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PubMed2002

Analysis of flavonoids in Ginkgo biloba L. and its phytopharmaceuticals by capillary electrophoresis with electrochemical detection.

A high-performance capillary electrophoretic (CE) method with electrochemical detection (ED) has been developed for determination of the pharmacologically active flavonoids in Ginkgo biloba L. and phytopharmaceuticals containing its extract. Epicatechin, catechin, rutin, apigenin, luteolin, and quercetin are important flavonoids in this plant. Operated in a wall-jet configuration, a 300 micro m diameter carbon-disk electrode was used as working electrode with good response to the six analytes at +1000 mV (relative to the SCE). Under the optimum conditions, the analytes were separated within 22 min in a borax buffer (pH 9.0). Excellent linearity was obtained over two orders of magnitude and detection limits (S/N=3) ranged from 1.4 x 10(-7) to 5.0 x 10(-7) g mL(-1) for all six analytes. The method was successfully used for assay of Ginkgo biloba L. and its phytopharmaceuticals after a relatively simple extraction procedure; the results obtained were satisfactory.

Drugs, Chinese Herbal↗
PubMedDate not supplied

Ginkgo biloba--an appraisal.

Ginkgo biloba has been used in traditional Chinese medicine for about 5000 years. A standardized preparation, EGb 761 has been recently prepared. The pharmacologically active constituents, flavonol glycosides and the terpene lactones are standardized. The terpene lactones comprise of ginkgolides A, B, C and bilobalides. The extract scavenges excess free radicals and pretreatment with EGb 761 reduces damage by free radicals in patients undergoing coronary bypass surgery. The action of platelet activating factor is antagonized and platelet aggregation is reduced. Blood flow is increased. Release of prostacyclines and nitric oxide was shown to be stimulated. Ginkgo biloba has been found to be useful in the treatment of Alzheimers disease and cognitive impairment. EGB 761 has shown beneficial effect in aging and mild cognitive impairment. Bilobalide has been shown to be protective against glutamate-induced excitotoxic neuronal death. Early studies indicate a potential role in age-related macular degeneration and some types of glaucoma. Anticancer action is related to antioxidant, anti-angiogenic and gene regulatory actions. Ginkgo biloba has shown overall improvement in about 65% of patients with cerebral impairment and a similar percentage suffering from peripheral vascular diseases. A recent study suggested that phytoestrogens in Ginkgo biloba may have a role as alternative hormone replacement therapy. Recent trials have not shown a beneficial effect of Ginkgo biloba in tinnitus and acute mountain sickness. Ginkgo biloba increased the bioavailability of diltiazem. The extract has been shown to protect against doxorubicin-induced cardiotoxicity and gentamicin-induced nephrotoxicity in animals. Ginkgo biloba inhibits microsomal enzymes and has a potential for drug interactions. Further studies to establish the efficacy of Ginkgo biloba are required.

Ginkgo biloba↗
PubMed2005

In vitro susceptibility of Helicobacter pylori to botanical extracts used traditionally for the treatment of gastrointestinal disorders.

The gram-negative bacterium Helicobacter pylori (HP), identified in 1982, is now recognized as the primary etiological factor associated with the development of gastritis and peptic ulcer disease. In addition, HP infections are also associated with chronic gastritis, gastric carcinoma and primary gastric B-cell lymphoma. For centuries, herbals have been used in traditional medicine to treat a wide range of ailments, including gastrointestinal (GI) disorders such as dyspepsia, gastritis and peptic ulcer disease (PUD). However, the mechanism of action by which these botanicals exert their therapeutic effects has not been completely elucidated. As part of an ongoing screening program, the study assessed the in vitro susceptibility of 15 HP strains to botanical extracts, which have a history of traditional use in the treatment of GI disorders. Methanol extracts of Myristica fragrans (seed) had a MIC of 12.5 microg/mL; Zingiber officinale (ginger rhizome/root) and Rosmarinus officinalis (rosemary leaf) had an MIC of 25 microg/mL. Methanol extracts of botanicals with a MIC of 50 microg/mL included Achillea millefolium, Foeniculum vulgare (seed), Passiflora incarnata (herb), Origanum majorana (herb) and a (1:1) combination of Curcuma longa (root) and ginger rhizome. Botanical extracts with a MIC of 100 microg/mL included Carum carvi (seed), Elettaria cardamomum (seed), Gentiana lutea (roots), Juniper communis (berry), Lavandula angustifolia (flowers), Melissa officinalis (leaves), Mentha piperita (leaves) and Pimpinella anisum (seed). Methanol extracts of Matricaria recutita (flowers) and Ginkgo biloba (leaves) had a MIC > 100 microg/mL.

