Selective ischemic-hemisphere targeting Ginkgolide B liposomes with improved solubility and therapeutic efficacy for cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion injury(CI/RI)remains the main cause of disability and death in stroke patients due to lack of effective therapeutic strategies.One of the main issues related to CI/RI treatment is the presence of the blood-brain barrier(BBB),which affects the intracerebral delivery of drugs.Ginkgolide B(GB),a major bioactive component in commercially available products of Ginkgo biloba,has been shown significance in CI/RI treatment by regulating inflammatory pathways,oxidative damage,and metabolic disturbance,and seems to be a candidate for stroke recovery.However,limited by its poor hydrophilicity and lipophilicity,the development of GB preparations with good solubility,stability,and the ability to cross the BBB remains a challenge.Herein,we propose a combinatorial strategy by conjugating GB with highly lipophilic docosahexaenoic acid(DHA)to obtain a covalent complex GB-DHA,which can not only enhance the pharmacological effect of GB,but can also be encapsulated in liposomes stably.The amount of finally constructed Lipo@GB-DHA targeting to ischemic hemisphere was validated 2.2 times that of free solution in middle cerebral artery occlusion(MCAO)rats.Compared to the marketed ginkgolide injection,Lipo@GB-DHA significantly reduced infarct volume with better neurobehavioral recovery in MCAO rats after being intravenously administered both at 2 h and 6 h post-reperfusion.Low levels of reactive oxygen species(ROS)and high neuron survival in vitro was maintained via Lipo@GB-DHA treatment,while microglia in the ischemic brain were polarized from the pro-inflammatory M1 phenotype to the tissue-repairing M2 phenotype,which modulate neuroinflammatory and angiogenesis.In addition,Lipo@GB-DHA inhibited neuronal apoptosis via regulating the apoptotic pathway and maintained homeostasis by activating the autophagy pathway.Thus,transforming GB into a lipophilic complex and loading it into liposomes provides a promising nanomedicine strategy with excellent CI/RI therapeutic efficacy and industrialization prospects.

Effects of ginkgolide B on neuronal discharges in paraventricular nucleus of rat hypothalamic slices

Objective To study the central role of ginkgolide B （BN52021） in regulating cardiovascular function of nerve center by examining the effects of ginkgolide B on the electrical activity of rat paraventricular nucleus （PVN） neurons in hypothalamic slice preparation and to elucidate the mechanism involved. Methods Extracellular single-unit discharge recording technique. Results （1） In response to the application of ginkgolide t3 （0.1, 1, 10 μmol/L; n = 27） into the perfusate for 2 rain, the spontaneous discharge rates （SDR） of 26 （26/27, 96.30%） neurons were significantly decreased in a dose-dependent manner. （2） Pretreatment with L-glutamate （L-Glu, 0.2 mmol/L） led to a marked increase in the SDR of all 8 （100%） neurons in an epileptiform pattern. The increased discharges were suppressed significantly after ginkgolide B （1 μmol/L） was applied into the perfusate for 2 min. （3） In 8 neurons, perfusion of the selective L-type calcium channel agonist, Bay K 8644 （0.1 μmol/L）, induced a significant increase in the discharge rates of 8 （8/8, 100%） neurons, while ginkgolide B （1μmol/L） applied into the perfusate, could inhibit the discharges of 8 （100%） neurons. （4） In 8 neurons, the broad potassium channels blocker, tetraethylammonium （TEA, 1 mmol/L） completely blocked the inhibitory effect of ginkgolide B （1 μmol/L）. Conclusion These results suggest that ginkgolide B can inhibit the electrical activity of paraventricular neurons. The inhibitory effect may be related to the blockade of L-type voltage-activated calcium channel and potentially concerned with delayed rectifier potassium channel （KDR）.

