Efficacy and safety of extract of Ginkgo biloba as an adjunct therapy in chronic schizophrenia: A systematic review of randomized, double-blind, placebo-controlled studies with meta-analysis

Herb-drug interactions: A short review on central and peripheral nervous system drugs

Herbal medicines are widely perceived as natural and safe remedies. However, their concomitant use with prescribed drugs is a common practice, often undertaken without full awareness of the potential risks and frequently without medical supervision. This practice introduces a tangible risk of herb-drug interactions, which can manifest as a spectrum of consequences, ranging from acute, self-limited reactions to unpredictable and potentially lethal scenarios. This review offers a comprehensive overview of herb-drug interactions, with a specific focus on medications targeting the Central and Peripheral Nervous Systems. Our work draws upon a broad range of evidence, encompassing preclinical data, animal studies, and clinical case reports. We delve into the intricate pharmacodynamics and pharmacokinetics underpinning each interaction, elucidating the mechanisms through which these interactions occur. One pressing issue that emerges from this analysis is the need for updated guidelines and sustained pharmacovigilance efforts. The topic of herb-drug interactions often escapes the attention of both consumers and healthcare professionals. To ensure patient safety and informed decision-making, it is imperative that we address this knowledge gap and establish a framework for continued monitoring and education. In conclusion, the use of herbal remedies alongside conventional medications is a practice replete with potential hazards. This review not only underscores the real and significant risks associated with herb-drug interactions but also underscores the necessity for greater awareness, research, and vigilant oversight in this often-overlooked domain of healthcare.

The mitochondria in schizophrenia with 22q11.2 deletion syndrome: From pathogenesis to therapeutic promise of targeted natural drugs

Schizophrenia is a complex multi-factor neurological disorder that caused an array of severe indelible consequences to the individuals and society. Additionally, anti-schizophrenic drugs are unsuitable for treating negative symptoms and have more significant side effects and drug resistance. For better treatment and prevention, we consider exploring the pathogenesis of schizophrenia from other perspectives. A growing body of evidence of 22q11.2 deletion syndrome (22q11DS) suggested that the occurrence and progression of schizophrenia are related to mitochondrial dysfunction. So combing through the literature of 22q11DS published from 2000 to 2023, this paper reviews the mechanism of schizophrenia based on mitochondrial dysfunction, and it focuses on the natural drugs targeting mitochondria to enhance mitochondrial function, which are potential to improve the current treatment of schizophrenia.

Ginkgo biloba extracts (GBE) protect human RPE cells from t-BHP-induced oxidative stress and necrosis by activating the Nrf2-mediated antioxidant defence

OBJECTIVES

Age-related macular degeneration (AMD) is a prevalent ocular disease. Dry AMD accounts for most cases of blindness associated with AMD but there are no treatments. Oxidative stress-induced damage to retinal pigment epithelial (RPE) cells is a major contributor to the pathogenesis of dry AMD. This study investigated the protective actions of Ginkgo biloba extracts (GBE) in human RPE cells subjected to tert-butyl hydroperoxide (t-BHP)-mediated oxidative stress.

METHODS

The human ARPE-19 cells were pre-treated with or without GBE before the exposure to t-BHP. Cell viability, cell death profile and lipid peroxidation were assessed. The findings were verified using human primary RPE cultures.

KEY FINDINGS

GBE pre-treatment prevented the increase in lipid peroxidation and necrosis/ferroptosis, and the concurrent viability decrease in RPE cells exposed to t-BHP. It enabled the pronounced activation of Nrf2 and its downstream genes. We found that ERK1/2 phosphorylation was increased to a similar extent by t-BHP and GBE.

CONCLUSION

This study revealed that GBE pre-treatment attenuates pro-oxidant stress and protects human RPE cells from oxidative injury by modulating ERK1/2-Nrf2 axis. These findings suggest that GBE has the potential to be developed as a agent that may be valuable in decreasing AMD progression.

Ginkgo biloba Efficacy in the Treatment of Drug-Induced Parkinsonism: A Randomized Clinical Trial

Background

Drug-induced parkinsonism (DIP) is one of the most common movement disorders in approximately 20 - 35% of patients on antipsychotic medications. Managing the symptoms of DIP is challenging due to the limited number of potentially effective medications. On the other hand, this restricted possible treatment could have numerous side effects that ultimately result in patients stopping the medication all at once. The neuroprotective property of Ginkgo biloba extract (EGb) emerged as an effective commodity for the additional treatment of psychiatric disorders.

