Melatonin D5, a deuterium-labeled version of melatonin, is a hormone produced by the pineal gland, known for its role as a selective ATF-6 inhibitor that promotes apoptosis in human hepatoma cells via COX-2 downregulation. Additionally, it activates melatonin receptors and exhibits antioxidative and anti-inflammatory properties.
TIK-301 is a chlorinated melatonin derivative and a potent, high-affinity, and orally active melatonin MT1 and MT2 receptors agonist (Kis: 0.081 nM and 0.042 nM, respectively). TIK-301 is also a 5-HT2B 5-HT2C receptor antagonist with antidepressant action. TIK-301 has the potential for sleep disorders and other circadian rhythm disorders treatment.
Cyclo(L-Leu-L-Trp) is a diketopiperazine metabolite initially derived from Penicillium, exhibiting antibacterial (MICs = 125-1000 µg/ml) and antifungal activities (MICs = 8-64 µg/ml). It also demonstrates antioxidant properties by reducing the production of hydroxy radicals, as evidenced in an electron spin resonance (ESR) spectroscopy assay (IC50 = 1.8 µM). Additionally, Cyclo(L-Leu-L-Trp) has been identified as a bitter compound capable of quickly crossing rat taste cell membranes ex vivo at a 1 mM concentration. Furthermore, it acts as a melatonin receptor agonist in X. laevis melanophores, suppressing cAMP accumulation at a 20 µM concentration, with this effect being negated by the melatonin receptor antagonist luzindole.