Isolation and Preparative Purification for Ginkgolides A and B

In this paper a simple preparative method for isolation and purification of ginkgolides A and B was developed,As starting material,a commercially available standardized ginkgo extract (EGb761,containing 24% flavonoid and 6% terpene trilactones) was used,After a pretreatment step,optimized by the uniform design method ,the concentrated intermediate extract with high content of GA and gb(+90%) was separated into the individual terpenes by preparative liquid chromatography eluted with petroleum ether-ethylacetate,Analysis of products was carried out by means of HPLC-ELSD(evaporative light -scattering detector),The results show that ginkgolides A and B are obtained in higher yield and better purity.

Mechanism and dose-effect of Ginkgolide B on severe acute pancreatitis of rats

AIM:To determine the optimal dosage and mechanism of Ginkgolide B(BN52021) on severe acute pancreatitis(SAP) of rats.METHODS:Seventy male Wistar rats were randomly divided into seven groups(10 for each group).Shamoperation group(SO),SAP model group(SAP),dimethyl sulfoxide(DMSO) contrast group(DMSO),and groups treated with 2.5 mg/kg BN52021(BN1),5 mg/kg BN52021(BN2),10 mg/kg BN52021(BN3),and 20 μg/kg Sandostatin(SS).The SAP model was established in Wistar rats by injecting 5% sodium taurocholate retrogradely into the common bilio-pancreatic duct.The rats of SO,DMSO and BN52021 were injected with 0.9% NaCl,0.5% DMSO and BN52021 through femoral vein 15 min after the operation.The SS group was injected with Sandostatin subcutaneously.All rats were anaesthetized at 6 h after operation,and venous blood was collected to determine the levels of serum amylase and phospholipase A2(PLA2),and pancreas tissue was harvested and stained.RESULTS:There was no significant difference between the SAP and DMSO groups in serum amylase level,PLA2,ascites and pathologic score,but significant difference was found in SAP/DMSO groups compared with those in SO group(P < 0.05) and the levels of serum amylase,PLA2,ascites,and pathologic score were lower in the BN1,BN2,BN3 and SS groups than in the SAP and DMSO groups(P < 0.05).However,among BN1,BN2,BN3 and SS groups,BN2 had the best effect in decreasing the levels of serum amylase and PLA2(P < 0.05).Expression of platelet activating factor(PAF) receptor(PAFR) mRNA and protein showed no significant difference between the SAP and DMSO groups,or among BN1,BN2,BN3 and SS groups,but there was remarkable difference between SAP/DMSO group and SO group(P < 0.05),and expression of PAFR mRNA and protein was higher in the BN1,BN2,BN3 and SS groups than in the SAP and DMSO groups(P < 0.05).PAFR expression was observed in the nucleus and cytoplasm of pancreatic islet cells in Wistar rats by immunohistochemistry.CONCLUSION:By iv injection,5 mg/kg of BN52021 is the optimal dosage for SAP rats.BN52021 may inhibit the interaction/binding of PAF with PAFR.

Ginkgolide K protects the heart against ER stress injury by activating the IRE1α/XBP1 pathway

OBJECTIVE Here we investigated the effects and the underlying mechanism of Ginkgolide K(1,10-dihydroxy-3,14-didehydroginkgolide,GK)on cardiac ER stress.METHODS Cell death,apoptosis,and ER stressrelated signalling pathwayswere measuredin cultured neonatal rat cardiomyocytes(NRCMs),treated with the ER stress inducers tunicamycin,hydrogen peroxide,and thapsigargin.Acute myocardial infarction was established using left coronary artery occlusion in mice,and infarct size was measured by triphenyltetrazolium chloride(TTC)staining.Echocardiography was used to assess heart function and transmission electron microscopy for evaluating ER expansion.RESULTS GK significantly decreased ER stress-induced cell death in both in vitro and in vivomodels.In ischemic injured mice,GK treatment reduced infarct size,rescued heart dysfunction and ameliorated ER dilation.Mechanistic studies revealed that the beneficial effects of GK occur through enhancement of inositol-requiring enzyme 1α(IRE1α)/X box-binding protein-1(XBP1)activity,which in turn leads to increased ER-associated degradation(ERAD)-mediated clearance of misfolded proteins and autophagy.In addition,GK is also able to partially repress the pro-apoptotic action of regulated IRE1-dependent decay(RIDD)and JNK pathway.CONCLUSION GK acts through selective activation of the IRE1α/XBP1 pathway to limit ER stress injury.GK is revealed as a promising therapeutic agent to ameliorate ER stress for treating cardiovascular diseases.

