Exploratory Purification of Compounds from Aqueous Extracts of <Emphasis Type="Italic">Pinus massoniana</Emphasis> Lamb. by Two-Dimensional Preparative Liquid Chromatography

An off-line orthogonal two-dimensional preparative liquid chromatography method was developed for isolation of high-purity compounds from aqueous extracts of Pinus massoniana Lamb., which has efficient therapeutic properties in recipes of traditional Chinese medicines. A polar-enhanced reversed-phase (RP) column, XAqua C18 was selected for the first-dimensional separation. A HILIC column and a hydrophobic RP column were both explored in the second dimension. The preparation results indicated hydrophilic RP × HILIC mode would provide better separation efficiency for polar complexes, i.e., the second-dimensional separation was finished in less than 30 min and high-purity compounds were obtained. In this work, 16 fractions were collected efficiently in the first dimension with a recovery up to 96%, and six compounds with high purity and enough quantity were identified by NMR and high resolution mass spectrometry, including epicatechin, betuloside, taxifolin-3-O-xyloside, cedrusin-4-O-glucoside, massonianoside C and massonianoside D, and five are glycosides, including flavonoid glycosides, lignanoid glycosides and an arylbutanoid glycoside. Betuloside was first reported in the preparation of Pinus massoniana Lamb. This work demonstrated a flexible strategy of compromise in between time and resolution for selecting solvent and column to enhance preparative efficiency of polar complex systems.     

Validation of Sun Exposure Reported Annually Against Interim Self‐report and Daily Sun Diaries

Data on personal sun exposure over a period exceeding the immediate past days or weeks are typically self‐reported in brief questionnaire items. The validity of such self‐reporting of longer term personal sun exposure, for example over a year, including detail on variation across seasons, has not previously been investigated. In a volunteer sample (n = 331) of Australian adults aged 18 years and over, we assessed the 12‐month reliability of sun exposure reported separately for each season, and its accuracy compared to a daily sun diary in the same season. Seasonal time outdoors displayed fair‐to‐good reliability between baseline and end of study (12 months), with responses showing higher agreement at lower levels of time outdoors. There was good agreement for ranking of individuals' time outdoors with the daily sun diary data, although the actual diary time outdoors was typically considerably lower than the self‐reported questionnaire data. Place of residence, education, being a smoker, day of the week (i.e. working day vs nonworking day) and working mainly outdoors were significant predictors of agreement. While participants overestimated their actual time outdoors, the self‐report questionnaire provided a valid ranking of long‐term sun exposure against others in the study that was reliable over time.     

基于合成方法学研究的有机化学实验教学改革与实践——以苯甲酸乙酯制备为例

以苯甲酸乙酯的制备实验为例,将合成方法学研究引入有机化学实验教学。采取抽签方式确定每个学生的实验内容,通过考查加热方式(电热套或微波辐射加热)、溶剂(甲苯或环己烷)以及反应时间对实验结果的影响,使学生了解科学研究的方法,并通过文献查阅及实验结果分析讨论等教学实践环节提高学生的创新思维和科研能力。     

以恩诺沙星为检测对象探究恩诺沙星与牛血清白蛋白的相互作用

在模拟生理条件下,分别以蛋白为检测对象和以药物为检测对象,用荧光光谱法研究了不同温度下恩诺沙星(EFLX)与牛血清白蛋白(BSA)之间的相互作用。以两种不同分子作为检测对象均表明EFLX与BSA的猝灭方式为静态猝灭,作用力类型以疏水作用为主。基于实验进行了计算,获得了以EFLX为检测对象所得的结合常数远大于以BSA为检测对象的结合常数。这表明以药物为检测对象的荧光光谱法能更准确、更全面地传达药物与蛋白的相互作用信息。这个结论的正确性得到了紫外光谱法的验证。此外,考察了离子强度对EFLX-BSA体系的影响,通过EFLX与曙红B(EB)、盐酸柔红霉素(DH)、赫斯特荧光染料(Hoechst)的竞争实验,推测了EFLX与BSA的结合方式为沟槽式。     

