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Biloba Extract (biloba + extract)
Kinds of Biloba Extract Selected AbstractsGINKGO BILOBA EXTRACT CAUSES DECREASE IN HEART RATE IN AGED SPONTANEOUSLY HYPERTENSIVE RATSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2007Y Kubota SUMMARY 1We previously reported that Ginkgo biloba extract (GBE) improves cardiovascular function in young spontaneously hypertensive rats (SHR). In the present study, changes in the cardiovascular parameters of aged SHR were examined following a 4-week diet of GBE. 2Feeding with GBE significantly decreased the heart rate and blood flow velocity in the tails of aged SHR. The contractile and relaxation responses were unchanged in isolated aortas and mesenteric arteries of aged SHR fed the GBE diet. The GBE diet did not influence the protein levels of endothelial nitric oxide synthase or soluble guanylyl cyclase in the aortas. 3These findings indicate that in aged SHR, the ingestion of GBE may cause bradycardia without a beneficial effect on the vascular relaxation response. Intake of GBE as a supplement in elderly hypertensive patients should be carefully monitored. [source] Acute cognitive effects of standardised Ginkgo biloba extract complexed with phosphatidylserineHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 4 2007D. O. Kennedy Abstract Recent data suggest that the complexation of standardised Ginkgo biloba extract (GBE) with soy-derived phospholipids enhances the bio-availablity of GBE's active components. The current study therefore aimed to assess the comparative cognitive and mood effects of a low dose of GBE and products complexing the same extract with either phosphatidylserine or phosphatidylcholine. The study utilised a placebo-controlled, multi-dose, double-blind, balanced-crossover design. Twenty-eight healthy young participants received 120,mg GBE, 120,mg GBE complexed with phosphatidylserine (VirtivaÔ), 120,mg GBE complexed with phosphatidylcholine and a matching placebo, on separate days 7 days apart. Cognitive performance was assessed using the Cognitive Drug Research (CDR) computerised test battery and Serial Subtraction tasks immediately prior to dosing and at 1, 2.5, 4 and 6,h thereafter. The primary outcome measures were the four aspects of cognitive performance, which have previously been derived by factor analysis of CDR subtests. Levels of terpenoids (bilobalide, ginkgolide A and ginkgolide B) were concomitantly assessed in plasma samples taken pre-dose and at 3 and 6.5,h post-dose. In keeping with previous research utilising the same methodology, 120,mg of GBE was not associated with markedly improved performance on the primary outcomes. However, administration of GBE complexed with phosphatidylserine resulted both in improved secondary memory performance and significantly increased speed of memory task performance across all of the post-dose testing sessions. Enhancement following GBE complexed with phosphatidylcholine was restricted to a modest improvement in secondary memory performance which was restricted to one post-dose time point. All three treatments were associated with improved calmness. There were no significant differences in post-dose levels of terpenoids between the Ginkgo containing treatments, although this latter finding may be attributable to methodological factors. Complexation with phosphatidylserine appears to potentiate the cognitive effects associated with a low dose of GBE. Further research is required to identify whether this effect is due to the complexation of the extracts, their mere combination, or the separate psychopharmacological actions of the two extracts. Copyright © 2007 John Wiley & Sons, Ltd. [source] Vasodilators and Nootropics as Predictors of Dementia and Mortality in the PAQUID CohortJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 3 2007Jean-François Dartigues MD OBJECTIVES: To assess the effects of treatment for memory impairment and the Ginkgo biloba extract (EGb 761) on dementia, mortality, and survival without dementia. DESIGN: Prospective community-based cohort study. SETTING: France. PARTICIPANTS: Three thousand five hundred thirty-four subjects aged 65 and older. MEASUREMENTS: Information on drug