The Efficacy and Safety of Alzheimer's Disease Therapies: An Updated Umbrella Review

Ginkgo biloba leaf extract EGb 761® for the treatment of various diseases: Overview of systematic reviews

BACKGROUND

Ginkgo biloba leaf extract EGb 761® might have diverse therapeutic effects.

OBJECTIVE

We conducted an overview of systematic reviews (SRs) to compile the efficacy and safety of EGb 761®.

METHODS

The Cochrane Database of Systematic Reviews, MEDLINE (via PubMed), Embase (via OVID) and PROSPERO were searched from inception until July 25th, 2023 with an update on January 30th, 2025. SRs were included if they evaluated the efficacy and safety of oral treatment with EGb 761® under any clinical condition or in healthy subjects for clinical reasons, such as prevention, or for health promotion. Two authors carried out screening, selection, data extraction and risk of bias assessment (AMSTAR 2). The degree of overlap was quantified. The overview was registered a priori (PROSPERO: CRD42023423789).

RESULTS

We screened 126 articles and included reviews on neurocognitive disorders (n = 13), tinnitus, macular degeneration and schizophrenia (all n = 1). For neurocognitive disorders, most SRs were in favor of EGb 761® regarding cognition and behavioral and/or psychological symptoms, while the results for functional activities of daily living varied. EGb 761® might have positive effects on tinnitus, macular degeneration or schizophrenia: however, more evidence is needed. In general, EGb 761® appears to be safe. Methodological quality was poor in all SRs. The overall overlap of the primary studies on neurocognitive disorders was very high, and pairwise overlap varied.

CONCLUSION

EGb 761® has been studied in various reviews, particularly regarding neurocognitive disorders and has been reported to be safe in many SRs. The results must be treated with caution due to the poor quality of the SRs.

Cholinesterase-based inhibitors as multitarget small molecules for the therapy of Alzheimer's disease

Herein, we have summarized the most significant results that we have communicated from our laboratories in the last thirty years, highlighting the most potent and attractive ChEIs based hit(lead)-Multitarget Small Molecules, such as (S)-p-methoxytacripyrine (1), ASS234 (2), Contilisant (3), and Contilistat (4), that we have identified in the search for new chemical entities for the therapy of Alzheimer's disease.

Healthy ageing in older adults with cardiovascular disease

As life expectancy continues to increase due to advancements in medical technology, public health, nutrition, and socioeconomic progress, the population of older adults in the USA and Europe is rapidly growing. By 2050, individuals aged 65 and older are projected to constitute over 20% of the US population and 29% of the European population, leading to a higher prevalence of chronic diseases, including cardiovascular disease. Cardiovascular disease, the leading cause of death in the USA, poses significant challenges to healthy ageing by contributing to accelerated biological ageing and the development of geriatric syndromes. This state-of-the-art review aims to (i) define healthy ageing for older patients living with cardiovascular disease; (ii) compare chronological vs biological ageing as it pertains to cardiovascular disease; (iii) describe the impact of geriatric syndromes and provide an approach to management and prevention; and (iv) address the gaps in knowledge and future directions for potential interventions that could promote healthy ageing.

Fractional amplitude of low-frequency fluctuations in right dorsal cingulum bundle associated with depression symptoms in AD patients: effects of donepezil intervention

OBJECTIVES

Our aim was to investigate the mechanisms of spontaneous brain activity of white matter functional signals in Alzheimer's disease (AD) patients after donepezil intervention.

METHODS

We used resting-state functional magnetic resonance imaging and the fractional amplitude of low-frequency fluctuations (fALFF) approach to investigate changes in spontaneous brain activity of white matter functional signals in AD patients before and after donepezil intervention. A total of 32 subjects participated in the study, including 16 healthy subjects (HCs) and 16 AD patients. The 16 AD patients underwent brain imaging and neuropsychological assessment before and after donepezil. ANOVA and post hoc t-test analysis were used to compare the differences in fALFF between the three groups. Pearson correlations were used to investigate the relationships between abnormal fALFF values and clinical variables in AD patients before and after intervention (P < 0.05).

RESULTS

Compared to HCs, AD patients before donepezil intervention had an abnormal fALFF in superior longitudinal fasciculus 2; AD patients after donepezil intervention had an abnormal fALFF in right superior longitudinal fasciculus 1,2 and right dorsal cingulum, Compared with baseline, AD patients after donepezil intervention had an abnormal fALFF in the right dorsal cingulum. Compared with the baseline, AD patients after donepezil intervention had significantly decreased depression scores (P < 0.0003).

CONCLUSIONS

Our study showed that spontaneous activity of functional signalling in the cholinergic pathway was altered in AD patients after donepezil intervention and that this change was associated with depressive symptoms in AD patients.

Ellagic acid(EA) ameliorates Alzheimer's disease by reducing Aβ levels, oxidative stress and attenuating inflammation

BACKGROUND

Ellagic acid (EA) serves as a pivotal coenzyme for various dehydrogenases, influencing diverse biological processes. Recognized for its potential in impeding disease progression, EA's effectiveness and mechanism in treating 5xFAD remain elusive.

AIM OF THE STUDY

This study aims to investigate EA's potential roles and underlying mechanisms in mitigating symptoms associated with 5xFAD.

