7-[3-(1-piperidinyl)propoxy]chromenones as potential atypical antipsychotics. 2. Pharmacological profile of 7-[3-[4-(6-fluoro-1, 2-benzisoxazol-3-yl)-piperidin-1-yl]propoxy]-3-(hydroxymeth yl)chromen -4-one (abaperidone, FI-8602)

Dopamine and Dopamine-Related Ligands Can Bind Not Only to Dopamine Receptors

The dopaminergic system is one of the most important neurotransmitter systems in the central nervous system (CNS). It acts mainly by activation of the D₁-like receptor family at the target cell. Additionally, fine-tuning of the signal is achieved via pre-synaptic modulation by the D₂-like receptor family. Some dopamine drugs (both agonists and antagonists) bind in addition to DRs also to α₂-ARs and 5-HT receptors. Unfortunately, these compounds are often considered subtype(s) specific. Thus, it is important to consider the presence of these receptor subtypes in specific CNS areas as the function virtually elicited by one receptor type could be an effect of other—or the co-effect of multiple receptors. However, there are enough molecules with adequate specificity. In this review, we want to give an overview of the most common off-targets for established dopamine receptor ligands. To give an overall picture, we included a discussion on subtype selectivity. Molecules used as antipsychotic drugs are reviewed too. Therefore, we will summarize reported affinities and give an outline of molecules sufficiently specific for one or more subtypes (i.e., for subfamily), the presence of DR, α₂-ARs, and 5-HT receptors in CNS areas, which could help avoid ambiguous results.

First total synthesis of chromanone A, preparation of related compounds and evaluation of their antifungal activity against Candida albicans, a biofilm forming agent

A straightforward and convenient approach for the first total syntheses of chromanone A and a related 7-OMe substituted natural product is reported. These unique C-3 substituted 2-hydroxymethyl chromones were recently isolated as fungal metabolites. Chromanone A was synthesized in 25.3% overall yield from the readily available pyrocatechol, whereas the second natural product was prepared in 39.7% global yield. A small library of chromones, including both natural products and some of their synthetic heterocyclic precursors, was evaluated against Candida albicans ATCC 10231, a biofilm forming agent. It was found that 8-methoxy-3-methyl-4-oxo-4H-chromene-2-carbaldehyde, a partially oxidized form of chromanone A, exhibited a minimum inhibitory concentration of 7.8 μg mL⁻¹ and significantly inhibited the yeast's virulence factors, including the adherence to buccal epithelial cells and the secretion of phospholipases, as well as the formation of germ tubes and the generation of the hyphal pseudomycelium. In addition, despite the heterocycle exhibiting non-significant inhibition of the formation of the Candida biofilm, it completely inhibited the growth of C. albicans in preformed biofilms at 62.5 μg mL⁻¹.

Chromanone A and its 7-OMe analogue were totally synthesized. 2-Formyl chromanone A derivative inhibited C. albicans and its virulence factors.

Developing antineoplastic agents that target peroxisomal enzymes: cytisine-linked isoflavonoids as inhibitors of hydroxysteroid 17-beta-dehydrogenase-4 (HSD17B4)

Cytisine-linked isoflavonoids (CLIFs) inhibited PC-3 prostate and LS174T colon cancer cell proliferation by inhibiting a peroxisomal bifunctional enzyme. A pull-down assay using a biologically active, biotin-modified CLIF identified the target of these agents as the bifunctional peroxisomal enzyme, hydroxysteroid 17β-dehydrogenase-4 (HSD17B4). Additional studies with truncated versions of HSD17B4 established that CLIFs specifically bind the C-terminus of HSD17B4 and selectively inhibited the enoyl CoA hydratase but not the d-3-hydroxyacyl CoA dehydrogenase activity. HSD17B4 was overexpressed in prostate and colon cancer tissues, knocking down HSD17B4 inhibited cancer cell proliferation, suggesting that HSD17B4 is a potential biomarker and drug target and that CLIFs are potential probes or therapeutic agents for these cancers.

Benzisoxazole: a privileged scaffold for medicinal chemistry

The benzisoxazole analogs represent one of the privileged structures in medicinal chemistry and there has been an increasing number of studies on benzisoxazole-containing compounds. The unique benzisoxazole scaffold also exhibits an impressive potential as antimicrobial, anticancer, anti-inflammatory, anti-glycation agents and so on. This review examines the state of the art in medicinal chemistry as it relates to the comprehensive and general summary of the different benzisoxazole analogs, their use as starting building blocks of multifarious architectures on scales sufficient to drive human drug trials. The number of reports describing benzisoxazole-containing highly active compounds leads to the expectation that this scaffold will further emerge as a potential candidate in the field of drug discovery.

Phomopsichin A-D; Four New Chromone Derivatives from Mangrove Endophytic Fungus Phomopsis sp. 33

Four new chromone derivatives, phomopsichins A-D (1-4), along with a known compound, phomoxanthone A (5), were isolated from the fermentation products of mangrove endophytic fungus Phomopsis sp. 33#. Their structures were elucidated based on comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction or theoretical calculations of electronic circular dichroism (ECD). They feature a tricyclic framework, in which a dihydropyran ring is fused with the chromone ring. Compounds 1-5 showed weak inhibitory activities on acetylcholinesterase as well as α-glucosidase, weak radical scavenging effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH) as well as OH, and weak antimicrobial activities. Compounds 1-4 showed no cytotoxic activity against MDA-MB-435 breast cancer cells. Their other bioactivities are worthy of further study, considering their unique molecular structures.

Comparative cytochrome p450 in vitro inhibition by atypical antipsychotic drugs

The goal of this study was to assess in human liver microsomes the inhibitory capacity of commonly used antipsychotics on the most prominent CYP450 drug metabolizing enzymes (CYP1A2, CYP2C9, CYP2D6, and CYP3A). Chlorpromazine was the only antipsychotic that inhibited CYP1A2 activity (IC₅₀ = 9.5 μM), whilst levomepromazine, chlorpromazine, and thioridazine significantly decreased CYP2D6-mediated formation of 1′-hydroxybufuralol (IC₅₀ range, 3.5–25.5 μM). Olanzapine inhibited CYP3A-catalyzed production of 1′, and 4′-hydroxymidazolam (IC₅₀ = 14.65 and 42.20 μM, resp.). In contrast, risperidone (IC₅₀ = 20.7 μM) and levomepromazine (IC₅₀ = 30 μM) showed selectivity towards the inhibition of midazolam 1′-hydroxylation reaction, and haloperidol did so towards 4′-hydroxylation (IC₅₀ of 2.76 μM). Thioridazine displayed a K_i of 1.75 μM and an inhibitory potency of 1.57 on CYP2D6, suggesting a potential to induce in vivo interactions. However, with this exception, and given the observed K_i values, the potential of the assayed antipsychotics to produce clinically significant inhibitions of CYP450 isoforms in vivo seems limited.

Synthesis and Pharmacological Evaluation of (6-Substituted 4-Oxo-4H-chromene-3 yl) methyl N-substituted Aminoacetates

A series of the title compounds were synthesized and characterized by spectral data. All the compounds were evaluated for in vitro antihistaminic activity by inhibition of isotonic contractions induced by histamine on isolated guinea pig ileum and the compound 6-k showed significant activity. A few compounds have also been screened for in vivo bronchodilatory activity. These compounds exhibited significant protection against histamine-induced convulsions in guinea pig at the dose of 50 μmol.