consumption was obtained by interview and visual assessment of patients' medicine chests. Active screening of dementia was performed every 2 years over a 13-year period. The independent effects of treatment for memory impairment and the Ginkgo biloba extract on the risks of dementia and death were estimated using Cox proportional hazards models, adjusted for potentially confounding factors (including comorbidities). RESULTS: The initial consumption of Ginkgo biloba did not modify the risk of dementia (relative risk (RR)=1.16, 95% confidence interval (CI)=0.84,1.60), whereas the consumption of other treatments for memory impairment was associated with a higher risk of dementia (RR=1.35, 95% CI=1.11,1.63). Subjects who took Ginkgo biloba had a significantly lower risk of mortality in the long term (RR=0.76, 95% CI=0.62,0.93), even after adjustment for potentially confounding factors. The initial consumption of treatment for memory impairment other than Ginkgo biloba did not modify the risk of mortality. CONCLUSION: These results suggest that treatment with EGb 761 may increase the probability of survival in the elderly population. These findings need to be corroborated and further assessed using randomized, controlled trials. [source] Ginkgo biloba affords dose-dependent protection against 6-hydroxydopamine-induced parkinsonism in rats: neurobehavioural, neurochemical and immunohistochemical evidencesJOURNAL OF NEUROCHEMISTRY, Issue 1 2005Muzamil Ahmad Abstract Ginkgo biloba extract (EGb), a potent antioxidant and monoamine oxidase B (MAO-B) inhibitor, was evaluated for its anti-parkinsonian effects in a 6-hydroxydopamine (6-OHDA) rat model of the disease. Rats were treated with 50, 100, and 150 mg/kg EGb for 3 weeks. On day 21, 2 µL 6-OHDA (10 µg in 0.1% ascorbic acid saline) was injected into the right striatum, while the sham-operated group received 2 µL of vehicle. Three weeks after 6-OHDA injection, rats were tested for rotational behaviour, locomotor activity, and muscular coordination. After 6 weeks, they were killed to estimate the generation of thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) content, to measure activities of glutathione- S -transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD), and to quantify catecholamines, dopamine (DA) D2 receptor binding, and tyrosine hydroxylase-immunoreactive (TH-IR) fibre density. The increase in drug-induced rotations and deficits in locomotor activity and muscular coordination due to 6-OHDA injections were significantly and dose-dependently restored by EGb. The lesion was followed by an increased generation of TBARS and significant depletion of GSH content in substantia nigra, which was gradually restored with EGb treatment. EGb also dose-dependently restored the activities of glutathione-dependent enzymes, catalase, and SOD in striatum, which had reduced significantly by lesioning. A significant decrease in the level of DA and its metabolites and an increase in the number of dopaminergic D2 receptors in striatum were observed after 6-OHDA injection, both of which were significantly recovered following EGb treatment. Finally, all of these results were exhibited by an increase in the density of TH-IR fibers in the ipsilateral substantia nigra of the lesioned group following treatment with EGb; the lesioning had induced almost a complete loss of TH-IR fibers. Considering our behavioural studies, biochemical analysis, and immunohistochemical observation, we conclude that EGb can be used as a therapeutic approach to check the neuronal loss following parkinsonism. [source] Bilobalide in ginkgo biloba extract is a major substance inducing hepatic CYPsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2007Keizo Umegaki In a search for substances related to the marked induction of hepatic cytochrome P450 (CYP) by ginkgo biloba extract (GBE), mice were given either GBE (1000 mg kg,1) or fractions of GBE for 5 days. The content and activity of CYPs were induced markedly by a bilobalide-rich fraction, but not by flavonoid-rich fractions. The level of induction by the bilobalide-rich fraction was almost the same as that induced by the unfractionated GBE, suggesting that bilobalide is largely responsible for the CYPs