Potential medicinal plants for CNS disorders: an overview

Although very few drugs are currently approved by regulatory authorities for treating multi-factorial ailments and disorders of cognition such as Alzheimer's disease, certain plant-derived agents, including, for example, galantamine and rivastigmine (a semi-synthetic derivative of physostigmine) are finding an application in modern medicine. However, in Ayurveda, the Indian traditional system of medicine which is more than 5000 years old, selected plants have long been classified as 'medhya rasayanas', from the Sanskrit words 'medhya', meaning intellect or cognition, and 'rasayana', meaning 'rejuvenation'. These plants are used both in herbal and conventional medicine and offer benefits that pharmaceutical drugs lack. In the present article, an attempt has been made to review the most important medicinal plants, including Ginkgo biloba, St John's wort, Kava-kava, Valerian, Bacopa monniera and Convolvulus pluricaulis, which are widely used for their reputed effectiveness in CNS disorders.

[Experimental research on application of hydrodynamic acoustic generator in extraction of Chinese medicine]

OBJECTIVE

To study the hydrodynamic ultrasonic energy extraction technique for Chinese Medicine.

METHOD

The content of baicalin in Radix Scutellariae extracts and total flavones in Folium Ginkgo extracts were as indexes respectively and measured by high performance liquid chromatography. We investigated the hydrodynamic ultrasonic energy extraction process for the extraction of Radix Scutellariae and Folium Ginkgo respectively, and compared with refluxing method, decoction and ultrasonic extraction. With the content of the extracts as indexes, Compound prescriptions of Traditional Chinese Medicine were extracted by the hydrodynamic ultrasonic extraction and decoction extraction.

RESULT

The content of baicalin of hydrodynamic ultrasonic energy extracts was significant higher than other extracts. The content of Ginkgo leaves flavones in hydrodynamic ultrasonic energy extracts and ultrasonic extracts had no significant difference. Compared with decocting extracts, hydrodynamic ultrasonic energy extracts of TCM compound prescriptions content was higher greatly.

CONCLUSION

The hydrodynamic ultrasonic energy extraction process showed higher extraction rate of baicalin of radix scutellariae than traditional extraction methods. And it was beneficial to the dissolution of water-soluble constituents in compound prescriptions of TCM. The content of Ginkgo leaves flavones in the hydrodynamic ultrasonic energy extracts and ultrasonic extracts had no obvious difference.

Selection of bioavailability markers for herbal extracts based on in silico descriptors and their correlation to in vitro permeability

Bioavailability data for herbal supplements in humans is not readily available or is difficult to obtain, because of the complexity of the composition and the diversity of the constituents. Potency of an herbal extract is due to the synergistic interactions between several constituents. Thus, the use of in silico methods is an attractive alternative to predict the qualitative intestinal permeability of the active constituents for the selection of appropriate bioavailability markers. Molecular descriptors such as CLogP, minimal cross-sectional area and polar surface area of 37 active components from selected herbal extracts such as milk thistle, kava, ginkgo, ginseng, valerian, black cohosh and garlic were estimated. In vitro permeability of the compounds was determined by SimBioDAS an in vitro epithelial cell permeability assay. Based on the in silico descriptors and their relationship with the in vitro permeability, the qualitative intestinal permeability of the active compounds was predicted. Bioavailability and bioequivalence markers were predicted for kava, Ginkgo biloba and milk thistle. Choosing a compound which has the least intestinal permeability as a marker is the most conservative approach toward ensuring the bioavailability of the entire extract.

[Ginkgo Biloba as a cognitive enhancer]

Ginkgo Biloba preparations exhibit nootropic activity in the absence of side effects, which is confirmed by numerous experimental observations and clinical results. The neuroprotector effect of these drugs is based on the antitoxicant action, antioxidant properties, and the ability to normalize the neuromediator and energy transfer mechanisms in cerebral neurons. In this review, recent data on the influence of various Ginkgo Biloba preparations on the cognitive functions in animals and humans and neurochemical mechanisms of the nootropic effect are summarized.

