Antiapoptotic Effects of EGb 761

Therapeutic Versus Preventative Use of Ginkgo biloba Extract (EGb 761) against Indomethacin-Induced Gastric Ulcer in Mice

The main bioactive constituents in the standardized Ginkgo biloba leaf extract (EGb 761) are the terpene lactones and flavonoid glycosides. EGb 761’s antioxidant and anti-inflammatory properties have previously been demonstrated. Indomethacin-induced gastric ulcers have a multifactorial etiology and represent a major restriction to its therapeutic utility. The underlying ulcerogenic process involves oxidative and inflammatory biomolecular insults. This study was performed to explore the curative and preventative benefits of EGb 761 in experimentally-induced ulcers. To develop gastric ulcers in mice, indomethacin (40 mg/kg) was administered orally. EGb 761 (200 mg/kg) was given by gavage for 7 days before (preventative) and after (therapeutic) indomethacin administration. The histological alterations and macroscopic mucosal lesions were assessed. In gastric tissue homogenates, malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO), and inflammatory cytokines were measured. The expressions of cyclooxygenase-2 (COX-2), cytokines, and proliferating cell nuclear antigen (PCNA) in the stomach mucosa were also investigated. The ulcer index, histological alterations, gastric oxidants, and inflammatory biomarkers were all significantly increased by indomethacin. In stomach specimens, it increased COX-2 and PCNA expression. EGb 761 treatments, both prophylactic and therapeutic, resulted in significant reductions in ulcer lesions, nitrosative and oxidative damage, and inflammatory markers, along with the lowering of COX-2 and PCNA expressions. Furthermore, in the fight against stomach ulcers, EGb 761 treatment was found to be more efficient than prevention.

Ginkgo biloba extract (EGb 761) mitigates methotrexate-induced testicular insult in rats: Targeting oxidative stress, energy deficit and spermatogenesis

Methotrexate (MTX) is commonly used as a therapeutic agent in the treatment of malignancies and autoimmune disorders. Risk of subsequent infertility following MTX administration has been reported as a significant side effect due to testicular toxicity. The aim of the study was to evaluate the modulatory effects of Ginkgo biloba (standardized extract, EGb 761) on MTX-induced testicular oxidative stress, energy deficits and spermatogenic status in rats. All groups received intraperitoneal injection of MTX (0.5 mg/kg) twice weekly for four weeks except the control group that received the corresponding vehicles. Other groups received oral EGb761, at doses 25, 50 or 100 mg/kg/day, for four weeks, concurrently with MTX. Blood and semen sampling followed by testis dissection were performed 24 h after last EGb 761 treatment. Semen was examined for sperm progressive motility, percent of normal spermatozoa and sperm cell concentration as well as seminal plasma essential and non-essential amino acids. Serum LH, FSH and testosterone were detected as well as testicular MDA, GSH, GSSG, TNF-α, IL-1β, IL-6, NF-κB and the nuclear, cytoplasmic and mRNA expression levels of Nrf-2 besides the testicular cell energy; AMP, ADP and ATP. Histopathological studies of interstitial fibrosis and the severity of germ cell degeneration were also conducted. MTX induced significant decline in sperm quality along with decreased essential and non-essential amino acids in seminal plasma. MTX reduced serum FSH, LH and testosterone as well as testicular ATP, GSH and Nrf2, while increased levels of testicular ADP, AMP, MDA, GSSG and TNF-α. Results were confirmed by prominent interstitial fibrosis and severe germ cell degeneration in MTX group. Concurrent treatment with EGb 761 alleviated MTX-induced testicular insult evidenced by amelioration of oxidative stress biomarkers, energy functions, seminal sperms abnormalities and spermatogenesis status. The present study suggests a beneficial role of EGb 761 in MTX-induced testicular injury and subsequent distortion of spermatogenesis.

Combination of docosahexaenoic acid and Ginko biloba extract improves cognitive function and hippocampal tissue damages in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases characterized by a progressive loss of memory and other cognitive functions among elder people. Nowadays, natural antioxidants have been used to recover the quality of life for those with AD. In this study, we investigated, for the first time, the combined effect of docosahexaenoic acid (DHA) and Ginkgo bilobastandardized extract (EGb761) on AD mice. AD was induced in adult male albino mice with AlCl₃ (20 mg/kg b.w, i.g.) and D-galactose (D-gal; 120 mg/kg, i.p.) for 90 days. 30 days after induction, mice were treated with DHA (200 mg/kg b.w., i.g.) and EGb761 (200 mg/kg b.w., i.g.) for two months. Our data revealed that the dual treatment of DHA and EGb761 significantly improved cognitive memory and spatial learning abilities in AD-induced mice. The drug treatments preserved the hippocampal CA3 architecture and restored neuronal ultrastructural alterations. Expression of protein phosphatase 2A (PP2A), the most implicated protein phosphatase in AD neurodegeneration, was highly upregulated in the CA3 hippocampus of AD mice treated with DHA and EGb761. Intriguingly, TNF-α expression was significantly reduced in the same group. In conclusion, our findings proved that the combined effect of DHA and EGb761 tended to be potent against the neurodegenerative effect of AlCl₃ and D-gal. The applied treatment enhanced neuronal survival and cognitive functions via upregulation of PP2A and restoration of TNF-α expression.

