In‐source collision‐induced dissociation (IS‐CID): Applications,issues and structure elucidation with single‐stage mass analyzers

A discussion of the definition, advantages, and issues with the formation of ions in the transition region between an electrospray ionization (ESI) source and the ion optics of a mass analyzer is presented. The various types of ions formed in the so‐called in‐source collision‐induced dissociation (IS‐CID) process are illustrated. Applications of IS‐CID with single‐stage mass analyzers, such as structure elucidation and quantitation, are demonstrated. The discussion is illustrated by examples of the in‐source fragmentation of ginkgolides, which are marker compounds found only in Ginkgo biloba. Supercritical fluid chromatography (SFC) with non‐aqueous eluents was used to achieve a fast resolution of the ginkgolides without the hydrolysis reactions possible with aqueous high‐performance liquid chromatography (HPLC) eluents. In‐source ion generation occurs at relatively high pressures (ca. 1–3 torr) compared to the low pressure normally observed in collision chambers of tandem mass spectrometry (MS/MS). As a result, the fragmentation process is complex and often generates ions other than the fragments observed with classic CID or the same ions at different intensities. The objective of the current tutorial is to illustrate the conditions under which single‐stage, quadrupole or time‐of‐flight mass analyzers with electrospray or in‐air (direct analysis in real time; DART) ionization can be used for quantitation and structure elucidation in a manner similar to that observed with MS/MS. While the low m/z (≤ [M±H]^±) ions formed in‐source often duplicate the ions observed in MS/MS systems, it is the focus of this discussion to illustrate the utility of in‐source generated fragment ions that may not be observed or observed at different intensities than in the collision cells of MS/MS instruments.     

弱氧化修饰低密度脂蛋白诱导ECV304组织因子基因表达及银杏内酯B的抑制作用

为研究弱氧化修饰低密度脂蛋白（mmLDL)对ECV304组织因子（TF）蛋白含量和mRNA水平的影响、对胞浆游离钙离子[Ca^2 ]i的影响，以及银杏内酯B等的干预作用。采用ELISA法检测细胞内TF蛋白含量，用RT－PCR法检测细胞内TF mRNA水平，用激光共聚焦显微镜观察[Ca^2 ]i的变化。结果显示，40mg/L mmLDL作用ECV304 4h，能使TF蛋白含量及mRNA水平显著增加，并迅速升高[Ca^2 ]i。抗氧化剂银杏内酯B及PKC抑制剂Staurosporine可拮抗mmLDL的上述诱导反应。以上结果提示，mmLDL可诱导ECV304 TF表达，Ca^2 与PKC参与mmLDL诱导ECV304 TF基因表达过程，并且银杏内酯B可抑制mmLDL的此种效应。     

小鼠皮层神经元缺氧损伤的模型制备及其实验观察

目的 :建立皮层神经元缺氧损伤的模型 ,为抗缺氧研究提供可靠的实验方法。方法 :采用形态学观察和 MTT比色分析比较了不同密度、不同缺氧时间对培养神经元形态及活性的影响 ;同时观察了银杏内酯、人参皂甙预处理对神经元缺氧损伤的保护作用。结果 :( 1)在进行原代皮层神经元培养时 ,细胞接种的密度以 1.6× 10 6～ 2 .0× 10 6个细胞 /ml为好。( 2 )随着缺氧时间延长 ,神经元活性降低 ,细胞死亡率增加。 ( 3 )银杏内酯和人参皂甙预处理均能使缺氧 8h的神经元比单纯缺氧对照组活性明显升高。结论 :实验结果稳定 ,重复性好 ,是离体抗缺氧研究的一种较理想的实验方法     

银杏内酯提取物中微量成分的LC/DAD/ESI/MS分析及结构鉴定

目的　银杏内酯提取物中有关微量成分的鉴别。方法　采用LC DAD ESI MS联用技术。结果　鉴别了已知的银杏内酯A ,B ,C ,J,M以及白果内酯,并发现了3个微量未知化合物。结论　根据UV ,IR ,MS和NMR光谱数据,鉴定了其中两个新化合物的结构,分别为1,10-二羟基-3,14-二去氢银杏内酯和10-羟基3,14-二去氢银杏内酯,并命名为GK和GL。     

星点设计-效应面法优化银杏内酯长循环固体脂质纳米粒的制备

目的 优化银杏内酯AB长循环固体脂质纳米粒(GAB-LSLN)的制备工艺.方法 以热融-匀质法制备固体脂质纳米粒,以平均粒径、包封率、载药量为评价指标,采用星点设计考察辅料单硬脂酸甘油酯用量、注射用大豆磷脂用量、Myrj 59用量3因素对制备工艺的影响,对结果进行多元线性和二项式拟合,效应面法选取最佳工艺条件进行预测分析.结果 从复相关系数上看,各指标二项式拟合方程均优于多元线性回归方程-以优化条件制备的GAB-LSLN平均粒径为169.5nm,包封率为92.3％,载药量为5.1％.结论 优选的GAB-LSLN制备工艺稳定可行,包封率高,可用于生产.     

The effects of Ginkgo biloba on metabolic syndrome: A review

The Ginkgo biloba (G. biloba), commonly known as ginkgo, brings considerable benefit to common medicine, including weight loss effects, as well as antidiabetic, antihypertensive, and antilipidemic properties that could be effective in the treatment of Metabolic syndrome (MetS ) associated with increased risk of cardiovascular disease events. Major compounds of G. biloba are terpene lactones (bilobalide and ginkgolides A, B, and C) and flavone glycosides (isorhamnetin, quercetin, and kaempferol). We evaluated the most relevant original articles to indicate the effects of G. biloba on different components of MetS, including obesity, high blood pressure, dyslipidemia, and hyperglycemia. Several electronic databases (Scopus, PubMed, Web of Science and Google Scholar) were searched and the articles that included Ginkgo's effect on one or more of the criteria for MetS were selected. This review indicated that G. biloba might be efficient in the improvement of MetS; however, more studies especially clinical trials are needed to evaluate safety and efficacy of G. biloba.     