Postnatal development of pups from nursing rats treated with Gingko biloba

The Gingko biloba extract is contraindicated during pregnancy and lactation due to the lack of information about its effects on these reproductive phases. Previous studies have shown that G. biloba extract contains components with estrogenic and antiestrogenic activities, thus nursing dams treated with the extract of this plant could show reduction in milk production, resulting in malnutrition and poor development of pups. This work analyzes the postnatal development of pups, whose mothers were treated with G. biloba extract during the lactation period. Nursing Wistar rats received 3.5 mg/kg/day of G. biloba aqueous extract, corresponding to the highest human dose. Clinical signs of maternal toxicity were evaluated. The growth rate, viability, survival during treatment and lactation indices of the pups were calculated. The physical, motor and sensorial development of the pups was also evaluated. No maternal signs of toxicity were observed. As there were no biological differences between control and G. biloba treated pups, it is possible to assume that, in this experimental design, the administration of G. biloba aqueous extract to nursing rats during the lactation period seems to be devoid of toxic effect to mothers and to the physical, motor and sensory development of the pups.

Lipid peroxidation and cyclooxygenase enzyme inhibitory activities of acidic aqueous extracts of some dietary supplements

The botanical supplement market is growing at a fast pace with more and more people resorting to them for maintaining good health. Echinacea, garlic, ginkgo, ginseng, Siberian ginseng, grape seed extract, kava kava, saw palmetto and St John's wort are some of the popular supplements used for a variety of health benefits. These supplements are associated with various product claims, which suggest that they possess cyclooxygenase (COX) enzyme and lipid s inhibitory activities. COX enzymes are found to be at elevated levels in inflamed and cancerous cells. To test some of the product claims, selected supplements were analysed for their ability to inhibit COX-1 and -2 enzymes and lipid peroxidation in vitro. The supplements were extracted with acidified water (pH 2) at 37 degrees C to simulate the gastric environment. The supplements tested demonstrated varying degrees of COX enzyme inhibition (5-85% for COX-1 and 13-28% for COX-2). Interestingly, extracts of garlic (Meijer), ginkgo (Solaray), ginseng (Nature's Way), Siberian ginseng (GNC, Nutrilite, Solaray, Natrol), kava kava (GNC, Sundown, Solaray) and St John's wort (Nutrilite) selectively inhibited COX-2 enzyme. These supplements also inhibited lipid peroxidation in vitro (5-99%). The results indicated that the consumption of these botanical supplements studied possess health benefits.

Cardioprotective activity of Ginkgo biloba Phytosomes in isoproterenol-induced myocardial necrosis in rats: a biochemical and histoarchitectural evaluation

The protective effects of Ginkgo biloba Phytosomes (GBP) in isoproterenol (ISO)-induced cardiotoxicity and the antioxidant activity involved in this protection were investigated in rats. Myocardial infarction was produced in rats with 65, 85, 120 and 200mg/kg of ISO administered subcutaneously (sc) twice at an interval of 24h. An ISO dose of 85mg/kg was selected for the present study as this dose offered significant alteration in biochemical parameters and moderate necrosis in heart. Effect of GBP oral treatment for 21 days at two doses (100mg and 200mg/kg body weight) was evaluated against ISO (85mg/kg, sc)-induced cardiac necrosis. Levels of marker enzymes (AST, LDH and CPK) were assessed in serum and heart, antioxidant parameters viz., reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) and malondialdehde (MDA) were assayed in heart homogenate. Significant myocardial necrosis, depletion of endogenous antioxidants and increase in serum levels of marker enzymes were observed in ISO-treated animals when compared with the normal animals. GBP elicited a significant cardioprotective activity by lowering the levels of serum marker enzymes and lipid peroxidation and elevated the levels of GSH, SOD, CAT, GPx and GR. The present findings have demonstrated that the cardioprotective effects of GBP in ISO-induced oxidative damage may be due to an augmentation of the endogenous antioxidants and inhibition of lipid peroxidation of membrane.

[Effect of combined therapy with hypha Cordyceps and ginkgo leaf tablet on micro-inflammation in patients undergoing maintenance hemodialysis]

OBJECTIVE

To investigate the status of the micro-inflammation in patients undergoing maintenance hemodialysis and the effect of combined therapy with hypha cordyceps and ginkgo leaf tablet for its prevention and treatment.

METHODS

Sixty-five patients undergoing long-term maintenance hemodialysis were randomly assigned to the treated group (33 patients) and the control group (32 patients). Patients in both groups underwent hemodialysis regularly, meanwhile, 3 capsules of Jinshuibao (each capsule containing hypha cordyceps 0.33 g) and 1 tablet of ginkgo leaf tablet (0.23 g/tablet) were additiolally given to the patients in the treated group orally, 3 times per day, and 3 months as 1 treatment course. Their serum inflammatory factors, such as high sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha), which could reveal the state of microinflammation, were determined before and after treatment. And the same index was also determined in 30 healthy persons allocated in a normal control group.

