银杏叶提取物猴头菌转化前后降血糖作用的比较研究

The regulatory effects of blood glucose, lipid metabolism and free radical elimination were compared in streptozotocin-induced hyperglycemic rats among the following treatments: Ginkgo biloba leaf extract (EGB), the biotransformation of EGB by Hericium erinaceus, a cultural filtrate of H.erinaceus, and the cultural filtrate of H.erinaceus plus EGB, together with the normal control, the model control and the positive control (Metformin). The best results were obtained from the biotransformation treatment group, which could significantly reduce the levels of blood glucose and fructosamine. However, the treatment did not increase the blood insulin level. The EGB transformed products could obviously increase the serum superoxide dismutase activity and reduce the malondialdehyde level, but the reduction of malondialdehyde was not obvious as compared with that of the other treatment groups. This study provides a useful information on improving the medical properties of the herb extracts by biotransformation.     

银杏叶提取物的微生物转化研究Ⅲ．转化产物的化学成分

为研究银杏叶提取物经微生物转化后的化学成分,采用微生物转化的方法对银杏叶提取物进行处理得到转化粗提物,采用硅胶、Sephadex^TM LH-20凝胶等色谱技术对转化粗提物进行分离纯化,通过波谱分析单体结构鉴定。结果发现,从银杏叶提取物的转化粗提物中分得5个化合物,分别为异鼠李素（isorhamnetin,1）、山奈酚（kaempferol,2）、斛皮素（quercefin,3）、山奈酚-3-O-α-L-鼠李糖苷（kaempferol-3-O-α-L-rhamnosid,4）、斛皮素-3-O-α-L-鼠李糖苷（quercetin-3-O-α-L-rhamnosid,5）。结果表明,这是首次用微生物转化的方法对银杏叶提取物进行处理。     

银杏叶提取物对自由基所致脑神经细胞损伤的保护作用研究

从细胞分子水平,采用大脑皮层神经细胞分离技术,自旋标记技术,酶学方法及细胞染色技术探讨自由基对神经细胞的损伤及ＥＧｂ保护作用。结果显示,用自由基攻击的细胞其自旋标记膜的序参数Ｓ,旋转相关时间τｃ及膜蛋白巯基的Ｓ／Ｗ比对照组高（Ｐ＜０．０５）,提示：受自由基攻击的细胞膜,其流动性比正常减低,且蛋白质构象发生了改变。加ＥＧｂ保护后,可减少自由基引起的膜流动性及蛋白质构象改变,起到保护神经细胞的作用。经·ＯＨ攻击的神经细胞,其ＬＤＨ活性及死细胞比率都比对照组高,而ＥＧｂ对此有保护作用。本文结果说明一定浓度ＥＧｂ可保护大脑皮层神经细胞免受自由基的损伤。     

银杏叶提取物761对矽肺大鼠的防护作用

目的 探讨银杏叶提取物761(Ginkgo biloba Extract 761,EGb761)对矽肺大鼠的肺保护作用.方法 采用二氧化硅悬液气管内灌注法建立矽肺大鼠模型.二氧化硅灌注1 d后,每日灌服EGb761,持续4周.处死大鼠,收集肺组织.HE和Van Gieson(VG)染色法观察肺组织病理形态学情况,采用E...     

银杏叶提取物新型制剂研究进展

银杏是最古老的中生代植物,很早就被用为中药,其提取物近年来备受人们的高度重视.在简述其药理活性成分以及现有国内外制剂基础上,重点阐述了近年来银杏叶提取物的新制荆以及新技术,为中药的新制剂开发提供科学的思路.     

