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At least 19 recordsLinked to original sources

PubMed2001

Evaluation of the allergenic potential of Ginkgo biloba extracts.

Ginkgo biloba extracts are used for the treatment of central and peripheral malperfusion, cerebral insufficiency and dementia. Between 1996 and 1998, several patients in Austria who had received parenteral Ginkgo extracts were reported to have developed allergy-like symptoms. The aim of the present study was to determine whether Ginkgo biloba extracts contain type I allergens. The protein content of Ginkgo biloba extracts was determined by BCA protein determination and SDS-PAGE. We used sera from 95 polysensitized plant-allergic patients (the sera contained IgE antibodies against most plant allergens), and rabbit antisera raised against defined recombinant plant allergens. The presence of allergens in Ginkgo extracts was determined by dot-blotting and Wester blot. Neither rabbit antisera nor IgE antibodies of patients reacted to the Ginkgo extracts. In addition, it was shown that prick testing of the skin could be conveniently used to study Gingko extracts for allergenic activity. In conclusion, no evidence for the presence of type I allergens in Ginkgo extracts was found. We recommend serological and/or skin testing to exclude sensitisation to components of Ginkgo biloba extracts.

Adult↗

PubMed2004

Estrogenic activities of Ginkgo biloba extracts.

Ginkgo biloba extracts (GBE) are extracted from the leaves of Ginkgo biloba tree. GBE contains 24% of phytoestrogens, which is kaempferol, quercetin, and isorhamnetin. It has been reported that phytoestrogens could be a part of SERMs (Selective estrogen receptor modulators) and possibly the alternative HRT (Hormone replacement therapy) for postmenopausal women. The goal of this study was to investigate the potencies of GBE and its major components (quercetin, kaempferol, isorhamnetin) for estrogenic effect, which confirms the capacity as an alternative HRP. It was found that GBE and its major components exerted a dual action on ER-alpha and ER-beta in competitive binding assay. The binding affinity of these chemicals to ER-beta was higher than to ER-alpha. In the E-screen assay, these chemicals induced cell proliferation in ER-positive MCF-7 cell, but not in ER-negative MDA-MB-231 cells. The cell proliferation induced by these chemicals was blocked by tamoxifen. Also, GBE and its major components induced pS2 and PR (progesterone receptor) transcription in MCF-7 cells. Therefore these results indicated that GBE and its major components had the weak estrogenic activities through the estrogen response pathway by an interaction with the ER. In conclusion, we provided the evidence of potential estrogenic activities of GBE, which could be useful as an alternative HRP. However, further studies are required to assess the physiological significance of GBE in animals and humans.

Binding, Competitive↗

PubMed1986

[Preparation and definition of Ginkgo biloba extract].

Ginkgo biloba extract is a well-defined and complex product prepared from green leaves of Ginkgo biloba. The leaves are harvested from trees growing in plantations in South Corea, Japan and France. The mode of culture, harvesting and extraction are perfectly standardized and controlled. Analysis of Ginkgo biloba extract makes it possible to confirm that undesirable substances have been eliminated and to measure the amount of active principles. The extract contains flavonoid substances, such as the Ginkgo-flavone glycosides and terponoids which are characteristic of Ginkgo and have a unique structure (ginkgolides, bilobalide).

Chemical Phenomena↗

PubMed2003

Neuroprotective effects of Ginkgo biloba extract.

Ginkgo biloba extract has been therapeutically used for several decades to increase peripheral and cerebral blood flow as well as for the treatment of dementia. The extract contains multiple compounds such as flavonoids and terpenoids that are thought to contribute to its neuroprotective and vasotropic effects. In this review, we summarize the experimental results on the mechanism of neuroprotection induced by standardized extract of Ginkgo biloba leaves (EGb 761) and its constituents. The effects described mostly in animals include those on cerebral blood flow, neurotransmitter systems, cellular redox state and nitric oxide level. Furthermore, we discuss the current status of clinical trials as well as undesired side effects of EGb 761.

Animals↗

PubMed1989

Superoxide anion scavenging effect and superoxide dismutase activity of Ginkgo biloba extract.