RESULTS

Compared with the normal control group, the serum levels of hs-CRP (4.94 +/- 2.21 mg/L), IL-6 (0.472 +/- 0.220 microg/L) and TNF-alpha (1.748 +/- 0.724 microg/L) in the treated group were higher before treatment, these indexes decreased markedly after treatment (3.28 +/- 1.28 mg/L, 0.379 +/- 0.163 microg/L, and 1.330 +/- 0.458 microg/L, respectively, all P < 0.01), but without significant change in the control group.

CONCLUSION

Micro-inflammation reaction exists popularly in patients undergoing maintenance hemodialysis, and the combined therapy with hypha cordyceps and ginkgo leaf tablet could effectively improve this kind of micro-inflammation reaction.

Free amino acids in botanicals and botanical preparations

Numerous studies were carried out about aminoacidic composition of vegetable proteins, but information about the free amino acid pool and the role of these substances is very incomplete. The aim of this paper was to contribute to the scarce knowledge concerning the composition of free amino acids in botanicals and botanical preparations widely used as food, in dietary supplements, and in pharmaceutical products. This work studied the composition of free amino acids, identified the major components of 19 species of plants, and evaluated the influence of different types of extraction on the amino acid profile. Amino acids were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and ultraviolet detection. The amounts of total free amino acids varied widely between plants, from approximately 12 g in 100 g of Echinacea pallida extract to less than 60 mg in the same amount of Coleus forskohlii, Garcinia cambogia, and Glycine max. In 13 plants arginine, asparagine, glutamine, proline, and gamma-aminobutyric acid were the free amino acids found in preponderant quantities. The levels of free amino acids above the quantification limit in 36 assayed samples of botanicals, extracts, and supplements are shown.

Fingerprint profile of Ginkgo biloba nutritional supplements by LC/ESI-MS/MS

Ginkgo biloba is one of the most popular herb nutrition supplements, with terpene lactones and flavonoids being the two major active components. A fingerprint profile method was developed using a capillary HPLC/MS method which can identify more than 70 components from the G. biloba product. The method allows the flavonoids and terpene lactones to be detected simultaneously and information of both the parent ion and its fragmentation can be obtained in just one HPLC/MS run. Targeted post-acquisition analysis allows mass spectrometric information regarding the identification of flavonoid components to be easily distinguished from other data, however the same approach for terpene lactones was less successful due to dimer formation and requires further development. The fingerprint profiles of five commercial G. biloba nutritional supplements were obtained and compared; variation of some components among the samples was observed and fortification could be detected. In the quality control analysis of the G. biloba product this method could be viewed as complementary to specific quantitative analysis of some bioactive components of the herb.

[Effect of total flavonoid in leaves of Ginkgo biloba on the apoptosis of eosinophil in broncho alveloar lavage fluid]

This study was to investigate the effect of total flavonoid in leaves of Ginkgo biloba (total flavonoid in leaves of Ginkgo biloba, FG) on the apoptosis of eosinophils (EOS) in broncho alveloar lavage fluid (BALF) of asthma mice. Mouse asthma model was established by ovalbumin (OVA) challenge methods. After atomizing therapy for two weeks, differential count in BALF, morphological change and proportion of apoptosis were detected by AO/EB stain and Annexin V-FITC/PI. The number of total leucocytes and eosinophils in BALF decreased obviously after FG treatment. Compared with model group, the number and proportion of EOS apoptosis increased significantly after FG treatment. The results indicated that one of the anti-inflammation mechanisms of FG might be promoting apoptosis of eosinophils.