induction. To confirm these findings, mice were given various doses of bilobalide (10.5, 21 and 42 mg kg,1), or GBE (1000 mg kg,1, containing bilobalide at 42 mg kg,1). Treatment with bilobalide induced CYPs markedly and in a dose-dependent manner, and the level of induction was quite similar between bilobalide (42 mg kg,1) and GBE. Treatment with GBE and with bilobalide greatly induced pentoxyresorufin O-dealkylase activity. These findings indicate that bilobalide is the major substance in GBE that induces hepatic CYPs. [source] Identification of Kaempferol as a Monoamine Oxidase Inhibitor and Potential Neuroprotectant in Extracts of Ginkgo Biloba LeavesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2000B. D. SLOLEY The effects of Ginkgo biloba leaf extract on rat brain or livermonoamine oxidase (MAO)-A and -B activity, biogenic amine concentration in nervous tissue, N -methyl- d -aspartate (NMDA)- and N -(2-chloroethyl)- N -ethyl-2-bromobenzylamine (DSP-4)-induced neurotoxicity and antioxidant activity was investigated to determine the effects of the extract on monoamine catabolism and neuroprotection. Ginkgo biloba leaf extract was shown to produce in-vitro inhibition of rat brain MAO-A and -B. The Ginkgo biloba extract was chromatographed on a reverse-phase HPLC system and two of the components isolated were shown to be MAO inhibitors (MAOIs). These MAOIs were identified by high-resolution mass spectrometry as kaempferol and isorhamnetin. Pure kaempferol and a number of related flavonoids were examined as MAOIs in-vitro. Kaempferol, apigenin and chrysin proved to be potent MAOIs, but produced more pronounced inhibition of MAO-A than MAO-B. IC50 (50% inhibition concentration) values for the ability of these three flavones to inhibit MAO-A were 7 times 10,7, 1 times 10,6 and 2 times 10,6m, respectively. Ginkgo biloba leaf extract and kaempferol were found to have no effect ex-vivo on rat or mouse brain MAO or on concentrations of dopamine, noradrenaline, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid. Kaempferol was shown to protect against NMDA-induced neuronal toxicity in-vitro in rat cortical cultures, but did not prevent DSP-4-induced noradrenergic neurotoxicity in an in-vivo model. Both Ginkgo biloba extract and kaempferol were demonstrated to be antioxidants in a lipid-peroxidation assay. This data indicates that the MAO-inhibiting activity of Ginkgo biloba extract is primarily due to the presence of kaempferol. Ginkgo biloba extract has properties indicative of potential neuroprotective ability. [source] A novel solid phase for selective separation of flavonoid compoundsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2007Yong-qing Xia Abstract A novel straightforward approach to selective separation for flavonoid compounds was reported. The solid phase material was prepared by copolymerization using allyl-bromide-modified chitosan as macromonomer, and ethylene glycol dimethacrylate as cross-linker. The material was evaluated by chromatographic analysis; it exhibited high selectivity separation for quercetin and its structural analogues using different mobile phases. The material could directly trap a specific class of compounds including quercetin and kaempferol from the hydrolyzate of Ginkgo biloba extract. These results demonstrated the possibility of direct extraction of certain constituents from herb using this material. [source] The effects of EGb 761 on lipid peroxide levels and superoxide dismutase activity in sunburnPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 3 2002Mehtap Kilinc Ozkur Background/Purpose: Free oxygen radicals are involved in inflammatory skin reactions induced by ultraviolet B (UVB). In this study, the effect of a herbal antioxidant Ginkgo biloba extract (EGb 761) was investigated in UVB irradiated mice skin. Methods: The study was carried out on four groups of mice (n = 6 in each group). The first group was a control group (G1). The second group (G2) was only exposed to acute UVB irradiation. The third group (G3) received 100 mg/kg/day of EGb 761 orally for 5 days before UVB irradiation and the fourth group (G4) was given only a single dose of EGb 761 immediately after UVB irradiation. Eighteen hours after exposing