Mass spectrometry analysis of terpene lactones in Ginkgo biloba

Terpene lactones are a family of compounds with unique chemical structures, first recognised in an extract of Ginkgo biloba. The discovery of terpene lactone derivatives has recently been reported in more and more plant extracts and even food products. In this study, mass spectrometric characteristics of the standard terpene lactones in Ginkgo biloba were comprehensively studied using both an ion trap and a quadrupole time-of-flight (QTOF) mass spectrometer. The mass spectral fragmentation data from both techniques was compared to obtain the mass spectrometric fragmentation pathways of the terpene lactones with high confidence. The data obtained will facilitate the analysis and identification of terpene lactones in future plant research via the fragmentation knowledge reported here.

The effect of Ginkgo biloba (EGb 761) on epileptic activity in rabbits

Different animal models are used to evaluate the process of epileptogenesis. In this investigation the kindling model of epilepsy was used. The epileptic focus was induced in Chinchilla rabbits by stimulation of the hippocampus with electric stimuli. We presumed that the extracts of Ginkgo biloba affect the formation of kindling epilepsy. Bioelectric activity of the brain was registered throughout the development of kindling with and without standardized extracts from dried ginkgo leaves (EGb 761). For each animal the following has been determined: the values of the minimum current strength necessary for the origination of threshold after-discharge (AD) - discharges appearing after the cessation of stimulation; duration of the threshold AD; number of stimulations necessary for the origination of full kindling; time latency for the development of full kindling; number of spontaneous epileptogenic discharges manifested in EEG two days following the formation of full kindling during 60-minute registration. The results show that the process of epileptogenesis was influenced by EGb 761. It has been established that if the animals received EGb 761, significantly weaker minimum current strength was necessary for the development of the epileptogenic focus and the AD were longer, while the number of necessary electrostimulations for the appearance of full kindling was less and the latency was shorter.

Isolation and purification of ginkgo flavonol glycosides from Ginkgo biloba leaves by high-speed counter-current chromatography

A high-speed counter-current chromatography method was developed for the separation and purification of bioactive flavonol glycosides from a crude ethanol extract of Ginkgo biloba leaves. The separation was performed with a two-phase solvent system composed of n-hexane-butanol-ethyl acetate-methanol-0.5% acetic acid (1:0.5:3.5:1:4, v/v) and three pure compounds were eluted in high purities in a one-step separation. Their purities were determined by HPLC and identified by MS,(1)H-NMR, and(13)C-NMR.

Anticlastogenic effect of Ginkgo biloba extract in Graves' disease patients receiving radioiodine therapy

BACKGROUND

Chromosomal damage, as assessed by clastogenic factors (CFs) and micronuclei (MN) appearance, after radioiodine therapy of Graves' disease has been reported.

OBJECTIVE AND METHODS

Our objective was to evaluate the effect of Ginkgo biloba extract (EGb 761) supplementation on the time course (up to 120 d) of CFs and MN appearance in lymphocytes from patients with Graves' disease after iodine-131 ((131)I) therapy. Patients were randomly assigned to EGb 761 or placebo, in a blinded manner.

RESULTS

In the placebo group, MN increased early (P < 0.001) after (131)I, peaking at the 21st day (P = 0.0003) and declining thereafter. In EGb 761-treated patients, MN increased early (P < 0.05), while returning toward baseline value thereafter. Therefore, mean MN increment was significantly higher in the placebo group as compared with EGb 761-treated patients (P < 0.01). Moreover, an early (P < 0.0001) and sustained (up to 35 d; P < 0.001) MN increase induced by CFs was observed in the placebo group. Conversely, in EGb 761-treated patients, MN increase induced by CFs never reached the statistical significance; therefore, the mean of the MN increments was significantly lower than in placebo (P < 0.05). A significant positive correlation between MN maximum increment and the bone marrow dose was observed in the placebo group only (P = 0.03). No significant difference was observed in clinical outcome between the two groups.