Effect of Ginkgo biloba on the reproductive outcome and oxidative stress biomarkers of streptozotocin-induced diabetic rats

The aim of the present study was to evaluate the effect of Ginkgo biloba treatment (EGb 761, 200 mg kg-1 day-1) administered from day 0 to 20 of pregnancy on maternal reproductive performance and on the maternal and fetal liver antioxidant systems of streptozotocin-induced diabetic Wistar rats. On day 21 of pregnancy, the adult rats (weighing approximately 250 +/- 50 g, minimum number = 13/group) were anesthetized to obtain maternal and fetal liver samples for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and total glutathione (GSH-t) determinations. The uterus was weighed with its contents. The diabetic (G3) and treated diabetic (G4) groups of rats presented significant maternal hyperglycemia, reduced term pregnancy rate, impaired maternal reproductive outcome and fetal-placental development, decreased GSH-Px (G3 = G4 = 0.6 +/- 0.2) and SOD (G3 = 223.0 +/- 84.7; G4 = 146.1 +/- 40.8), and decreased fetal CAT activity (G3 = 22.4 +/- 10.6; G4 = 34.4 +/- 14.1) and GSH-t (G3 = G4 = 0.3 +/- 0.2), compared to the non-diabetic groups (G1, untreated control; G2, treated). For G1, maternal GSH-Px = 0.9 +/- 0.2 and SOD = 274.1 +/- 80.3; fetal CAT = 92.6 +/- 82.7 and GSH-t = 0.6 +/- 0.5. For G2, G. biloba treatment caused no toxicity and did not modify maternal or fetal-placental data. EGb 761 at the nontoxic dose used (200 mg kg-1 day-1), failed to modify the diabetes-associated increase in maternal glycemia, decrease in pregnancy rate, decrease in antioxidant enzymes, and impaired fetal development when the rats were treated throughout pregnancy (21 days).

Improvement of short-term memory performance in aged beagles by a nutraceutical supplement containing phosphatidylserine, Ginkgo biloba, vitamin E, and pyridoxine

Aged dogs demonstrate cognitive decline that is linked to brain aging. The purpose of the present study was to examine if a commercially available nutraceutical supplement that may be neuroprotective and contains phosphatidylserine, Ginkgo biloba, vitamin E, and pyridoxine could improve cognitive function in aged beagles. Nine aged beagles were tested on performance on a delayed-non-matching-to-position task, which is a neuropsychological test of short-term visuospatial memory. All subjects were tested on 5 baseline sessions; then, to assess the supplement, a crossover design was used in which 1 group received the supplement and the other a control substance in the 1st phase, with treatment conditions being reversed in the 2nd phase. Performance accuracy was significantly improved in supplemented dogs compared with control dogs and the effect was long lasting. These findings suggest that the nutraceutical supplement can improve memory in aged dogs.

Spectroscopic investigation of Ginkgo biloba terpene trilactones and their interaction with amyloid peptide Abeta(25-35)

The beneficial effects of Ginkgo biloba extract in the "treatment" of dementia are attributed to its terpene trilactone (TTL) constituents. The interactions between TTLs and amyloid peptide are believed to be responsible in preventing the aggregation of peptide. These interactions have been investigated using infrared vibrational absorption (VA) and circular dichroism (VCD) spectra. Four TTLs, namely ginkgolide A (GA), ginkgolide B (GB), ginkgolide C (GC) and bilobalide (BB) and amyloid Abeta(25-35) peptide, as a model for the full length peptide, are used in this study. GA-monoether and GA-diether have also been synthesized and investigated to help understand the role of individual carbonyl groups in these interactions. The precipitation and solubility issues encountered with the mixture of ginkgolide+Abeta peptide for VA and VCD studies were overcome using binary ethanol-D(2)O solvent mixture. The experimental VA and VCD spectra of GA, GB, GC and BB, GA-monoether and GA-diether have been analyzed using the corresponding spectra predicted with density functional theory. The time-dependent experimental VA and VCD spectra of Abeta(25-35) peptide and the corresponding experimental spectra in the presence of TTLs indicated that the effect of the TTLs in modulating the aggregation of Abeta(25-35) peptide is relatively small. Such small effects might indicate the absence of a specific interaction between the TTLs and Abeta(25-35) peptide as a major force leading to the reduced aggregation of amyloid peptides. It is possible that the therapeutic effect of G. biloba extract does not originate from direct interactions between TTLs and the Abeta(25-35) peptide and is more complex.