Curcuma↗
PubMed2005

Liquid chromatography/electrospray tandem mass spectrometry of terpenoid lactones in Ginkgo biloba.

Ginkgo biloba (ginkgo) is one of most frequently used botanical dietary supplements. The bioactive constituents include the terpenoid lactones consisting of bilobalide and the ginkgolides A, B, C and J. A new assay based on high-performance liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) was developed for the measurement of the terpenoid lactones in ginkgo products such as leaf powder and extracts. Initially, the MS/MS fragmentation pathways of ginkgolides were investigated to identify abundant fragment ions that might be useful for the sensitive and selective detection of ginkgolides and bilobalide during LC/MS/MS. Then, sample preparation and clean-up procedures were streamlined to maximize throughput by taking advantage of the selectivity of LC/MS/MS detection. Analyte recoveries exceeded 90%, the intra-assay and inter-assay relative standard deviations were <5%, the relative error was <8% and the limits of detection and quantification were 3.6-120 and 11-350 fmol, depending on the analyte that was injected on to the LC column. Therefore, this LC/MS/MS assay facilitated the rapid quantitative analysis of ginkgolides A, B, C and J and bilobalide in ginkgo dietary supplements with excellent recovery, reproducibity, accuracy and sensitivity.

Chromatography, Liquid↗
PubMedDate not supplied

Protection of endotoxin-induced oxidative renal tissue damage of rats by vitamin E or/and EGb 761 treatment.

The aim of the present study was to evaluate the possible protective effects of vitamin E and EGb 761 treatments, alone or in combination, against oxidative renal tissue damage in experimentally induced endotoxaemic rats. Fifty healthy male Wistar albino rats, weighing 150-250 g and averaging 12 weeks old, were allotted randomly into one of five experimental groups: A (untreated), B (endotoxaemic), C (endotoxaemic + vitamin E treated), D (endotoaxemic + EGb 761 treated) and E (endotoxaemic + vitamin E and EGb 761 treated), each containing ten animals. Group A received only an intraperitoneal (i.p.) injection of 2 ml of normal saline solution and served as the control. Groups B, C, D and E were administrated a single i.p. injection of 0.5 ml of endotoxin solution. In addition, groups C, D and E received i.p. injections of 600 mg kg(-1) body mt. of vitamin E and oral extract of 50 mg kg(-1) body wt. of EGb 761, alone or in combination, immediately after the endotoxin injection. The experiment lasted for 24 h. At the end of the experiment blood and tissue samples were obtained for biochemical and histopathological investigation. Endotoxin injection produced renal damage, increased lipid peroxidation and decreased antioxidant enzyme activity. Vitamin E or/and EGb 761 treatment decreased lipid peroxidation, increased antioxidant enzyme activity and also prevented renal tissue damage in experimentally induced endotoxaemic rats. In conclusion, vitamin E and EGb 761 treatment, alone or in combination, appears to be beneficial in preventing endotoxin-induced oxidative renal tissue damage and therefore shows potential for clinical use.

Animals↗
PubMed2002

Influence of the severity of cognitive impairment on the effect of the Gnkgo biloba extract EGb 761 in Alzheimer's disease.

