Mechanism of adrenocortical toxicity induced by quinocetone and its bidesoxy-quinocetone metabolite in porcine adrenocortical cells in vitro

Quinocetone (QCT) is a new feeding antibacterial agent in the QdNOs family. The mechanism of its adrenal toxicity is far from clear. This study was conducted to estimate the adrenal cell damage induced by QCT and its bidesoxy-quinocetone (B-QCT) metabolite and to further investigate their mechanisms. Following doses of QCT increasing from 5 to 50 μM, cell apoptosis and necrosis, mitochondrial dysfunction and redox imbalance were observed in porcine adrenocortical cells. The mRNA levels of the six components of intermediary enzymes and the adrenal renin-angiotensin-aldosterone system (RAAS) displayed a dysregulation induced by QCT, indicating that QCT might influence aldosterone secretion not only through the upstream of the production but also through the downstream of the adrenal RAAS pathway. In contrast, B-QCT had few toxic effects on the cell apoptosis, mitochondrial dysfunction and redox imbalance. Moreover, LCMS-IT-TOF analysis showed that no desoxy metabolites of QCT were found in either cell lysate or supernatant samples. In conclusion, we reported on the cytotoxicity in porcine adrenocortical cells exposed to QCT via oxidative stress, which raised awareness that its toxic effects resulted from N→O groups, and its toxic mechanism might involve the interference of the steroid hormone biosynthesis pathway.     

Liquid Chromatography at Critical Conditions of Poly(propylene)

Liquid chromatography at critical conditions (LCCC) of poly(propylene) (PP) holds unique potential to further augment the understanding of molecular heterogeneities present in PP. The critical conditions for isotactic poly(propylene) (iPP) and syndiotactic poly(propylene) (sPP) have been identified using porous graphitic carbon as stationary phase and combinations of adsorption and desorption promoting solvents. It is found that 1,2,4‐trichlorobenzene is a stronger desorption promoting eluent compared to 1,2‐dichlorobenzene, while 2‐octanol shows a weaker adsorption promoting effect compared to 2‐ethyl‐1‐hexanol for all stereo‐isomeric forms of PP. The fraction of desorption promoting solvent needs to reach critical conditions decreased in a linear manner with the temperature. High temperature 2D liquid chromatography with infrared detection provides quantitative information about the fractions of the constituents (iPP and ethylene–propylene copolymer) of a model high impact PP sample at LCCC of iPP.

     

高效液相色谱法测定草酸钙结石大鼠尿中草酸含量

目的 建立高效液相色谱法(HPLC)检测大鼠尿液中草酸含量。方法 将SPF级雄性健康Wistar大鼠24只采用随机数字表法分为空白对照组(n=12)和乙二醇组(n=12)。空白对照组给予去离子水喂养,每天以1 ml生理盐水灌胃;乙二醇组给予1%乙二醇自由饮水喂养,每天2%氯化铵2 ml灌胃。造模28 d后收集两组大鼠24 h尿液,采用HPLC法测定尿中草酸含量,并与铬酸钾氧化甲基红催化光度法的结果进行比较。HPLC法采用色谱柱Aglient 5TC-C₁₈(250×4.6 mm,5 μm),以甲醇(0.1 mol/L)、醋酸铵水溶液(15∶85)为流动相,流速为1.2 ml/min,紫外检测波长为314 nm,柱温20 ℃。结果 大鼠尿液中高、低浓度草酸标准曲线分别为y=5909.1x+378730,R²=0.9984和y=7810.5x-16635,R²=0.9967;最低检测浓度为5 μg/ml,大鼠尿液中草酸高浓度线性范围为62.50~2000.00 μg/ml,低浓度线性范围为6.25~100.00 μg/ml。平均回收率为95.1%,日内及日间精密度分别为3.4%~10.8%和3.8%~9.4%。HPLC法和铬酸钾氧化甲基红催化光度法均显示乙二醇组大鼠尿草酸浓度和24 h尿草酸含量显著高于空白对照组[尿草酸浓度:(736.35±254.52)μg/ml比(51.56±36.34)μg/ml,(687.35±234.53)μg/ml比(50.24±42.34)μg/ml;24 h尿草酸含量:(11.23±4.12)mg比(0.87±0.45)mg,(9.89±3.55)mg比(0.77±0.65)mg;P均＜0.01];两种方法检测出的尿草酸浓度和24 h尿草酸含量差异无统计学意义(P均＞0.05)。结论 HPLC法简单快速、回收率高、精密度好,与铬酸钾氧化甲基红催化光度法检测结果一致,适用于大鼠尿中草酸含量的测定。     

复方白芍颗粒质量控制研究

目的 建立复方白芍颗粒的质量标准.方法 采用薄层色谱法对制剂中的白芍、泽泻进行定性鉴别,采用高效液相色谱法测定制剂中芍药苷含量.结果 薄层色谱斑点清晰,且阴性对照无干扰;芍药苷浓度在33.35～333.50μg/mL范围内与峰面积的线性关系良好,平均回收率为97.39％(RSD=1.35％,n=6).结论 所建立的方法操作简单,重复性好,可有效控制复方白芍颗粒质量.     