Objectives

This study aimed to evaluate the efficacy of EGb in psychiatric patients with symptoms of DIP.

Methods

A sample of 63 patients who met the inclusion criteria were recruited and randomly assigned to control and experimental groups. Both groups were followed for 3 months. One group received 80 mg of G. biloba three times a day, and the control group received a placebo. The patients were evaluated using the Unified Parkinson's Disease Rating Scale and Montreal Cognitive Assessment.

Results

Ginkgo could change the intensity of rest tremors, the severity of motor symptoms, rigidity, and bradykinesia. Ginkgo biloba might alleviate the severity of parkinsonism and motor symptoms and could lead to changes in the two components of working memory and short-term memory.

Conclusions

Ginkgo biloba extract can be used as an effective and safe treatment in the management of DIP, whether in patients diagnosed with psychotic disorders or mood disorders.

Clinician guidelines for the treatment of psychiatric disorders with nutraceuticals and phytoceuticals: The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce

OBJECTIVES

The therapeutic use of nutrient-based 'nutraceuticals' and plant-based 'phytoceuticals' for the treatment of mental disorders is common; however, despite recent research progress, there have not been any updated global clinical guidelines since 2015. To address this, the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Disorders (CANMAT) convened an international taskforce involving 31 leading academics and clinicians from 15 countries, between 2019 and 2021. These guidelines are aimed at providing a definitive evidence-informed approach to assist clinicians in making decisions around the use of such agents for major psychiatric disorders. We also provide detail on safety and tolerability, and clinical advice regarding prescription (e.g. indications, dosage), in addition to consideration for use in specialised populations.

METHODS

The methodology was based on the WFSBP guidelines development process. Evidence was assessed based on the WFSBP grading of evidence (and was modified to focus on Grade A level evidence - meta-analysis or two or more RCTs - due to the breadth of data available across all nutraceuticals and phytoceuticals across major psychiatric disorders). The taskforce assessed both the 'level of evidence' (LoE) (i.e. meta-analyses or RCTs) and the assessment of the direction of the evidence, to determine whether the intervention was 'Recommended' (+++), 'Provisionally Recommended' (++), 'Weakly Recommended' (+), 'Not Currently Recommended' (+/-), or 'Not Recommended' (-) for a particular condition. Due to the number of clinical trials now available in the field, we firstly examined the data from our two meta-reviews of meta-analyses (nutraceuticals conducted in 2019, and phytoceuticals in 2020). We then performed a search of additional relevant RCTs and reported on both these data as the primary drivers supporting our clinical recommendations. Lower levels of evidence, including isolated RCTs, open label studies, case studies, preclinical research, and interventions with only traditional or anecdotal use, were not assessed.

RESULTS

Amongst nutraceuticals with Grade A evidence, positive directionality and varying levels of support (recommended, provisionally recommended, or weakly recommended) was found for adjunctive omega-3 fatty acids (+++), vitamin D (+), adjunctive probiotics (++), adjunctive zinc (++), methylfolate (+), and adjunctive s-adenosyl methionine (SAMe) (+) in the treatment of unipolar depression. Monotherapy omega-3 (+/-), folic acid (-), vitamin C (-), tryptophan (+/-), creatine (+/-), inositol (-), magnesium (-), and n-acetyl cysteine (NAC) (+/-) and SAMe (+/-) were not supported for this use. In bipolar disorder, omega-3 had weak support for bipolar depression (+), while NAC was not currently recommended (+/-). NAC was weakly recommended (+) in the treatment of OCD-related disorders; however, no other nutraceutical had sufficient evidence in any anxiety-related disorder. Vitamin D (+), NAC (++), methylfolate (++) were recommended to varying degrees in the treatment of the negative symptoms in schizophrenia, while omega-3 fatty acids were not, although evidence suggests a role for prevention of transition to psychosis in high-risk youth, with potential pre-existing fatty acid deficiency. Micronutrients (+) and vitamin D (+) were weakly supported in the treatment of ADHD, while omega-3 (+/-) and omega-9 fatty acids (-), acetyl L carnitine (-), and zinc (+/-) were not supported. Phytoceuticals with supporting Grade A evidence and positive directionality included St John's wort (+++), saffron (++), curcumin (++), and lavender (+) in the treatment of unipolar depression, while rhodiola use was not supported for use in mood disorders. Ashwagandha (++), galphimia (+), and lavender (++) were modestly supported in the treatment of anxiety disorders, while kava (-) and chamomile (+/-) were not recommended for generalised anxiety disorder. Ginkgo was weakly supported in the adjunctive treatment of negative symptoms of schizophrenia (+), but not supported in the treatment of ADHD (+/-). With respect to safety and tolerability, all interventions were deemed to have varying acceptable levels of safety and tolerability for low-risk over-the-counter use in most circumstances. Quality and standardisation of phytoceuticals was also raised by the taskforce as a key limiting issue for firmer confidence in these agents. Finally, the taskforce noted that such use of nutraceuticals or phytoceuticals be primarily recommended (where supportive evidence exists) adjunctively within a standard medical/health professional care model, especially in cases of more severe mental illness. Some meta-analyses reviewed contained data from heterogenous studies involving poor methodology. Isolated RCTs and other data such as open label or case series were not included, and it is recognised that an absence of data does not imply lack of efficacy.