银杏叶提取物对过氧化氢刺激下的血管内皮细胞的影响

目的:探讨银杏叶提取物对血管内皮细胞的保护作用及可能的保护机制。方法:进行血管内皮细胞培养。用过氧化氢(H2O2)处理血管内皮细胞建立细胞凋亡模型。将细胞分为四组:空白对照组、H2O2处理组、单独银杏叶提取物处理组、银杏叶提取物预处理组(提前2h给药后H2O2处理)。进行MTT检测细胞的相对活力、RT-PCR检测目的基因CHOP的表达、Western Blot分析目的蛋白CHOP的表达等。结果:与对照处理组比较,H2O2处理组细胞凋亡率、CHOPmRNA相对表达及CHOP蛋白表达量明显升高。与H2O2处理组比较,银杏叶提取物预处理组细胞凋亡指数、CHOPmRNA相对表达及CHOP蛋白表达量明显降低(P0.05)。结论:作为一种清除自由基、抗氧化、抗衰老药物,银杏叶提取物可能通过调节CHOP蛋白选择性地抑制过度的内质网应激来保护血管内皮细胞。     

银杏叶提取物抗肿瘤机制研究进展

银杏叶提取物已被广泛应用于治疗心血管和外周血管灌注不足、过敏性疾病和神经性疾病等,最近研究证明银杏叶提取物对多种肿瘤具有抑制作用,其机制主要包括诱导凋亡、抗氧化和免疫调节等,银杏叶提取物抗肿瘤作用的具体研究对指导临床预防和治疗肿瘤有重要意义,对目前银杏叶提取物的抗肿瘤机制做一综述。     

银杏叶提取物联合治疗消化性溃疡的临床研究

银杏叶提取物为银杏科植物银杏的干燥叶提取物,此种药物具有促进身体循环,抗氧化作用以及抗衰老功能,本文就介绍了银杏叶提取物的一些功能,以及银杏叶提取物联合治疗消化性溃疡类疾病的的临床研究。     

银杏叶提取物和槲皮素对心肌细胞肥大的防治作用及其机制

目的：探讨银杏叶提取物（EGb）及其单体槲皮素（Que）对心肌细胞肥大的防治作用及其机制。方法：采用血管紧张素Ⅱ（AngⅡ）诱导新生大鼠心肌细胞肥大模型;分别在培养液中加入EGb（40／μg／ml）或Que（4／μg／m1）,观察Lowry法测定心肌细胞蛋白质含量的变化;测定SOD活性和MDA含量观察心肌细胞氧自由基代谢的变化;Western blot方法检测心肌细胞p-ERK1／2、p-JNK和p-P38蛋白表达;应用RT-PCR法检测心肌细胞c-fos mRNA表达。结果：①EGb和Que能明显抑制AngⅡ引起的心肌细胞总蛋白质含量的增加;②EGb和Que可显著提高SOD活性,降低MDA含量;③AngⅡ诱导的心肌细胞p-ERK1／2、p-JNK和p-P38表达均明显增强,Que能明显抑制AngⅡ诱导的p-JNK表达;④EGb、Que、可降低AngⅡ诱导心肌细胞c-fos mRNA表达的上调水平。结论：EGb和Que对AngⅡ诱导的心肌细胞肥大有明显的防治作用,Que的作用机制可能与ROS／JNK／c-fos信号通路有关。氧化应激参与了心肌肥大的发生发展过程。     

三七总皂甙和银杏叶提取物预防急性氧中毒的实验研究

目的:研究三七总皂甙和银杏叶提取物对急性氧中毒的预防作用及其可能机制.方法:分别给小鼠连续腹腔注射三七总皂甙和银杏叶提取物5 d后,在500kPa高压氧中暴露60 min,观察惊厥潜伏期、惊厥次数、惊厥间隔时间等指标;另外测定高压氧暴露15 min后脑组织中活性氧单位、脂质过氧化物、一氧化氮、谷胱甘肽的含量和过氧化氢酶、谷胱甘肽过氧化物酶、单胺氧化酶的活性.结果:三七总皂甙和银杏叶提取物可以明显延长氧惊厥潜伏期和惊厥间隔时间,减少惊厥次数;降低高压氧暴露后脑组织中脂质过氧化物、一氧化氮的含量,使活性氧单位、谷胱甘肽含量和谷胱甘肽过氧化物酶活性保持在较高的水平;对过氧化氢酶和单胺氧化酶活性的影响则不显著.结论:三七总皂甙和银杏叶提取物可以有效预防急性氧中毒,其机制可能与它们的抗氧化活性有关.     