Ginkgo biloba extract is known to be efficient in diseases associated with free radical generation. The purpose of this work was to study, under in vitro conditions, the action of Ginkgo biloba extract (Gbe) against superoxide anion (O2-.), which is directly or indirectly implicated in cell damage. Gbe appears to have both an O2-. scavenging effect and also a superoxide dismutase activity. Its antiradical effect was demonstrated by low temperature electron spin resonance and in a non-enzymatic system (phenazine methosulfate-NADH), and its enzymatic activity was shown by polarographic determination.

Animals↗

PubMedDate not supplied

Induction of superoxide dismutase and catalase activity in different rat tissues and protection from UVB irradiation after topical application of Ginkgo biloba extracts.

Ginkgo biloba extract (GBE) prepared from the leaves of Ginkgo biloba with 50% diluted alcohol was found to locally induce superoxide dismutase (SOD) and catalase (CAT) enzyme activity in epidermis after topical application, and also to systemically increase the activity of both enzymes in the liver, heart and kidney of Sprague Dawley rats. Skin pretreated with 50% diluted alcohol-extracted liquid formulation was protected from exacerbation of UVB damage. Changes in the lipid structure of the skin of rats determined by ATR/FT-IR spectroscopy demonstrated penetration of active components from GBE dosage formulations.

Administration, Topical↗

PubMed1986

[Neuromediator changes during cerebral aging. The effect of Ginkgo biloba extract].

Ginkgo biloba extract exerts a specific effect on the noradrenergic system and on beta-receptors. No variation was found in alpha 2-receptors and serotonin uptake. These findings provide the first evidence of central effects of a drug acting on cerebral ageing, connected specifically to reactivation of the noradrenergic system in the cerebral cortex.

Aging↗

PubMed2006

A new capillary zone electrophoresis method for the analysis of Ginkgo biloba extracts and Ginkgo biloba pharmaceutical products.

Ginkgo biloba, traditional Chinese medicine is now generally accepted. Separation and determination of active components in G. biloba is important for the product quality control. Therefore, the development of an effective and reliable separation method is important. In this work, a new capillary electrophoretic (CZE) method for separation of the G. biloba leaf extracts components was developed and optimized by the use of experimental design and artificial neural network (ANN). Under best separation conditions, in gamma-CD-modified buffer, the separation was reached within 10 min (36 mM borate BGE, pH 9.2, 1 mM gamma-CD), while the hydrodynamic mode for sample injection (2 s) and UV detection at 270 nm were applied. The method developed was validated and applied for analysis of various extracts and G. biloba products.

Cyclodextrins↗

PubMed1992

[Superoxide dismutase activity of Ginkgo biloba extract].

The Ginkgo biloba extract is obtained from green leaves of the Ginkgo biloba tree. Preparations with this active substance are among others used for the treatment of disturbances of the cerebral function and arteriosclerotic diseases. In in-vitro and in-vivo studies antagonistic effects of radical scavenger and PAF (platelet activating factor) were described. In this study a concentration-depending superoxide dismutase activity of the Ginkgo biloba extract rökan liquid could be made evident.

Diterpenes↗

PubMed2004

Inhibition of human P450 enzymes by multiple constituents of the Ginkgo biloba extract.

The Ginkgo biloba extract EGb761 was tested for its ability to inhibit the major human cytochrome P450 enzymes (CYPs). The full extract was found to strongly inhibit CYP2C9 (Ki = 14+/- 4 microg/mL), and to a lesser extent, CYP1A2 (Ki = 106 +/- 24 microg/mL), CYP2E1 (Ki = 127 +/- 42 microg/mL), and CYP3A4 (Ki = 155 +/- 43 microg/mL). The terpenoidic and flavonoidic fractions of the extract were tested separately against the same P450s to identify the source of inhibition by EGb761. The terpenoidic fraction inhibited only CYP2C9 (Ki = 15 +/-6 microg/mL) whereas the flavonoidic fraction of EGb761 showed high inhibition of CYP2C9, CYP1A2, CYP2E1, and CYP3A4 (Ki's between 4.9 and 55 microg/mL). The flavonoidic fraction was further fractionated using extraction and chromatography. Inhibition studies indicated that the majority of these fractions inhibited P450s at a significant level (IC50 < 40 microg/mL).

