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Chem Pharm Bull [journal]
- Design, synthesis, and potent antiepileptic activity with latent nerve rehabilitation of novel γ-aminobutyric acid derivatives. [JOURNAL ARTICLE]
- Chem Pharm Bull (Tokyo) 2014 Jul 18.
We aimed to design and synthesize novel γ-aminobutyric acid (GABA) derivatives with the combination of aspirin (ASA) of nerve rehabilitative pharmacophores so as to develop multifunctional drugs useful in the treatment of neurological disorders. Twenty-four novel esters and amides of 1a were synthesized, biologically evaluated for antiepileptic activity with the model of 4-aminopyridine (4-AP), and tested for their capacity of penetrating the blood-brain barrier (BBB) with HPLC. The distribution of 8a, ASA freed by 8a, 7c, and ASA freed by 7c within 24 h in brain tissue was measured. The structure-activity relationship (SAR) was established and the data of Computer Aided Drug Design (CADD) showed good results. With ED50 values of 0.3684-0.5199 mmol/kg, LD50 1.1487-1.3944 mmol/kg, and therapeutic index (TI) 2.65-3.15, compounds 8a, 3b, 4b, 6c, and 7c exhibited better antiepileptic activities in multiples of 0.3 to 2.2 against the control sodium valproate (VPA). Most importantly, 8a and 7c exhibited excellent antiepileptic activities with TI values of 3.15 and 3.12, respectively.
- Functionalized Oxatriquinanes and Their Structural Equilibrium in Protic Solvent. [JOURNAL ARTICLE]
- Chem Pharm Bull (Tokyo) 2014 Jul 10.
We synthesized oxatriquinane hexafluorophosphate bearing an ethoxycarbonylmethyl group 7 or a 2-oxopropyl group 11. Both of these organic oxonium cation compounds were obtained as stable solids. However, (1)H-NMR analysis showed that oxatriquinane 7 was present as the oxonium cation in aprotic solvent CD3CN, but was in rapid equilibrium with ring-opened bicyclic compound 8 in protic solvent CD3OD. The oxatriquinane 11 also showed similar behavior in protic solvent. Phenyl-substituted oxatriquinanes 12 and 14 were also obtained as stable solids, and showed similar properties to 7 and 11.
- 1,4-Benzoxazine- 3(4H)-ones as potent inhibitors of platelet aggregation: design, synthesis and structure-activity relations. [JOURNAL ARTICLE]
- Chem Pharm Bull (Tokyo) 2014 Jul 9.
A series of novel potentially platelet aggregation-inhibiting 1,4-benzoxazine-3(4H)-one derivatives was designed and synthesized through Smiles rearrangement, reduction and acetylation reactions. The antiaggregatory activities of the target molecules on arterial blood samples from rabbits, expressed by IC50 values (μM), were then evaluated in vitro against ADP induced platelet aggregation. The favorable IC50 values of compound 8c (IC50 = 8.99 μM) and 8d (IC50 = 8.94 μM) indicated that these two compounds were the most potent molecules among all the synthesized compounds. A detailed molecular docking study to explore the interaction of compounds 8c and 8d with GP IIb/IIIa receptor showed that they these two compounds were docked into the active site of GPIIb/IIIa receptor. These results suggest that the 1,4-benzoxazine-3(4H)-one derivatives are promising lead compounds to develop new platelet aggregation inhibitors.
- New Cassane-Type Diterpenoids from Caesalpinia bonduc. [Journal Article]
- Chem Pharm Bull (Tokyo) 2014; 62(7):729-33.
Six new cassane diterpenoids, named caesalls H-M (1-6), were isolated from the seed kernels of Caesalpinia bonduc. Their structures were elucidated on the basis of spectroscopic analysis, mainly NMR and MS. The absolute configurations of compounds 1 and 3 were determined by a single-crystal X-ray study using a mirror CuKα radiation and circular dichroism (CD) spectra, respectively. None of the compounds were cytotoxic against HepG-2, MCF-7 and MG-63 cells.