Ginkgolide K protects cardiomyocytes against ER stress through stimulating ER-associated degradation （ERAD） and autophagy

Aim Endoplasmic reticulum （ER） stress is increasingly recognized as an important contributor to the pathophysiology of many diseases, and therapeutic interventions that target ER stress response emerge as new thera- peutic modalities to treat cardiovascular diseases driven by prolonged ER stress. Ginkgolides K （GK） is a diterpene lactone constituent isolated from the leaves of Ginkgo biloba and has been found to possess potent neuroprotective properties. This study is aimed to investigate the cytoprotective effect of GK in cultured cardiomyocytes subjected to ER stress injury. Neonatal rat cardiomyocytes （NRCMs） were treated with ER stress inducer tunicamycin to mimic the ER stress injury. We demonstrated that GK pre-treatment mitigated ER stress-induced apoptosis in tunicamycin treated NRCMs. We observed that the activation of ER-associated degradation （ERAD） and autophagy were in- volved in the ER stress inhibition exerted by GK. These beneficial effects of GK were nearly abolished by the addi- tion of specific short interfering RNA （siRNA） for IRElα and XBP-1. Therefore, we conclude that GK might be a promising therapeutic agent for ER stress-mediated cardiovascular diseases, and ER-associated degradation （ERAD） and autophagy play a vital role in GK mediated cytoprotection.

Ginkgolide C Stimulates CFTR-mediate Anion Conductance in Distal Colon:Implication for Therapy of Gastrointestinal Diseases

The effects and the mechanisms of natural compounds ginkgolides on CFTR-mediate anion transport were investigated. The CFTR-mediate iodide influx rates were studied via a cell-based fluorescence assay done for FRT cells stably transfected by CFTR; transepithelial short-circuit current recordings of FRT cells and rat distal colon mucosa were respectively obtained. Cellular cAMP concentrations were measured via a radioimmunoassay analysis kit. Ginkgolide C dose-dependently increases CFTR-mediate anion transport, whereas ginkgolide A and B show no effect. The activation is sensitive to CFTR specific activator CFTRinh-172. Ginkgolide C stimulated amiloride and indomethacin pre-treated Cl currents in rat distal colon mucosa. Studies on FRT cells also manifest that ginkgolide C had additive effect with FSK/IBMX mixture and didn＇t elevate intracellular cAMP concentration, which implies it works through a direct binding mechanism. In conclusion, Ginkgolide C directly stimulates CFTR-mediate anion transport. Ginkgolide C may be a promising drug for the prevention and treatment of CFTR-related diseases such as idiopathic chronic pancreatitis（ICP）, habitual constipation, and kcratoconjunctivitis sicca（KCS）.

Effects of adjuvant ginkgolide injection therapy in perioperative period of hypertensive cerebral hemorrhage on neural functional recovery