CONCLUSIONS

EGb 761 supplementation neutralized genotoxic damage induced by radioiodine treatment, without affecting the clinical outcome. Although (131)I therapy is generally safe, our data suggest that Gingko biloba extracts may prevent genetic effects of radioiodine therapy for hyperthyroid Graves' disease.

Ginkgo biloba extract EGb 761 attenuates hippocampal neuronal loss and cognitive dysfunction resulting from chronic restraint stress in ovariectomized rats

We have recently found that a combination of ovariectomy (OVX) and chronic restraint stress causes cognitive dysfunction and reduces hippocampal CA3 neurons in female rats and that estrogen replacement suppresses the OVX/stress-induced behavioral and morphological changes. In this study, we examined the effect of Ginkgo biloba extract (EGb 761), a popular herbal supplement, on the cognitive dysfunction and neuromorphological change in OVX/stress-subjected rats. Female Fisher 344 rats were randomly divided into three groups: vehicle-treated OVX, EGb 761 (50 mg/kg) -treated OVX and vehicle-treated sham-operated control groups. Two months after ovariectomy, all animals received restraint stress for 21 days (6 h/day), and were then subjected to a novel object recognition test followed by morphological examination by Nissl staining. EGb 761 was orally administered once daily until the behavioral analysis was done. Treatment with EGb 761 improved memory impairment and neuronal loss of hippocampus in the OVX/stress-subjected group in the same ways as 17beta-estradiol. On the other hand, EGb 761 did not affect the loss of bone mineral density and increase in body weight after OVX, although 17beta-estradiol attenuated them. These results have important implications for neuroprotective and cognition enhancing effects of EGb 761 in postmenopausal women and suggest that the effects are mediated by a different mechanism from estrogen.

Polysaccharides fraction isolated from ginkgo biloba folium: immunopharmacological properties

Many macromolecular compounds of vegetal polysaccharides type develop important immunostimulatory properties.

MATERIALS AND METHODS

Crude macromolecular fraction was isolated from the leaves of Ginkgo biloba L. (codified as PGfol) harvested from Botanical Gardens of Iaşi, Romania. The hot water extract was partially purified and submitted to chemical and immunopharmacological studies. The immunostimulatory activity of PGfol was further investigated by a series of tests on rats: phagocytosis capacity of PMN cells by NBT test, serum complement activity and determination of the activity of splenic T-lymphocytes.

RESULTS

PGfol has a good immunostimulatory activity which is equal or higher to Levamisole (positive control).

Effects of Ginkgo biloba extract on expressions of IL-1beta, TNF-alpha, and IL-10 in U937 foam cells

This study is to investigate the protein and mRNA expressions of pro-inflammatory and anti-inflammatory cytokines in U937 foam cells and effects of Ginkgo biloba extract (GbE) on the cytokines. U937 cells were cultured with different concentrations of GbE (0.1, 1, and 10 microg x L(-1)), and stimulated by 100 mg x L(-1) oxidized low density lipoprotein (ox-LDL) for 24 h. The expressions of interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) in culture solution were detected by enzyme-linked immunosorbant assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR). The results showed that incubated with 100 mg x L(-1) ox-LDL for 24 h, the U937 cells became foam cells, the protein or mRNA expressions of IL-1beta, TNF-alpha, IL-10, and its receptor IL-10R in U937 foam cells were higher markedly than those in normal U937 cells. When the cells were pretreated with GbE (0.1, 1, and 10 microg x L(-1)), the increases of IL-1beta and TNF-alpha in U937 foam cells were remarkably inhibited, but IL-10 expression increased greatly. Especially when cells were pretreated with 10 microg x L(-1) GbE, the protein and mRNA expressions of IL-1beta and TNF-alpha were markedly lower than those in U937 foam cells. The protein expression of IL-10 and mRNA expressions of IL-10 and its receptor IL-10R were markedly higher than those in U937 foam cells. GbE inhibited production of pro-inflammatory cytokines IL-1beta and TNF-alpha, but up-regulated the production of anti-inflammatory cytokine IL-10 and its receptor IL-10R in U937 foam cells, which might be related with its anti-atherosclerotic actions.