Chemical Fractionation↗

PubMed2003

EGb 761: ginkgo biloba extract, Ginkor.

EGb 761 [Ginkgo biloba extract EGb 761, Rökan, Tanakan, Tebonin] is a standardised extract of Ginkgo biloba leaves and has antioxidant properties as a free radical scavenger. A standardised extract of Ginkgo biloba leaves is a well defined product and contains approximately 24% flavone glycosides (primarily quercetin, kaempferol and isorhamnetin) and 6% terpene lactones (2.8-3.4% ginkgolides A, B and C, and 2.6-3.2% bilobalide). Ginkgolide B and bilobalide account for about 0.8% and 3% of the total extract, respectively. Other constituents include proanthocyanadins, glucose, rhamnose, organic acids, D-glucaric and ginkgolic acids. EGb 761 promotes vasodilation and improves blood flow through arteries, veins and capillaries. It inhibits platelet aggregation and prolongs bleeding time. EGb 761, which was originated by Dr Willmar Schwabe Pharmaceuticals (Dr Willmar Schwabe Group), has been available in Europe as a herbal extract since the early 1990s. However, products containing EGb 761 are not approved for use by the US FDA. As a dietary supplement, Nature's Way in the US distributes and markets a standardised extract of Ginkgo biloba leaves (the EGb 761 Formula) under the name Gingold Nature's Way. The French company Beaufour-Ipsen and its German subsidiary Ipsen Pharma are co-developing EGb 761 with Dr Willmar Schwabe Group. Beaufour-Ipsen (France) is developing EGb 761 as Tanakan, Dr Willmar Schwabe Pharmaceuticals (Germany) as Tebonin and Ipsen Pharma (Germany) as Rökan. Intersan was formerly developing EGb 761 in Germany, but Intersan appears to have been merged into Ipsen Pharma. However, there has been no recent development for these indications. In the UK and other European countries, the cardioprotective effects of EGb 761 in myocardial ischaemia and reperfusion are being investigated in preclinical studies. The psychological and physiological benefits of ginkgo are said to be based on its primary action of regulating neurotransmitters and exerting neuroprotective effects in the brain, protecting against or retarding nerve cell degeneration. Ginkgo also benefits vascular microcirculation by improving blood flow in small vessels and has antioxidant activity. There has been conflicting evidence about the benefits of ginkgo, e.g. the ginkgo clinical trial published in August 2002 in JAMA concluded that a leading ginkgo supplement did not produce measurable benefits for memory in healthy adults over 60, although a month earlier, another study concluded that the same ginkgo extract is effective in helping normal healthy older adults in memory and concentration. However, in December 2002, the Cochrane Collaboration, the world's most respected scientific reviewer of clinical trials in medicine, concluded that the published literature strongly supports the safety and potential benefits of ginkgo in treating memory loss and cognitive disorders associated with age- related dementia. A phase II study of EGb 761 in combination with fluorouracil is in progress in Germany in patients with pancreatic cancer. German researchers are investigating the potential of EGb 761 for the treatment of sudden deafness and tinnitus in clinical studies. EGb 761 was undergoing preclinical development for the potential treatment of diabetes in France, diabetic neuropathies in Russia, and cancer in Brazil. However, there has been no recent development for these indications. Beaufour-Ipsen has expressed the intention to license out its diabetes projects that may include EGb 761.

Animals↗

PubMed1994

The nitric oxide-scavenging properties of Ginkgo biloba extract EGb 761.

Ginkgo biloba extract EGb 761 was found to be a scavenger of nitric oxide in in vitro acellular systems, under physiological conditions. EGb 761 competed with oxyhemoglobin for reaction with nitric oxide generated during the interaction of hydroxylamine with Complex I of catalase. An EGb 761 dose-dependent decrease in the amount of nitrite formed in the reaction of oxygen with nitric oxide produced from solution of 5 mM sodium nitroprusside was also observed. These data implicate it as a potential therapeutic agent in conditions of altered production of nitric oxide.