CONCLUSIONS

Based on the current data and clinician input, a range of nutraceuticals and phytoceuticals were given either a supportive recommendation or a provisional recommendation across a range of various psychiatric disorders. However several had only a weak endorsement for potential use; for a few it was not possible to reach a clear recommendation direction, largely due to mixed study findings; while some other agents showed no obvious therapeutic benefit and were clearly not recommended for use. It is the intention of these guidelines to inform psychiatric/medical, and health professional practice globally.

Plant-based Medicines (Phytoceuticals) in the Treatment of Psychiatric Disorders: A Meta-review of Meta-analyses of Randomized Controlled Trials: Les médicaments à base de plantes (phytoceutiques) dans le traitement des troubles psychiatriques: une méta-revue des méta-analyses d'essais randomisés contrôlés

OBJECTIVES

Plant-based medicines have had a long-standing history of use in psychiatric disorders. Highly quantified and standardized extracts or isolates may be termed "phytoceuticals," in a similar way that medicinal nutrients are termed as "nutraceuticals." Over the past 2 decades, several meta-analyses have examined the data for a range of plant-based medicines in the treatment of psychiatric disorders. The aim of this international project is to provide a "meta-review" of this top-tier evidence.

METHODS

We identified, synthesized, and appraised all available up to date meta-analyses... of randomized controlled trials (RCTs) reporting on the efficacy and effectiveness of individual phytoceuticals across all major psychiatric disorders.

RESULTS

Our systematic search identified 9 relevant meta-analyses of RCTs, with primary analyses including outcome data from 5,927 individuals. Supportive meta-analytic evidence was found for St John's wort for major depressive disorder (MDD); curcumin and saffron for MDD or depression symptoms, and ginkgo for total and negative symptoms in schizophrenia. Kava was not effective in treating diagnosed anxiety disorders. We also provide details on 22 traditional Chinese herbal medicine formulas' meta-analyses (primarily for depression studies), all of which revealed highly significant and large effect sizes. Their methodology, reporting, and potential publication bias were, however, of marked concern. The same caveat was noted for the curcumin, ginkgo, and saffron meta-analyses, which may also have significant publication bias.

CONCLUSIONS

More rigorous international studies are required to validate the efficacy of these phytoceuticals before treatment recommendations can be made. In conclusion, the breadth of data tentatively supports several phytoceuticals which may be effective for mental disorders alongside pharmaceutical, psychological therapies, and standard lifestyle recommendations.

Structure, synthesis, biosynthesis, and activity of the characteristic compounds from Ginkgo biloba L

Covering: 1928-2021Ginkgo biloba L. is one of the most distinctive plants to have emerged on earth and has no close living relatives. Owing to its phylogenetic divergence from other plants, G. biloba contains many compounds with unique structures that have served to broaden the chemical diversity of herbal medicine. Examples of such compounds include terpene trilactones (ginkgolides), acylated flavonol glycosides (ginkgoghrelins), biflavones (ginkgetin), ginkgotides and ginkgolic acids. The extract of G. biloba leaf is used to prevent and/or treat cardiovascular diseases, while many ginkgo-derived compounds are currently at various stages of preclinical and clinical trials worldwide. The global annual sales of G. biloba products are estimated to total US$10 billion. However, the content and purity of the active compounds isolated by traditional methods are usually low and subject to varying environmental factors, making it difficult to meet the huge demand of the international market. This highlights the need to develop new strategies for the preparation of these characteristic compounds from G. biloba. In this review, we provide a detailed description of the structures and bioactivities of these compounds and summarize the recent research on the development of strategies for the synthesis, biosynthesis, and biotechnological production of the characteristic terpenoids, flavonoids, and alkylphenols/alkylphenolic acids of G. biloba. Our aim is to provide an important point of reference for all scientists who research ginkgo-related compounds for medicinal or other purposes.