[Protective effects of extract of Ginkgo biloba on vascular endothelial dysfunction induced by AGEs-BSA in vivo]

OBJECTIVE

To explore the effect of extract of Ginkgo biloba (EGb) on vascular endothelial dysfunction induced by AGEs and to investigate the potential mechanisms.

METHODS

Exogenous glycosylated bovine serum Albumin (AGEs-BSA) was prepared according to the methods of article. Vascular endothelial dysfunction was induced by tail vein injection of AGEs-BSA. The treatment group rats were given tail vein injections with AGEs-BSA followed by immediate intragastric of EGb (15,30 mg/kg/day, respectively) for 30 days. At the end of 30 days period, rats were anaesthetized with an intraperitoneal injection of sodium pentobarbital. Blood samples were collected from the carotid artery for biochemical assay of NO, MDA, SOD, DDAH, ADMA. The thoracic aorta was immediately isolated and cut into rings of 3 - 4 mm. Then ACh-induced EDR response and sodium SNP-induced endothelium-independent relaxation of aortic rings were examined.

RESULTS

Results from in vivo experiments showed that the injection of AGEs-BSA significantly inhibited ACh-induced EDR response, but had no effect on SNP-induced endothelial-independent relaxation. The injection of AGEs-BSA decreased concentration of serum NO, activity of serum SOD and elevated serum MDA and ADMA level. Egb markedly attenuated AGEs-BSA induced inhibition of EDR response, increase of serum MDA and ADMA level, reduction of both NO level and activity of serum SOD.

Chromatographic fingerprint analysis for evaluation of Ginkgo biloba products

The flavonoids and the terpene lactones are regarded as the two main active components of Ginkgo biloba that affect human health. In the work discussed in this paper, two analytical methods for the characterization of G. biloba authentic materials and commercial products, an LC-UV chromatographic fingerprinting method and a traditional flavonol quantification method, were compared. The traditional method was used to determine the total flavonol content (as glycosides) after acid hydrolysis. The fingerprinting method examined the chromatographic profiles of methanol-water extracts using chemometric methods. The traditional method showed that all the commercial products met the current voluntary standard of 24% flavonols by weight. The chromatographic fingerprinting method revealed significant variations in the commercial products with regard to the relative concentration of individual flavonols.

[Effects of extracts of Ginseng and Ginkgo biloba on hippocampal acetylcholine and monoamines in PDAP-pV717I transgenic mice]

OBJECTIVE

To study the effects and its possible mechanism of Naoweikang (NWK), a composite of ginseng and ginkgo extracts, on hippocampal neurotransmitters in APP transgenic mice.

METHODS

P-DAPPV717I transgenic mice were taken as the model of Alzheimer's disease (AD) and be treated with different doses of NWK (31 mg/kg and 62 mg/kg) respectively by gastrogavage once per day for 12 weeks. Contents of hippocampal acetylcholine (ACh), monoamine neurotransmitters and their metabolites were determined with high performance liquid chromatography.

RESULTS

Compared with nontransgenic mice, the levels of ACh and 5-HIAA in hippocampus of transgenic mice lowered significantly (P < 0.01), while 5-HT increased significantly (P < 0.05), and the levels of norepinephrine and dopamine increased by 14.6% and 17.7%, respectively. After 12-week administration, the ACh level increased significantly in the two NWK treated groups (P<0.05), and the 5-HT level in the high dose NWK treated group decreased (P<0.05), as compared with those in the untreated transgenic mice.