Animals↗

PubMed2005

Stabilization of mitochondrial membrane potential and improvement of neuronal energy metabolism by Ginkgo biloba extract EGb 761.

Ginkgo biloba extract EGb 761 has been used for many years to treat age-related cognitive disorders including Alzheimer's disease. EGb 761 given shortly after initiating mitochondrial damage by sodium nitroprusside (nitric oxide donor) improved the mitochondrial membrane potential of PC12 cells significantly and dose dependently. Under these conditions, EGb 761 also reversed the decrease in ATP production. In addition, similar protection against oxidative damage was found in dissociated brain cells and isolated brain mitochondria after in vitro or in vivo treatment with EGb 761. Moreover, PC12 cells bearing an Alzheimer's disease-related mutation in the amyloid precursor protein, which leads to enhanced beta amyloid production, showed greater benefit from treatment with EGb 761 than did control cells. Taken together, our findings clearly show stabilization and protection of mitochondrial function as a specific and very sensitive property of EGb 761 at therapeutically relevant doses.

Animals↗

PubMed1995

Lipid peroxide, phospholipids, glutathione levels and superoxide dismutase activity in rat brain after ischaemia: effect of ginkgo biloba extract.

The influence of ginkgo biloba extract on the lipid peroxide product (malondialdehyde, MDA), glutathione (GSH) and phospholipids levels as well as superoxide dismutase (SOD, 1.15.1.1) and lactate dehydrogenase (LDH, 1.1.1.27) activities in rat brain after occlusion of common carotid arteries was investigated. Two experimental models were studied: 60 min ischaemia without reperfusion and 60 min ischaemia followed by 60 min reperfusion. Compared to sham-operated animals, ischaemia followed by reperfusion increased cytosolic LDH activity and mitochondrial lipid peroxide content and decreased the superoxide dismutase activity and mitochondrial total phospholipids level. Preischaemic administration of ginkgo biloba extract (150 mg kg-1, p.o.) could normalize the SOD activity of the rat brain. The extract was also able to reduce the lipid peroxide and phospholipids contents of the mitochondrial rat brain. These effects could be explained on the basis of the antioxidant property of ginkgo biloba extract and suggests its beneficial role in the protection against post-ischaemic injury.

Animals↗

PubMed2005

Inhibition of platelet activating factor (PAF)-induced aggregation of human thrombocytes by ginkgolides: considerations on possible bleeding complications after oral intake of Ginkgo biloba extracts.

The special Ginkgo biloba leaf extract EGb 761 is marketed for more then two decades. During this time its therapeutic efficacy and favorable safety profile have been proven in numerous clinical trails as well as by postmarketing surveillance in accordance with German drug regulations. During recent years, however, several cases of hemorrhage have been reported to occur in coincidence with the use of Ginkgo products. Although a clear causality between Ginkgo intake and bleeding could not be established, these observations have generally been explained by the platelet-activating factor (PAF)-antagonistic action of ginkgolides, which represent characteristic constituents of Ginkgo extracts. PAF was originally characterized by inducing aggregation and secretion of serotonin and histamine from rabbit platelets. We now confirmed that induction of aggregation of human platelets by PAF requires at least 200 times higher concentration when compared to rabbit cells. Under the chosen experimental conditions, PAF-mediated aggregation of human platelets was half-maximally inhibited by ginkgolide B, A, C and J at concentrations of 2.5, 15.8, 29.8 and 43.5 microg/ml, respectively. These concentrations are generally more than 100 times higher as the peak plasma values measured after oral intake of EGb 761 at recommended doses between 120 and 240 mg. As PAF is a 'weak' platelet activator, which does not appear to be of importance for primary hemostasis, our results rise serious doubts that the PAF antagonistic effect of ginkgolides could be responsible for hemorrhage in patients taking EGb 761.