Procyanidin B2 and rutin in Ginkgo biloba extracts protect human retinal pigment epithelial (RPE) cells from oxidative stress by modulating Nrf2 and Erk1/2 signalling

Oxidative stress plays an important role in the pathogenesis of human retinal diseases. Ginkgo biloba products are widely consumed herbal supplements that contain ingredients with anti-oxidant potentials. However, the active agents in ginkgo biloba extracts (GBE) are unclear. This study assessed the anti-oxidant effects of 19 natural compounds isolated from GBE to provide a rational basis for their use in preventing retinal diseases. The compounds were tested in retinal pigment epithelial (RPE) cells subjected to tert-butyl hydroperoxide (t-BHP)-induced oxidative stress. Cell viability and intracellular reactive oxygen species (ROS) were assessed and flow cytometry was used to delineate the cell death profile. The expression of nuclear factor erythroid 2-related factor-2 (Nrf2) was activated in RPE cells by t-BHP accompanied with an activation of Erk1/2 signaling. GBE-derived rutin and procyanidin B2 ameliorated t-BHP-induced cell death and promoted cell viability by suppressing intracellular ROS generation. These agents also enhanced Nrf2 expression with activating Erk1/2 signaling in RPE cells. In contrast, the other compounds tested were minimally active and did not prevent the loss of cell viability elicited by t-BHP. The present findings suggest that rutin and procyanidin B2 may have potential therapeutic values in the prevention of retinal diseases induced by oxidative damage.

Therapeutic efficacy of the Ginkgo special extract EGb761® within the framework of the mitochondrial cascade hypothesis of Alzheimer's disease

OBJECTIVES

The mitochondrial cascade hypothesis of dementia assumes mitochondrial dysfunction as an important common pathomechanism for the whole spectrum of age-associated memory disorders from cognitive symptoms in the elderly over mild cognitive impairment to Alzheimer's dementia. Thus, a drug such as the Ginkgo special extract EGb 761^® which improves mitochondrial function should be able to ameliorate cognitive deficits over the whole aging spectrum.

METHODS

We review the most relevant publications about effects of EGb 761^® on cognition and synaptic deficits in preclinical studies as well as on cognitive deficits in man from aging to dementia.

RESULTS

EGb 761^® improves mitochondrial dysfunction and cognitive impairment over the whole spectrum of age-associated cognitive disorders in relevant animal models and in vitro experiments, and also shows clinical efficacy in improving cognition over the whole range from aging to Alzheimer's or even vascular dementia.

CONCLUSIONS

EGb 761^® shows clinical efficacy in the treatment of cognitive deficits over the whole spectrum of age-associated memory disorders. Thus, EGb 761^® can serve as an important pharmacological argument for the mitochondrial cascade hypothesis of dementia.

Molecular Insights into NR4A2(Nurr1): an Emerging Target for Neuroprotective Therapy Against Neuroinflammation and Neuronal Cell Death

NR4A2 is a nuclear receptor and a transcription factor, with distinctive physiological features. In the cell nuclei of the central nervous system, it is widely expressed and identified as a crucial regulator of dopaminergic (DA) neuronal differentiation, survival, and maintenance. Importantly, it has regulated different genes crucial for dopaminergic signals, and its expression has been diminished in both aged and PD post-mortem brains and reduced in PD patients. In microglia and astrocytes, the expression of NR4A2 has been found where it can be capable of inhibiting the expression of proinflammatory mediators; hence, it protected inflammation-mediated DA neuronal death. In addition, NR4A2 plays neuroprotective role via regulating different signals. However, NR4A2 has been mainly focused on Parkinson's research, but, in recent times, it has been studied in Alzheimer's disease (AD), multiple sclerosis (MS), and stroke. Altered expression of NR4A2 is connected to AD progression, and activation of its may improve cognitive function. It is downregulated in peripheral blood mononuclear cells of MS patients; nonetheless, its role in MS has not been fully clear. miR-145-5p known as a putative regulator of NR4A2 and in a middle cerebral artery occlusion/reperfusion model, anti-miR-145-5p administration promoted neurological outcomes in rat. To date, various activators and modulators of NR4A2 have been discovered and investigated as probable therapeutic drugs in neuroinflammatory and neuronal cell death models. The NR4A2 gene and cell-based therapy are described as promising drug candidates for neurodegenerative diseases. Moreover, microRNA might have a crucial role in neurodegeneration via affecting NR4A2 expression. Herein, we present the role of NR4A2 in neuroinflammation and neuronal cell death focusing on neurodegenerative conditions and display NR4A2 as a promising therapeutic target for the therapy of neuroprotection.

