薄层紫外分光光度法测定氟乐灵

一、实验部分1.定量波长及溶剂的确定选用一系列溶剂,在波长375纳米的紫外区,测定氟乐灵的溶剂吸收值,以正己烷、丙酮为好。氟乐灵以正己烷为溶剂,在375纳米处有最大特征吸收峰;以丙酮为溶剂在390纳米处有最大特征吸收峰。2.展开剂的选择为了更好地将氟乐灵和杂质分离,对不同     

酶偶联分光光度法测定胞内黄嘌呤氧化酶活性

建立了新的酶反应体系显色分光光度法检测节杆菌胞内黄嘌吟氧化酶的活性。考察了温度、pH值和底物浓度对检测体系的影响,确定了黄嘌呤氧化酶活性检测的最优条件,获得了良好的检测线性关系。此检测方法操作简便,结果准确可靠,可作为普通实验室和临床上测定黄嘌呤氧化酶活性的有效生化手段。     

紫外分光光度法直接测定三聚氰胺的研究

利用三聚氰胺的甲醇溶液在203 nm波长处有最大吸光度,建立了紫外分光光度法直接测定三聚氰胺的新方法,并研究了反应的各种影响因素。该方法对三聚氰胺的检出限为1.5×10-4 mg/mL;线性范围为0.25×10-3～2.5×10-3 mg/mL,对浓度为1.25×10-3 mg/mL的三聚氰胺进行11次平行测定,得到相对标准偏差为3.8%。将本法用于合成样品中三聚氰胺的测定,回收率为100.3%～101%,结果令人满意。     

紫外分光光度法测定磷酸氯喹注射液的含量

本文采用紫外分光光度法测定磷酸氯喹注射液的含量。方法简便，重现性较好。平均回收率为１００．５６％ＲＳＤ＝０．０６％。     

紫外分光光度法测定盐酸诺氟沙星

采用紫外分光光度法在２７３ｎｍ波长处测定盐酸诺氟沙星的含量,该方法较非水滴定法更简单、快速、精确。     

紫外分光光度法测定六价铬的研究

本文借助于紫外分光光度法测定了六价铬，碱性条件下六价铬在紫外区有一较强的吸收峰，因此建立了对六价铬的测定方法。用该法对六价铬的测定，取得了满意的效果，而且操作简便，快速准确，适用于各种含铬废水的测定。     

紫外分光光度法测定双酚S

建立了测定双酚S的紫外分光光度法。在pH值为6.0的磷酸盐缓冲溶液中,双酚S浓度在4.8×10-7~4.0×10-5mol.L-1范围内与其吸光度值呈显著线性相关,相关系数为0.9999,相对标准偏差为0.12%,检测限为4.0×10-7mol.L-1。该方法快速、灵敏,可用于常见样品中双酚S的测定。     

紫外分光光度法对微量油的测定

本文利用油在紫外光谱区的特定波长有最大吸收值,油含量与吸光度呈线性关系的原理,确定了紫外分光光度法对微量油的测定方法。并对该法的测定条件做了一定的试验。油的平均回收率为99.29%(96.73%～102.11%)(n=5)。本法简单快速,有较高的准确度和置信度。     

紫外光谱法评价27种中药的防晒效果

以紫外光谱法为基本原理,结合太阳光谱及相对红斑发生频率标准数据,对4种品牌的防晒霜及27种中药的防晒效果进行了体外研究。结果表明:在各种中药的乙醇〔φ(C2H5OH)=50%〕提取液中,生药质量浓度达到0.8 mg/mL时,黄芩、丁香、金银花、红花的防晒指数SPF值分别达到了35、29、20、19;根据布特的星级分类系统有19种中药的UVA防御达到三星级以上。该研究为天然广谱防晒化妆品的筛选提供了参考。     

几种中药的美白作用研究

研究了黄芩、虎杖和地榆等中药提取物对B16黑色素细胞的增殖、细胞内酪氨酸酶活性及黑色素合成的影响。结果显示,各中药提取物能不同程度地抑制细胞增殖,对细胞内酪氨酸酶活性有明显抑制作用,能明显减少细胞内黑色素的含量。人体皮肤实验表明,用这几种中药制备的护肤品有较好的美白效果。本研究提示,这几种中药具有良好的美白功能,是较为理想的化妆品美白添加剂。     

中药活性组分与人血清白蛋白相互作用研究进展

中药活性组分与人血清白蛋白（Human serum albumin,HSA）相互作用的研究可为探讨人类疾病机制,诊断、预防疾病,制药和新药开发提供重要的理论基础,是毒理学、生命科学、化学及临床医学的一个重要研究领域。基于研究中药活性组分与HSA相互作用具有重要的意义,文章在总结前人工作的基础上,综合各种实验技术及化学信息学,从HSA的功能和作用,研究方法,基本公式等几个方面来阐述HSA与中药活性组分的相互作用。     