Objective: To study the effects of adjuvant ginkgolide injection therapy in perioperative period of hypertensive cerebral hemorrhage on neural functional recovery. Methods: Patients with hypertensive cerebral hemorrhage who underwent evacuation of hematoma in Traditional Chinese Medicine Hospital of Shunyi District Beijing between June 2015 and October 2017 were selected and divided into ginkgolide group and normal control group according to the perioperative application of ginkgolide injection or not in the history data. The levels of nerve injury markers and inflammatory stress mediators in serum as well as the expression of inflammatory stress signal molecules in peripheral blood were measured before treatment and 7 d after treatment. Results: Compared with same group before treatment, serum GNS and BDNF levels as well as peripheral blood Wnt1, GSK-3β and β-catenin expression of both groups of patients were significantly higher whereas serum Tau, NSE, OPN, MIF, HMGB1, TNF-α and MDA levels as well as peripheral blood eNOS and p38MAPK expression were significantly lower 7 d after treatment, and serum GNS and BDNF levels as well as peripheral blood Wnt1, GSK-3β and β-catenin expression of ginkgolide group 7 d after treatment were higher than those of normal control group whereas serum Tau, NSE, OPN, MIF, HMGB1, TNF-α and MDA levels as well as peripheral blood eNOS and p38MAPK expression were lower than those of normal control group. Conclusion: Adjuvant ginkgolide injection therapy in perioperative period of hypertensive cerebral hemorrhage can reduce the degree of nerve injury and inhibit the degree of inflammatory stress.

THE APPLICATION OF A NOVEL ADSORBENT IN RAPID SAMPLE CLEAN-UP OF GINKGOLIDES AND BILOBALIDE IN EXTRACTS OF GINKGO BILOBA LEAVES

A rapid method has been developed for rapid sample clean-up in the determination of the pharmocologically active terpenoid including ginkgolide A, B. C and bilobalide in ginkgo biloba leaves extracts (GBE). The extracts are dissolved in 7% of ethanol aqueous solution and then purified by a highly selective polymeric absorbent solid-phase chromatographic column. After being concentrated, the separated terpenoids with no phenolic disturbance are determined by highperformance liquid chromatography on a Nova-Pak C18 column with methanol-water (30:70) as effluent and refractive index defection. The recovery of the method is about 95% and the new method saves more time than the conventional two-column purification method.

Influence of ginkgolide combined with edaravone on the brain function of elderly patients with acute cerebral infarction and its preventive effect on ischemia reperfusion injury

Objective: To explore the influence of ginkgolide combined with edaravone on the brain function of elderly patients with acute cerebral infarction and its preventive effect on ischemia reperfusion injury. Methods: A total of 126 patients with acute cerebral infarction who were treated in Dazhou Central Hospital between February 2016 and May 2017 were divided into the control group (n=67) and ginkgolide group (n=59) according to different therapies. Control group received routine intravenous thrombolysis + edaravone therapy, and ginkgolide group received routine intravenous thrombolysis + edaravone + ginkgolide therapy. The differences in brain function and nerve ischemia reperfusion injury extent were compared between the two groups. Results: At T1 and T2, serum nerve function indexes NT-proBNP and NSE levels of ginkgolide group were lower than those of control group whereas BDNF levels were higher than those of control group;serum inflammatory mediators MCP-1, NF-κB, CRP and TNF-α levels were lower than those of control group;serum apoptosis molecules caspase-3 and Bax levels were lower than those of control group whereas Bcl-2 levels were higher than those of control group. Conclusion: Ginkgolide combined with edaravone therapy on the basis of intravenous thrombolysis can effectively optimize the brain function and alleviate the ischemia reperfusion injury caused by inflammatory response and apoptosisis in elderly patients with acute cerebral infarction.

GC-MS测定家犬血浆中银杏内酯A、B的含量

银杏叶制剂作为治疗和预防动脉粥样硬化的有效药物,越来越为人们关注.银杏叶成分复杂,其中银杏黄酮具有扩张血管,降血脂,改善微循环的作用;银杏内酯是血小板活化因子强拮抗剂,对免疫系统,中枢神经系统,缺血损伤有保护作用,并有抗休克、抗过敏及抗炎作用.由于银杏内酯含量较低,对其进行的药动力学研究较少,且多采用的是非特异性的生物测定方法.……

Anti-atherosclerotic effects and molecular targets of ginkgolide B from Ginkgo biloba