CONCLUSION

NWK shows a significant regulatory effect on the activities of hippocampal acetylcholine and monoamine system, especially the cholinergic and 5-HT systems, in APP transgenic mice, which might be one of its mechanisms in improving learning and memory of AD model, and therefore, NWK might exert certain curative effect on AD.

A novel solid phase for selective separation of flavonoid compounds

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.

Heme oxygenase-1 upregulated by Ginkgo biloba extract: Potential protection against ethanol-induced oxidative liver damage

Oxidative stress plays a pivotal role in the pathogenesis and progression of alcoholic liver disease (ALD) and HO-1 induction is suggested to protect hepatocytes from ethanol hepatotoxicity. Here, we present the data to explore the hepatoprotective effect and underlying mechanism(s) of Ginkgo biloba extract (EGB), a naturally occurring HO-1 inducer, against ethanol-induced oxidative damage. Ethanol-fed (2.4 g/kg) male rats were pretreated by EGB (48 or 96 mg/kg) for 90 days. Liver damage was evaluated by histopathology and serum aminotransferase assay. Hepatic redox parameters were measured by spectrophotometry. Heme oxygenase-1 (HO-1) expression was determined by RT-PCR and flow cytometry on mRNA and protein level, respectively. Our results showed that EGB, especially at high dose, ameliorated ethanol-induced macrovesicular steatosis and parenchymatous degeneration in hepatocytes, and decreased serum aminotransferases level. Furthermore, EGB reduced ethanol-derived glutathione depletion and lipid peroxidation, and inhibited the inactivation of superoxide dismutase, glutathione peroxidase and catalase, although EGB itself had no influence on such parameters. Importantly, EGB induced hepatic microsomal HO-1 on mRNA, protein expression and enzymatic activity, which is paralleled to the EGB-derived hepatoprotective effect. Hence, HO-1 upregulation by EGB may enhance the antioxidative capacity against the ethanol-induced oxidative stress and maintain the cellular redox balance.

[Preparation of five ginkgolic acid monomers and their molluscicidal effects against Oncomelania hupensis]

OBJECTIVE

To investigate the molluscicidal activities of the ginkgolic acid(GA) monomers isolated and purified from GAs.

METHODS

Five monomers of GAs from the sarcotesta of Ginkgo biloba. were extracted by petrol ether, separated by silica gel column chromatography, purified by semi-prepared reversed-phased HPLC, and identified by LC-MS analysis. The molluscicidal activities of GAs and their monomers against Oncomelania hupensis were determined as referring to the WHO guidelines for laboratory molluscicidal test.

RESULTS

The five purified ginkgolic acid monomers were GA(13:0), GA(15:0), GA(15:1), GA(17:1) and GA(17:2), with a side chain of 13, 15, 17 alkyl or ethylenic radicals res pectively on their benzene loop. The five monomer proportions to the total GAs were 17.6%, 3.2%, 52.3%, 23.3% and 3.6% respectively. The order of molluscicidal activities for the five monomers was as follows: GA(13:0)>GA(15:1)>GA(15:0)>GA(17:1)>GA(17:2), and their LC50 for snails was 20.79 mg/L, 22.28 mg/L, 33.76 mg/L, 51.89 mg/L, and 59.10 mg/L respectively after immersion for 24 hours. Two monomers, GA(13:0), and GA(15:1) inhibited the snails' climbing up significantly.

CONCLUSION

The molluscicidal activities of GAs may be dependent on the monomer's structure with different number of carbon molecules and double-bonds on the side carbon-chain. The two monomers, GA(13:0) and GA(15:1), are mainly responsible for the molluscicidal activities of GAs and both effectively inhibit snails' climbing up as well. GA(15:0) also shows certain molluscicidal activity.