Target Proteins in the Dorsal Hippocampal Formation Sustain the Memory-Enhancing and Neuroprotective Effects of Ginkgo biloba

We have previously shown that standardized extracts of Ginkgo biloba (EGb) modulate fear memory formation, which is associated with CREB-1 (mRNA and protein) upregulation in the dorsal hippocampal formation (dHF), in a dose-dependent manner. Here, we employed proteomic analysis to investigate EGb effects on different protein expression patterns in the dHF, which might be involved in the regulation of CREB activity and the synaptic plasticity required for long-term memory (LTM) formation. Adult male Wistar rats were randomly assigned to four groups (n = 6/group) and were submitted to conditioned lick suppression 30 min after vehicle (12% Tween 80) or EGb (0.25, 0.50, and 1.00 g⋅kg^-1) administration (p.o). All rats underwent a retention test session 48 h after conditioning. Twenty-four hours after the test session, the rats were euthanized via decapitation, and dHF samples were removed for proteome analysis using two-dimensional polyacrylamide gel electrophoresis, followed by peptide mass fingerprinting. In agreement with our previous data, no differences in the suppression ratios (SRs) were identified among the groups during first trial of CS (conditioned stimulus) presentation (P > 0.05). Acute treatment with 0.25 g⋅kg^-1 EGb significantly resulted in retention of original memory, without prevent acquisition of extinction within-session. In addition, our results showed, for the first time, that 32 proteins were affected in the dHF following treatment with 0.25, 0.50, and 1.00 g⋅kg^-1 doses of EGb, which upregulated seven, 19, and five proteins, respectively. Additionally, EGb downregulated two proteins at each dose. These proteins are correlated with remodeling of the cytoskeleton; the stability, size, and shape of dendritic spines; myelin sheath formation; and composition proteins of structures found in the membrane of the somatodendritic and axonal compartments. Our findings suggested that EGb modulates conditioned suppression LTM through differential protein expression profiles, which may be a target for cognitive enhancers and for the prevention or treatment of neurocognitive impairments.

Brain Ageing, Cognition and Diet: A Review of the Emerging Roles of Food-Based Nootropics in Mitigating Age-related Memory Decline

BACKGROUND

Age-related cognitive decline has been suggested to result from an increase in the brain neuron loss, which is attributable to continued derangement of the brain's oxidant/ antioxidant balance. Increased oxidative stress and a concomitant decrease in the brain's antioxidant defense system have been associated with functional senescence and organismal ageing. However, nature has configured certain foods to be rich sources of nootropic agents, with research showing that increased consumption of such foods or food ingredients may be protective against ageing-related memory decline. This knowledge is becoming increasingly valuable in an era when the boundary that separates food from medicine is becoming blurred. In this review, we examine extant literature dealing with the impact of ageing on brain structure and function, with an emphasis on the roles of oxidative stress. Secondly, we review the benefits of food-based antioxidants with nootropic effects and/or food-based nootropic agents in mitigating memory decline; with a view to improving our understanding of likely mechanisms. We also highlight some of the limitations to the use of food-based nootropics and suggest ways in which they can be better employed in the clinical management of age-related cognitive decline.

CONCLUSION

While it is known that the human brain endures diverse insults in the process of ageing, food-based nootropics are likely to go a long way in mitigating the impacts of these insults. Further research is needed before we reach a point where food-based nootropics are routinely prescribed.