OBJECTIVE: To explore the treatment effect of EGb 761((R)) (EGb) in Alzheimer's disease depending on baseline severity. METHODS: We applied stratification to the intent-to-treat data set collected during a 52-week, randomized, double-blind, placebo-controlled, parallel-group, multicenter study with 120 mg of EGb, using cutoff points of 23 and 14 for the Mini-Mental State Examination (MMSE) score. Outcome measures used were the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog) and the Geriatric Evaluation by Relative's Rating Instrument (GERRI). RESULTS: In the severity stratum 1 (MMSE >23), the placebo group did not show significant changes, while the EGb group improved significantly by 1.7 points on the ADAS-Cog and by 0.09 points on the GERRI. In the severity stratum 2 (MMSE <24), the placebo group worsened by 4.1 points on the ADAS-Cog and 0.18 points on the GERRI, whereas the EGb group showed 60% less decline on the ADAS-Cog (treatment difference of 2.5 points) and no change on the GERRI (treatment difference of 0.25 points). The most severely impaired subgroup (MMSE <15) showed slightly more pronounced worsening for both treatment groups. However, in comparison to placebo, EGb induced virtually the same magnitude of effect as was observed in the entire stratum 2. CONCLUSIONS: The results of this retrospective analysis indicated that a treatment effect favorable to EGb could be observed with respect to cognitive performance (p = 0.02) and social functioning (p = 0.001) regardless of the stage of dementia, whether mild or moderately severe. However, the relative changes from baseline measured at endpoint depended heavily on the severity at baseline. Improvement was observed in the group of patients with very mild to mild cognitive impairment, while in more severe dementia, the mean EGb effect should be considered more in terms of stabilization or slowing down of worsening, as compared to the greater deterioration observed with placebo.

Aged↗
PubMed2000

Antioxidant compounds EGB-761 and BN-520 21 attenuate heat shock protein (HSP 72 kD) response, edema and cell changes following hyperthermic brain injury. An experimental study using immunohistochemistry in the rat.

Influence of the extract of Gingko biloba (EGB-761) and one of its constituent Gingkolide B (BN-52021) on hyperthermia induced cellular damage and heat shock protein (HSP 72kD) response was examined in a rat model. Rats subjected to 4h heat stress at 38 degrees C in a biological oxygen demand (BOD) incubator (relative humidity 50-55%, wind velocity 20-25cm/sec) resulted in profound edema and cell injury in many parts of the cerebral cortex, hippocampus, cerebellum, thalamus, hypothalamus and brain stem. Immunostaining of HSP 72 kD showed marked upregulation in the damaged and distorted neurons located within the edematous area. Pretreatment with EGB-761 (50mg/kg/day, p.o.) and BN-520 21 (2mg/kg, p.o.) per day for 5 days significantly reduced HSP expression and attenuated cell damage. Our results show that EGB-761 and its component Gingkolide B (BN-52021) has the capacity to reduce edema and cell injury following hyperthermia and this effect of the compound is somehow associated with a reduction in cellular stress response as evidenced with a reduction in HSP expression.

Animals↗
PubMed2001

Therapeutic efficacy of EGb761 (Gingko biloba extract) in a transgenic mouse model of amyotrophic lateral sclerosis.

EGb761 is a standardized extract of green Gingko biloba, which exerts protective effects against mitochondrial damage and oxidative stress. We examined whether oral administration of 0.022% or 0.045% EGb761 in the diet could impart neuroprotective effects in a transgenic mouse model (G93A) of amyotrophic lateral sclerosis (ALS). EGb761 significantly improved motor performance and survival, and protected against a loss of spinal-cord anterior motor horn neurons in male G93A mutant transgenic ALS mice, but not in littermate female mutant transgene mice. While EGb761 extended survival in littermate female G93A mice, significance was not reached. EGb761, however, significantly improved weight loss in both male and female transgenic ALS mice. These findings provide evidence for a gender-specific neuroprotective effect of EGb761 in a transgenic model of ALS and suggest that EGb761 may be a potential effective treatment in patients with ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1999

Protective effects of Gingko biloba extract EGb 761 on myocardium of experimentally diabetic rats. I: ultrastructural and biochemical investigation on cardiomyocytes.