Inhibition of HIV-1 protease and RNase H of HIV-1 reverse transcriptase activities by long chain phenols from the sarcotestas of Ginkgo biloba

Nine long-chain phenols: four cardanols (1-4), two bilobols (5, 6) and three alkylsalicylic acids (7-9) [corrected] were isolated from the CH(2)Cl(2) extracts of the sarcotestas of Ginkgo biloba as HIV-1 protease (PR) inhibitors. From these phenols, the bilobols (IC (50), 2.6 - 5.8 microM) and alkylsalicylic acids (IC (50), 10.2 - 24.9 microM) exhibited dose-dependent potent inhibitory activities on HIV-1 PR, while the cardanols did not. On the other hand, only the alkylsalicylic acids (IC (50), 33.7 - 170.3 microM) inhibited the activities of RNase H of HIV-1 reverse transcriptase (RT), while all of the compounds failed to affect the RNA dependent DNA polymerase (RDDP) of HIV-1 RT. Therefore, we regard bilobols as a new class and selective inhibitors of HIV-1 PR; in addition, alkylsalicylic acids are elucidated as a new class of inhibitors against HIV-1 PR and RNase H of HIV-1 RT.

[Ginkgo biloba extract enhances testosterone synthesis of Leydig cells in type 2 diabetic rats]

OBJECTIVE

To investigate the effects of Ginkgo biloba extract (EGB) on the testosterone synthesis in the Leydig cells of type 2 diabetic rats.

METHODS

Thirty male SD rats were equally randomised into a normal control, a type 2 diabetic and an EGB group. Morphological changes of Leydig cells were observed by light microscopy (LM) and transmission electron microscopy (TEM), concentrations of serum luteinizing hormone (LH) and testosterone (T) were determined by enzyme linked immunosorbent assay (ELISA), and the mRNA levels in the steroidogenic acute regulatory protein (StAR), cytochrome P450 side chain cleavage (P450scc), cytochrome P450 17a-hydroxylase (P450c17), 17beta-hydroxysteroid dehydrogenase 3 (17beta-HSD3) and 3beta-hydroxysteroid dehydrogenase (3beta-HSD1) from the Leydig cells were examined by RT-PCR.

RESULTS

Compared with the normal control, there was a significant decrease in the number and volume of Leydig cells, the levels of serum LH and T and the expression of mRNA in StAR, P450scc, 17beta-HSD3 and 3beta-HSD1 in the type 2 diabetes group. And the expression of the P450c17 gene showed a tendency of descending, but with no significance. Compared with the type 2 diabetes group, 12 weeks of EGB treatment caused very slight pathological changes in the Leydig cells, significantly increased the concentrations of blood LH and T, markedly elevated the levels of mRNA in StAR and P450scc and induced an ascending tendency of the expressions of P450c17, 17beta-HSD3 and 3beta-HSD1.

CONCLUSION

EGB enhances testosterone synthesis and secretion of Leydig cells by reducing the impairment of the testis in type 2 diabetic rats.

Ginkgo biloba extract improves coronary blood flow in healthy elderly adults: role of endothelium-dependent vasodilation

Advancing age decreases endothelial function; accordingly, it alters the physiological regulation of coronary blood flow. Ginkgo biloba extract (GBE) has well-documented anti-ageing effects. However, little is yet known about the pharmacological actions of GBE on endothelial dysfunction and coronary blood flow in healthy elderly adults. We designed the study to test the effects of GBE on distal left anterior descending coronary artery (LAD) blood flow and endothelium-dependent brachial artery flow-mediated dilation (FMD) in healthy elderly adults. Sixty healthy elderly adults were randomly assigned to either GBE or control groups. LAD blood flow and brachial artery FMD were measured non-invasively using high-resolution ultrasound before and after intravenous administration of GBE or saline. GBE significantly increased LAD blood flow in maximal diastolic peak velocity (MDPV), maximal systolic peak velocity (MSPV) and diastolic time velocity integral (DTVI) compared with the placebo group (19.16+/-13.91% vs. 0.30+/-2.55%, 17.76+/-14.56% vs. 0.53+/-2.32%, and 21.73+/-16.13% vs. 0.81+/-2.33%, MDPV, MSPV, and DTVI improvement from baseline, respectively, p<0.01). Brachial artery FMD was also increased by 56.03% (from 7.21+/-2.52% to 11.28+/-3.95%, p<0.01). A linear correlation was found between the percentage change in MDPV, MSPV, or DTVI of LAD blood flow and the percentage change in brachial artery FMD following treatment with GBE (r=0.538, 0.366, or 0.573, respectively, p<0.01, p<0.05, or p<0.01). Our data demonstrate that GBE treatment in healthy elderly adults leads to the increase of LAD blood flow in MDPV, MSPV and DTVI, and the increased response might relate to the improved endothelium-dependent vasodilatory capacity. This study implies an important future therapeutic strategy of using GBE to counteract the detrimental effects of ageing.