Role of Ginkgo biloba extract as an adjunctive treatment of elderly patients with depression and on the expression of serum S100B

OBJECTIVE

To explore the effect of ginkgo biloba extract (EGb) as an adjunctive treatment of elderly patients with depression and the effect on the expression of serum S100B.

METHODS

136 elderly patients with depression were divided into EGb +  citalopram (Cit) group and Cit group equally. Efficacy was evaluated by Hamilton Depression Rating Scale (HAMD). Wisconsin Card Classification Test (WCST) was used to evaluate cognitive function. Serum S100B expression was measured with ELISA. The relationship of S100B with HAMD, Hamilton Anxiety Scale (HAMA) score, and WCST results was evaluated subsequently.

RESULTS

The time of onset of efficacy was significantly shorter in EGb + Cit group. There were significant differences in HAMD and HAMA scores after treatment than before treatment between groups (all P < .05). After treatment, total number of WCST test, the number of continuous errors and non-persistent errors in both groups were less than those before treatment. The correct number and classifications number were increased than before treatment. In EGb + Cit group, correct numbers and classifications were increased, and the number of persistent errors was decreased. After treatment, S100B level was decreased, and S100B levels change in EGb + Cit group was greater than in Cit group. Serum S100B level was positively correlated with HAMD and HAMA scores before treatment and positively correlated with persistent errors number in WCST.

CONCLUSION

EGb, as an adjunctive treatment, can effectively improve depressive symptoms and reduce expression of serum S100B, which is a marker of brain injury, suggesting that EGb restores neurologic function during the treatment of depression in elderly patients and S100B participates in the therapeutic mechanism. EGb combined with depressive drugs plays synergistic role, and the time of onset of efficacy is faster than single antidepressants.

An epidemiological study on herbal product self-medication practice among psychotic outpatients from Serbia: A cross-sectional study

Utilization of herbal products (HPs) is a common practice in the traditional medicine of people from southeastern Serbia. In this study, we focused on the usage of HPs as a self-medication practice among patients diagnosed with a mental illness, by aiming to ascertain the usage prevalence, the identity of the main plant taxa utilized, their formulations and target symptoms. This was accomplished through a cross-sectional study of psychiatric outpatients, conducted in the Clinic for Mental Health Protection in Niš, and which included a questionnaire on HP utilization and a non-structured psychiatric interview. Typically, single, middle-aged males, with a secondary education degree, utilized Matricaria chamomilla and/or Melissa officinalis in a form of an infusion (tea) for relieving anxiety and psychotic symptoms. In some cases, adverse effects were noted when HPs were used in combination with prescribed psychotropic medications. Our and previous results urge a thorough evaluation of possible benefits and/or harmful interactions of HP with standard medication in the treatment of psychiatric patients.

Ginkgo biloba induced mood dysregulation: a case report

Background

Impairment of cognitive function as well as negative symptom is the major factor causing the decline of a patient’s functioning in chronic stages of schizophrenia. However, until now, there were no definite treatment options that could effectively reduce the impairment.

Case presentation

We report a case of mood dysregulation associated with use of Ginkgo biloba in a patient with schizophrenia. After Ginkgo biloba was given, the patient experienced cluster symptoms of mood dysregulation including irritability, difficulty in controlling anger, agitation and restlessness. We estimated the possibility as “probable” according to Naranjo scale considering circumstantial evidence.

Conclusions

This case suggests that Ginkgo biloba may have caused mood dysregulation in this patient. Although it is generally accepted as safe, more attention should be given to the adverse effect when treating with Ginkgo biloba.

