银杏内酯B前体药物的抗血小板聚集活性研究

目的考察银杏内酯B前体药物(PGB)的抗血小板聚集作用。方法采用LC-MS/MS法测定PGB在体外和体内的降解情况,并以比浊法观察PGB体外、体内给药对PAF诱导兔血小板聚集的影响。结果 PGB在体外血浆中的降解反应为表观一级反应,体内外均能迅速水解出银杏内酯B(GB);在体外、体内均呈剂量依赖性抑制PAF诱导的兔血小板聚集,体外最大抑制率分别为8.67、20.01、50.60、73.01,体内最大抑制率分别为42.24、58.03,其作用强度接近于原药GB。结论 PGB通过分解出的GB拮抗PAF受体实现血小板聚集抑制作用,是一个具有良好前景的脑血管疾病治疗前体药物。     

LC-MS/MS法测定Wistar大鼠组织中银杏内酯B的浓度

目的建立LC-MS/MS法测定大鼠组织中银杏内酯B的浓度,并将此方法应用于银杏内酯B注射液在Wistar大鼠体内的组织分布研究。方法色谱柱:AQVASIL C18柱(100 mm×2.0 mm I.D.,5μm),流动相:乙腈-水-甲酸(体积比为60.0∶40.0∶0.4),流速:0.4 mL.min-1,离子源为电喷雾电离(electrospray ionization,ESI)源,负离子化方式,以选择反应监测(selective reaction monito-ring,SRM)方式进行扫描定量,用于定量分析的离子反应分别为m/z 423→m/z 367(银杏内酯B)和m/z 444→m/z 138(格列吡嗪)。测定了18只Wistar大鼠静脉注射给予银杏内酯B(给药剂量为3.75 mg.kg-1)后大鼠体内各组织和脏器中银杏内酯B的质量浓度。结果测定大鼠组织匀浆液中银杏内酯B的线性为1.0～500.0μg.L-1,定量下限为1.00μg.L-1。低、中、高3个质量浓度质控样品的日内和日间精密度分别小于6.4%和14.5%,准确度为97.3%～103.6%。银杏内酯B在心、肝、脾、肺、肾、胰、胃、小肠、脑、肌肉、脂肪、子宫、卵巢和睾丸14种组织中(除脑组织6 h时间点外)均被检出。银杏内酯B在大鼠各组织中分布广泛,自各组织中消除也较快。结论该方法适用于银杏内酯B注射液在Wistar大鼠体内的组织分布研究。     

环孢素A对银杏内酯B大鼠体内药动学的影响

研究环孢素A (cyclosporine A, CyA) 对大鼠静脉注射中药成分银杏内酯B (ginkgolide B, GB) 药动学的影响, 并进行作用机制研究。实验建立了测定大鼠血浆、脑组织和尿液中GB浓度的LC-MS方法, 研究了CyA对GB在大鼠体内血药浓度、脑分布和肾排泄的影响。结果表明静脉注射CyA (10及20 mg·kg⁻¹) 可以显著增加GB的AUC_{0−360 min} (P < 0.01), 降低其CL (P < 0.001); 静脉注射CYP3A抑制剂伊曲康唑 (itraconazole, ICZ) 则对GB的药动学行为无影响。脑分布结果显示, 高、中、低剂量的CyA均可增加GB在脑中的浓度, 此作用具有浓度和时间依赖性, 在5 min时不同剂量的CyA均可显著增加GB在脑中的分布 (P < 0.001), 但在20及60 min时仅高剂量CyA组可显著增加GB脑中的浓度 (P < 0.01及P < 0.001)。不同P-gp抑制剂均可减少GB的肾排泄, 其中CyA (20 mg·kg⁻¹) 组、维拉帕米 (verapamil, VER) 组及地高辛 (digoxin, DGX) 组GB 8 h累积排泄百分率仅分别为对照组的34.8% (P < 0.001)、59.4% (P < 0.001) 及79.7% (P < 0.05); 而ICZ组则无此作用。大鼠静脉给予P-gp抑制剂CyA可以显著提高GB的血药浓度, 减少肾脏对GB排泄且能增加GB在脑中的分布。     