Antidepressant and antistress activity of GC-MS characterized lipophilic extracts ofGinkgo bilobaleaves

Lipophilic extracts of Ginkgo biloba L. leaves were tested for their possible role on rodent models of depression and stress. Lipophilic extracts of Ginkgo leaves (LEG) at (50 and 100 mg/kg, p.o.) exhibited dose dependent, significant antidepressant activity in the behavioral despair test and learned helplessness rodent model of depression. The activities were comparable to that of imipramine (15 mg/kg) and EGb 761 (50 mg/kg). In the cold immobilization stress induced gastric ulcer model of stress, only the LEG showed a significant reduction in the ulcer index. GC-MS characterization of this bioactive extract was found to be rich in a group of 6-alkyl salicylates (6-AS), along with a fatty alcohol, fatty acids and cardanols. The n-heptadecenyl salicylate represented 60% of the 6-AS. Notable was the absence of dihydroxy alkylphenols which are linked to allergic reactions similar to the urushiols present in poison ivy. In commercial products of Ginkgo, these dihydroxy phenols as well as the favorable 6-AS are removed during enrichment of flavonol glycosides and terpenic lactones. The current findings suggest that intact carboxylic acid groups containing 6-AS are the bioactive components of the lipophilic extract of Ginkgo leaves with antidepressant and antistress activities.

Characterization of a suite of ginkgo-containing standard reference materials

A suite of three ginkgo-containing dietary supplement Standard Reference Materials (SRMs) has been issued by the National Institute of Standards and Technology (NIST) with certified values for flavonoid aglycones, ginkgolides, bilobalide, and selected toxic trace elements. The materials represent a range of matrices (i.e., plant, extract, and finished product) that provide different analytical challenges. The constituents have been determined by at least two independent analytical methods with measurements performed by NIST and at least one collaborating laboratory. The methods utilized different extractions, chromatographic separations, modes of detection, and approaches to quantitation. The SRMs are primarily intended for method validation and for use as control materials to support the analysis of dietary supplements and related botanical materials.

Validation of capillary gas chromatographic method for determination of bilobalide and ginkgolides A, B, C in Ginkgo biloba dry and liquid extracts

A method for identification and quantitative determination of ginkgolides A, B, and C and bilobalide in liquid and dry extracts of Ginkgo biloba extracts has been developed. Determinations made by employing capillary gas chromatography technique with FID detection were preceded by derivatization using BSTFA with TMCS addition at 120 degrees C. Cholesterol was used as an internal standard. Validation of the method shows no interferences with concurrent constituents; average resolution (R), controlled for peaks of cholesterol and ginkgolide A was 1.53 (SD = 0.06). In the temperature program used (from 50 degrees C to 300 degrees C) the analyte retention times range from 11.2 min. (bilobalide) to 13.8 min. (ginkgolide C) and are of high repeatability of relative values (RRT): RSD = 0.05% / 0.07% for ginkgolides. High correlation coefficients (r), detector signal linearity: from 0.99962 for ginkgolide C to 0.99985 for ginkgolide A were obtained within the concentration range under investigation. The method is of high sensitivity: limits of detection and limits of determination are 35 pg and 44 pg for bilobalide, respectively, while for ginkgolides (Gk) are: 78 pg and 92 pg for GkA, 57 pg and 68 pg for GkB, and 213 pg and 320 pg for GkC.

Ginkgo Biloba Extract (EGb 761) in Alzheimers Disease: Is there Any Evidence?

For centuries, extracts from the leaves of the Ginkgo biloba tree have been used as Chinese herbal medicine to treat a variety of health disorders. The standardized Ginkgo biloba extract EGb 761 was marketed in France and Germany 30 years ago for various vascular and cerebral deficits and is now classified as a food supplement in the United States. EGb 761 is currently the focus of phase-III clinical trials, GEM and GuidAge studies, to evaluate its efficacy on the prevention of Alzheimer's disease (AD) in subjects over 70 years old. This review summarizes recent advancements in our understanding of the potential role of EGb 761 in the prevention of AD. Besides its well-known free radical scavenging properties, the ability of EGb 761 to protect neurons probably also involves other intracellular pathways. We will point out potential targets of EGb 761 in the amyloid cascade such as its antiamyloidogenic properties or the regulation of gene expression. Moreover we will discuss the complexity of the cellular and molecular mechanisms of EGb 761 and the significance of the synergic effect of different constituents of EGb 761.

