Discovery of isatin and 1H-indazol-3-ol derivatives as d-amino acid oxidase (DAAO) inhibitors

Construction of Diversified Penta-Spiro-Heterocyclic and Fused-Heterocyclic Frameworks with Potent Antitumor Activity

Multiple-spiro/fused-heterocyclic frameworks containing indazolone are structurally unique and represent a class of potentially dominant skeletons. In this work, we successfully fulfilled Rh(III)-catalyst mediated substrate- and pH- controlled strategies to construct four novel types of complicated penta-spiro/fused-heterocyclic frameworks via C-H activation/[4+1] and [4+2] annulation cascades. This method had mild reaction conditions, a broad scope of substrates, moderate to good yields, and valuable applications, which could realize for the first time the generation of the novel di-spiro-heterocyclic and multiple fused-heterocyclic products with unique structures. More importantly, novel spiro[cyclohexane-indazolo[1,2-a]indazole] scaffold constructed by this method exhibited potent antitumor activity against a variety of refractory solid tumors and hematological malignancies in vitro. Overall, our work provided new insights into the construction of complex and diverse multiple spiro/fused-heterocyclic systems and offered novel valuable lead compounds for the discovery of antitumor drugs.

Tryptophan Metabolites as Mediators of Microbiota-Gut-Brain Communication: Focus on Isatin

Isatin (indole-2,3-dione) is an endogenous regulator, exhibiting various behavioral, biological, and pharmacological activities. Synthesis of isatin includes several crucial stages: cleavage of the tryptophan side chain and subsequent oxidation of the indole nucleus. Although these stages require concerted action of bacterial and host enzymes, there are two pathways of isatin formation: the host and bacterial pathways. Isatin acts as a neuroprotector in different experimental models of neurodegeneration. Its effects are realized via up- and downregulation of isatin-responsive genes and via interaction with numerous isatin-binding proteins identified in the brain. The effect of isatin on protein-protein interactions in the brain may be important for realization of weak inhibition of multiple receptor targets.

D-Serine as the gatekeeper of NMDA receptor activity: implications for the pharmacologic management of anxiety disorders

Fear, anxiety, and trauma-related disorders, including post-traumatic stress disorder (PTSD), are quite common and debilitating, with an estimated lifetime prevalence of ~28% in Western populations. They are associated with excessive fear reactions, often including an inability to extinguish learned fear, increased avoidance behavior, as well as altered cognition and mood. There is an extensive literature demonstrating the importance of N-methyl-D-aspartate receptor (NMDAR) function in regulating these behaviors. NMDARs require the binding of a co-agonist, D-serine or glycine, at the glycine modulatory site (GMS) to function. D-serine is now garnering attention as the primary NMDAR co-agonist in limbic brain regions implicated in neuropsychiatric disorders. L-serine is synthesized by astrocytes, which is then transported to neurons for conversion to D-serine by serine racemase (SR), a model we term the 'serine shuttle.' The neuronally-released D-serine is what regulates NMDAR activity. Our review discusses how the systems that regulate the synaptic availability of D-serine, a critical gatekeeper of NMDAR-dependent activation, could be targeted to improve the pharmacologic management of anxiety-related disorders where the desired outcomes are the facilitation of fear extinction, as well as mood and cognitive enhancement.

Synthesis and Activity Evaluation of Nasopharyngeal Carcinoma Inhibitors Based on 6-(Pyrimidin-4-yl)-1H-indazole

Human nasopharyngeal carcinoma is a common head and neck malignancy with high incidence in Southeast Asia and Southern China. It is necessary to develop safe, effective and inexpensive anticancer agents to improve the therapeutics of patients with nasopharyngeal carcinoma. A series of small molecular compounds based on 6-(pyrimidin-4-yl)-1H-indazole were synthesized and evaluated for antiproliferative activities against human nasopharyngeal carcinoma cell lines SUNE1. Compounds 6b, 6c, 6e and 6l showed potent antiproliferative activities similar to positive control drug cisplatin in vitro with lower nephrotoxicity than it. N-[4-(1H-Indazol-6-yl)pyrimidin-2-yl]benzene-1,3-diamine (6l) was selected for further study. It was found that 6l induced mitochondria-mediated apoptosis and G₂ /M phase arrest in SUNE1 cells. Furthermore, compound 6l at 10 mg/kg can suppress the growth of an implanted SUNE1 xenograft with a TGI% (tumor growth inhibition) value of 50 % and did not cause serious side effects in BALB/c nude mice. This study suggests that 6-(pyrimidin-4-yl)-1H-indazole derivatives are a series of small molecule compounds with anti-nasopharyngeal carcinoma activities.