HPLC-ELSD法测定白果中银杏内酯A、银杏内酯B和银杏内酯C

目的建立HPLC-ELSD法同时测定白果药材中银杏内酯A、银杏内酯B和银杏内酯C 3个萜杏内酯成分。方法采用Agilent 5TC C18色谱柱(250 mm×4.6 mm,5μm),以甲醇–四氢呋喃–水(25∶10∶65)为流动相,体积流量1 m L/min,柱温30℃,蒸发光散射检测器检测,对照品进样量为10、20μL,供试品溶液进样量为5~20μL。结果银杏内酯A在0.37~5.92μg、银杏内酯B在2.8~44.8μg、银杏内酯C在0.65~10.4μg时线性关系良好。银杏内酯A、银杏内酯B、银杏内酯C平均回收率分别为92.40%、95.03%、91.29%,RSD值分别为2.75%、2.06%、2.88%。结论本法操作简单,重复性好,为白果药材的质量控制提供了依据。     

Transport characteristics of ginkgolide B by Caco-2 cells and examination of ginkgolide B oral absorption potential using rat in situ intestinal loop method

The intestinal absorptive characteristics of ginkgolide B were investigated. The Caco-2 cells and the in situ closed loop were used as models of the intestinal mucosa to assess transepithelial transport of ginkgolide B. The determination of ginkgolide B was performed by HPLC-MS. In the Caco-2 cells, the absorptive transepithelial transport of ginkgolide B was pH dependent and the transport was enhanced at weakly acidic pH on the apical side. No concentration dependence and saturation were observed for the absorptive transport of ginkgolide B at concentrations up to 50 microM. In the in situ closed loop, the absorption of ginkgolide B was intestinal segment-selective. The results indicate that the intestinal absorption of ginkgolide B in the upper intestine was significantly higher than that in the lower intestine.     

银杏内酯B对缺血/再灌脑损伤大鼠的保护作用

目的探讨银杏内酯B对缺血/再灌注脑损伤大鼠的保护作用及其可能的作用机制。方法通过颈总动脉栓线造成大脑中动脉缺血,缺血3h后将线拔出以实现大脑中动脉血流再灌注,同时观察银杏内酯B对大鼠神经症状,脑梗死范围以及银杏内酯B对缺血侧脑组织匀浆SOD活力,MDA含量,LDH活力及LD含量的影响。并且进行了病理组织切片检查。结果银杏内酯B对缺血3h大鼠神经症状无影响,对再灌21h大鼠神经症状有明显的改善作用。银杏内酯B10、5mg·kg-1能明显降低脑梗死范围,同时银杏内酯B能升高SOD活力,减少MDA含量及LDH活力,但对LD含量无明显作用。病理切片检查结果表明,银杏内酯B能减轻缺血侧大脑的水肿及空泡现象。结论银杏内酯B对缺血/再灌注脑损伤有保护作用,该作用可能与其升高SOD活力,降低MDA含量及LDH活力有关。     

银杏内酯B对胚胎大鼠中脑神经元发育的影响

目的:探讨银杏内酯B(GB)对胚胎大鼠中脑神经元发育的影响。方法:体外原代培养胚胎大鼠中脑神经细胞,实验分6组:对照组、NGF(神经生长因子)阳性药物组、GB组、KA(海人藻酸)毒性模型组,NGF+KA组、GB+KA组,采用SP法进行免疫组化染色,观察中脑神经细胞在不同条件处理下,神经特异性烯醇化酶表达情况;测量NSE(神经特异性烯醇化酶)阳性神经细胞数、胞体面积、突起数/细胞、最长突起长度在不同组间的差异。结果:NGF组和GB组4项指标值均大于对照组;KA组则小于对照组;GB+KA组和NGF+KA组明显大于KA组,小于对照组。NGF组和GB组;GB+KA组和NGF+KA组之间差异无显著性。结论:GB可促进胚胎大鼠中脑神经元发育。其机制可能与提高糖代谢过程中NSE酶蛋白的表达有关。     

银杏内酯B对ApoE基因敲除小鼠动脉粥样硬化的影响

目的探讨银杏内酯B(ginkgolide B,GB)对ApoE基因敲除(ApoE-/-)小鼠动脉粥样硬化的影响。方法 12只8周龄C57BL/6J小鼠为正常组,24只8周龄♂ApoE-/-小鼠为阳性模型组以及药物组;药物组每天给予GB 0.6 mg灌胃。8周后处死小鼠,用病理学方法观察小鼠动脉斑块、脂质沉积以及巨噬细胞表达。用ELISA方法测定血浆RAN-TES含量。结果电镜结果显示模型组动脉斑块较大,血管内膜损伤明显,而GB组小鼠动脉内表面损伤明显减轻,斑块较小。HE染色显示了同样的结果,模型组斑块较大,GB组斑块较小。血浆RANTES测定正常组为123.81 ng.L-1,模型组为359.16 ng.L-1,GB组为193.36 ng.L-1,各组之间差异存在统计学意义(P<0.01)。结论 GB能有效地减轻ApoE-/-小鼠的动脉粥样硬化损伤,并降低血浆RANTES含量,其药理学机制可能与抑制血小板功能相关。     

