Ginkgolide B

The leaves of Ginkgo biloba L.

Ginkgolide B, an important active terpenoid from Ginkgo biloba leaves, is reported to increase cell viability and decrease cell apoptosis. IC50 value: Target: In vitro: Ginkgolide B (0.2 or 0.4 μg/ml) was added to the culture medium in vitro led to increases in cell viability and decreases in the number of hippocampal cells undergoing AAPH-induced apoptosis [1]. Ginkgolide B caused a dose-related protection against dysrhythmias; the antiarrhythmic effect of ginkgolide B was comparable to that of diltiazem and superior to the activity of metoprolol. Ginkgolide B can presumably prevent the re-entry mechanism involved in the development of ischemia-induced rhythm disturbances [2]. In vivo: Oral administration of ginkgolide B (2 mg/kg/day, p.o.) caused a significant increase in cell viability and a highly significant decrease in the numbers of both spontaneously occurring and AAPH-induced apoptoses.

References:
[1]. Jean R. Rapin, et al. In vitro and in vivo effects of an extract of Ginkgo biloba (EGb 761), ginkgolide B, and bilobalide on apoptosis in primary cultures of rat hippocampal neurons. Drug Development Research, 1998, 45 (1):1-43 [2]. Matyas Koltai, et al. Ginkgolide B protects isolated hearts against arrhythmias induced by ischemia but not reperfusion. European Journal of Pharmacology, 1989, 164 (2): 293-302

Inhibitory effects of the platelet-activating factor receptor antagonists, CV-3988 and Ginkgolide B, on alkali burn-induced corneal neovascularization.[Pubmed:24754407]

Cutan Ocul Toxicol. 2015 Mar;34(1):53-60.

PURPOSE: Platelet-activating factor (PAF) has been found in various ocular tissues; the activity of PAF depends on the binding to its specific receptor, PAF-receptor. We investigated the therapeutic effects of PAF-receptor antagonists (CV-3988 and Ginkgolide B) on alkali burn-induced corneal neovascularization (CNV). METHODS: CNV was induced by applying a 0.2 N sodium hydroxide (3 microl, NaOH) solution directly on mice corneas. CV-3988 (1 mM/10 microl) and Ginkgolide B (1 mM/10 microl) were administered topically on the corneas three times daily for three consecutive days. CNV was evaluated under a slit-lamp microscope. Corneas were processed for histological, immunohistochemical and reverse transcription polymerase chain reaction analysis. Human umbilical vein endothelial cells were used for the migration and tube formation assay. RESULTS: Application of CV-3988 and Ginkgolide B inhibited CNV caused by alkali burn. CV-3988 and Ginkgolide B attenuated the expression of PAF-receptor mRNA. Alkali injury induced a massively increased intraocular mRNA expression of an angiogenic factor in cornea tissues, whereas these increments were attenuated by the application of CV-3988 and Ginkgolide B. CONCLUSIONS: CV-3988 and Ginkgolide B reversed opacity and neovascularization in alkali burn-induced corneas. Our findings suggest that CV-3988 and Ginkgolide B may be therapeutically useful in the treatment of CNV and inflammation.

Ginkgolide B inhibits platelet release by blocking Syk and p38 MAPK phosphorylation in thrombin-stimulated platelets.[Pubmed:25223809]

Thromb Res. 2014 Nov;134(5):1066-73.

INTRODUCTION: Atherosclerosis is a chronic vascular inflammatory disease. Platelets play a critic role in the initiation of vascular inflammation in atherosclerosis. In the present study, we investigated the effects of Ginkgolide B on the inhibition of platelet release and the potential mechanisms. METHODS: Experiments were performed in freshly human platelets. Platelet aggregation and ATP release were measured with a Lumi-aggregometer. Thrombin (0.5 U/ml) was used to induce platelet activation. Protein expression and phosphorylation was examined by Western blotting. RESULTS: The results showed that Ginkgolide B significantly suppressed ATP release by 50.8% in thrombin-activated platelets. Ginkgolide B completely abolished the expression of platelet factor 4 (PF4) and CD40 Ligand (CD40L). Moreover, Ginkgolide B fully attenuated the phosphorylation of Syk and p38MAPK. Similarly, R788 (a syk inhibitor) and SB203580 (a p38 MAPK inhibitor) inhibited the expression PF4 and CD40L, respectively. Furthermore, the combination of low concentrations of Ginkgolide B and R788 or SB203580 has synergistic inhibition on the expression of PF4 and CD40L. Ginkgolide B partially reduced calcium efflux by 52.7% in thrombin-stimulated platelets. CONCLUSION: Ginkgolide B potently inhibited the expression of PF4 and CD40L in thrombin-activated platelets. Ginkgolide B partially decreased ATP release and Ca(2+) efflux. The mechanism might be associated with the inhibition of Syk and p38 MAPK phosphorylation. These results demonstrated that Ginkgolide B might be a promising drug on inhibiting platelet function and reducing inflammation in atherosclerosis.