Effect of Levopimaradiene on Terpene Trilactones Biosynthesis and Gene Expression Profiling in Ginkgo biloba Cells

Ginkgolides (GKs) and Bilobalide (BB) are rare terpene trilactones obtained from Ginkgo biloba, but their biosynthetic pathway is still unclear. In this paper, effects of levopimaradiene (LP) on increasing the production of terpene trilactones of G. biloba dedifferentiated cells (DDCs) and cambial meristematic cells (CMCs) were reported. The productions of ginkgolide A (GA) and ginkgolide B (GB) were 1.61 and 1.32 folds larger than that of the control groups when G. biloba DDCs was treated with LP, and the productions of ginkgolide C (GC) and BB reached 234 and 161 μg L−1 after treated with LP for 60 h. The production of GA, GB, GC and BB was 2.03, 1.43, 1.22 and 1.19 folds larger than that of the control groups in LP-treated CMCs groups. The results demonstrated that BB could be produced from the methylerythritol 4-phosphate (MEP) pathway. qRT-PCR experiments showed that LP was a significant precursor manipulated the biosynthesis of terpene trilactones via affecting the transcript levels of several related genes in the MEP pathway.

Ginkgo biloba L. attenuates spontaneous recurrent seizures and associated neurological conditions in lithium-pilocarpine rat model of temporal lobe epilepsy through inhibition of mammalian target of rapamycin pathway hyperactivation

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. (Ginkgoaceae) has been widely used in traditional medicine for variety of neurological conditions particularly behavioral and memory impairments.

AIM OF THE STUDY

The present study was envisaged to explore the effect of a standardized fraction of Ginkgo biloba leaves (GBbf) in rat model of lithium-pilocarpine induced spontaneous recurrent seizures, and associated behavioral impairments and cognitive deficit.

MATERIALS AND METHODS

Rats showing appearance of spontaneous recurrent seizures following lithium pilocarpine (LiPc)-induced status epilepticus (SE) were treated with different doses of GBbf or vehicle for subsequent 4 weeks. The severity of seizures and aggression in rats were scored following treatment with GBbf. Further, open field, forced swim, novel object recognition and Morris water maze tests were conducted. Histopathological, protein levels and gene expression studies were performed in the isolated brains.

RESULTS

Treatment with GBbf reduced seizure severity score and aggression in epileptic animals. Improved spatial cognitive functions and recognition memory, along with reduction in anxiety-like behavior were also observed in the treated animals. Histopathological examination by Nissl staining showed reduction in neuronal damage in the hippocampal pyramidal layer. The dentate gyrus and Cornu Ammonis 3 regions of the hippocampus showed reduction in mossy fiber sprouting. GBbf treatment attenuated ribosomal S6 and pS6 proteins, and hippocampal mTOR, Rps6 and Rps6kb1 mRNA levels.

CONCLUSIONS

The results of present study concluded that GBbf treatment suppressed lithium-pilocarpine induced spontaneous recurrent seizures severity and incidence with improved cognitive functions, reduced anxiety-like behavior and aggression. The effect was found to be due to inhibition of mTOR pathway hyperactivation linked with recurrent seizures.

Review of Ginkgo biloba-induced toxicity, from experimental studies to human case reports

Ginkgo biloba seeds and leaves have been used as a traditional herbal remedy for thousands of years, and its leaf extract has been consumed as a botanical dietary supplement for decades. Ginkgo biloba extract is a complex mixture with numerous components, including flavonol glycosides and terpene lactones, and is one of the most widely sold botanical dietary supplements worldwide. Concerns about potential health risks for the general population have been raised because of the widespread human exposure to Ginkgo biloba and its potential toxic and carcinogenic activities in rodents. The National Toxicology Program conducted 2-year gavage studies on one Ginkgo biloba leaf extract and concluded that there was clear evidence of carcinogenic activity of this extract in mice based on an increased incidence of hepatocellular carcinoma and hepatoblastoma. Recently, Ginkgo biloba leaf extract has been classified as a possible human carcinogen (Group 2B) by the International Agency for Research on Cancer. This review presents updated information on the toxicological effects from experimental studies both in vitro and in vivo to human case reports (caused by ginkgo seeds or leaves), and also summarizes the negative results from relatively large clinical trials.

