HPLC法测定银杏叶粉针中总黄酮醇苷和萜类内酯

目的采用高效液相色谱法测定银杏叶粉针中总黄酮醇苷和总萜类内酯。方法黄酮醇苷水解后,采用HPLC-UV法测定;萜类内酯用醋酸乙酯萃取后采用HPLC-ELSD法测定。结果槲皮素、山柰素、异鼠李素分别在5.104～51.04、5.000～50.00、1.38～13.8μg/mL呈良好线性关系,平均回收率分别为99.34%、99.25%、101.2%(n=5);银杏内酯A、B、C及白果内酯分别在0.415～2.075、0.402～2.010、0.426～2.130、0.803～4.015mg/mL呈良好线性关系,平均回收率分别为99.28%、100.1%、101.0%、99.31%(n=5)。结论本实验采用的方法简便快速,结果准确,重现性好,可用于银杏叶粉针中黄酮和内酯类成分的质量控制。     

银杏内酯B对胆固醇和apoE4共损伤海马神经元胆碱能系统的保护作用

[目的]探讨银杏内酯B对高胆固醇和载脂蛋白E4(apoE4)诱导海马神经元胆碱能系统损伤的保护作用。[方法]应用胆固醇和apoE4共处理海马神经元,分别采用微量羟胺比色法,羟胺比色法和放射化学法测定海马神经元乙酰胆碱含量,乙酰胆碱酯酶和胆碱乙酰基转移酶活性。[结果]银杏内酯B可以提高乙酰胆碱酯酶活性和乙酰胆碱水平,对乙酰胆碱酯酶作用不明显。[结论]高胆固醇和apoE4损伤海马神经元胆碱能系统,参与老年性痴呆发生,银杏内酯B对损伤神经元有保护作用。     

HPLC-RI法测定银杏叶提取物中4种内酯的含量

目的:建立高效液相色谱法测定银杏叶提取物中4种内酯(银杏内酯 A、银杏内酯 B、银杏内酯 C、白果内酯)的含量。方法:采用 Symmetryshield 型 C_(18)色谱柱(3.9 mm×150 mm,5 μm),以甲醇-水(30:70)为流动相,流速为1.0 mL·min~~(-1),用外标法测定,示差折光检测器检测。结果:4种内酯浓度在0.02～0.24 mg·mL~(-1)范围内,与色谱峰面积呈良好线性关系,相关系数在0.9984～0.9998之间,检测限在0.025～0.035 μg之间,回收率在99.0%～100.2%之间。结论:本方法简单、准确、可靠、灵敏,适用于实验室和企业常规质量控制。     

高速逆流色谱法分离纯化银杏叶中白果内酯和银杏内酯A、B、C

目的从银杏叶中分离纯化白果内酯和银杏内酯A、B、C。方法银杏叶提取液经醋酸乙酯萃取、D-101大孔吸附树脂柱和Al2O3柱纯化后得到总内酯提取物,提取物再经两次高速逆流色谱分离制备4种内酯单体。结果25%乙醇热提取、醋酸乙酯萃取、D-101柱、pH4.0的Al2O3柱对总内酯的提纯最终使总内酯质量分数达到44.98%。经高速逆流色谱制备得到的白果内酯和银杏内酯A、B、C最高质量分数分别为98.3%、98.9%、98.8%、98.4%。结论本法简便快速、回收率高,为银杏叶中内酯单体的制备提供了一种新方法     

白果内酯抗大鼠卡氏肺孢子虫肺炎的实验研究

目的　研究白果内酯治疗实验大鼠卡氏肺孢子虫肺炎的疗效。方法　以地塞米松皮下注射大鼠 6周诱导建立肺孢子虫肺炎动物模型 ,用不同剂量白果内酯治疗实验大鼠 ,以免疫抑制为对照组 ,通过大鼠肺质量 /体质量的值 ,肺印片每视野的包囊均数为指标评价疗效。结果　白果内酯 2 0mg/kg、3 0mg/kg治疗组大鼠肺质量 /体质量的值分别为 0 0 0 97± 0 0 0 3 3、0 0 10 2± 0 0 0 2 1,明显低于免疫抑制组对照组 0 0 14 6± 0 0 0 3 4(P <0 0 5 )。白果内酯 2 0mg/kg、3 0mg/kg治疗组大鼠肺印片每视野的包囊均数分别为 2 3 1± 0 88、1 95± 0 5 7明显低于免疫抑制组对照组 7 3 9± 2 3 3 (P <0 0 1)。结论　白果内酯具有一定抗卡氏肺孢子虫肺炎作用     

Protection by bilobalide of the ischaemia-induced alterations of the mitochondrial respiratory activity

Ischaemia is a common feature of most vascular diseases. There is evidence from experimental and clinical studies that Ginkgo biloba extract protects tissues from ischaemia/reperfusion damages. Bilobalide seems to be responsible, at least in part, for this activity. However, the mechanism of the protection afforded by bilobalide is not yet known. In this work, the effects of bilobalide on mitochondrial respiration were investigated during liver and brain ischaemia, since mitochondria alteration is an early event in ischaemia-induced damage. Bilobalide could prevent the decrease in respiratory activity induced by ischaemia in liver and in brain, both when glutamate/malate or succinate was used as substrate. Ischaemia decreased state 3 respiration rate and bilobalide prevented this decrease. While bilobalide was not able to prevent the decrease in adenine translocase activity, it protected complex I activity. Bilobalide allows mitochondria to maintain their respiratory activity in ischaemic conditions by protecting complex I and probably complex III activities. Hence, the energetic pool of tissues is preserved during the ischaemic period as well as its viability. This mechanism provides, a possible explanation for the anti-ischaemic properties of bilobalide and of Ginkgo biloba extract in therapeutic interventions.     