Ginkgo biloba leave extract: biological, medicinal, and toxicological effects

Ginkgo biloba leave extract is among the most widely sold herbal dietary supplements in the United States. Its purported biological effects include: scavenging free radical; lowering oxidative stress; reducing neural damages, reducing platelets aggregation; anti-inflammation; anti-tumor activities; and anti-aging. Clinically, it has been prescribed to treat CNS disorders such as Alzheimer's disease and cognitive deficits. It exerts allergy and changes in bleeding time. While its mutagenicity or carcinogenic activity has not been reported, its components, quercetin, kaempferol and rutin have been shown to be genotoxic. There are no standards or guidelines regulating the constituent components of Ginkgo biloba leave extract nor are exposure limits imposed. Safety evaluation of Ginkgo biloba leave extract is being conducted by the U.S. National Toxicology Program.

Effects of extract of ginkgo biloba on intracranial pressure, cerebral perfusion pressure, and cerebral blood flow in a rat model of subarachnoid haemorrhage

The purpose of this study was to investigate in effect of extract of Ginkgo biloba (EGb) on cerebral blood perfusion in a subarachnoid haemorrhage (SAH) rat model. SAH lead to an increase in intracranial pressure and decrease in cranial perfusion pressure and regional cerebral blood flow in all groups. However, the intracranial pressure increases in EGb groups were less than that of the vehicle group (p < .01), whereas the reduction in cranial perfusion pressure and regional cerebral blood flow in the EGb group was less than that of the vehicle and SAH groups (p < .01). It was concluded that EGb attenuates the increase in intracranial pressure and reduction in cerebral blood perfusion after SAH.

Effects of Ginkgo biloba on prevention of development of experimental diabetic nephropathy in rats

AIM

To observe the preventive and therapeutic effects of Ginkgo biloba extract (GbE) on early experimental diabetic nephropathy (DN) in rats.

METHODS

After an early DN model was induced by streptozotocin, rats were administered GbE at 3 doses for 12 weeks. Fasting blood glucose, creatinine (Cr), blood urea nitrogen (BUN), urine protein, kidney index, anti-oxidase, advanced glycosylation end products (AGE), collagen IV and laminin, matrix metalloproteinases-2 (MMP-2) and the tissue inhibitor of metalloproteinase-2 (TIMP-2), connective tissue growth factor (CTGF), and transforming growth factor-beta1 (TGF-beta1) mRNA were measured by different methods. The ultrastructural morphology and the thickness of glomerular base membrane (GBM) were observed by a transmission electron microscope.

RESULTS

For the GbE-treated DN rats, when compared with the vehicle-treated DN rats, the fasting blood glucose level, Cr, BUN, urine protein level, and the intensity of oxidative stress were significantly decreased. The expression of MMP-2 greatly increased, and TIMP-2 decreased. Also, AGE, either in serum or in renal, the collagen IV, laminin, CTGF levels, and TGF-beta1 mRNA were reduced. Furthermore, both relative grades of mesangium hyperplasia by microscopical observation and the thickness of GBM by electron microscope measurement decreased significantly.

CONCLUSION

GbE has protective effects on several pharmacological targets in the progress of DN and is a potential drug for the prevention of early DN.

Acute cognitive effects of standardised Ginkgo biloba extract complexed with phosphatidylserine

Recent data suggest that the complexation of standardised Ginkgo biloba extract (GBE) with soy-derived phospholipids enhances the bioavailability 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 (Virtiva), 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.