Bioactive compounds derived from herbal medicinal plants modulate various therapeutic targets and signaling pathways associated with cardiovascular diseases(CVDs),the world’s primary cause of death.Ginkgo biloba,a well-known traditional Chinese medicine with notable cardiovascular actions,has been used as a cardio-and cerebrovascular therapeutic drug and nutraceutical in Asian countries for centuries.Preclinical studies have shown that ginkgolide B,a bioactive component in Ginkgo biloba,can ameliorate atherosclerosis in cultured vascular cells and disease models.Of clinical relevance,several clinical trials are ongoing or being completed to examine the efficacy and safety of ginkgolide B-related drug preparations in the prevention of cerebrovascular diseases,such as ischemia stroke.Here,we present a comprehensive review of the pharmacological activities,pharmacokinetic characteristics,and mechanisms of action of ginkgolide B in atherosclerosis prevention and therapy.We highlight new molecular targets of ginkgolide B,including nicotinamide adenine dinucleotide phosphate oxidases(NADPH oxidase),lectin-like oxidized LDL receptor-1(LOX-1),sirtuin 1(SIRT1),platelet-activating factor(PAF),proprotein convertase subtilisin/kexin type 9(PCSK9)and others.Finally,we provide an overview and discussion of the therapeutic potential of ginkgolide B and highlight the future perspective of developing ginkgolide B as an effective therapeutic agent for treating atherosclerosis.

Lipopolysaccharide-induced cerebral inflammatory damage and the therapeutic effect of platelet activating factor receptor antoganist

Objective To investigate lipopolysaccharide （LPS） induced acute cerebral inflammatory damage and the therapeutic effect of ginkgolide B （BN52021）. Methods Thirty Sprague-Dawley rats were randomly divided into 3 groups （n = 10 for each group）： Control group, Model group and Treatment group （treated with BN52021）. LPS were injected into the fourth ventricle of rat to make a neuroinflammatory murine model. Morris water maze was used to detect the learning and memory ability of rats; changes of synapse number and subcellular ultrastructures were observed under a transmission electron microscope; OX-42 positive microglia in the brain was detected by immunohistochemical method. Results The average escape latency in the Treatment group were significantly shortened than that in the Model group; and the percentage of swimming distance traveled in platform quadrant accounting for total distance increased markedly. The rough endoplasmic reticulum and polyribosomes in the Treatment group were more than that in the Model group, but the number of synapses seemed to have no obvious change. The number of OX-42 positive microglia in the Treatment group decreased markedly than that in the Model group, and the grey density of OX-42-positive cells increased significantly. Conclusion LPS can induce inflammatory damages to the brain, but the damage could be antagonized by BN52021. Platelet activating factor receptor antagonist may offer an effective therapy for neurodegeneration diseases.

Effects of Ginkgo biloba extract EGb761 on neural differentiation of stem cells offer new hope for neurological disease treatment

Stem cell transplantation has brought new hope for the treatment of neurological diseases.The key to stem cell therapy lies in inducing the specific differentiation of stem cells into nerve cells.Because the differentiation of stem cells in vitro and in vivo is affected by multiple factors,the final differentiation outcome is strongly associated with the microenvironment in which the stem cells are located.Accordingly,the optimal microenvironment for inducing stem cell differentiation is a hot topic.EGb761 is extracted from the leaves of the Ginkgo biloba tree.It is used worldwide and is becoming one of the focuses of stem cell research.Studies have shown that EGb761 can antagonize oxygen free radicals,stabilize cell membranes,promote neurogenesis and synaptogenesis,increase the level of brain-derived neurotrophic factors,and replicate the environment required during the differentiation of stem cells into nerve cells.This offers the possibility of using EGb761 to induce the differentiation of stem cells,facilitating stem cell transplantation.To provide a comprehensive reference for the future application of EGb761 in stem cell therapy,we reviewed studies investigating the influence of EGb761 on stem cells.These started with the composition and neuropharmacology of EGb761,and eventually led to the finding that EGb761 and some of its important components play important roles in the differentiation of stem cells and the protection of a beneficial microenvironment for stem cell transplantation.