Ginkgolide B induces apoptosis and developmental injury in mouse embryonic stem cells and blastocysts.[Pubmed:16877372]

Hum Reprod. 2006 Nov;21(11):2985-95.

BACKGROUND: Ginkgolide B, the major active component of Ginkgo biloba extracts, can both stimulate and inhibit apoptotic signalling. We previously showed that ginkgolide treatment of mouse blastocysts induces apoptosis, decreases cell numbers, retards early post-implantation blastocyst development and increases early-stage blastocyst death. Here, we report more detailed examinations of the cytotoxic effects of Ginkgolide B on mouse embryonic stem cells (ESCs) and blastocysts and their subsequent development in vitro and in vivo. METHODS AND RESULTS: Using cell culture assay model, we revealed in our results that Ginkgolide B treatment of ESCs (ESC-B5) induced apoptosis via reactive oxygen species (ROS) generation, c-Jun N-terminal kinase (JNK) activation, loss of mitochondrial membrane potential (MMP) and the activation of caspase-3. Furthermore, an in vitro assay model showed that Ginkgolide B treatment inhibited cell proliferation and growth in mouse blastocysts. Finally, an in vivo model showed that treatment with 10 microM Ginkgolide B caused resorption of post-implantation blastocysts and fetal weight loss. CONCLUSIONS: Our results reveal for the first time that Ginkgolide B retards the proliferation and development of mouse ESCs and blastocysts in vitro and causes developmental injury in vivo.

Ginkgolide B reduces LOX-1 expression by inhibiting Akt phosphorylation and increasing Sirt1 expression in oxidized LDL-stimulated human umbilical vein endothelial cells.[Pubmed:24069345]

PLoS One. 2013 Sep 17;8(9):e74769.

Oxidized low-density lipoprotein (ox-LDL) is an important risk factor in the development of atherosclerosis. LOX-1, a lectin-like receptor for ox-LDL, is present primarily on endothelial cells and upregulated by ox-LDL, tumor necrosis factor a, shear stress, and cytokines in atherosclerosis. Recent studies demonstrated that Ginkgolide B, a platelet-activating factor receptor antagonist, has antiinflammatory and antioxidant effects on endothelial and nerve cells. The present study investigated the effects of Ginkgolide B on LOX-1 expression and the possible mechanism of action. Our results showed that Ginkgolide B inhibited LOX-1 and intercellular cell adhesion molecule-1 (ICAM-1) expression in ox-LDL-stimulated endothelial cells through a mechanism associated with the attenuation of Akt activation. Similar data were obtained by silencing Akt and LY294002. We also evaluated Sirt1 and nuclear factor erythroid 2-related factor 2 (Nrf2) expression. These molecules play a protective role in endothelial cell injury. The results showed that Ginkgolide B increased Sirt1 expression in ox-LDL-treated cells. The inhibitory effects of Ginkgolide B on LOX-1 and ICAM-1 expression were reduced in Sirt1 siRNA-transfected cells. Nrf2 expression was increased in ox-LDL-treated cells, and Ginkgolide B downregulated Nrf2 expression. These results suggest that Ginkgolide B reduces Nrf2 expression by inhibiting LOX-1 expression, consequently reducing oxidative stress injury in ox-LDL-stimulated cells. Altogether, these results indicate that the protective effect of Ginkgolide B on endothelial cells may be attributable to a decrease in LOX-1 expression and an increase in Sirt1 expression in ox-LDL-stimulated endothelial cells, the mechanism of which is linked to the inhibition of Akt activation. Ginkgolide B may be a multiple-target drug that exerts protective effects in ox-LDL-treated human umbilical vein endothelial cells.

Ginkgolide B increases hydrogen sulfide and protects against endothelial dysfunction in diabetic rats.[Pubmed:25727037]

Croat Med J. 2015 Feb;56(1):4-13.