银杏内酯固体分散体的制备和体外特性研究

目的:优选银杏内酯固体分散体的制备工艺,提高银杏内酯的体外溶出度.方法:以银杏内酯B的体外溶出度为指标,通过单因素试验,考察处方和工艺因素对银杏内酯固体分散体中药物溶出的影响;以X-射线衍射法和差示扫描量热法对固体分散体进行表征.结果:差示扫描量热法和X-射线衍射分析试验表明药物以无定形态存在于固体分散体中.银杏内酯B从PVP固体分散体中的溶出速率比原药粉末显著提高,且药物中银杏内酯A,B,C和白果内酯从固体分散体中的溶出相似性(f_2值均大于50)优于原药粉末.结论:将银杏内酯制成固体分散体能显著提高药物的溶出速率,可用于进一步制备其固体剂型.     

银杏内酯B对自发性高血压大鼠左室肥厚及心肌纤维化的影响

目的:观察银杏内酯B对自发性高血压大鼠模型左室肥厚心肌纤维化的影响。方法:选择12周龄雄性SHR大鼠(二级)40只,随机分成4组,每组10只,分别为银杏内酯B大剂量组(YH,120 mg.kg-1.d-1)、银杏内酯B小剂量组(YL,60mg.kg-1.d-1)、氯沙坦组(LOS,30 mg.kg-1.d-1)和SHR大鼠模型对照组(SHR),以及周龄、性别相匹配的Wistar Kyoto(WKY)大鼠10只作为空白对照。每日灌胃给药一次,对照组给等量CMCNa溶液。治疗12周后尾袖法测定动脉血压,称量后处死。计算左室质量与体质量比(LVM/BW)。天狼星红染色,计算机图像分析计算心肌胶原容积分数。结果:给药后,YH、YL组大鼠SBP均明显低于SHR组(P<0.01),YH、YL2组组间比较无显著性差异;YH组大鼠给药前后SBP比较有显著差异(P<0.01),给药后明显低于给药前,而YL组给药前后比较无统计学意义。YH、YL组大鼠心肌胶原纤维含量均明显低于SHR组(P<0.01),YH、YL2组间比较无显著性差异。结论:银杏内酯B可以抑制SHR大鼠的心肌纤维化,改善高血压所致的心肌重塑。     

银杏叶提取物及其不同成分对CYP3A4活性的影响

目的:研究银杏叶提取物及其中2种主要活性物质黄酮和内酯对人体内CYP3A4酶活性的影响。方法:构建了可用于体外高通量检测基于PXR诱导的CYP3A4系统,通过细胞培养实验,化学发光检测仪检测银杏叶不同组分对CYP3A4的激活水平。采用反相高效液相色谱法测定银杏叶不同组分对细胞内尼卡地平代谢的影响。结果:高通量检测系统检测表明,银杏叶提取物对体内的CYP3A4酶表达具有显著的激活作用。进一步研究证实银杏叶提取物的两类主要活性物质黄酮和内酯呈剂量的方式激活CYP3A4的表达。银杏叶内酯明显加速尼卡地平的代谢速率,而银杏叶黄酮则降低细胞内尼卡地平的降解速率。结论:银杏叶提取物及其主要活性成分黄酮和内酯能显著提高CYP3A4的活性,内酯能提高CYP3A4代谢尼卡地平的能力,而黄酮则可能由于药物相互作用的原因,抑制了CYP3A4酶活性,降低其代谢尼卡地平的能力。     

Protective Effects of Two Constituents of Chinese Herbs on Spinal Motor Neurons from Embryonic Rats with Hypoxia Injury

Neuroprotective agents are becoming significant tools in the repair of central nervous system injuries. In this study, we determined whether ginkgolides (Gin, extract of GinkgoBiloba) and Acanthopanax senticosus saponins (ASS, flavonoids extracted from Acanthopanax herbal preparations) have protective effects on rat spinal cords exposed to anoxia and we explored the mechanisms that underlie the protective effects. Spinal motor neurons (SMNs) from rat spinal cords were obtained and divided into five groups with 10 wells in each group. In control group, SMNs suffered no injury under normal oxygen; in hypoxia- inducible (HI) group, SMNs suffered injury from hypoxia; in Gin group, 37.5µg/ml Gin were used before 24 hrs of hypoxia; in ASS group, 50µg/ml ASS were used before 24 hrs of hypoxia;in glial cell-lined derived neurotrophic factor (GDNF) group, 0.1µg/ml GDNF were used before 24 hrs of hypoxia. Changes in morphology, neuron viability, and lactate dehydrogenase (LDH) release were observed. In addition, the expression of HIF-1α induced by hypoxia was measured. The neuronal viability in the Gin, ASS, and GDNF pretreated groups was higher than that in the HI group (P<0.05). The viability in the Gin group was better than that in the ASS group (P<0.05), but there was no significant difference between the ASS and GDNF groups (P>0.05). The quantity of LDH released in the three pretreated groups was lower than that in the HI group (P<0.05). The expression of HIF-1α in the HI group was greater than that in the control group (P<0.05), and the expression in the three pretreated groups was greater than that in the HI and the control groups (P<0.05). Our results indicate that Gin and ASS which was not as effective as Gin, but its effects were similar to those of GNDF could all enhance the viability of SMNs and have protective effects on hypoxic neurons.