Autophagic and Apoptotic Pathways as Targets for Chemotherapy in Glioblastoma

Glioblastoma multiforme is the most malignant and aggressive type of brain tumor, with a mean life expectancy of less than 15 months. This is due in part to the high resistance to apoptosis and moderate resistant to autophagic cell death in glioblastoma cells, and to the poor therapeutic response to conventional therapies. Autophagic cell death represents an alternative mechanism to overcome the resistance of glioblastoma to pro-apoptosis-related therapies. Nevertheless, apoptosis induction plays a major conceptual role in several experimental studies to develop novel therapies against brain tumors. In this review, we outline the different components of the apoptotic and autophagic pathways and explore the mechanisms of resistance to these cell death pathways in glioblastoma cells. Finally, we discuss drugs with clinical and preclinical use that interfere with the mechanisms of survival, proliferation, angiogenesis, migration, invasion, and cell death of malignant cells, favoring the induction of apoptosis and autophagy, or the inhibition of the latter leading to cell death, as well as their therapeutic potential in glioma, and examine new perspectives in this promising research field.

Characterization of UGT716A1 as a Multi-substrate UDP:Flavonoid Glucosyltransferase Gene in Ginkgo biloba

Ginkgo biloba L., a "living fossil" and medicinal plant, is a well-known rich source of bioactive flavonoids. The molecular mechanism underlying the biosynthesis of flavonoid glucosides, the predominant flavonoids in G. biloba, remains unclear. To better understand flavonoid glucosylation in G. biloba, we generated a transcriptomic dataset of G. biloba leaf tissue by high-throughput RNA sequencing. We identified 25 putative UDP-glycosyltransferase (UGT) unigenes that are potentially involved in the flavonoid glycosylation. Among them, we successfully isolated and expressed eight UGT genes in Escherichia coli, and found that recombinant UGT716A1 protein was active toward broad range of flavonoid/phenylpropanoid substrates. In particular, we discovered the first recombinant UGT protein, UGT716A1 from G. biloba, possessing unique activity toward flavanol gallates that have been extensively documented to have significant bioactivity relating to human health. UGT716A1 expression level paralleled the flavonoid distribution pattern in G. biloba. Ectopic over-expression of UGT716A1 in Arabidopsis thaliana led to increased accumulation of several flavonol glucosides. Identification and comparison of the in vitro enzymatic activity of UGT716A1 homologs revealed a UGT from the primitive land species Physcomitrella patens also showed broader substrate spectrum than those from higher plants A. thaliana, Vitis vinifera, and Medicago truncatula. The characterization of UGT716A1 from G. biloba bridges a gap in the evolutionary history of UGTs in gymnosperms. We also discuss the implication of UGT716A1 for biosynthesis, evolution, and bioengineering of diverse glucosylated flavonoids.

Characterization, Function, and Transcriptional Profiling Analysis of 3-Hydroxy-3-methylglutaryl-CoA Synthase Gene (GbHMGS1) towards Stresses and Exogenous Hormone Treatments in Ginkgo biloba

3-Hydroxy-3-methylglutaryl-CoA synthase (HMGS) is one of the rate-limiting enzymes in the mevalonate pathway as it catalyzes the condensation of acetoacetyl-CoA to form 3-hydroxy-3-methylglutaryl-CoA. In this study, A HMGS gene (designated as GbHMGS1) was cloned from Ginkgo biloba for the first time. GbHMGS1 contained a 1422-bp open-reading frame encoding 474 amino acids. Comparative and bioinformatics analysis revealed that GbHMGS1 was extensively homologous to HMGSs from other plant species. Phylogenetic analysis indicated that the GbHMGS1 belonged to the plant HMGS superfamily, sharing a common evolutionary ancestor with other HMGSs, and had a further relationship with other gymnosperm species. The yeast complement assay of GbHMGS1 in HMGS-deficient Saccharomyces cerevisiae strain YSC6274 demonstrated that GbHMGS1 gene encodes a functional HMGS enzyme. The recombinant protein of GbHMGS1 was successfully expressed in E. coli. The in vitro enzyme activity assay showed that the k_cat and K_m values of GbHMGS1 were 195.4 min⁻¹ and 689 μM, respectively. GbHMGS1 was constitutively expressed in all tested tissues, including the roots, stems, leaves, female flowers, male flowers and fruits. The transcript accumulation for GbHMGS1 was highest in the leaves. Expression profiling analyses revealed that GbHMGS1 expression was induced by abiotic stresses (ultraviolet B and cold) and hormone treatments (salicylic acid, methyl jasmonate, and ethephon) in G. biloba, indicating that GbHMGS1 gene was involved in the response to environmental stresses and plant hormones.

Anti-apoptotic effect of banhasasim-tang on chronic acid reflux esophagitis

AIM

To evaluate the anti-apoptotic effect of banhasasim-tang (BHSST) on chronic acid reflux esophagitis (CARE) using a rat model.