直接蛋白沉淀-超高效液相色谱法测定氟尿嘧啶血药浓度

建立直接蛋白沉淀-超高效液相色谱法测定血浆中微量氟尿嘧啶的方法。以6%高氯酸为沉淀剂,5-氯尿嘧啶为内标物,样品经涡旋振荡等处理后,高速离心获取上清液作为供试液。供试液测定采用Acquity HSS T₃色谱柱,水-乙腈为流动相,流速为0.2 mL/min,进样量为5 μL,柱温为20 ℃。方法的专属性、准确度、精密度、线性等指标经验证后完全符合定量测定要求,与传统的测定方法相比,可显著缩短进样分析时间、降低试剂成本。本方法已经被成功用于临床病人的血药浓度检测,具有良好的临床应用前景。     

Novel Diketopiperazine Dihydroorotate Dehydrogenase Inhibitors Purified from Traditional Tibetan Animal Medicine Osteon Myospalacem Baileyi

Traditional Tibetan medicine provides an abundant source of knowledge on human ailments and their treatment. As such, it is necessary to explore their active single compounds used to treat these ailments to discover lead compounds with good pharmacologic properties. In this present work, animal medicine, Osteon Myospalacem Baileyi extracts have been separated using a two‐dimensional preparative chromatographic method to obtain single compounds with high purity as part of the following pharmacological research. Five high‐purity cyclic dipeptides from chromatography work were studied for their dihydroorotate dehydrogenase inhibitory activity on recombinant human dihydroorotate dehydrogenase enzyme and compound Fr. 1‐4 was found to contain satisfying inhibition activity. The molecular modeling study suggests that the active compound Fr. 1‐4 may have a teriflunomide‐like binding mode. Then, the energy decomposition study suggests that the hydrogen bond between Fr. 1‐4 and Arg136 can improve the binding mode to indirectly increase the van der Waals binding energy. All the results above together come to the conclusion that the 2, 5‐diketopiperazine structure group can interact with the polar residues well in the active pocket using electrostatic power. If some proper hydrophobic groups can be added to the sides of the 2, 5‐diketopiperazine group, it is believed that better 2, 5‐diketopiperazine dihydroorotate dehydrogenase inhibitors will be found in the future.     

Structural and Binding Studies of SAP-1 Protein With Heparin

SAP-1 is a low molecular weight cysteine protease inhibitor (CPI) which belongs to type-2 cystatins family. SAP-1 protein purified from human seminal plasma (HuSP) has been shown to inhibit cysteine and serine proteases and exhibit interesting biological properties, including high temperature and pH stability. Heparin is a naturally occurring glycosaminoglycan (with varied chain length) which interacts with a number of proteins and regulates multiple steps in different biological processes. As an anticoagulant, heparin enhances inhibition of thrombin by the serpin antithrombin III. Therefore, we have employed surface plasmon resonance (SPR) to improve our understanding of the binding interaction between heparin and SAP-1 (protease inhibitor). SPR data suggest that SAP-1 binds to heparin with a significant affinity (K_D = 158 nm ). SPR solution competition studies using heparin oligosaccharides showed that the binding of SAP-1 to heparin is dependent on chain length. Large oligosaccharides show strong binding affinity for SAP-1. Further to get insight into the structural aspect of interactions between SAP-1 and heparin, we used modelled structure of the SAP-1 and docked with heparin and heparin-derived polysaccharides. The results suggest that a positively charged residue lysine plays important role in these interactions. Such information should improve our understanding of how heparin, present in the reproductive tract, regulates cystatins activity.     

虎杖药材的HPLC-DAD-ELSD指纹图谱研究

目的建立虎杖药材的HPLC-DAD-ELSD指纹图谱,对10个不同产地的虎杖药材进行质量评价。方法使用Luna C_(18)(2)色谱柱(250mm×4.6mm,5μm),乙腈-水为流动相进行梯度洗脱,体积流量1.0mL/min,柱温35℃,检测波长254 nm,进样量10μL。蒸发光检测器漂移管温度109℃,载气体积流量3.0 L/min。结果通过10批虎杖药材建立了指纹图谱的共有模式,其中HPLC-DAD指纹图谱共有峰19个,相似度为0.938~0.993;HPLC-ELSD指纹图谱共有峰14个,相似度为0.905~0.999。确认了虎杖苷、白藜芦醇、大黄素-8-O-β-D-葡萄糖苷、大黄素甲醚-8-O-β-D-葡萄糖苷、大黄素和大黄素甲醚。结论方法准确、稳定,为客观评价虎杖药材的质量提供了科学依据。     

细胞膜色谱法筛选川芎-白芷中5-HT受体激动剂的研究

偏头痛是临床的常见病和多发病,研究表明,5-羟色胺(5-HT)受体在偏头痛的发病中起重要作用。实验通过大鼠纹状体组织制备得到色谱固定相,并利用细胞膜色谱与液相色谱的离线联用来特异性地识别川芎-白芷药对中可与固定相上受体相互作用的配体,发现了欧前胡素是其中潜在的活性成分。以不同浓度(2.42×10-8~4.84×10-7mol·L-1)的5-HT1D受体激动剂舒马普坦为模型药物,记录样品在模型中的容量因子,测得欧前胡素与5-HT1D受体作用的平衡解离常数为(4.59±0.33)×10-6mol·L-1,并采用硝酸甘油致大鼠偏头痛模型验证其药理活性。该研究为体外快速有效地研究药物与受体之间的相互作用提供了一种新方法。     

代谢组学在中医中药领域的应用进展

代谢组学采用的系统研究方法在本质上与中医系统理论相一致,其从代谢网络的终端代谢产物来反映生物机体的功能,以了解各种干预因素对生物机体产生的代谢变化,可以识别"证"相关的特征性代谢物,以揭示"证"的本质和相关中药的作用机制,这与中医的整体理论完全一致。