<unk> , or 14,15-deoxygedunin, is a naturally occurring tetranortriterpenoid isolated from the Indian neem tree (Azadirachta indica), a plant that has been used in India since ancient times as a remedy for various ailments.<unk>  has been found to act as a potent, selective, small-molecule agonist of TrkB, the main receptor of brain-derived neurotrophic factor (BDNF). It produces TrkB-dependent neurotrophic and neuroprotective effects in mice and enhances learning processes. In addition,<unk>  evokes rapid TrkB-dependent antidepressant-like effects in the forced swim test, an animal model of depression, similarly to 7,8-dihydroxyflavone (7,8-DHF) and ketamine, and notably with a greater potency than 7,8-DHF. The compound was discovered by the same group that identified 7,8-DHF and N-acetylserotonin as TrkB agonists. With intraperitoneal injection to mice,<unk>  crosses the blood-brain-barrier into the central nervous system and possesses a long duration of action, with onset of action at 2 hours post-administration and peaking between 4–8 hours. Relative to 7,8-DHF,<unk>  has weaker binding affinity for TrkB (Kd = 1.4 μM). However, it is more potent than 7,8-DHF in vivo with intraperitoneal injection in multiple assays.<unk>  has also been found to be orally and topically active. Unfortunately, the compound, in contrast to 7,8-DHF, has poor water solubility, and hence its bioavailability, especially oral, may be suboptimal. The researchers who discovered<unk>  expressed that they were attempting to find analogues with improved water solubility that retained the biological activity of<unk> , but, as of 2016, there appear to have been no subsequent reports on this effort since the original paper (2010) was published. They also stated in the paper that 7,8-DHF has a simpler chemical structure and that the flavonoids were easier to modify for improved biological effects than the gedunins. Similarly to gedunin, a closely structurally related compound also found in Azadirachta indica,<unk>  has additionally been found to activate HSF1 and induce Hsp70, and was observed to possess neuroprotective effects in a model of Huntington's disease.
Deoxygedunin
Dihydroartemisinin
Bempedoic acid
Prosultiamine
Rubitecan
Tuberculinic acid
Quarantine
Arabinopyranosyl-N-methyl-N-nitrosourea