- Transannular Cyclization of (4S,5S)-Germacrone-4,5-epoxide under Basic Conditions to Yield Eudesmane-Type Sesquiterpenes. [Journal Article]
- Chem Pharm Bull (Tokyo) 2014; 62(7):725-8.
Transannular cyclizations of germacrone-4,5-epoxide under acidic and thermal conditions have been reported in our previous study. However, this process gave the different and interesting results under basic conditions. (4S,5S)-Germacrone-4,5-epoxide (1) was treated under basic conditions to yield four products (2-5). Compound 2 was an isomer of 1 -(4S,5S,9Z)-4,5-epoxygermacra-7(11),9-dien-8-one- and the remaining three compounds (3-5) were eudesmane-type derivatives. Compounds 4 and 5 are new compounds. The structures of the new compounds were determined using high resolution (HR)-MS, one dimensional (1D)-NMR, 2D-NMR and circular dichroism (CD) spectroscopic data. Products 3-5 had the same carbon skeleton as that of eudesmane-type compounds; however, these compounds showed different arrangement of isoprene units to the natural eudesmane-type sesquiterpenes.
- Hg(2+)-Trapping Beads: Hg(2+)-Specific Recognition through Thymine-Hg(II)-Thymine Base Pairing. [Journal Article]
- Chem Pharm Bull (Tokyo) 2014; 62(7):709-12.
Mercury pollution poses a severe threat to human health. To remove Hg(2+) from contaminated water, we synthesized Hg(2+)-trapping beads that include oligo-thymidine functionalities that can form thymine-Hg(II)-thymine base pairs on the solid support. The beads can selectively trap Hg(2+) even in the presence of other metal cations. More interestingly, Hg(2+)-trapping efficiency was higher in the presence of the co-existing cations. Thus, the developed Hg(2+)-trapping beads can capture Hg(2+) without affecting the mineral balance of water so much. The Hg(2+)-trapping beads presented here show promise for removing Hg(2+) from environmental water.
- Synthesis and Structure-Activity Relationship Study of Triazine-Based Inhibitors of the DNA Binding of NF-κB. [Journal Article]
- Chem Pharm Bull (Tokyo) 2014; 62(7):700-8.
Nuclear transcription factor nuclear factor-kappa B (NF-κB) has diverse pathophysiological functions, and NF-κB inhibitors are considered to be candidates for multiple therapeutic applications. We previously reported a novel triazine-based NF-κB inhibitor, 2-anilino-4,6-dichloro-1,3,5-triazine (NI241), that directly inhibits DNA binding of NF-κB. Here, we report synthesis of a series of triazine derivatives and evaluation of their structure-activity relationships for NF-κB inhibition. We found that 2-amino-4,6-dichloro-1,3,5-triazine substructure is essential for the inhibitory activity of the lead compound NI241, and modification of NI241 by introduction of an m-methoxy substituent on the phenyl ring afforded the more potent derivative 28. The structure-activity relationships identified in this study suggested a possible mechanism of irreversible NF-κB inhibition by NI241, and should be helpful in the design of other NF-κB inhibitors.
- Molecular Modeling Studies and Synthesis of Novel Methyl 2-(2-(4-Oxo-3-aryl-3,4-dihydroquinazolin-2-ylthio)acetamido)alkanoates with Potential Anti-cancer Activity as Inhibitors for Methionine Synthase. [Journal Article]
- Chem Pharm Bull (Tokyo) 2014; 62(7):675-94.