磁性石墨烯@聚多巴胺纳米复合材料分离去除水中双酚A

本文通过水热法和多巴胺的自我团聚反应合成了磁性石墨烯@聚多巴胺(PDA@MG)纳米复合材料,该材料具有表面积大,含有丰富的π电子共轭体系、很好的水溶液分散性,易分离及可重复使用等特点。以PDA@MG为吸附剂材料,研究了其对水溶液中双酚A(BPA)的吸附性能。考察了吸附时间、温度、溶液的pH、吸附剂的用量等因素对该材料吸附性能的影响。结果表明在优化实验条件下,PDA@MG对BPA的最大吸附容量为151.3mg/g。PDA@MG具有优异的循环吸附性能,经过10次循环使用后其吸附能力没有明显减弱。     

Enzyme-Inspired Chiral Secondary-Phosphine-Oxide Ligand with Dual Noncovalent Interactions for Asymmetric Hydrogenation

Inspired by the unique character of enzymes, we developed novel chiral SPO (secondary-phosphine-oxide) ligand (SPO-Wudaphos) which can enter into both ion pair and H-bond noncovalent interactions. The novel chiral SPO-Wudaphos exhibited excellent results in the asymmetric hydrogenation of α-methylene-γ-keto carboxylic acids, affording the chiral γ-keto acids with up to over 99 % ee. A series of control experiments and DFT calculations were conducted to illustrate the critical roles of both the ion pair and H-bond noncovalent interactions.     

Imaging Endogenous Metal Ions in Living Cells Using a DNAzyme–Catalytic Hairpin Assembly Probe

DNAzymes are a promising platform for metal ion detection, and a few DNAzyme-based sensors have been reported to detect metal ions inside cells. However, these methods required an influx of metal ions to increase their concentrations for detection. To address this major issue, the design of a catalytic hairpin assembly (CHA) reaction to amplify the signal from photocaged Na⁺-specific DNAzyme to detect endogenous Na⁺ inside cells is reported. Upon light activation and in the presence of Na⁺, the NaA43 DNAzyme cleaves its substrate strand and releases a product strand, which becomes an initiator that trigger the subsequent CHA amplification reaction. This strategy allows detection of endogenous Na⁺ inside cells, which has been demonstrated by both fluorescent imaging of individual cells and flow cytometry of the whole cell population. This method can be generally applied to detect other endogenous metal ions and thus contribute to deeper understanding of the role of metal ions in biological systems.     

3种香叶基取代黄烷酮的合成及抗肿瘤活性

3种香叶基黄烷酮是从毛泡桐(Paulownia tomentosa)水果中分离出的3种具有相似结构的黄酮类化合物。我们以廉价的2,4,6-三羟基苯乙酮,羟基苯甲醛为原料经过取代、氯甲基甲基醚保护、羟醛缩合、分子内的麦克加成反应以及脱甲基甲基醚合成了3个香叶基取代黄烷酮。其结构经过核磁共振氢谱及碳谱(1H NMR,13C NMR)和高分辨质谱(HRMS)等技术手段进行了表征,并采用四氮唑蓝(MTT)法测试了合成化合物对肺癌细胞A459的体外抗肿瘤活性。结果表明,所合成的化合物均具有一定的抗肺癌细胞活性,其中化合物2抗肺癌活性明显优于化合物1和3,其半数抑制浓度为25.6μmol/L,为临床疾病的治疗和药物的研发提供了参考。     

Synthesis and biological evaluation of novel 1, 2, 3-benzotriazin-4-one derivatives as leukotriene A4 hydrolase aminopeptidase inhibitors

A series of novel 1,2,3-benzotriazin-4-one derivatives were designed,synthesized and their inhibitory activities against leulcotriene A_4 hydrolase aminopeptidase in vitro were evaluated.Many compounds showed moderate to good activities at the concentration of 10 μmol/L.Among them,compound Ⅳ-16 exhibited the highest inhibitory activity up to 80.6% with an IC_(50) of 1.30 ± 0.20 μmol/L The compound Ⅳ-16 was also tested the proliferation inhibitory activities in THP1 human AML cell line and its binding model with LTA_4H enzyme by molecular docking was studied.It indicated that 1,2,3-benzotriazin-4-one was a promising scaffold for further study.The relationship between structure and inhibitory activity was also preliminarily discussed.