银杏内酯B对内皮细胞的保护作用及分子机制研究

目的探讨银杏内酯B对氧化型低密度脂蛋白刺激脐静脉内皮细胞保护作用的分子机制。方法分别用银杏内酯B 0.2、0.4、0.6 g.L-1预孵育内皮细胞1 h,再加入ox-LDL(0.1 g.L-1)刺激细胞。用Western blot检测Lectin-likeoxidized LDL receptor-1(LOX-1)、PI3K、Nrf2、SIRT1表达及Akt磷酸化。结果 1.ox-LDL刺激内皮细胞LOX-1表达增加,银杏内酯B以剂量依赖方式抑制了LOX-1表达。2.银杏内酯B有效地抑制了ox-LDL刺激的Akt磷酸化,但对PI3K的表达无影响。3.ox-LDL刺激内皮细胞SIRT1表达降低,银杏内酯B有意义地增加了细胞SIRT1表达。4.ox-LDL刺激细胞抗氧化应激蛋白Nrf2表达明显增加,银杏内酯B下调了Nrf2的表达。结论银杏内酯B对内皮细胞保护作用与抑制LOX-1表达、Akt磷酸化,启动细胞内源性保护机制相关。     

The synthesis and biological evaluation of 10-O-dialkylaminoethyl ginkgolide B as platelet-activating factor antagonist

Four nitrogen-containing derivatives of ginkgolide B were synthesized to improve the physical–chemical properties and bioavailability of ginkgolide B. The reaction was accomplished with the nitrogen atom as neighboring group participating in the replacement reaction. All of the four compounds were proved to have excellent inhibiting effect on rabbit platelet aggregation induced by platelet-activating factor which is as well as ginkgolide B.     

In vivo biodistribution of ginkgolide B, a constituent of Ginkgo biloba, visualized by MicroPET

The in vivo dynamic behavior of ginkgolide B (GB), a terpene lactone constituent of the Ginkgo biloba extracts, in the living animal was visualized by positron emission tomographic (PET) imaging using a GB analogue labeled with the positron emitter (18)F. The in vivo imaging studies, combined with ex vivo dissection experiments, reveal that GB exists in 2 forms in the body: the original GB with its lactone rings closed and a second form with one of the rings open. The original GB in plasma is taken up rapidly by various organs including the liver, the intestine and possibly the stomach. Consequently, in plasma, the proportion of the ionized form of GB increases dramatically with time. Thereafter the ratio between the 2 forms appears to shift slowly towards equilibrium. The results suggest that more attention needs to be focused on in vivo dynamics between the 2 forms of GB.     

银杏内酯B对肺癌细胞增殖和凋亡的影响

目的：探讨银杏内酯B（Ginkgolide B,GB）抑制肺癌细胞增殖,诱导细胞凋亡的作用机制。方法：以人肺腺癌细胞A549、人肺鳞癌细胞NCI-H520、人非小细胞肺癌NCI-H1975共3种肺癌细胞株为实验对象,MTT法检测GB对肺癌细胞增殖的抑制作用;Transwell小室法检测GB对肺癌细胞侵袭力的影响;划痕法检测GB对肺癌细胞迁移能力的影响;流式细胞术检测GB对肺癌细胞增殖周期、凋亡的影响;Western blot检测Bcl-2、Bax、Cleaved caspase-3蛋白表达。结果：GB对A549、NCI-H520及NCI-H1975细胞的生长抑制作用均呈时间和剂量依赖性,抑制率随着GB浓度的增加和处理时间的延长而升高;GB处理细胞后,小室膜下表面的细胞数与对照组相比明显减少,对A549、NCI-H520及NCI-H1975细胞的侵袭抑制率分别为35.6%、28.9%、30.2%;GB作用后肺癌细胞较对照组移行愈合率明显降低（P<0.05）。与对照组相比,低、中、高剂量的GB作用于肺癌细胞后,各给药组细胞G₀/G₁比例均明显升高（P<0.05）,细胞凋亡率显著增加（P<0.05）,并呈剂量相关性。并下调Bcl-2蛋白表达、上调Bax和Cleaved caspase-3蛋白表达（P<0.05）。结论：GB对肺癌细胞的侵袭迁移具有明显的抑制作用,对肺癌细胞生长的抑制作用与阻断细胞增殖周期、诱导凋亡有关。其作用机制与下调Bcl-2蛋白表达、上调Bax和Cleaved caspase-3蛋白表达水平有关。     