to UVB, lipid peroxide levels, and superoxide dismutase (SOD) activities were studied and UVB damage was evaluated histopathologically according to ,sun-burn cell count'. Results: The SOD activities and Malondialdehyde (MDA) levels in G2, G3 and G4 were found to be decreased significantly when compared with G1 (P < 0.05). The SOD activities of G3 and G4 were higher when compared with G2 (P < 0.05). The number of sunburn cells (SBCs) was the highest in G2. Conclusions: Our results suggest that EGb 761 may have an important effect, both as a protective and therapeutic agent, in sunburn after UVB irradiation. [source] Ginkgo biloba extract improves coronary artery circulation in patients with coronary artery disease: contribution of plasma nitric oxide and endothelin-1PHYTOTHERAPY RESEARCH, Issue 6 2008Yu-Zhou Wu Abstract In patients with coronary artery disease (CAD), coronary blood flow is usually impaired due to imbalanced vasoactive substances such as nitric oxide (NO) and endothelin-1 (ET-1). The study was designed to test the effects of Ginkgo biloba extract (GBE) on the distal left anterior descending coronary artery (LAD) blood flow and plasma NO and ET-1 levels. Eighty CAD patients were randomly assigned to GBE (n = 42) and control (n = 38) groups. The LAD blood flow was assessed non-invasively using Doppler echocardiography at baseline and after 2 weeks. GBE treatment demonstrated a significant improvement in maximal diastolic peak velocity (MDPV), maximal systolic peak velocity (MSPV) and diastolic time velocity integral (DTVI) compared with controls (14.61 ± 4.51% vs 0.67 ± 2.66%, 9.03 ± 4.81% vs 0.34 ± 2.67% and 14.69 ± 5.08% vs 0.68 ± 3.00%, respectively, p < 0.01). NO was increased by 12.42% (p < 0.01), whereas ET-1 was decreased by 5.82% (p < 0.01). The NO/ET-1 ratio was increased by 19.47% (p < 0.01). A linear correlation was confirmed between the percentage change in LAD blood flow and in NO, ET-1 or NO/ET-1 ratio following GBE treatment. The results suggest that GBE treatment in CAD patients led to an increase of LAD blood flow, which might at least be related partly to the restoration of the delicate equilibrium between NO and ET-1. Copyright © 2008 John Wiley & Sons, Ltd. [source] Protective effects of Ginkgo biloba extract against mercury(II)-induced cardiovascular oxidative damage in ratsPHYTOTHERAPY RESEARCH, Issue 1 2007Tugba Tunali-Akbay Abstract This study was designed to determine the possible protective effect of Ginkgo biloba extract (EGb) against Hg II-induced oxidative damage and also thromboplastic activity in the aorta and heart tissues. Wistar albino rats of either sex (200,250 g) were divided into four groups. Rats were injected intraperitoneally with (1) control (C) group: 0.9% NaCl; (2) EGb group: Ginkgo biloba extract (Abdi Ibrahim Pharmaceutical Company, Istanbul, Turkey) at a dose of 50 mg/kg/day; (3) Hg group: a single dose of 5 mg/kg mercuric chloride (HgCl2); and (4) Hg + EGb group: First day EGb at a dose of 50 mg/kg/day, i.p., 1 hour after HgCl2 (5 mg/kg) injection; following four days EGb at a dose 50 mg/kg/day, i.p. After decapitation of the rats, trunk blood was obtained and serum tumor necrosis factor- , (TNF- ,), lactate dehydrogenase (LDH) activity, and malondialdehyde (MDA) and glutathione (GSH) levels were analysed. In the aorta and heart tissues total protein, MDA, GSH levels and thromboplastic activity were determined. The results revealed that HgCl2 induced oxidative tissue damage, as evidenced by increases in MDA levels and decreased GSH levels both in serum and tissue samples. Thromboplastic activity was increased significantly following Hg administration, which verifies the cardiotoxic effects of HgCl2. Serum LDH and TNF- , were elevated in the Hg group compared with the control group. Since EGb treatment reversed these responses, it seems likely that Ginkgo biloba extract can protect the cardiovascular tissues against HgCl2 -induced oxidative damage. Copyright © 2006 John Wiley & Sons, Ltd. [source] Induction of glutathione synthesis in human keratinocytes by Ginkgo biloba extract (EGb761)BIOFACTORS, Issue 1 2001Gerald Rimbach Abstract The objective of the present study was to characterize the action of Ginkgo