Simultaneous determination of ginkgo flavonoids and terpenoids in plasma: ammonium formate in LC mobile phase enhancing electrospray ionization efficiency and capacity

Extracts from Ginkgo biloba leaves confer their therapeutic effects through the synergistic actions of flavonoid and terpenoid components. We herein describe the development of an LC-MS/MS-based method for simultaneous determination of flavonoids (quercetin, kaempferol, and isorhamnetin) and terpenoids (bilobalide, ginkgolides A, B, C, and J) in acid-hydrolyzed plasma by circumventing cross-interference between the flavonoids and terpenoids identified. Notably, inclusion of ammonium formate (0.2 mM) in the mobile phase generated beneficial LC-electrolyte effects, including increased ESI efficiency and capacity, with the result that the newly developed procedure exhibits the highest analytical performance reported to date for ginkgo-associated studies. The method yields high sensitivity, negligible matrix interference and cross-interference, wide linear dynamic ranges, high sample throughput, and quite small initial sample size. The assay utility to dog pharmacokinetic measurements of commercial ginkgo products yielded the most comprehensive data on systemic exposure to the ginkgo compounds to date. The newly developed multi-analyte procedure should be widely useful.

Suppression of tissue necrosis factor-alpha or hydrogen peroxide-activated primary human T lymphocytes by Ginkgo biloba extract through down-regulation of activator protein-1 signal transduction

PURPOSE

It was unknown whether Ginkgo biloba extract has regulatory effects on human T lymphocytes activated by tissue necrosis factor-alpha (TNF-alpha), which has an important role on the progression of inflammatory atherosclerotic plaques. We evaluated the effects of G. biloba extract on activated human peripheral T lymphocytes, which were isolated from human whole blood.

METHODS

The human T lymphocytes were treated with 25-100 microg G. biloba extract for 2h first. Then they were activated by TNF-alpha and H(2)O(2) to investigate the modulatory effects of G. biloba extract on human T lymphocytes. Electrophoretic mobility shift assay, Western blot (Immunoblot) analysis and immunoprecipitation kinase assays were used.

RESULTS

The inhibition of activated human T lymphocyte specifically correlated with the down-regulation of AP-1 DNA-binding activities. G. biloba extract was unique in its ability to inhibit the activation of c-Jun NH2-terminal protein kinase.

CONCLUSIONS

G. biloba extract might have its novel therapeutic effects on inflammation-based atherosclerotic diseases.

Subunit-specific potentiation of recombinant glycine receptors by NV-31, a bilobalide-derived compound

Bilobalide, a major bioactive component of Ginkgo biloba herbal extracts, exhibits neuroprotective and anti-ischaemic activity. However, its therapeutic potential is limited because of its instability. Attempts to synthesise a more stable analogue culminated in the development of NV-31. This compound recapitulates some aspects of bilobalide pharmacology. However, although bilobalide inhibits recombinant glycine receptor Cl channels (GlyRs), NV-31 potentiates hippocampal neuron GlyRs. Because of the possible therapeutic relevance of this effect, the present study investigated the molecular mechanism and subunit specificity of NV-31 actions at recombinantly expressed alpha1, alpha1beta, alpha2 and alpha3 GlyRs. NV-31 potentiated alpha1 GlyRs by approximately 135% with an EC50 near 170 nM. Its potentiating effect was observed only at low (EC10) glycine concentrations. The magnitude of its potentiating effect was reduced at alpha1beta GlyRs and it had no effect at all at alpha2 and alpha3 GlyRs. NV-31 was unlikely to bind at the bilobalide pore-binding site as its efficacy was not affected by the alpha1 subunit G2'A and T6'S mutations. However, the S15'C mutation to the alcohol-binding site abolished its effects, suggesting that NV-31 modulates the GlyR via a specific (steric or allosteric) interaction with S15'. GlyRs are potential therapeutic targets for chronic anti-inflammatory pain and movement disorders. NV-31, as a positive modulator of these receptors, thus remains viable as a therapeutic candidate for these disorders.

[Progress of study on treatment of Alzheimer's disease with active ingredients of Chinese herbal medicines]

In order to advance the treatment of Alzheimer's disease with active ingredients of Chinese herbal medicines and the research on these ingredients and their effective targets in treating the disease, the relative representative literatures published in recent years were reviewed and summarized in this paper.