作用于不同活性位点的单胺氧化酶抑制剂

从单胺氧化酶（MAo）活性位点的角度,介绍了近年来报道的单胺氧化酶抑制剂。其包括作用于”AromaticCage”、I2型咪唑活性位点的单胺氧化酶抑制剂以及作用于单胺氧化酶通道的抑制剂,对这些作用于不同活性位点的抑制剂的分析将对认识和研究酶的结构和功能具有重要的指导作用,同时也为研究高活性和高选择性的抑制剂提供新的思路和方法。     

Exploration of Novel Xanthine Oxidase Inhibitors Based on 1,6-Dihydropyrimidine-5-Carboxylic Acids by an Integrated in Silico Study

Xanthine oxidase (XO) is an important target for the effective treatment of hyperuricemia-associated diseases. A series of novel 2-substituted 6-oxo-1,6-dihydropyrimidine-5-carboxylic acids (ODCs) as XO inhibitors (XOIs) with remarkable activities have been reported recently. To better understand the key pharmacological characteristics of these XOIs and explore more hit compounds, in the present study, the three-dimensional quantitative structure–activity relationship (3D-QSAR), molecular docking, pharmacophore modeling, and molecular dynamics (MD) studies were performed on 46 ODCs. The constructed 3D-QSAR models exhibited reliable predictability with satisfactory validation parameters, including q² = 0.897, R² = 0.983, r_pred² = 0.948 in a CoMFA model, and q² = 0.922, R² = 0.990, r_pred² = 0.840 in a CoMSIA model. Docking and MD simulations further gave insights into the binding modes of these ODCs with the XO protein. The results indicated that key residues Glu802, Arg880, Asn768, Thr1010, Phe914, and Phe1009 could interact with ODCs by hydrogen bonds, π-π stackings, or hydrophobic interactions, which might be significant for the activity of these XOIs. Four potential hits were virtually screened out using the constructed pharmacophore model in combination with molecular dockings and ADME predictions. The four hits were also found to be relatively stable in the binding pocket by MD simulations. The results in this study might provide effective information for the design and development of novel XOIs.     

正交设计法对中药制剂提取工艺的研究

目的:通过正交试验法考察中药制备工艺.方法:以绿原酸和干膏收率的综合指标作为考核指标,通过L9(34)正交试验设计考察制备工艺条件,确定中药的最佳水提工艺.结果:水提制备工艺影响因素大小依次是:加水量(A)＞煎煮时间(B)＞煎煮次数(C),最佳制备工艺条件为A3B3C3,即处方药材加12倍量水,提取3 h,提取3次.结论:筛选出最佳的水提工艺条件.     

阻抑褪色动力学光度法测定镀银溶液中的银

研究了银阻抑高碘酸钾氧化玫瑰桃红R的褪色反应。结果表明,在醋酸介质中,70℃水浴加热条件下,银能够灵敏地阻抑高碘酸钾氧化玫瑰桃红R的褪色反应,且阻抑程度与银的量在一定范围内成正比关系。据此,建立了阻抑动力学光度法测定银的新方法,找到了最佳条件,测定了反应的速率常数和表观活化能。该方法线性范围为0.0~2.0μg/mL,应用于镀银溶液中银的测定,结果满意。     

Role of NADPH Oxidase and Xanthine Oxidase in Mediating Inducible VT/VF and Triggered Activity in a Canine Model of Myocardial Ischemia

Background: Ventricular tachycardia or fibrillation (VT/VF) of focal origin due to triggered activity (TA) from delayed afterdepolarizations (DADs) is reproducibly inducible after anterior coronary artery occlusion. Both VT/VF and TA can be blocked by reducing reactive oxygen species (ROS). We tested the hypothesis that inhibition of NADPH oxidase and xanthine oxidase would block VT/VF. Methods: 69 dogs received apocynin (APO), 4 mg/kg intraveneously (IV), oxypurinol (OXY), 4 mg/kg IV, or both APO and OXY (BOTH) agents, or saline 3 h after coronary occlusion. Endocardium from ischemic sites (3-D mapping) was sampled for Rac1 (GTP-binding protein in membrane NADPH oxidase) activation or standard microelectrode techniques. Results (mean ± SE, * p < 0.05): VT/VF originating from ischemic zones was blocked by APO in 6/10 *, OXY in 4/9 *, BOTH in 5/8 * or saline in 1/27; 11/16 VT/VFs blocked were focal. In isolated myocardium, TA was blocked by APO (10⁻⁶ M) or OXY (10⁻⁸ M). Rac1 levels in ischemic endocardium were decreased by APO or OXY. Conclusion: APO and OXY suppressed focal VT/VF due to DADs, but the combination of the drugs was not more effective than either alone. Both drugs inhibited ischemic Rac1 with inhibition by OXY suggesting ROS-induced ROS. The inability to totally prevent VT/VF suggests that other mechanisms also contribute to ischemic VT.