Paeonenoides D and E: Two New Nortriterpenoids from Paeonia lactiflora and Their Inhibitory Activities on NO Production

Two new nortriterpenoids, paeonenoides D and E ( 1 and 2 , resp.), together with seven known compounds, were isolated from the roots of Paeonia lactiflora. Their structures were elucidated on the basis of spectroscopic evidence. Compounds 1 – 7 were screened for inhibitory effects against NO production in LPS‐induced RAW246.7 macrophages and for cytotoxic activities against HL‐60, Hep‐G2, and SK‐OV‐3 cell lines. Compounds 1 – 3 and 5 – 7 exhibited inhibitory activities with IC₅₀ values in the range of 9.6–32.2 μM . Triterpenoids with an epoxide ring and a free COOH function, 1 – 3 , showed effectively increased activities compared with other pentacyclic triterpenoids. Compounds 1 – 6 showed significant cytotoxic activities against the Hep‐G2 cell line and modest cytotoxic activities against HL‐60 and SK‐OV‐3 cell lines.     

A Novel C22 Terpenoid from the Cultured Perovskia atriplicifolia

A novel terpenoid, named perovskiaol ( 1 ), was isolated from the cultured Perovskia atriplicifolia. Its structure was elucidated by comprehensive spectroscopic analysis as well as by quantum chemical computation of electronic circular dichroism spectra. Perovskiaol ( 1 ) was a novel C₂₂ terpenoid containing a unique D‐ring simultaneously fused with rings A, B, and C, and encountered in nature for the first time. Cytotoxic bioassay suggested perovskiaol ( 1 ) possessed significant cytotoxic activity inhibiting NB4, A549, and HepG 2 cell lines with IC₅₀ values of 2.35, 1.47, and 0.81 μm , respectively.     

Effect of cationic surfactant cetyltrimethylammonium bromide on the enzymatic hydrolysis of cellulose

Effect of cationic surfactants alkyltrimethylammonium bromide (C_nTAB) with varied alkyl chain lengths on the enzymatic hydrolysis of Avicel and the surface charge of cellulase was investigated. Enzymatic hydrolysis of Avicel increased linearly from 42.1 to 61.4 % with the increase of the concentration of cetyltrimethylammonium bromide (C₁₆TAB) logarithmically from 0.0001 to 0.01 mM, and reached a maximum value at the concentration of 0.01–0.03 mM. When the concentration was increased further, the cellulase solution became positively charged and the enzymatic hydrolysis of Avicel decreased rapidly. With the increasing alkyl chain length, C_nTAB provided more proton and neutralized the negative charge of cellulase more obviously. Therefore, the required concentration of C_nTAB could be less to enhance the enzymatic hydrolysis of Avicel. In addition, C₁₆TAB could enhance enzymatic hydrolysis efficiency of corncob at high solid content from 35.0 to 56.3 %; C₁₆TAB could reduce about 60 % of the cellulase loading in the enzymatic hydrolysis of corncob to obtain the same glucose yield. Effect of C₁₆TAB on the enzymatic hydrolysis of typical pretreated softwood and hardwood was also investigated. This study laid the foundation for using C_nTAB to recover cellulase, and provided the design direction for cellulase with higher activity and better stability by adjusting its hydrophilicity and chargeability.     

傅克烷基化反应在超高交联聚合物中的应用

超高交联聚合物主要是通过傅克烷基化反应来制备的,具有合成简单、多孔、无毒、结构稳定、质轻等特点。本文介绍了傅克烷基化反应的条件和机理,展示了超高交联聚合物的合成方法及这些材料在气体储存/分离、水处理、催化、传感等领域中的应用,并对傅克烷基化反应与超高交联聚合物的进一步结合做出了展望。     

超宽禁带半导体 β-Ga2O3单晶生长突破2英寸

<正>氧化镓(β-Ga_2O_3)单晶是一种第四代超宽禁带氧化物半导体,其禁带宽度为4.8~4.9eV,具有独特的紫外透过特性(吸收截止边~260nm);击穿电场强度高达8MV/cm,是Si的近27倍、SiC及GaN的2倍以上,巴利加优值分别是SiC、GaN的10倍、4倍以上,并且可以采用熔体法生长大尺寸体单晶,因此β-Ga_2O_3已成为超高压功率器件和深紫外光电子器件的优选材料之一。由于其在军事、能源、医疗、环境等领域的重要应用价值,近年来,氧化镓材料及器件的研究与应用成为当前美国、日本、德国等国家的研究热点和竞争重     

Characterization of In Vivo Metabolites of a Potential Anti-obesity Compound,the 3-Methyl-1H-Purine-2,6-Dione Derivative C-11, Employing Ultra-High Performance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Mass Spectrometry

C-11 (2-((7-Ethyl-3-methyl-8-(4-(2-(methyl(pyridin-2-yl)-amino)-ethoxy)phenyl)-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-1-yl)methyl)benzonitrile-one hydrochloride), which is based on the structure of rosiglitazone, was first synthesized in our laboratory and shown to be a promising anti-obesity drug candidate in our previous pharmacological study. Considering the importance of metabolic fate in vivo in the further development of drug candidates during early drug discovery, it is essential to characterize the metabolism of C-11 in vivo. In this work, a method based on ultra-high performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was successfully developed to investigate the in vivo metabolic profile of C-11 in rats. Rat urine, feces, and plasma samples were collected from male Sprague–Dawley rats after intravenous administration of C-11 in a single dose of 30 mg kg⁻¹ body weight. Besides the parent drug, a total of 25 metabolites (including 18 phase I and 7 phase II metabolites) were detected and tentatively identified by comparing their mass spectrometry profiles with those of C-11. This enabled the metabolic pathways of C-11 to be proposed for the first time. Our results revealed that N-depyridinylation, N-demethylation, hydroxylation, glucuronidation, and sulfate conjugation are the predominant metabolic pathways of C-11 in rats. The present study provides systematic information on the metabolism of C-11 in vivo, which should lead to a better understanding of its safety and mechanism of action.

     

Silica-Based Phenyl and Octyl Bifunctional Imidazolium as a New Mixed-Mode Stationary Phase for Reversed-Phase and Anion-Exchange Chromatography

In this study, octylbenzimidazolium-modified silica (BeImC8-Sil) was prepared by covalent attachment of 1-octylbenzimidazole to γ-chloropropyl silica. The synthesized materials were characterized by the elemental analysis, IR spectrum, and thermogravimetric analysis. Due to the introduction of phenyl and octyl groups on the quaternary imidazolium, the developed BeImC8-Sil column can function via both reversed-phase and anion-exchange retention mechanisms. The chromatographic properties of the synthesized material were investigated by the separations of polycyclic aromatic hydrocarbons, mono-substituted derivatives of benzene, anilines, and phenols, revealing the existence of multiple interactions, including hydrogen bonding, π–π stacking, electrostatic forces, and hydrophobic interactions in reversed-phase mode; inorganic and organic anions were also separated mainly through anion-exchange interaction. The proposed BeImC8-Sil is a promising mixed-mode stationary phase for the separation of complex samples in high-performance liquid chromatography.