[Effects of EGb761 on hippocamal synaptic plasticity of vascular dementia rats]

AIM

To investigate the effects of ginkgo biloba extract 761 (EGb761) on synaptic plasticity in hippocampus of vascular dementia (VD) rats.

METHODS

The escape latency (EL) of Morris water maze (MWM) task was measured at different time points (4 W, 8 W and 16 W), and the population spikes (PS) of granule cell layer in the dentate gyrus were induced by single pulse stimulation to perfo rate path fibers before and after high frequency stimulation (HFS) in vivo.

RESULTS

MWM test showed that the escape latency (EL) of VD model group were highly longer than that of the sham-operated group, while the EL of EGb761-treated group was significantly shorter than that of model group, but still longer than that of the sham-operated group. The incidence rates of LTP induction in 1 m, 2 m and 4 m subgroups of model group were significantly lower than that of sham-operated group and EGb761-treated group at different time point. The relative amplitudes of PS after HFS in 1 m, 2 m and 4 m subgroups of model group were obviously reduced compared with that of the corresponding subgroups of sham-operated group and EGb761-treated group. There was no obvious significance in the peak latency of PS between different subgroups and different LTP-tested time point.

CONCLUSION

VD model rats had apparent and long-lasting dysfunction of learning and memory, EGb761 could accelerate the recovery of the pathological synaptic plasticity. This suggested that EGb761 played an important and improving role on learning and memory dysfunction of VD.

[Effect of extract of Ginkgo biloba on doxorubicin-associated cardiotoxicity in patients with breast cancer]

OBJECTIVE

To study the effect of extract of Ginkgo biloba (Egb761) on doxorubicin-associated cardiotoxicity in patients with breast cancer (BC).

METHODS

Sixty BC patients in stage IV were randomly assigned to two groups, the control group was treated with chemotherapy, using 4 cycles of PA protocol alone and the treated group with the same chemotherapy and Egb761. Changes in electrocardiogram (ECG), myocardial enzyme spectrum (MES) and ultrasono-cardiogram (USCG) before and after treatment were observed.

RESULTS

After treatment, the incidence of abnormal ECG was lower in the treated group than in the control group (6.7% vs 30.0%); significant differences were found between the two groups in the parameters of MES (P< 0.05); USCG showed significant difference between the two groups in left ventricular diastolic diameter (LVDd), left ventricular systolic diameter (LVDs), ratio of early and late diastolic transmitral peak flow velocity (E/A) and fractional shortening (FS), while there was no significant difference in ejection fraction (EF).

CONCLUSION

Egb761 is an ideal drug for preventing and reducing the acute doxorbincin-induced cardiotoxicity; it could also be helpful for alleviating the chronic cardiotoxicity.

Induction of cytochrome P450 3A by the Ginkgo biloba extract and bilobalides in human and rat primary hepatocytes

Ginkgo biloba is one of the most popular herbal medicines in the world, due to its purported pharmacological effects, including memory-enhancing, cognition-improving, and antiplatelet effects. The study aimed to investigate the activity and expression of cytochrome P450 (CYP) 3A in human and rat primary hepatocytes treated with standardized G. biloba extract (100, 500, and 2500 ng/ml) for 72 hr, and to measure the protein expression of CYP3A in human and rat primary hepatocytes treated with bilobalide (2, 10, and 50 ng/ml) and ginkgolides B (2, 10, and 50 ng/ml). The activity of CYP3A was measured by the quantification of dehydronifedipine formation using a validated tandem liquid chromatography mass spectrometry (LC/MS/MS) method. The levels of mRNA and protein of CYP3A were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western-blotting analysis, respectively. The G. biloba extract at 100-2,500 ng/ml significantly induced the activity, protein and mRNA expression of CYP3A in a dose-dependent manner in human and rat primary hepatocytes. Bilobalide at 2-50 ng/ml significantly increased CYP3A protein expression in a dose-dependent manner in human and rat primary hepatocytes. However, ginkgolide B did not affect CYP3A protein expression in vitro. The results indicate that G. biloba extract pretreatment significantly induced the expression of CYP3A protein and mRNA and increased CYP3A activity, and there was no significant species difference between human and rat. G. biloba may cause potential interactions with substrate drugs of CYP3A. Bilobalide might play a key role in the enzyme-inducing effects of G. biloba extract. Further study is needed to identify the substances in GBE that induce CYPs in vivo, and elucidate the molecular mechanism of CYP3A induction by GBE and bilobalides.