Ginkgo biloba and ovarian cancer prevention: Epidemiological and biological evidence

There is considerable interest in herbal therapies for cancer prevention but often with little scientific evidence to support their use. In this study, we examined epidemiological data regarding effects of commonly used herbal supplements on risk for ovarian cancer and sought supporting biological evidence. 4.2% of 721 controls compared to 1.6% of 668 cases regularly used Ginkgo biloba for an estimated relative risk (and 95% confidence interval) of 0.41 (0.20,0.84) (p=0.01); and the effect was most apparent in women with non-mucinous types of ovarian cancer, RR=0.33 (0.15,0.74) (p=0.007). In vitro experiments with normal and ovarian cancer cells showed that Ginkgo extract and its components, quercetin and ginkgolide A and B, have significant anti-proliferative effects ( approximately 40%) in serous ovarian cancer cells, but little effect in mucinous (RMUG-L) cells. For the ginkgolides, the inhibitory effect appeared to be cell cycle blockage at G0/G1 to S phase. This combined epidemiological and biological data provide supportive evidence for further studies of the chemopreventive or therapeutic effects of Ginkgo and ginkgolides on ovarian cancer.

Effect of Ginkgo biloba extract on the rat heart mitochondrial function

Ginkgo biloba L. (Ginkgoaceae) originated from China, first introduced to Europe in the 18th century, it is now distributed all over the world. The leaves of Ginkgo biloba include a rich complex of active compounds responsible for various pharmacological properties. Ginkgo biloba extract improves blood circulation, protects against oxidative cell damage, blocks platelet aggregation that could be important for prevention of cardiovascular diseases. Therefore the fluid extract from Ginkgo biloba leaves was prepared and tested for it is effect on rat mitochondrial function. Our data showed that 0.5 microl/ml of GE (containing 0.57 ng/ml of rutin, 0.23 ng/ml of quercitrin, 0.105 ng/ml of hyperosid and 0.02 ng/ml of quercetin) had no effect on the State 2 respiration rate of mitochondria with all used substrates: pyruvate+malate, succinate and palmitoyl-L-carnitine. Further increase in GE concentration (2 and 4 microl/ml), increased the State 2 respiration rate with all respiratory substrates in a dose-dependent manner (by 35-116%). The State 3 respiration rate was not affected by GE. In order to identify which compounds of GE could be responsible for the observed effects, we measured the effect of pure flavonoids: rutin, quercetin, hyperosid and quercitrin on mitochondrial respiration. All flavonoids (except of hyperosid) at maximal used concentration, comparable/identical to that in GE, stimulated the State 2 respiration rate only by 8-20%, i.e. less effectively as compared to GE. Therefore, for the explanation of the GE-induced uncoupling of oxidative phosphorylation, other biologically active compounds of GE have to be taken into account in future studies.

[Effect of EGb and quercetin on culture neonatal rat cardiomyocytes hypertrophy and mechanism]

AIM

To investigate the effect of extract of ginkgo biloba (EGb) and quercetin (Que) on the hypertrophic response induced by angiotensin II (Ang II) in the primary culture of neonatal rat cardiomyocytes and its mechanism.

METHODS

Total protein content of cardiomyocytes was measured by lowry's method. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were measured by SOD and MDA assay kits. The expression of phospho-ERK1/2, phospho-JNK and phospho-P38 were detected by Western blot. The expression of c-fos mRNA was checked by RT-PCR.

RESULTS

(1) The total protein content and cell size of cardiomyocytes increased significantly after Ang II treatment, EGb and Oue inhibited these effects of Ang II. (2) EGb and Que were able to enhance the SOD activity and reduce the production of MDA. (3) Ang II significantly activated ERK1/2, JNK and P38, only JNK activation was inhibited by Que and DPI but not ERK1/2 and P38 activation. (4) EGb, Que, Captopril and DPI all decreased Ang II-stimulated early response gent c-fos mnRNA expression.

CONCLUSION

EGb and Que could inhibit AngII-induced cardiomyocyte hypertrophy through a ROS-dependent pathway, the effect of Que might be related to the JNK and c-fos cascade.