Neuroprotective Effects of 4-phenylbutyric Acid and Its Derivatives： Possible Therapeutics for Neurodegenerative Diseases

The pathogenesis of neurodegenerative diseases such as Alzheimer＇s and Parkinson＇s diseases involves the aggregation of denatured and misfolded nascent proteins. Consequently, many pharmacological approaches have been developed to prevent protein aggregation. 4-Phenylbutyric acid （4-PBA） is a chemical chaperone that shows potential as a candidate drug for the treatment of neurodegenerative diseases. The main actions of chemical chaperones are the amelioration of unfolded proteins and the suppression of their aggregation, which result in protective effects against endoplasmic reticulum stress-induced neuronal cell death. Furthermore, 4-PBA exhibits inhibitory activity against histone deacetylases （HDACs）. However, owing to the problematically high doses of 4-PBA currently required for therapeutic efficacy, the optimization of 4-PBA is crucial for its effective medicinal application. In the present review, we summarize the recent advances in research on the basic actions of 4-PBA and its derivatives. We also discuss whether these compounds could be viable therapeutic agents against neurodegenerative diseases.

Enantioselective Hydrogenation of Ethyl 2-Oxo-4-phenylbutyrate on Cinchona-Platinum Catalysts

Enantioselective hydrogenation of ethyl 2-oxo-4-phenylbutyrate to ethyl （R）-2-hydroxy-4-phenyl- bu- tyrate on Pt/γ-Al2O3 modified by 10,11-dihydrocinchonidine was studied by investigating the influences of the amount of modifier, initial concentration of reactant, pressure and temperature on conversion and enantiometric excess in a stirred autoclave and the effects of the liquid velocity, gas velocity, modifier concentration and various catalytic beds in a trickle-bed reactor. The maximum optical yields were about 50% and 60% in the two types of reactors, respectively. It was assumed that the total hydrogenation rate included the reaction rates over the unmodified and modified active sites on platinum surface and a kinetic model, which fitted the experimental data well in autoclave, was obtained. A simplified plug-flow model was proposed to describe the bed average efficiency of trickle-bed reactor.

Simultaneous Determination of Dopamine and Uric Acid at 2-Amino-5-mercapto-[1, 3, 4]triazole Self-assembled Monolayers Gold Electrode

A newly synthesized reagent 2-amino-5-mercapto-[1, 3, 4]triazole (MATZ) has been usedto fabricate self-assembled monolayers (SAMs) on gold electrode for the first time. The SAMselectrode was characterized by electrochemical methods and scanning electronic microscopy (SEM),the SAMs electrode can be used to determinate dopamine (DA) and uric acid (UA) simultaneouslywith a detection limit of 8×10-7 mol/L for DA and 1×10-6 mol/L for UA respectively. The SAMscan also be used to detect the contents of DA and UA in synthetic urine sample with satisfactoryresults.

Sodium 4-phenylbutyrate Attenuates High-fat Diet-induced Impaired Spermatogenesis

Objective To determine the mitigating effects of sodium 4-phenylbutyrate(4-PBA) on high-fat diet(HFD)-induced spermatogenesis dysfunction. Methods Male rats(n = 30) were randomly divided into three groups: control, HFD, and 4-PBA(HFD +4-PBA). After 13 weeks, rats were euthanized. Testes and epididymis were harvested for further analysis. Sex hormones were detected, and hematoxylin and eosin staining was performed to examine the histological changes in the testes. Semen samples were collected to evaluate sperm quality. Spermatogenic cell apoptosis was detected by TUNEL assay. Results Compared with the control group, the final body weight and body weight gain were significantly higher in HFD-fed rats, while the testicle/body weight ratios were lower(P < 0.05). In HFD-fed rats, obvious pathological changes in the testicular tissue were observed. Treatment with 4-PBA attenuated HFD-induced histological damage, ameliorated the HFD-induced decrease in serum testosterone(T), and reduced the rate of testicular cell apoptosis(P < 0.05) in obese male rats. Finally, 4-PBA significantly improved semen parameters in HFD rats(P < 0.05). Conclusion HFD exposure induced detrimental effects on spermatogenesis, semen quality, serum T level, and testicular cell apoptosis in rats. Treatment with 4-PBA ameliorated HFD-induced impaired spermatogenesis via inhibition of apoptosis in rats. 4-PBA may have therapeutic value in the treatment of obesity-related impairment of spermatogenesis.

Synthesis,Crystal Structure and Fluorescence Property of N-n-butyl-4-[di(bromoethyl)]amino-1,8-naphthalimide

The halogen as a kind of alkylating reagent is used to introduce new group to realize the fluorescence sensors efficient of metal ion detection. The substituent at C-4 position was double bromine, which defined that the halogen as an alkylating reagent should be further researched and detected for Hg2＋. Therefore, the N-n-butyl-4-[di（bromoethyl）]amino-1,8-naphthalimide has been synthesized to detect some metal ions. The title compound has been prepared via substitute reaction and was characterized by IR, 1H NMR, 13 C NMR, and MS. It crystallizes in triclinic, space group P1 with a = 9.0071（18）, b = 9.804（2）, c = 13.073（3）A, α = 73.17（3）, β = 71.73（3）, γ = 62.95（3）°, Z = 2, V = 961.5（3） A3, Dc = 1.666 g/cm3, F（000） = 484, μ（Mo Kα） = 4.232 mm-1, R = 0.0429 and w R = 0.1004. The presence of intermolecular hydrogen bonds as well as π-π stacking interaction led to the stability of the compound. The fluorescence intensity was obviously lower than that of other ions when Hg2＋ was added with the concentration of 1 × 10^-5 mol·L-1.