AIM: To evaluate the effect of Ginkgolide B treatment on vascular endothelial function in diabetic rats. METHODS: The study included four groups with 15 male Sprague-Dawley rats: control group; control group treated with Ginkgolide B; diabetic group; and diabetic treated with Ginkgolide B. The activity of superoxide dismutase (SOD), malondialdehyde content, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, and glutathione peroxidase 1 (GPX1) protein expression were determined in aortic tissues. Vasoconstriction to phenylephrine (PHE) and vasorelaxation to acetylcholine (Ach) and sodium nitroprusside (SNP) were assessed in aortic rings. Nitric oxide (NO) and hydrogen sulfide (H2S) were measured, as well as cystathionine gamma lyase (CSE) and cystathionine beta synthetase (CBS) protein expression, and endothelial nitric oxide synthase (eNOS) activity. RESULTS: Diabetes significantly impaired PHE-induced vasoconstriction and Ach-induced vasorelaxation (P<0.001), reduced NO bioavailability and H2S production (P<0.001), SOD activity, and GPX1 protein expression (P<0.001), and increased malondialdehyde content and NADPH oxidase subunits, and CSE and CBS protein expression (P<0.001). Ginkgolide B treatment improved PHE vasoconstriction and Ach vasorelaxation (P<0.001), restored SOD (P=0.005) and eNOS (P<0.001) activities, H2S production (P=0.044) and decreased malondialdehyde content (P=0.014). Vasorelaxation to SNP was not signi fi cantly different in control and diabetic rats with or without Ginkgolide B treatment. Besides, Ginkgolide B increased GPX1 protein expression and reduced NADPH oxidase subunits, CBS and CSE protein expression. CONCLUSION: Ginkgolide B alleviates endothelial dysfunction by reducing oxidative stress and elevating NO bioavailability and H2S production in diabetic rats.

Ginkgolide B protects isolated hearts against arrhythmias induced by ischemia but not reperfusion.[Pubmed:2759177]

Eur J Pharmacol. 1989 May 19;164(2):293-302.

The effect of Ginkgolide B (BN 52021), a specific platelet-activating factor (PAF) antagonist, applied in doses of 1.5, 3.0, 6.0 X 10(-5) and 1.2 X 10(-4) mol/l, in comparison to that of metoprolol (10(-5) mol/l) and diltiazem (10(-7) mol/l), two widely used antiarrhythmic agents, on ischemia- and reperfusion-induced arrhythmias and heart functions, such as heart rate (HR), coronary flow (CF), aortic flow (AF), left ventricular developed pressure (LVDP), its first derivative (LVdp/dtmax), and left ventricular end-diastolic pressure (LVEDP) in isolated working rat hearts was examined. BN 52021 caused a dose-related protection against dysrhythmias, such as ventricular fibrillation, ventricular tachycardia, and premature ventricular beats induced by ischemia (30 min ligation of the left anterior descending coronary artery). The antiarrhythmic effect of BN 52021 given in a dose of 6.0 X 10(-5) mol/l was comparable to that of diltiazem and superior to the activity of metoprolol. None of the drugs influenced reperfusion-induced rhythm disturbances. BN 52021 did not alter heart functions, while metoprolol reduced (LVEDP only, and diltiazem increased CF, decreased AF, LVDP, and LVdp/dtmax during regional ischemia, indicating a negative inotropic effect. The antiarrhythmic effect of BN 52021 appears to be related to an antagonism of an increase in slow calcium influx induced by PAF in myocardial cells. Similarly to the mechanism of action of established antiarrhythmic drugs, BN 52021 can presumably prevent the re-entry mechanism involved in the development of ischemia-induced rhythm disturbances.

Inhibition of NF-kappaB activation is associated with anti-inflammatory and anti-apoptotic effects of Ginkgolide B in a mouse model of cerebral ischemia/reperfusion injury.[Pubmed:22850444]

Eur J Pharm Sci. 2012 Nov 20;47(4):652-60.

Ginkgolide B (GB) has potent neuroprotective effects against ischemia-induced brain injury in vivo and in vitro. However, the underlying mechanisms of GB's neuroprotection remain poorly understood. Excessive inflammation and apoptosis contribute to the pathogenesis of ischemic brain damage, and NF-kappaB is considered to be a key player in these processes. In the present study, we examined the detailed mechanisms underlying the inhibitory effects of GB on inflammatory and apoptotic responses induced by focal cerebral ischemia/reperfusion (I/R). Transient middle cerebral artery occlusion (tMCAO) model was produced by using an intraluminal filament technique in mice. GB (10, 20 and 40 mg/kg) was administered intravenously (i.v.) 2h after MCAO. The results demonstrated that MCAO-induced cerebral injury was associated with an upregulation of p-IKK, p-IkappaB-alpha and degradation of IkappaB-alpha, indicating of NF-kappaB activation. Meanwhile activation of microglial and increases in levels of TNF-alpha, IL-1beta and iNOS were observed. Furthermore upregulation of the expression of NF-kappaB target gene p53 and p53 downstream gene Bax, but downregulation of Bcl-2 and activation of caspase-3 were found. GB treatment showed marked reduction in infarction volume, brain edema and neurological deficits. GB also inhibited I/R induced NF-kappaB, microglia activation and production of pro-inflammatory cytokines. We also demonstrated that GB reduced Bax protein levels and increased Bcl-2 protein levels in the post-ischemic brains. These results suggest that GB's neuroprotection is attributable to its anti-inflammatory and anti-apoptotic effect through inhibition of NF-kappaB.