银杏叶滴丸中萜类内酯测定方法的改进研究

目的 以银杏叶对照提取物为对照建立银杏叶滴丸中萜类内酯的定量测定方法。方法 采用HPLC-ELSD法,色谱柱为Diamonsil C₁₈柱（150 mm×4.6 mm,5 μm）,流动相为甲醇-水（30∶70）,体积流量0.8 mL/min,ELSD检测器,漂移管温度105 ℃,氮气体积流量3.0 L/min。结果 银杏内酯A、银杏内酯B、银杏内酯C、白果内酯分别在1 672.2～10 033.2、1 026.4～6 158.4、527.8～3 166.8、2 200.8～13 204.8 ng呈良好的对数线性关系;银杏内酯A、银杏内酯B、银杏内酯C、白果内酯及总萜类内酯的平均回收率分别为100.3%（RSD 2.5%）、108.1%（RSD 3.5%）、116.0%（RSD 4.9%）、90.4%（RSD 0.6%）及99.3%（RSD 1.1%）。结论 本方法简单易行、可控性强、重复性好,可用于银杏叶滴丸中萜类内酯的定量测定,并为中成药中多指标成分同时测定提供了有效的思路和解决方案。     

LC-MS/MS快速测定不同采摘时间银杏叶中银杏内酯和白果内酯的含量

 目的建立银杏叶中银杏内酯和白果内酯的高效液相电喷雾二级质谱(LC-MS/MS)定量分析方法,并对不同采摘时间银杏叶中银杏内酯和白果内酯含量进行测定。方法银杏叶样品以甲醇-水(1:9)提取,并用乙酸乙酯萃取,采用Phenomenex ODS柱分离,流动相为甲醇-水(60:40),流速0.7 mL·min^-1。电离方式为电喷雾正离子,采用多反应检测模式(MRM),捡测离子分别为m/z 409.4→345.3(银杏内酯A)、m/z 425.3→361.3(银杏内酯B)、m/z 441.4→325.3(银杏内酯C)和m/z 327.4→309.3(白果内酯)。结果分析过程仅需8.5 min,且无杂质干扰,4种成分回收率为91.79%～101.48%银杏内酯A,B和白果内酯含量分别在7月18日、8月19日和7月5日采摘的样品达到最高。结论方法快速、准确、选择性好,适合银杏内酯和白果内酯的定量分析,七月份叶子中内酯含量最高,为最佳采摘时间。     

Effect of bilobalide B on cholinergic hippocampal neurons exposed to cholesterol and apoliprotein E4

BACKGROUND: Extracts of ginkgo biloba leaves have been reported to improve nerve function and activity in Alzheimer's disease, which is associated with reduced secretion of cholinergic neurotransmitter in hippocampal neurons.OBJECTIVE: To validate the protective effect of bilobalide B against in vitro injury of cholinergic neurons of the hippocampus induced by combined cholesterol and apoE4DESIGN, TIME AND SETTING: This randomized, controlled animal experiment was performed in the Pathology Laboratory, Tianjin University of Traditional Chinese Medicine from July 2003 to July 2006.MATERIALS: Neonatal Wistar rats, 1-day-old, both male and female, and mean body mass of 5g were selected for this study. Cholesterol and apolipoprotein E4 (apoE4) were purchased from Sigma Company (USA), bilobalide B was purchased from Tianjin Zhongyi Pharmaceutical Factory, batch number 20050312.METHODS: Hippocampal neurons were divided into three groups; a normal control group (routinely added media), a model group (exposed to media containing 40mg/L cholesterol and 30mg/L apoE4 for 24 hours) and a bilobalide B group (exposed to media containing 160mg/L bilobalide B for 16 hours, and then with addition of 40mg/L cholesterol and 30mg/L apoE4 for an additional 24 hours).MAIN OUTCOME MEASURES: Levels of acetylcholine (ACh) and activity of acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) in hippocampal neurons were determined by microdosage hydroxylamine colorimetry, hydroxylamine colorimetry and radiological chemistry, respectively.RESULTS: The ACh level was significantly lower in the model group than that in the normal control group (P<0.01), while it was markedly higher in the bilobalide B group than in the model group (P<0.05). Activity of AChE was significantly decreased in the model group compared with the normal control group (P<0.05). However, there was no significant difference between the model group and the bilobalide B group (P>0.05). Activity of ChAT was significantly lower in the model group than in the normal control group (P<0.01), while the activity was significantly higher in the bilobalide B group than in the model group (P<0.05).CONCLUSION: Bilobalide B can enhance the ACh level of hippocampal neurons damaged by combined cholesterol and apoE4, by promoting the synthesis, but not the degradation, of ACh.