4-Phenylbutyric acid accelerates rehabilitation of barrier function in IPEC-J2 cell monolayer model

As the first line of defence against pathogens and endotoxins crossing the intestine-blood barrier,the intestinal epithelial barrier plays a determinant role in pigs’health and growth.4-Phenylbutyric acid(4-PBA),an aromatic fatty acid,was reported to benefit homeostasis of endoplasmic reticulum and protein synthesis.However,whether 4-PBA affects intestinal epithelial barrier function in pigs is unknown.This study aimed to explore the effects of 4-PBA on the intestinal barrier function,using in vitro models of well-differentiated intestinal porcine epithelial cell(IPEC-J2)monolayers in the transwell plates.Cell monolayers with or without 4-PBA(1.0 mmol/L)treatment were challenged with physical scratch,deoxynivalenol(DON,2.0μg/mL,48 h),and lipopolysaccharide(LPS,5.0μg/mL,48 h),respectively.Transepithelial electrical resistance(TEER)and fluorescein isothiocyanate-dextran(FD-4)permeability were measured to indicate barrier integrity and permeability.Real-time PCR and Western blot were conducted to determine relative gene and protein expressions of tight junction proteins.As expected,physical scratch,DON,and LPS challenges decreased TEER and increased FD-4 permeability.4-PBA treatment accelerated cell mitigation and rehabilitation of the physical scratch-damaged intestinal epithelial barrier but did not alleviate DON or LPS induced barrier damage.However,once 48-h DON and LPS challenges were removed,rehabilitation of the epithelial barrier function of IPEC-J2 monolayer was accelerated by the 4-PBA treatment.Also,the relative gene and protein expressions of zonula occludens-1(ZO-1),occludin,and claudin-1 were further upregulated by the 4-PBA treatment during the barrier rehabilitation.Taken together,4-PBA accelerated the IPEC-J2 cell monolayer barrier recovering from physical scratch,DON-,and LPS-induced damage,via enhancing cell mitigation and expressions of tight junction proteins.

Synthesis of a New Polymer-supported Reagent──Poly{[4- hydroxy(tosyloxy)iodo]styrene} and Its Application to the Synthesis of 2-Amino-4-arylthiazoles

A new polymer-supported reagent--poly{[4-hydroxy(tosyloxy)iodo]styrene} has good reactivity in the formation of 2-amino-4-arylthiazoles, and the procedure of regeneration and cycle are also described.

Growth inhibition and gene induction in human hepatocellular carcinoma cell exposed to sodium 4-phenylbutanoate

Background Sodium 4-phenylbutanoate （NaPB） can induce cellular differentiation and cell cycle arrest. However, its potential anticancer properties in hepatocellular carcinoma and influence on normal liver cell are still unclear. We observed the effects of NaPB on growth inhibition, including differentiation and phase growth arrest in normal liver cell line L-02 and hepatocellular carcinoma cell line Bel-7402. Furthermore, we investigated its mechanism in Bel-7402. Methods Hepatocellular carcinoma cells Bel-7402 and normal liver cell line L-02 were treated with NaPB at different concentrations. Light microscopy was used to find morphological change in cells. Cell cycle was detected by flow cytometry. Expression of acetylating histone H4 and of histones deacetylase 4 （HDAC4） were determined by Western blot. The expression of P21WAF1/CIP1 and E-cadherin were observed through immunocytochemistry. Results NaPB treatment led to time dependent growth inhibition in hepatocellular carcinoma cells Bel-7402. NaPB treatment caused a significant decline in the fraction of S phase cells and a significant increase in Go/G1 cells. NaPB increased the expression of P21wAFVCIP1 and E-cadherin in Bel-7402 and significantly decreased the level of HDAC4 in Bel-7402. NaPB significantly improved the level of acetylating histone H4. The normal liver cell line L-02 showed no distinct changes under treatment with NaPB. Conclusions NaPB inhibited the growth of hepatocellular carcinoma cells Bel-7402 and induced partial differentiation through enhancing the acetylating histones. In Bel-7402, the expressions of P21WAF1/CIP1 and E-cadherin may be related to level of acetylating histones and inhibition of cellular growth. NaPB showed no significant effect on normal liver cells.

Michael-Addition Reaction of Malononitrile with a,β-Unsaturated Cycloketones Catalyzed by KF/Al_2O_3

A series of KF/Al2O3 catalyzed Michael-addition reactions between malononitrile and a,b-unsaturated cycloke-tones in DMF solution were studied. At room temperature, 2-cyano-3-aryl-3-(1,2,3,4-tetrahydronaphthalen- 1-one-2-yl) propionitrile derivatives were synthesized by the reaction between 2-arylmethylidene-1,2,3,4-tetra-hydronaphthalen-1-one and malononitrile. However, if the temperature was increased to 80 ℃, 2-amino-3-cyano-4- aryl-4H-benzo[h]chromene derivatives were obtained in high yields. When the a,b-unsaturated ketones were re-placed by 2,6-biarylmethylidenecyclohexanone or 2,5-biarylmethylidenecyclopentanone, another series of 2-amino- 3-cyano-4H-pyran derivatives was isolated successfully. The structures of the products were confirmed by X-ray diffraction analysis.