METHODS

A surgically-induced CARE model was established in Sprague-Dawley rats. The modeled rats were divided into a treatment group or untreated group, and given BHSST (1 g/kg body weight per day) or water, respectively, for 15 consecutive days (n = 7 each group). Changes in expression of proteins related to nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and apoptosis were assessed by western blotting. Changes in esophageal pathology were analyzed by gross and histological examinations.

RESULTS

The CARE exposure modeled rats showed increased levels of the NADPH oxidase subunit, NOX4 and p47^phox in the esophagus. The BHSST treatment completely resolved these CARE-related increases. The CARE rats also showed markers of cytokine stress, including elevated levels of TNF-α and reactive oxygen species as well as of the consequent increase in JNK activation, and subsequent decrease in pro-survival gene expression, such as of Bcl-2. BHSST treatment resolved the CARE-related changes. BHSST also exerted an anti-apoptotic effect, as evidenced by altered expression of the apoptosis-related genes for bax, cytochrome c, and caspase 3. Finally, the BHSST treatment markedly ameliorated the CARE-related esophageal mucosal ulcerations.

CONCLUSION

In the rat model of CARE, BHSST can suppress development of esophageal mucosal ulceration via regulation of reactive oxygen species-dependent apoptosis.

Ginkgo Biloba Ameliorates Subfertility Induced by Testicular Ischemia/Reperfusion Injury in Adult Wistar Rats: A Possible New Mitochondrial Mechanism

Testicular torsion, a surgical emergency, could affect the endocrine and exocrine testicular functions. This study demonstrates histopathological and physiological effects of testicular ischemia/perfusion (I/R) injury and the possible protective effects of Ginkgo biloba treatment. Fifty adult male Wistar rats, 180–200 gm, were randomly divided into sham-operated, Gingko biloba supplemented, ischemia only, I/R, and Gingko biloba treated I/R groups. Overnight fasted rats were anaesthetized by Pentobarbital; I/R was performed by left testis 720° rotation in I/R and treated I/R groups. Orchiectomy was performed for histopathological studies and detection of mitochondrial NAD⁺. Determination of free testosterone, FSH, TNF-α, and IL1-β in plasma was performed. Plasma-free testosterone was significantly decreased, while plasma FSH, TNF-α, IL-1β, and testicular mitochondrial NAD⁺ were significantly increased in I/R group compared to control group. These parameters were reversed in Gingko biloba treated I/R group compared to I/R group. I/R caused marked testicular damage and increased APAF-1 in the apoptotic cells which were reversed by Ginkgo biloba treatment. It could be concluded that I/R caused subfertility induced by apoptosis and oxidative stress manifested by the elevated testicular mitochondrial NAD⁺, which is considered a new possible mechanism. Also, testicular injury could be reduced by Gingko biloba administration alone.

The Synergistic Beneficial Effects of Ginkgo Flavonoid and Coriolus versicolor Polysaccharide for Memory Improvements in a Mouse Model of Dementia

This study reports the combination of Ginkgo flavonoid (GF) and Coriolus versicolor polysaccharide (CVP) in the prevention and treatment of a mouse model of Alzheimer's disease (AD). GF is a traditional health product, and CVP is the main active ingredient of the medicinal fungus Coriolus versicolor. The Morris water maze test, the Y maze, and the step-through test showed that the combinational use of CVP and GF synergistically improved memory in a mouse model of AD. Based on H&E staining analysis, the combination of CVP and GF decreased the severity of the pathological findings in the brain. Given that the expression of IL-1β, IL-6, and TNF-α was downregulated, the inflammation response in AD mice was considered to be inhibited. The downregulation of GFAP further demonstrated that inflammation was reduced in the brain of AD mice following treatment. Moreover, the expression levels of superoxide dismutase (SOD) and catalase (CAT) were elevated in the brains of treated mice, indicating that oxidation levels were reduced upon the combination treatment. Our results provide new insights into the efficient utilization of traditional medicine for preventing dementia.

[Tanakan as a multimodal cytoprotective factor in general medicine]

The first section of the review provides recent results regarding the mechanism of the action of a standardized extract of ginkgo biloba leaves EGb761 (tanakan), its effects on apoptosis, neuroplasticity, hemorheology, inhibition of the amyloid genesis and inflammatory response it cause, activation of proteasomes in conformational diseases. Current experimental and clinical results suggest that EGb761 (tanakan) is a high-effective cytoprotective agent in cognitive disorders of various genesis, cardiovascular diseases (in the process of rehabilitation and as a medicine capable to reduce the volume of brain damage in stroke). The effect of tanakan on anxiety and depression in patients with cognitive impairment should be considered as clinically significant.