Chronic diabetes in man and animal models develops cardiomyopathic alterations which cannot be absolutely avoided by insuline therapy. Since diabetic damage is partly attributed to oxidative stress antioxidative treatment could be able to reduce the alterations. Aim of this study was to investigate the cardioprotective effects of EGb 761, known as a radical scavenger, against diabetic alterations in rats. The diabetes was induced by i.p. injection of 60 mg/kg body weight streptozotocin. Duration of diabetes was 4 months, the protected group received 100 mg/kg body weight EGb 761 with the drinking water over 3 months. Electron and light microscopic morphometry of left-ventricular samples revealed typical diabetic alterations consisting in decrease of volume fraction of myofibrils, SR and t-tubules and diminishing of cardiomyocyte diameter, increase of interstitial volume, mitochondrial size and volume fraction, and of vacuoles and of lipid drops. EGb treatment could gradually prevent the loss of myofibrils and reduction of myocyte diameter but has only little influence on interstitial and mitochondria volume. The diabetic-induced increase of lipid and vacuoles and the decrease of SR and t-tubules were not influenced. Biochemical parameters of oxidative stress: malondialdehyde (MDA) was only insignificantly altered by diabetes and EGb. The superoxide dismutase (SOD) activity was increased by diabetes and more increased by EGb treatment. Creatine kinase (CK) activity was diminished by diabetes but slightly increased by EGb. The polymerase chain reaction (PCR) of i-NOS was not different between the diabetic and protected diabetic groups.

Animals↗
PubMed2002

Pharmaceutical quality of different Ginkgo biloba brands.

Ginkgo biloba-containing brands are one of the top sellers within the growing market for herbal remedies in many European countries as well as in the USA. In the consumers' interest, these brands should feature a certain quality and should be transparent in quality claims. In this investigation, a variety of products on the USA market was studied with respect to pharmaceutical quality, such as quantity of constituents and in-vitro dissolution. In terms of the content of active substances, flavone glycosides ranged from 24% to 36% and terpene lactones from 4% to 11%. With ginkgolic acids, there was a very large range, from < 500 ppm to about 90000 ppm. Comparing the dissolution rates of terpene lactones and flavone glycosides within the single products, most were approximately the same. Thus, terpene lactones and flavone glycosides were released from these products and dissolved at the same rate in most cases. Furthermore, most of the products investigated released more than the required 75% of the content of both components within 30 min. However, several products showed clear and relevant differences in dissolution rates to the rest (e.g. < 75% within 30 min or even less than 25% after 60 min in one case, indicating much poorer pharmaceutical quality). Beside the comparability respectively standardisation of the extracts used, the in-vitro dissolution of the relevant constituents should be similar to other drugs to guarantee comparable in-vivo performance of herbal products. An important step in standardising pharmaceutical quality is the pharmacopoeial monograph for Ginkgo biloba extract in Germany, standardising the content of pharmacologically relevant substances (flavone glycosides 22-27% and terpenlactones 5-7%, 2.8-3.4% ginkgolides A, B, C and 2.6-3.2% bilobalide thereof). Many of the investigated products, which refer to the German Commission E (of the Federal Institute for Drugs and Medicinal Devices) monograph, are not in accordance with this specification. Thus, they can not be considered to be pharmaceutically equivalent.

Chromatography, High Pressure Liquid↗
PubMed2006

In vitro peroxynitrite scavenging activity of 6-hydroxykynurenic acid and other flavonoids from Gingko biloba yellow leaves.