HPLC法测定银杏叶征剂中决黄酮甙的含量

银杏 (ＧｉｎｋｇｏｂｉｌｏｂａＬｉｎｎ .)叶提取物 (ＧＢＥ)是银杏叶经提取、分离而得的干浸膏 ,是银杏叶制剂的主要原料。药理及临床表明 ,它能增加冠状动脉血流量 ,可用于动脉硬化及高血压所致的冠状动脉供血不全、心绞痛、心肌梗塞、脑血栓、脑血管痉挛等症[1] 。其活性成分主要是黄酮类和萜内酯[2 ] 。银杏叶黄酮类成分的测定方法 ,有紫外分光光度法和高效液相色谱法 ,因前者专属性较差 ,现多数厂家均采用后者。高效液相色谱法测定总黄酮甙的含量时 ,在对照品的使用上 ,既有单用槲皮素 (ｑｕｅｒｃｅｔｉｎ)为对照品的测定方法[3 ] ,…     

Ginkgo biloba extract modifies hypoglycemic action of tolbutamide via hepatic cytochrome P450 mediated mechanism in aged rats

We examined hepatic cytochrome P450 (CYP)-mediated interactions between Ginkgo biloba extract (GBE) and tolbutamide, an oral anti-diabetic agent, in aged and young rats. Tolbutamide was orally given to rats with or without GBE treatment, and time-dependent changes in blood glucose were monitored. The basal activity of six CYP subtypes in liver was lower in the aged rats than in the young rats, while the inductions of these enzymes by 5 day pretreatment of 0.1% GBE diet were more in the aged rats. Further, the pretreatment of GBE significantly attenuated the hypoglycemic action of tolbutamide in the aged rats, corresponding well to the enhanced activity of (S)-warfarin 7-hydroxylase, which is responsible for CYP2C9 subtype, a major isoform metabolizing tolbutamide. In contrast, the simultaneous administration of GBE with tolbutamide potentiated the hypoglycemic action of this drug. The in vitro experiments revealed that GBE competitively inhibited the metabolism of tolbutamide by (S)-warfarin 7-hydroxylase in the rat liver microsomes. In the young rats, the 5 day pretreatment with GBE significantly attenuated the hypoglycemic action of tolbutamide, but a simultaneous treatment had little influence on the tolbutamide effect. In conclusion, the present study has shown that the simultaneous and continuous intake of GBE significantly affects the hypoglycemic action of tolbutamide, possibly via a hepatic CYP enzyme-mediated mechanism, particularly in the aged rats. Therefore, it is anticipated that the intake of GBE as a dietary supplement with therapeutic drugs should be cautious, particularly in elderly people.     

高效液相色谱分析银杏萜内酯的含量

用高效液相色谱法测定银杏叶及提取物中银杏内酯Ａ、Ｂ、Ｃ和白果内酯的含量。采用Ｃ１８分离柱,示差检测器,甲醇：水（３３：６７）为流动相,方法回收率平均达９７％以上,变异系数（ＣＶ）为２．１％。     

银杏叶超临界流体提取物对杉木种子的发芽效应

采用正交试验设计L8(2^7)及超临界萃取技术,乙醇作夹带剂,就银杏(Ginkgo biloba L.)叶提取物对杉木[Cunninghamia lanceolata (Lamb.) Hook.]种子的发芽效应进行了生物检测。结果表明：不同萃取条件下,纯CO2及夹带剂和CO2混合萃取的银杏叶提取物对杉木种子发芽的影响不同;就尉值(敏感指数)而言,在纯CO2萃取的浓度为200mg／kg银杏叶提取物中,杉木种子绝对发芽率为0．23,绝对发芽势为0．15,胚根长为0．01,胚轴长为-0．02;夹带剂和CO2混合萃取的浓度为200mg／kg银杏叶提取物除了对杉木种子绝对发芽率和绝对发芽势表现为促进作用外(尉值分别为0．03和0．34),对胚根长及胚轴长则表现为轻微的抑制作用(尉值分别为-0．09和-0．03)。     