鲍曼不动杆菌通过活化血小板激活因子受体引起感染人支气管上皮细胞的氧化应激和细胞凋亡

目的探讨血小板激活因子受体(PAFR)在鲍曼不动杆菌(A.baumannii)感染人支气管上皮(HBE)细胞过程中的作用。方法 HBE细胞分为对照组、银杏内酯B(GB)处理组、A.baumannii感染组、A.baumannii感染联合GB处理组。使用临床分离的A.baumannii感染HBE细胞,GB处理组分别用1×10~3CFU/m L、1×10~5CFU/m L和1×10~7CFU/m L的A.baumannii感染HBE细胞,A.baumannii感染联合GB处理组则先用10μmol/L GB阻断PAFR活性而后进行1×10~3CFU/m L A.baumannii感染。采用Western blot法检测HBE细胞PAFR、磷酸化的Janus激酶1(p-JAK1)、磷酸化的信号转导子与转录激活子1(p-STAT1)的蛋白水平,使用CCK-8法检测细胞增殖能力,使用超氧化物歧化酶(SOD)和丙二醛(MDA)试剂盒检测各组细胞氧化应激水平;异硫氰酸荧光素标记的膜联素Ⅴ/碘化丙啶(annexinⅤ-FITC/PI)染色结合流式细胞术检测细胞凋亡。结果与对照组相比,A.baumannii感染的HBE细胞中PAFR蛋白水平显著升高,细胞活力显著下降,细胞内MDA水平和细胞凋亡明显增加,p-JAK1和p-STAT1蛋白水平增加。结论 A.baumannii感染的HBE细胞PAFR活化,激活JAK1/STAT1信号通路促进HBE细胞的氧化应激和细胞凋亡。

Pharmacological action and mechanisms of ginkgolide B

Objective To review the recent research progress in pharmacological actions and mechanisms of ginkgolide B. Data sources Information included in this article was identified by searching of PUBMED （1987-2006） online resources using the key terms ＂ginkgolide B＂, ＂platelet activating factor＂, and ＂pharmacological＂. Study selection Mainly original milestone articles and critical reviews written by major pioneer investigators of the field were selected. Results The key issues related to the pharmacological actions and mechanisms of ginkgolide B were summarized. The ginkgolide B possesses a number of beneficial effects such as anti-inflammatory, anti-allergic, antioxidant, and neuroprotective effects. Meantime, their mechaniams were discussed. Conclusions The Ginkgolide B is the most potent antagonist of platelet activating factor （PAF） and exhibits therapeutic action in a variety of diseases mainly by the PAF receptor.

Improving effect of Ginkgolide B on mitochondrial respiration of ischemic neuron after cerebral thrombosis in tree shrews

Background It has been known that platelet activating factor receptors （PAFR） may mediate many acute pathological responses and that PAFR antagonist Ginkgolide B （GB） possesses multiple effects, but the actions of GB on PAFR affinity and mitochondrial respiration in the ischemic neuron were unclear until now. This study explored the possible effects of GB on PAFR and the mitochondrial respiration of the neuron in the ischemic microenvironment. Methods Thrombotic cerebral ischemia in tree shrews was induced by a photochemical reaction; changes in the regional cerebral blood flow （rCBF, using ^99rnTc tracer technique ）, the brain water content （specific gravimetric method）, PAFR （3H-labelled PAF assay）, the respiratory control rate （RCR）, the phosphorus-oxygen （P/O） ratio of mitochondrial respiration （Clark oxygen electrode）, mitochonddal permeability transition （MPT） pore, and the mitochondrial ultrastructure in the ischemic neurons were also observed. Data were compared between the two groups （the ischemia group vs the sham group, and the ischemia group vs the GB group）. Results There were high affinity and low affinity sites for PAFR on the tree threws＇ brain cell membranes. The varying-affinity PAFR binding sites, the respiration state Ⅲ, the state Ⅳ, RCR, the P/O ratio of the mitochondria, and the rCBF all decreased markedly （respectively, P〈0.01 and P〈0.05）, but the water content increased （P〈0.01） in the ischemia group after the application of cerebral thrombosis. In tree shrews treated with GB （5 mg/kg i.v.） 6 hours after photochemical reaction, their PAFR binding sites and respiratory state increased markedly. The rCBF gradually increased and the brain edema ameliorated （P〈0.01） at 24h after cerebral ischemia. There were significant differences between the ischemJa group and sham group （P〈0.01）. In GB treated isolated neurons＇ mitochondria, with or without cerebral ischemia, the energy metabolism of the mitochondria had not been changed. Conclusions The activation of the PAFR may play an important role in the inhibition of the mitochondrial respiration and the induction of neuronal damage after cerebral thrombosis; however, GB possesses neuroprotective effects by improving mitochondrial metabolism.