As part of our research on phytochemicals that exert protective effects against diseases related to reactive nitrogen species, we have evaluated the scavenging activity of the yellow leaves of Ginkgo biloba on ONOO-. The methanol extract and ethyl acetate fraction obtained from yellow leaves of G. biloba evidenced a marked scavenging activity on authentic ONOO-. Repeated column chromatography of the active ethyl acetate soluble fraction on silica gel, Sephadex LH-20, and RP-18, resulted in the purification of 15 known compounds, including sciadopitysin (1), ginkgolide B (2), bilobalide (3), isoginkgetin (4), kaempferol (5), luteolin (6), protocatechuic acid (7), bilobetin (8), amentoflavone (9), beta-sitosterol glucopyranoside (10), kaempferol 3-O-rhamnopyranoside (11), kaempferol 3-O-glucopyranoside (12), kaempferol 3-O-[6"'-O-p-coumaroyl-beta-D-glucopyranosyl(1 --> 2)-alpha-L-rhamnopyranoside] (13), kaempferol 3-O-rutinoside (14), and 6-hydroxykynurenic acid (15). Among the compounds isolated, flavonoids (5, 6 and 11-14), protocatechuic acid (7), and 6-hydroxykynurenic acid (15) all exhibited marked scavenging activities on authentic ONOO-. The IC50 values of 5-7, 11-14 and 15 were as follows: 2.86 +/- 0.70, 2.30 +/- 0.04, 2.85 +/- 0.10, 5.60 +/- 0.47, 4.16 +/- 1.65, 2.47 +/- 0.15, 3.02 +/- 0.48, and 6.24 +/- 0.27 microM, respectively. DL-Penicillamine (IC50 = 4.98 +/- 0.27 microM) was utilized as a positive control. However, the other compounds (1-4, 8-10) exerted no effects against ONOO-.

Ethanol↗
PubMed1997

Chemistry and biology of alkylphenols from Ginkgo biloba L.

Ginkgolic acid and related alkylphenols constitute major components of the lipid fraction of the fruit pods of Ginkgo biloba L. In addition, this class of substances is present in Ginkgo leaves which are widely used to prepare extracts for the treatment of peripheral or cerebral circulatory disorders, as well as vascular and Alzheimer type dementia. The present paper reviews the literature on chemical and biological aspects of alkylphenols from Ginkgo with special reference to their allergic and other undesired properties. As these compounds are present in crude leaf extracts, their completest possible removal has therefore to be guaranteed for therapeutically used extracts by the production process. Technically this does not imply any problem and most preparations available on the market fulfil the requirements of the Monograph of the Commission E of the former Federal German Health Authority (Bundesgesundheitsamt, BGA) requesting a maximal concentration of 5 ppm ginkgolic acids.

Animals↗
PubMed2006

Inhibition of chronic skin inflammation by topical anti-inflammatory flavonoid preparation, Ato Formula.

Flavonoids are known as natural anti-inflammatory agents. In this investigation, an anti-inflammatory potential of new topical preparation (SK Ato Formula) containing flavonoid mixtures from Scutellaria baicalensis Georgi roots and Ginkgo biloba L. leaves with an extract of Gentiana scabra Bunge roots was evaluated in an animal model of chronic skin inflammation. Multiple 12-O-tetradecanoylphorbol-13-acetate treatments for 7 consecutive days on ICR mouse ear provoked a chronic type of skin inflammation: dermal edema, epidermal hyperplasia and infiltration of inflammatory cells. When topically applied in this model, this new formulation (5-20 microL/ear/treatment) reduced these responses. Furthermore, it inhibited prostaglandin E2 generation (17.1-33.3%) and suppressed the expression of proinflammatory genes, cyclooxygenase-2 and interleulin-1beta in the skin lesion. Although the potency of inhibition was lower than that of prednisolone, all these results suggest that Ato Formula may be beneficial for treating chronic skin inflammatory disorders such as atopic dermatitis.

Administration, Topical↗
PubMed2005

Ginkgolide B stimulates signaling events in neutrophils and primes defense activities.