银杏叶提取物对小鼠离体小肠平滑肌收缩特性的影响

目的观察不同浓度的银杏叶提取物(Extract of Ginkgo biloba, EGb)对小鼠离体小肠平滑肌活动的影响,探讨EGb对小肠平滑肌的作用机制.方法制备离体肠段标本,灌流给药后记录不同浓度EGb作用下小肠收缩变化.结果低浓度和中浓度的EGb对离体小肠平滑肌有兴奋作用,随浓度增加,低浓度EGb的兴奋程度呈降低趋势,中浓度EGb的兴奋程度呈升高趋势;高浓度EGb引发抑制效应,随浓度增加,抑制程度降低.结论不同浓度范围的EGb对离体小肠平滑肌有不同作用,可能通过对平滑肌的直接作用或调节激素释放,影响离子通道等途径发挥作用.     

Mapping of rat hippocampal neurons with NeuN after ischemia/reperfusion and Ginkgo biloba extract (EGb 761) pretreatment

1. The neuroprotective effect of Ginkgo biloba extract (EGb 761) against transient forebrain ischemia following 7 days of reperfusion was studied in male Wistar rats after four-vessel occlusion for 20 min.2. NeuN, a neuronal specific nuclear protein was used for immunohistochemical detection of surviving pyramidal neurons in the hippocampus, as well as counterstaining with hematoxylin in the same sections for detection of neurons that underwent delayed neuronal death and for glial nuclei staining. GFAP immunohistochemistry was used for detection of astrocytes in the studied area of CA1 region.3. In the group of rats pretreated 7 days with Ginkgo biloba extract (EGb 761), following 20 min of ischemia and 7 days of reperfusion without EGb 761, increased number of NeuN immunoreactive cells were counted in the most vulnerable CA1 pyramidal layer of hippocampus. On the other hand, the group of rats with 7 days of EGb 761 pretreatment following 20 min of ischemia and 7 days of reperfusion with EGb 761 showed decreased number of surviving NeuN immunoreactive CA1 pyramidal cells in comparison with the first above-mentioned experimental group.4. Increased number of reactive astrocytes immunolabeled for GFAP (Glial fibrilary acidic protein) was observed in both experimental groups in the stratum oriens and stratum lacunosum and moleculare.5. Twenty minutes of ischemia is lethal for most population of CA1 pyramidal cell layer. Our results showed that prophylactic oral administration of Ginkgo biloba extract (EGb 761) in the dose 40 mg/kg/day during the 7 days protects the most vulnerable CA1 pyramidal cells against 20 min of ischemia.     

The effects of melatonin and Ginkgo biloba extract on memory loss and choline acetyltransferase activities in the brain of rats infused intracerebroventricularly with beta-amyloid 1-40

Intraventricular infusion of rats with beta-amyloid for 14 days resulted in memory deficit in the water maze as well as decreases in choline acetyltransferase activities and somatostatin levels in the cerebral cortex and hippocampus. These changes were not altered by daily intraperitoneal injection of 20 mg/Kg melatonin. Orally administered Ginkgo biloba extract, however, partially reversed the memory deficit and the decrease in choline actyltransferase activities in the hippocampus. The latter treatment failed to reverse the decrease in somatostatin levels. The results indicate that orally administered Ginkgo biloba extract can protect the brain against beta-amyloid from changes leading to memory deficit through its effect on the cholinergic system.     

银杏内生菌Chaetomium globosum ZY-22次生代谢产物分离鉴定

采用柱层析方法从银杏叶内生真菌Chaetomium globosum ZY-22的培养菌丝体提取物中分离得到脑苷脂B(1)、脑苷脂C(2)、尿囊素(3)、9(11)-去氢麦角甾醇过氧化物(4)以及4,6,8,22-四烯-3-酮-麦角甾烷(5)和球毛壳甲素(6)共6个次生代谢物;经波谱分析确定了6个化合物的结构,其中脑苷脂B、脑苷脂C和尿囊素是首次从内生真菌中得到;海虾致死试验结果显示,化合物1～6在10 μg/mL浓度下对丰年虾的致死率分别为1.6%、4.2%、7.4%、16.9%、12.8%、83.6%、表明球毛壳甲素对海虾表现出很强的毒性作用.