银杏内酯B对慢性炎症血管生成的抑制作用

目的研究银杏内酯B对慢性炎症血管生成的作用及部分作用机制。方法比色法测定小鼠慢性肉芽肿气囊模型血管生成指数，组织形态学方法检测气囊病理变化；放射免疫方法测定白介素-1β(IL-1β)含量；L929生物测定法测定肿瘤坏死因子(TNF-α)含量；RT-PCR法检测IL-1β和TNF-α mRNA的表达。结果银杏内酯B可显著抑制模型小鼠的血管指数，与病理观察结果相符；银杏内酯B可显著抑制模型小鼠血清中IL-1和TNF-α的分泌；能显著抑制PMA诱导的U937细胞IL-1β和TNF-α的分泌及其mRNA的表达。结论银杏内酯B能抑制小鼠慢性炎症性血管生成模型的血管生成，能抑制促血管生成细胞因子IL-1β和TNF-α的转录及表达，这可能是其抑制慢性炎症血管生成的机制之一。     

The beta subunit increases the ginkgolide B sensitivity of inhibitory glycine receptors

We investigated the effect of ginkgolide B (GB), a component of the extract from the leaves of the Ginkgo biloba tree, on recombinant glycine receptors (GlyRs) expressed in Xenopus oocytes by using voltage-clamp recording. GB (0.01-10 microM) inhibited glycine-induced currents of homo-oligomeric alpha1, alpha2 and alpha 3 GlyRs, with the highest potency being found at the alpha1 GlyR (IC(50) value=0.61+/-0.1 microM). Coexpression of the alpha subunits with the beta subunit resulted in a shift of the IC(50) value of GB to nanomolar values, indicating selectivity of GB for beta subunit containing GlyRs. We also analyzed the mechanism of GB inhibition and the effect of point mutations introduced into the alpha1 subunit. Our results are consistent with a channel blocking effect, since (i) GB inhibited glycine currents non-competitively, and (ii) a point mutation in the pore forming M2 domain reduced GB potency. In conclusion, GB is a potent blocker of beta subunit containing GlyR channels and hence can be used to discriminate homo- from hetero-oligomeric GlyRs. As hetero-oligomeric GlyRs are known to be synaptically localized, GB represents a channel blocker that may be employed to separate extrasynaptic from synaptic glycine currents.     

银杏内酯B对血小板活化因子刺激的大鼠中性粒细胞功能的影响银杏内酯B对血小板活化因子刺激的大鼠中性粒细胞功能的影响

目的 研究银杏内酯B对血小板活化因子(PAF)刺激的大鼠中性粒细胞粘附、趋化及脱颗粒功能的影响。方法 从大鼠外周血分离中性粒细胞,用MTT比色法、Boyden小室法及β-葡萄糖苷酸酶释放法分别检测PAF诱导的粒细胞粘附、趋化及脱颗粒反应。结果10 μmol·L^-1 银杏内酯B可显著抑制中性粒细胞的粘附反应;1～1 000 nmol·L^-1 可剂量依赖性抑制10 nmol·L^-1 PAF诱发的粒细胞趋化反应,其IC₅₀为4.84 nmol·L^-1; 0.01～10 μmol·L^-1可抑制1 μmol·L^-1 PAF诱发的粒细胞释放β-葡糖苷酸酶,其IC₅₀为3.56 μmol·L^-1。结论银杏内酯B能够抑制PAF刺激的大鼠中性粒细胞粘附、趋化及脱颗粒反应。     