Pharmacokinetics of the prototype and hydrolyzed carboxylic forms of ginkgolides A, B, and K administered as a ginkgo diterpene lactones meglumine injection in beagle dogs

Ginkgo diterpene lactones meglumine injection(GDLI)is a commercially available product used for neuroprotection.However,the pharmacokinetic properties of the prototypes and hydrolyzed carboxylic forms of the primary components in GDLI,i.e.,ginkgolide A(GA),ginkgolide B(GB),and ginkgolide K(GK),have never been fully evaluated in beagle dogs.In this work,a simple,sensitive,and reliable method based on ultra-fast liquid chromatography-tandem mass spectrometry(UFLC-MS/MS)was developed,and the prototypes and total amounts of GA,GB,and GK were determined in beagle dog plasma.The plasma concentrations of the hydrolyzed carboxylic forms were calculated by subtracting the prototype concentrations from the total lactone concentrations.For the first time,the pharmacokinetics of GA,GB,and GK were fully assessed in three forms,i.e.,the prototypes,the hydrolyzed carboxylic forms,and the total amounts,after intravenous administration of GDLI in beagle dogs.It was shown that ginkgolides primarily existed in the hydrolyzed form in plasma,and the ratio of hydrolysates to prototype forms of GA and GB decreased gradually to a homeostatic ratio.All of the three forms of the three ginkgolides showed linear exposure of AUC to the dosages.GA,GB,and GK showed a constant half-life approximately 2.7,3.4,and 1.2 h,respectively,which were consistent for the forms at three dose levels(0.3,1.0,and 3.0 mg·kg^(-1))and after a consecutive injection of GDLI for 7 days(1.0 mg·kg^(-1)).

Quantum chemical investigation on solvation of Ginkgolides

Great attention has been paid to ginkgolides in modem medical science due to their special medicinal functions. Ginkgolides can be used to treat asthma and tracheitis, etc. Pharmacological studies indicated that ginkgolides are potent antagonists of platelet activating factor (PAF). We have calculated the molecular structures and electronic structures of ginkgolides in hexadecane solution and aqueous solution with AM1 -SM1 method. The results provided a model of hydrophobicity and hydrogen bonds for ginkgolides interacting with PAF.

银杏二萜内酯有效部位(GA,GB,GK)配伍活性研究

研究银杏二萜内酯（ginkgolide）A,B,K（GA,GB,GK）最佳活性配伍。比较化合物GA,GB,GK单用,两两配伍及三者配伍对PAF诱导的血小板聚集活性及大鼠脑缺血再灌注模型（tMCAO）的影响。GA,GB,GK不同配伍均可明显降低血小板活化因子（platelet-activating,PAF）诱导的血小板聚集的最大聚集率,其中三者联用抑制率最高;GA,GB,GK不同配伍对大鼠tMCAO模型的神经功能,脑梗死体积和脑水肿有不同程度的减轻,其作用强弱为三者组合大于两两配伍及单用。GA,GB,GK三者联用抗血小板聚集及改善tMCAO大鼠引起的神经损伤的作用最强。