biloba extract (EGb761) and its sub-fractions on glutathione homeostasis in a human keratinocyte cell culture model. Cells were incubated with EGb761, its purified flavonoid (quercetin, kaempferol, rutin) or terpenoids (gingkolides A, B, C, J, bilobalide) constituents or the vehicle for up to 72 hours. Incubation of keratinocytes with the purified flavonoids or terpenoids did not affect cellular GSH levels. However, EGb761 treatment (up to 200 ,g/ml) resulted in a dose-dependent increase of cellular GSH. Western blot analysis of extracts from cells treated with EGb761 revealed increased levels of the catalytic subunit of ,glutamylcysteinyl synthetase (,GCS), the rate-limiting enzyme in GSH synthesis. The abundance of mRNA for the catalytic subunit (assayed by RT-PCR) was also increased by the treatment with EGb761. Increased levels of cellular GSH by EGb761 were also observed in other cell lines including those from human bladder and liver as well as in murine macrophages indicating that the induction of ,GCS mRNA, protein and GSH may be an ubiquitous effect of EGb761 in mammalian cells. [source] The effect of ginkgo biloba on the rat retinal ganglion cell survival in the optic nerve crush modelACTA OPHTHALMOLOGICA, Issue 5 2010Ke Ma Abstract. Purpose:, To investigate the effect of ginkgo biloba on the retinal ganglion cell survival in a rat optic nerve crush model. Methods:, Twenty-four Sprague,Dawley rats were divided randomly into a study group of 12 animals receiving intraperitoneal injections of ginkgo biloba and a control group of 12 animals receiving intraperitoneal saline injections. All injections were performed 1 hr before the optic nerve crush and daily afterwards. For each animal, the right optic nerve was crushed closely behind the globe for 60 seconds using a microclip with 40 g power. The left optic nerve was kept intact. At 23 days after the optic nerve crush, the retinal ganglion cells were labelled retrogradely by injecting 3% fluorogold into both sides of the superior colliculus of the brain. At 4 weeks after the optic nerve crush, the animals were killed. Photographs taken from retinal flat mounts were assessed for the number and density of the retinal ganglion cells. Results:, The survival rate, defined as the ratio of the retinal ganglion cell density in the right eye with the optic nerve crush divided by the retinal ganglion cell density in left eye without an optic nerve trauma, was significantly (p = 0.035) higher in the study group with ginkgo biloba than in the control group (60.0 ± 6.0% versus 53.5 ± 8.0%). Conclusion:, The results suggest that intraperitoneal injections of a ginkgo biloba extract given prior to and daily after an experimental and standardized optic nerve crush in rats were associated with a higher survival rate of retinal ganglion cells. [source] Influence of Ginkgo biloba on ocular blood flowACTA OPHTHALMOLOGICA, Issue 4 2007Barbara Wimpissinger Abstract. Purpose:, To investigate the effect of Ginkgo biloba extract (EGb761) on ocular blood flow. Methods:, This randomized, double-masked, placebo-controlled, two-way crossover study included 15 healthy male volunteers. Measurements were taken with laser Doppler flowmetry, laser Doppler velocimetry, a retinal vessel analyser, laser interferometry and applanation tonometry, before and up to 3 hours after oral intake of 240 mg EGb761. Results:, At baseline, no significant differences in ocular and systemic haemodynamic parameters were observed between the two study days. Ginkgo biloba significantly decreased retinal venous diameters (p < 0.05 versus baseline), but there was no significant difference between the two groups. Blood pressure, retinal arterial and venous diameters, choroidal blood flow, fundus pulsation amplitude, intraocular pressure and retinal blood flow remained unchanged in both groups and did not differ between groups. Optic nerve head blood flow significantly increased in response to Ginkgo biloba (p < 0.002 versus baseline), but this effect was not significant compared with that of placebo. Conclusions:, The results of this study indicate that a single administration of Ginkgo biloba does not influence ocular blood flow to a relevant degree. Whether the drug may