The efficacy of cerebellar vermal deep high frequency (theta range) repetitive transcranial magnetic stimulation (rTMS) in schizophrenia: A randomized rater blind-sham controlled study

Repetitive transcranial magnetic stimulation (rTMS) is a promising therapeutic for schizophrenia. Treatment effects of rTMS have been variable across different symptom clusters, with negative symptoms showing better response, followed by auditory hallucinations. Cerebellum, especially vermis and its abnormalities (both structural and functional) have been implicated in cognitive, affective and positive symptoms of schizophrenia. rTMS to this alternate site has been suggested as a novel target for treating patients with this disorder. Hypothesizing cerebellar vermal magnetic stimulation as an adjunct to treat schizophrenia psychopathology, we conducted a double blind randomized sham controlled rTMS study. In this study, forty patients were randomly allocated (using block randomization method) to active high frequency (theta patterned) rTMS (n=20) and sham (n=20) groups. They received 10 sessions over 2 weeks. The Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale for Schizophrenia (CDSS) scores were assessed at baseline, after last session and at 4 weeks (2 weeks post-rTMS). We found a significantly greater improvement in the group receiving active rTMS sessions, compared to the sham group on negative symptoms, and depressive symptoms. We conclude that cerebellar stimulation can be used as an effective adjunct to treat negative and affective symptoms.

Nurr1-Based Therapies for Parkinson's Disease

Previous studies have documented that orphan nuclear receptor Nurr1 (also known as NR4A2) plays important roles in the midbrain dopamine (DA) neuron development, differentiation, and survival. Furthermore, it has been reported that the defects in Nurr1 are associated with Parkinson's disease (PD). Thus, Nurr1 might be a potential therapeutic target for PD. Emerging evidence from in vitro and in vivo studies has recently demonstrated that Nurr1-activating compounds and Nurr1 gene therapy are able not only to enhance DA neurotransmission but also to protect DA neurons from cell injury induced by environmental toxin or microglia-mediated neuroinflammation. Moreover, modulators that interact with Nurr1 or regulate its function, such as retinoid X receptor, cyclic AMP-responsive element-binding protein, glial cell line-derived neurotrophic factor, and Wnt/β-catenin pathway, have the potential to enhance the effects of Nurr1-based therapies in PD. This review highlights the recent progress in preclinical studies of Nurr1-based therapies and discusses the outlook of this emerging therapy as a promising new generation of PD medication.

A Critical Approach to Evaluating Clinical Efficacy, Adverse Events and Drug Interactions of Herbal Remedies

Systematic reviews and meta-analyses represent the uppermost ladders in the hierarchy of evidence. Systematic reviews/meta-analyses suggest preliminary or satisfactory clinical evidence for agnus castus (Vitex agnus castus) for premenstrual complaints, flaxseed (Linum usitatissimum) for hypertension, feverfew (Tanacetum partenium) for migraine prevention, ginger (Zingiber officinalis) for pregnancy-induced nausea, ginseng (Panax ginseng) for improving fasting glucose levels as well as phytoestrogens and St John's wort (Hypericum perforatum) for the relief of some symptoms in menopause. However, firm conclusions of efficacy cannot be generally drawn. On the other hand, inconclusive evidence of efficacy or contradictory results have been reported for Aloe vera in the treatment of psoriasis, cranberry (Vaccinium macrocarpon) in cystitis prevention, ginkgo (Ginkgo biloba) for tinnitus and intermittent claudication, echinacea (Echinacea spp.) for the prevention of common cold and pomegranate (Punica granatum) for the prevention/treatment of cardiovascular diseases. A critical evaluation of the clinical data regarding the adverse effects has shown that herbal remedies are generally better tolerated than synthetic medications. Nevertheless, potentially serious adverse events, including herb-drug interactions, have been described. This suggests the need to be vigilant when using herbal remedies, particularly in specific conditions, such as during pregnancy and in the paediatric population. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of Enzyme Inhibitors on Terpene Trilactones Biosynthesis and Gene Expression Profiling in Ginkgo biloba Cultured Cells

The biosynthetic pathway of terpene trilactones of Ginkgo biloba is unclear. In this present study, suspension cultured cells of G. biloba were used to explore the regulation of the mevalonic acid (MVA) and methylerythritol 4-phosphate (MEP) pathways in response to specific enzyme inhibitors (lovastatin and clomazone). The results showed that the biosynthesis of bilobalide was more highly correlated with the MVA pathway, and the biosynthesis of ginkgolides was more highly correlated with the MEP pathway. Meanwhile, according to the results, it could be speculated that bilobalide might be a product of ginkgolide metabolism.