Administration, Oral↗

PubMed1997

The bioavailability of ginkgolides in Ginkgo biloba extracts.

A new Ginkgo biloba leaf extract, BioGinkgo 27/7, was prepared using a method that enriches ginkgolide B. The bioavailability of ginkgolides in these extracts was assessed in rabbits in comparison with a commercially available standardized 24/6 extract. It was found that, after a single dose, a higher concentration of ginkgolides was maintained for a longer period of time with these extracts than was found with commercial extract prepared by existing methods.

Animals↗

PubMed1986

[From the body to the cell membrane: the different levels of pharmacological action of Ginkgo biloba extract].

The pharmacological study of Ginkgo biloba extract has required numerous experiments over several years: different pathological models of cerebral ischaemia to evaluate its effects, and experiments at both cellular and molecular levels to determine its mechanisms of action. In experimental models of ischaemia, oedema and hypoxia, Ginkgo biloba extract reduced vascular, tissular and metabolic disturbances as well as their neurological and behavioural consequences. The pharmacological effects of Ginkgo biloba extract concern vascular, rheological and metabolic processes. Several membrane mechanisms seem to be involved: protection of the membrane ultrastructure against free radicals, modulation of some enzymatic systems and ionic pumps. The originality of the pharmacological properties of Ginkgo biloba extract lies in preferential focusing of its effects on ischaemic areas.

Aging↗

PubMed2006

The use of Ginkgo biloba extract in acute ischemic stroke.

BACKGROUND: Ginkgo biloba extract is widely used in the treatment of acute ischemic stroke in China. The Cochrane Re-view authors aimed to assess the evidence from randomized controlled trials and quasirandomized controlled trials on the use of Ginkgo biloba extract in acute ischemic stroke. OBJECTIVES: The primary objective is to determine whether Ginkgo biloba extract improves functional outcome without causing undue harm in patients with acute ischemic stroke. Secondary objectives are to assess the effect of Ginkgo biloba extract on neurological impairment and quality of life. SEARCH STRATEGY: The authors searched the Cochrane Stroke Group Trials Register (last searched October 2004), the Trials Register of the Cochrane Complementary Medicine Field (last searched October 2004), and the Chinese Stroke Trials Register (last searched June 2004). In addition,the authors searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3,2004), MEDLINE (1966 to August 2004), EMBASE (1980 to June 2004), AMED(1985 to May 2002), and the China Biological Medicine Database (CBM-disk,1979 to August 2004). The authors searched relevant clinical trials and re-search registers and contacted pharmaceutical companies and researchers in an ef-fort to identify further published and unpublished studies. SELECTION CRITERIA: Randomized controlled trials or quasirandomized controlled clinical trials comparing Ginkgo biloba extract with placebo or open control(no placebo) in patients with acute ischemic stroke. DATA COLLECTION AND ANALYSIS: Two authors independently selected trials for inclusion, assessed trial quality, and extracted data. MAIN RESULTS: Fourteen trials were identified, of which 10 trials (792 patients)were included. Four trials are awaiting assessment. In the 10 included trials, follow-up was performed at 14 to 35 days after stroke. In all studies, neurological outcome was assessed, but none of them reported on disability (activities of daily living function) or quality of life. Only three trials reported adverse events. In nine trials, all of them assessed to be of inferior quality, significant improvement in neurological deficit at the end of the treatment was used as the outcome measure. When analyzing these trials together, Ginkgo biloba extract was associated with a significant increase in the number of improved patients (Peto odds ratio (OR)2.66; 95% confidence interval (CI): 1.79-3.94). One placebo-controlled trial, assessed to be of good quality, reported neurological outcome as a continuous variable. It failed to show an improvement of neurological deficit at the end of treatment (weighted mean difference (fixed)0.81; 95% CI: -8.9-10.52). No deaths or major adverse events were reported during the follow-up period. CONCLUSIONS: There was no convincing evidence from trials of sufficient methodological quality to support the routine use of Ginkgo biloba extract to promote recovery after stroke. High-quality and large-scale randomized controlled trials are needed to test its efficacy.

Activities of Daily Living↗