influence ocular blood flow in patients with ocular vascular disease after longterm treatment remains to be investigated in a randomized, placebo-controlled clinical trial. [source] GINKGO BILOBA EXTRACT CAUSES DECREASE IN HEART RATE IN AGED SPONTANEOUSLY HYPERTENSIVE RATSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2007Y Kubota SUMMARY 1We previously reported that Ginkgo biloba extract (GBE) improves cardiovascular function in young spontaneously hypertensive rats (SHR). In the present study, changes in the cardiovascular parameters of aged SHR were examined following a 4-week diet of GBE. 2Feeding with GBE significantly decreased the heart rate and blood flow velocity in the tails of aged SHR. The contractile and relaxation responses were unchanged in isolated aortas and mesenteric arteries of aged SHR fed the GBE diet. The GBE diet did not influence the protein levels of endothelial nitric oxide synthase or soluble guanylyl cyclase in the aortas. 3These findings indicate that in aged SHR, the ingestion of GBE may cause bradycardia without a beneficial effect on the vascular relaxation response. Intake of GBE as a supplement in elderly hypertensive patients should be carefully monitored. [source] Ginkgo biloba extracts and cancer: a research area in its infancyFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 4 2003Francis V. DeFeudis Abstract Recent studies conducted with various molecular, cellular and whole animal models have revealed that leaf extracts of Ginkgo biloba may have anticancer (chemopreventive) properties that are related to their antioxidant, anti-angiogenic and gene-regulatory actions. The antioxidant and associated anti-lipoperoxidative effects of Ginkgo extracts appear to involve both their flavonoid and terpenoid constituents. The anti-angiogenic activity of the extracts may involve their antioxidant activity and their ability to inhibit both inducible and endothelial forms of nitric oxide synthase. With regard to gene expression, a Ginkgo extract and one of its terpenoid constituents, ginkgolide B, inhibited the proliferation of a highly aggressive human breast cancer cell line and xenografts of this cell line in nude mice. cDNA microarray analyses have shown that exposure of human breast cancer cells to a Ginkgo extract altered the expression of genes that are involved in the regulation of cell proliferation, cell differentiation or apoptosis, and that exposure of human bladder cancer cells to a Ginkgo extract produced an adaptive transcriptional response that augments antioxidant status and inhibits DNA damage. In humans, Ginkgo extracts inhibit the formation of radiation-induced (chromosome-damaging) clastogenic factors and ultraviolet light-induced oxidative stress , effects that may also be associated with anticancer activity. Flavonoid and terpenoid constituents of Ginkgo extracts may act in a complementary manner to inhibit several carcinogenesis-related processes, and therefore the total extracts may be required for producing optimal effects. [source] Ginkgo biloba: no robust effect on cognitive abilities or mood in healthy young or older adultsHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 1 2006Nicholas R. Burns Abstract Ginkgo biloba extracts are commonly used to prevent or treat memory problems but evidence on the efficacy of ginkgo is equivocal. In any case, the psychological locus of ginkgo's effects is unknown. A 12-week, double-blind, placebo-controlled study assessed effects of ginkgo (120,mg per day) on a wide range of cognitive abilities, executive function, attention and mood in 93 healthy older adults (55,79 years) and in 104 young adults (18,43 years). For the older adult sample, longer-term memory assessed by associational learning tasks showed improvement with ginkgo (d,=,0.52, p,=,0.04). There was no statistically significant difference on any other measure. For the young adult group no measure showed statistically significant effects of ginkgo enhancement. There were no side effects unequivocally attributable to treatment with ginkgo and those reported by participants in the ginkgo groups were mild and similar to those reported elsewhere. Copyright © 2005 John Wiley & Sons, Ltd. [source] | |||||||||||||