal and cell models.

SB-271046 is one of the first selective 5-HT6 receptor antagonists to be discovered. SB-271046 is a potent, selective and orally active 5-HT6 receptor antagonist with a pKi value of 8.9. This compound provides a useful tool for further elucidating the physiological function of 5-HT6 receptors in vivo. SB-271046 was found to increase levels of the excitatory amino acid neurotransmitters glutamate and aspartate, as well as dopamine and noradrenaline in the frontal cortex and hippocampus of rats, and 5-HT6 antagonists have been shown to produce nootropic effects in a variety of animal studies. Suggested applications of SB-271046 included treatment of schizophrenia and other psychiatric disorders. A phase I clinical development of SB-271046 by GlaxoSmithKline (GSK) was discontinued due to a poor BBB permeability.

S-5751, an orally active prostanoid DP receptor antagonist, had potent anti-inflammatory effects in guinea pig and sheep asthma models. S-5751 had been in phase II clinical trials by Shionogi for the treatment of bronchial asthma. However, this study was discontinued in 2006.

Manoalide is a sesquiterpenoid isolated from the Indo-Pacific sponge Luffariella variabilis. It is a potent analgesic and anti-inflammatory agent. Manoalide acts by inhibiting PLA2. At low concentrations, manoalide also inhibited calcium channels with no effect on phosphoinositide metabolism. Manoalide was licensed to Allergan Pharmaceuticals and reached Phase II clinical trials as a topical anti-psoriatic, its development was however, discontinued due to formulation problems.

Clove oil is a natural product, derived from the Eugenia caryophyllata tree. Clove oil is 85 to 95% eugenol. Isoeugenol and methyleugenol make up 5 to 15% of the remaining ingredients. Isoeugenol is manufactured from eugenol by a process of isomerization. Isoeugenol have been used in foods and eugenol has been used in animal feeds. Isoeugenol is used as a fish anesthetic. The mechanism of action of isoeugenol in fish has not been determined. It is hypothesised that its effects are mediated via receptors controlling cellular ion channels in a similar way to that described for local anaesthetics. Reports of adverse reactions involving the use of isoeugenol in humans are primarily confined to incidents of contact sensitization or allergy following dermal exposure.

Propylparaben is a bacteriostatic and fungistatic agent used as a preservative in cosmetic products, food and drugs. As a food additive, it has the E number E216. To increase the activity and reduce its dose propylparaben is used in a mixture with other parabens and in combination with other types of preservatives. Propylparaben is a chemical allergen capable of producing immunologically mediated hypersensitivity reactions. Chemically it is an ester of p-hydroxybenzoic acid.

Eugenol is sometimes called clove oil because it is the active element in cloves. It causes the aromatic smell typical of cloves and because of this property is often found in perfumes. Eugenol’s properties make it a good local antiseptic and analgesic. It is used in dentist offices to make zinc-oxide eugenol paste for temporary fillings. Eugenol also demonstrates antifungal and antimicrobial activity, showing efficacy against Candida albicans biofilms, Listeria monocytogenes and Escherichia coli. Eugenol is further described to induce reactive oxygen species (ROS) production and to scavenge ROS, thus demonstrating prooxidant and antioxidant effects. Also, Eugenol is used as a pesticide.

Daprodustat (DUVROQ) is a small molecule inhibitor of hypoxia-inducible factor prolyl hydroxylase (PHD) developed by GlaxoSmithKline for the treatment of anaemia in patients with chronic kidney disease (CKD). Inhibition of PHD prevents degradation of hypoxia-inducible factor (HIF), leading to the production of erythropoietin and subsequent induction of erythropoiesis. In June, daprodustat received its first approval in Japan for the treatment of renal anaemia.

Gepirone (brand name Travivo) is an investigational azapirone antidepressant and anxiolytic drug in development for the treatment of major depressive disorder but has yet to be marketed. Like other azapirones, it acts as a selective partial agonist of the 5-HT1A receptor. Gepirone has been under development in the U.S. in an extended release form (referred to as Gepirone ER). It has been rejected multiple times by the FDA during the drug approval process and Phase III studies evaluating its use in the treatment of MDD were prematurely terminated. These were the initial Phase III studies of gepirone ER in MDD, and the effective dose range had not been determined. In March 2016, the FDA reversed its decision and gave gepirone ER a positive review, clearing the way for the drug to finally gain market approval in the U.S. In addition to its antidepressant and anxiolytic properties, gepirone has been found to improve symptoms of sexual dysfunction in men and women, similarly to the marketed 5-HT1A receptor agonist flibanserin. The pro-sexual effects appear to be independent of its antidepressant and anxiolytic effects. Mechanism of action studies have demonstrated that gepirone possesses a much greater selectivity for 5-HT1A receptors over dopamine D2 receptors. Long-term studies have shown that gepirone has a differential action at presynaptic (agonist) and post-synaptic (partial agonist) 5-HT1A receptors. Treatment with gepirone ER desensitizes presynaptic 5-HT1A receptors, which decreases serotonin autoregulatory inhibition and enhances activation of postsynaptic 5-HT1A receptors. As a partial agonist gepirone ER acts as an agonist when endogenous serotonin is not present and as an antagonist when endogenous serotonin is present. Overall, gepirone ER increases serotonin production when insufficient amounts are present, and decreases serotonin production when excess amounts are present. Gepirone has been tested in Phase II clinical trial as antidepressant medication for pharmacotherapy for cocaine dependent subjects.