Cobalamin-dependant cytosolic enzyme methionine synthase (MetS) catalyses the transfer of a methyl group from the methyltetrahydrofolate (MTHF) to homocysteine (Hcy) to produce methionine and tetrahydrofolate (THF). MetS is over-expressed in the cytosol of certain breast and prostate tumour cells. Methionine used as a source of one carbon atom for the building of the DNA of the tumour cells, structural protein and enzymes. In this study, we designed, synthesized and evaluated the cytotoxic activity of a series of substituted methyl 2-(2-(4-oxo-3-aryl-3,4-dihydroquinazolin-2-ylthio)acetamido)acetate and dipeptide that mimic the substructure of MTHF. These inhibitors were docked in to the MTHF binding domain in such the same way as MTHF in its binding domain. The free energies of the binding were calculated and compared to the IC50 values. This series has been developed by dicyclohexylcarbodiimide (DCC) and azide coupling methods of amino acid esters with carboxylic acid derivatives, respectively. Compound methyl 3-hydroxy-2-(2-(3-(4-methoxyphenyl)-4-oxo-3,4-dihydroquinazolin-2-ylthio)acetamido)propanoate exhibited the highest IC50 value 20 µg/mL against PC-3 cell line and scored the lowest free energy of the binding (-207.19 kJ/mol).
- Molecular dynamics simulation-based evaluation of the binding free energies of computationally designed drug candidates: importance of the dynamical effects. [Journal Article]
- Chem Pharm Bull (Tokyo) 2014; 62(7):661-7.
The computational structure-based drug design (SBDD) mainly aims at generating or discovering new chemical compounds with sufficiently large binding free energy. In any de novo drug design methods and virtual screening methods, drug candidates are selected by approximately evaluating the binding free energy (or the binding affinity). This approximate binding free energy, usually called "empirical score," is critical to the success of the SBDD. The purpose of this work is to yield physical insight into the approximate evaluation method in comparison with an exact molecular dynamics (MD) simulation-based method (named MP-CAFEE), which can predict binding free energies accurately. We calculate the binding free energies for 58 selected drug candidates with MP-CAFEE. Here, the compounds are generated by OPMF, a novel fragment-based de novo drug design method, and the ligand-protein interaction energy is used as an empirical score. The results show that the correlation between the binding free energy and the interaction energy is not strong enough to clearly distinguish compounds with nM-affinity from those with µM-affinity. This implies that it is necessary to take into account the natural protein motion with explicitly surrounded by water molecules to improve the efficiency of the drug candidate selection procedure.
- Preparation and characterization of high-content aripiprazole-loaded core-shell structure microsphere for long-release injectable formulation. [Journal Article]
- Chem Pharm Bull (Tokyo) 2014; 62(7):654-60.
The aim of this study was to obtain injectable high-drug-loading core-shell structure microspheres that release aripiprazole over 2 months. The microparticles were prepared by the oil-in-water emulsion solvent evaporation method and characterized. The microparticles were prepared with aripiprazole and 3 types of poly(lactic acid) (PLA) (DL-PLA: molecular weight (MW), ca. 20000; DL-PLA: MW, ca. 95000; or L-PLA: MW, ca. 110000), which were dissolved within the organic phase, and prepared in 3 temperature conditions for the external aqueous phase (two fixed temperature conditions and a gradually increased temperature condition). The theoretical drug loading in the particles was set to 80%. When prepared at fixed temperature conditions, all of the microparticles that were prepared with the 3 types of PLA were not spherical or smooth-surfaced. These microparticles released 100% of the drug within 1 week in the in vitro study. However, the microparticles that were prepared with DL-PLA (MW, 95000) in the gradually increased temperature condition were spherical with a smooth surface. The dissolution profile of the microparticles showed a long release over 7 weeks in vitro. The actual drug loading in the microspheres was 73-80%. A core-shell structure was observed in the inner structure of the microspheres. The core-shell microspheres were injected subcutaneously into rabbits. Aripiprazole was detected in the serum over 12 weeks. Production of high-drug-loading core-shell structure microspheres was successfully achieved by using high molecular weight of PLA and specific temperature condition at preparation. It showed long release profile in vitro and in vivo.