The CNS effects of Ginkgo biloba extracts and ginkgolide B.[Pubmed:12169298]

Prog Neurobiol. 2002 Jun;67(3):235-57.

Ginkgo biloba extracts such as EGb-761 have been suggested to have a multitude of beneficial effects on CNS function, from enhancing cognitive function in dementia to facilitating recovery from acute forms of neural damage such as hypoxia/ischemia. Ginkgolide B, one of the major components of EGb-761, is a potent platelet-activating factor (PAF) receptor antagonist, which is also regarded as having neuroprotective effects in the CNS. The aim of this review is to summarise and to critically evaluate the current evidence on the CNS effects of EGb-761 and Ginkgolide B, with particular emphasis on the data relating to their neuroprotective effects.

Inhibition by BN 52021 (ginkgolide B) of the binding of [3H]-platelet-activating factor to human neutrophil granulocytes.[Pubmed:2825685]

Biochem Biophys Res Commun. 1987 Nov 13;148(3):1412-7.

The inhibitory effect of BN 52021, a specific antagonist of platelet-activating factor (PAF) on PAF-induced activation of human polymorphonuclear granulocytes (PMNL) and on the binding of [3H]-PAF to neutrophils were examined. BN 52021 over the range of 10(-9)-10(-4) M inhibited PAF-induced degranulation and superoxide production of PMNLs in a dose-dependent manner with Kd values of 0.6 +/- 0.1 x 10(-6) M and 0.4 +/- 0.1 x 10(-6) M, respectively. BN 52021 (up to 1 mM) did not show any agonistic activity and it did not affect neutrophil responses to N-formyl-methionyl-leucyl-phenylalanine or leukotriene B4. The Ki value of BN 52021 for the specific binding of [3H]-PAF to neutrophils was 1.3 +/- 0.5 x 10(-6) M versus a Ki of 1.1 +/- 0.3 x 10(-7) M for PAF itself. BN 52021 did not affect metabolism of PAF by PMNL. These studies indicate that BN 52021 inhibits neutrophil responses to PAF by inhibiting binding of PAF to its specific PMNL receptor.

Interference of BN 52021 (ginkgolide B) with the bronchopulmonary effects of PAF-acether in the guinea-pig.[Pubmed:3019727]

Eur J Pharmacol. 1986 Aug 7;127(1-2):83-95.

The interaction between the Ginkgolide BN 52021 and the effects of PAF-acether on the bronchopulmonary system of the guinea-pig was studied. In pentobarbitone or ethyl carbamate-anaesthetized animals, BN 52021 (1 mg/kg i.v. or 10 mg/kg p.o.) inhibited bronchoconstriction, the hematocrit increase and the accompanying thrombopenia and leukopenia induced by PAF-acether (33-100 ng/kg) and failed to block the bronchoconstriction produced by collagen, arachidonic acid and the tripeptide formyl-Met-Leu-Phe (FMLP). BN 52021, 3 mg/kg, reduced the bronchoconstriction induced by aerosolized PAF-acether. BN 52021, 300 microM, also inhibited the superoxide production by PAF-acether-stimulated alveolar macrophages and failed to reduce the same effects when triggered by FMLP (0.01-1 microM). BN 52021 blocked the formation of thromboxane-triggered by PAF-acether (100 ng) injected into perfused lung, under conditions where the effects of arachidonic acid where not modified. Finally, pretreatment of parenchyma lung strips with BN 52021 (100 microM) partially inhibited the contraction induced by PAF-acether (0.1 microM) and suppressed the accompanying release of thromboxane. BN 52021 is a selective antagonist of the effects of PAF-acether on the bronchopulmonary system and on circulating blood cells of the guinea-pig.

Ginkgolide B (BN-52021), an important active terpenoid from Ginkgo biloba leaves, is reported to increase cell viability and decrease cell apoptosis.

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