Ginkgolide B (GKB) is a bioactive component of the standardized extract from the leaves of the Ginkgo biloba tree (EGb 761), which is used in Chinese and in occidental medicine. GKB is known as a platelet-activating factor receptor antagonist. Here, we provide evidence that GKB per se (0.25-5 microM) stimulated tyrosine phosphorylation of proteins, phospholipase D activation, calcium transients, and activation of p38 but not p44/42 Map kinases in human polymorphonuclear leukocytes (PMN). These stimulatory effects remained relatively weak and primed PMN for subsequent stimulation of respiratory burst (RB) or directed locomotion by the chemoattractant fMet-Leu-Phe (fMLP) or complement-derived factor C5a. A similar RB priming was observed with rat exudate PMN after in vivo administration of EGb 761 (25 and 50 mg/kg) to rats before pleurisy induction. Thus, GKB primarily induces activation of intracellular signaling events and has the potential to prime cellular functions such as PMN defense activities.

Animals↗
PubMed2005

The beta subunit increases the ginkgolide B sensitivity of inhibitory glycine receptors.

We investigated the effect of ginkgolide B (GB), a component of the extract from the leaves of the Ginkgo biloba tree, on recombinant glycine receptors (GlyRs) expressed in Xenopus oocytes by using voltage-clamp recording. GB (0.01-10 microM) inhibited glycine-induced currents of homo-oligomeric alpha1, alpha2 and alpha 3 GlyRs, with the highest potency being found at the alpha1 GlyR (IC(50) value=0.61+/-0.1 microM). Coexpression of the alpha subunits with the beta subunit resulted in a shift of the IC(50) value of GB to nanomolar values, indicating selectivity of GB for beta subunit containing GlyRs. We also analyzed the mechanism of GB inhibition and the effect of point mutations introduced into the alpha1 subunit. Our results are consistent with a channel blocking effect, since (i) GB inhibited glycine currents non-competitively, and (ii) a point mutation in the pore forming M2 domain reduced GB potency. In conclusion, GB is a potent blocker of beta subunit containing GlyR channels and hence can be used to discriminate homo- from hetero-oligomeric GlyRs. As hetero-oligomeric GlyRs are known to be synaptically localized, GB represents a channel blocker that may be employed to separate extrasynaptic from synaptic glycine currents.

Animals↗
PubMed1999

Production of ginkgolides and bilobalide by Ginkgo biloba plants and tissue cultures.

The accumulation of the terpenes ginkgolides and bilobalide in Ginkgo biloba was reported in plants as well as in plant cell cultures. Several hundred plants cultivated under controlled conditions in the field have been analyzed for their terpene production over many years. Cross-pollination experiments were performed with mature trees and the terpene content of the progeny was analyzed. The age of the tree is the main factor influencing the terpene content of the leaves as the level always decreases dramatically between young and old trees. 80 cell culture strains have been established and ginkgolides analyzed by GC/MS. These cell cultures reveal very low amounts of terpenes (1 microgram g-1 D.W. or less). On the contrary, isolated in vitro root cultures accumulate terpenes at the same concentration as the young plant leaves (4 mg g-1 D.W.). Attempts to obtain rapid growing roots or even hairy-roots did not succeed but the possibility to transform Ginkgo cell strains has been demonstrated.

Gas Chromatography-Mass Spectrometry↗
PubMed1993

Regeneration of motor nerves in bilobalide-treated rats.

Bilobalide, a terpene extracted from the leaves of the Ginkgo biloba tree, has been proposed to exert trophic and protective effects on neurons and on Schwann's cells in various neuropathies. The reinnervation of the extensor digitorum longus muscle following traumatic nerve damage was investigated in rats by using electrophysiological and histological techniques. Evaluation parameters included the membrane resting potential of muscle cells, the spontaneous quantal release of acetylcholine, and the percentage of muscle cells receiving multiple innervation. The percentage of muscle cells receiving multiple innervation reached a peak more rapidly in treated animals and declined subsequently to values lower than those found in controls. These data suggest that the rearrangement of regenerated innervation occurs more rapidly in bilobalide-treated animals.

Animals↗