银杏内酯B及银杏内酯提取物大鼠体内药动学比较

目的:研究银杏内酯B、银杏内酯提取物在大鼠体内的药动学。方法:LC-MS测定血浆中银杏内酯B的血药浓度,采用3p87药动学处理软件,计算药动学参数,Cmax、tmax采用实测值。结果:银杏内酯B单体、银杏内酯提取物大鼠口服后的t1/2α分别为(0.18±0.09)、(0.17±0.07)h;t1/2β分别为(2.3±2.0)、(2.3±1.5)h;AUC0-12h分别为(2701±655)、(2889±836)μg.L-1.h;AUC0-∞分别为(2778±680)、(2966±854)μg.L-1.h,银杏内酯提取物中银杏内酯B的生物利用度是单体的1.07倍。结论:银杏内酯B单体、银杏内酯提取物大鼠口服后的药动学参数差异均无统计学意义,银杏内酯提取物中共存成分对银杏内酯B的大鼠体内药动学行为影响无统计学意义。     

Radiolabeling of ginkgolide B with 18F

Ginkgolide B, a terpene trilactone constituent of Gingko biloba extracts and an antagonist for the platelet activating factor (PAF) receptor, was radiolabeled with the positron emitter ¹⁸F for visualizing its in vivo behavior using positron emission tomography (PET). The 7‐[¹⁸F]fluoro analog of ginkgolide B (7‐¹⁸FGB) was synthesized via nucleophilic displacement of the triflate group at C7 with [¹⁸F]fluoride. The reaction was complete in 5–10 min, affording 7‐¹⁸FGB in an average radiochemical yield of approximately 16% (decay corrected). The average specific activity at E.O.S. was approximately 40 GBq/µmol, and the radiochemical and chemical purity was greater than 95%. Copyright © 2004 John Wiley & Sons, Ltd.     

银杏内酯B抑制血小板CD40Ligand表达的分子机制研究

目的探讨银杏内酯B(ginkgolide B)对活化血小板CD40 Ligand(CD40L)的影响以及相关的分子机制。方法取正常人血分离血小板,用不同浓度银杏内酯B孵育血小板5 min,然后用胶原(collagen)刺激血小板活化。用Westernblot分析PI3K表达,Akt磷酸化,CD40L的变化。结果①用collagen刺激血小板聚集,银杏内酯B(0.2、0.4、0.6 g.L-1)预处理血小板5 min,血小板聚集率明显降低,聚集率分别为77%,60%和48%。②Western blot结果显示胶原刺激血小板活化后CD40L表达明显增加,银杏内酯B以剂量依赖方式抑制了CD40L表达。③银杏内酯B对胶原刺激的血小板PI3K表达无明显影响。④collagen刺激血小板活化后Akt的磷酸化增加,银杏内酯B抑制了Akt磷酸化。结论银杏内酯B能够有效抑制collagen诱导的血小板聚集以及CD40L的表达,并明显抑制了Akt磷酸化,表明银杏内酯B能够通过PI3K/Akt信号传导通路抑制血小板活化。     

Paradoxical effects of ginkgolide B on cardiomyocyte contractile function in normal and high-glucose environments

AIM: Ginkgo biloba extract is a natural product used widely for cerebral and cardiovascular diseases. It is mainly composed of terpene lactones (ginkgolide A and B) and flavone glycosides (eg quercetin and kaempferol). To better understand the cardiac electromechanical action of Ginkgo biloba extract in normal and diabetic states, this study was designed to examine the effect of ginkgolide B on cardiomyocyte contractile function under normal and high-glucose environments. METHODS: Isolated adult rat ventricular myocytes were cultured for 6 h in a serum-free medium containing either normal (NG; 5.5 mmol/L) or high (HG; 25.5 mmol/L) glucose with or without ginkgolide B (0.5-2.0 microg/mL). Mechanical properties were evaluated using the IonOptix MyoCam system. Contractile properties analyzed included peak shortening (PS), maximal velocity of shortening/relengthening (+/-dl/dt), time-to-PS (TPS) and time-to-90% relengthening (TR90). Levels of essential Ca(2+) regulatory proteins sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a), phospholamban (PLB) and Na(+)-Ca(2+) exchanger (NCX) were assessed by Western blotting. RESULTS: Ginkgolide B nullified HG-induced prolongation in TR90. However, ginkgolide B depressed PS, +/-dl/dt and shortened TPS in NG and HG cells. Ginkgolide B also prolonged TR90 in NG cells. Western blot analysis revealed that HG upregulated SERCA2a and downregulated PLB expression without affecting that of NCX. Ginkgolide B disrupted the NG-HG response pattern in SERCA2a and NCX without affecting that of PLB. CONCLUSION: Ginkgolide B affects cardiomyocyte contractile function under NG or HG environments in a paradoxical manner, which may be attributed to uneven action on Ca(2+) regulatory proteins under NG and HG conditions.     

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。