MATERIALS AND METHODS

5 × FAD mice underwent a 12-week EA treatment regimen. The efficacy of EA against 5 × FAD was assessed through in vivo experiments, including Morris water maze and contextual fear conditioning tests for learning and memory abilities. Immunofluorescence (IF) and thioflavin staining examined changes in Aβ/neurons in brain tissue. RT‒qPCR evaluated inflammatory cytokine expression, while Bcl2/Bax protein levels were analyzed via Western blot (WB).

RESULTS

EA demonstrates promise in alleviating symptoms associated with 5xFAD. It significantly reduced the mice's escape latency in the Morris water maze, increased the frequency of crossings in the target quadrant, and prolonged freezing time in the contextual fear memory test. EA also improved neuronal pathology in the hippocampus and cortex, decreased neuronal loss, and reduced Aβ levels. Moreover, EA significantly increased MDA and SOD levels, effectively modulated the Bcl2/Bax ratio, and decreased the production of proinflammatory factors in brain tissue of 5xFAD model mice.

IN CONCLUSION

Our findings highlight the potential therapeutic efficacy of EA in addressing 5xFAD-related nervous system disorders by targeting Aβ levels, oxidative stress, and inflammation.

Contilisant+Tubastatin A Hybrids: Polyfunctionalized Indole Derivatives as New HDAC Inhibitor-Based Multitarget Small Molecules with In Vitro and In Vivo Activity in Neurodegenerative Diseases

Herein, we describe the design, synthesis, and biological evaluation of 15 Contilisant+Tubastatin A hybrids. These ligands are polyfunctionalized indole derivatives developed by juxtaposing selected pharmacophoric moieties of Contilisant and Tubastatin A to act as multifunctional ligands. Compounds 3 and 4 were identified as potent HDAC6 inhibitors (IC50 = 0.012 μM and 0.035 μM, respectively), so they were further evaluated in Drosophila and human cell models of Parkinson's disease (PD). Both compounds attenuated PD-like phenotypes, such as motor defects, oxidative stress, and mitochondrial dysfunction in PD model flies. Ligands 3 and 4 were also studied in the transgenic Caenorhabditis elegans CL2006 model of Alzheimer's disease (AD). Both compounds were nontoxic, did not induce undesirable animal functional changes, inhibited age-related paralysis, and improved cognition in the thrashing assay. These results highlight 3 and 4 as novel multifunctional ligands that improve the features of PD and AD hallmarks in the respective animal models.

Approved drugs and natural products at clinical stages for treating Alzheimer's disease

Alzheimer's disease (AD) remains the foremost cause of dementia and represents a significant unmet healthcare need globally. The complex pathogenesis of AD, characterized by various pathological and physiological events, has historically challenged the development of anti-AD drugs. However, recent breakthroughs in AD drug development, including the approvals of aducanumab, lecanemab, and sodium oligomannate (GV-971), have ended a nearly two-decade hiatus in the introduction of new AD drugs. These developments have addressed long-standing challenges in AD drug development, marking a substantial shift in the therapeutic landscape of AD. Moreover, natural products (NPs) have shown promise in AD drug research, with several currently under clinical investigation. Their distinct properties and mechanisms of action offer new avenues to complement and enhance existing AD treatment approaches. This review article aims to provide an overview of the recent advancements and prospects in AD therapeutics, focusing on both NPs and approved drugs.

Effect of acetylcholinesterase inhibition on immune cells in the murine intestinal mucosa

The gastrointestinal tract (GI) is the largest immune organ whose function is controlled by a complex network of neurons from the enteric nervous system (ENS) as well as the sympathetic and parasympathetic system. Evolving evidence indicates that cross-communication between gut-innervating neurons and immune cells regulates many essential physiological functions including protection against mucosal infections. We previously demonstrated that following paraoxon treatment, 70 % of the mice were able to survive an oral infection with S. typhimurium, a virulent strain of Salmonella enterica serovar Typhimurium. The present study aims to investigate the effect that rivastigmine, a reversible AChE inhibitor used for the treatment of neurodegenerative diseases, has on the murine immune defenses of the intestinal mucosa. Our findings show that, similar to what is observed with paraoxon, administration of rivastigmine promoted the release of secretory granules from goblet and Paneth cells, resulting in increased mucin layer. Surprisingly, however, and unlike paraoxon, rivastigmine treatment did not affect overall mortality of infected mice. In order to investigate the mechanistic basis for the differential effects observed between paraoxon and rivastigmine, we used multi-color flowcytometric analysis to characterize the immune cell landscape in the intraepithelial (IE) and lamina propria (LP) compartments of intestinal mucosa. Our data indicate that treatment with paraoxon, but not rivastigmine, led to an increase of resident CD3+CD8+ T lymphocytes in the ileal mucosa (epithelium and lamina propria) and CD11b- CD11c+ dendritic cells in the LP. Our findings indicate the requirement for persistent cholinergic pathway engagement to effect a change in the cellular landscape of the mucosal tissue that is necessary for protection against lethal bacterial infections. Moreover, optimal protection requires a collaboration between innate and adaptive mucosal immune responses in the intestine.

Discovery of Potential Drug Targeting Key Genes in Alzheimer's Disease: Insights from Transcriptome Analysis and Molecular Docking

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder that presents a significant global health challenge. To explore drugs targeting key genes in AD, R software was used to analyze the data of single nuclei transcriptome from human cerebral frontal cortex in AD, and the differentially expressed genes (DEGs) were screened. Then the gene ontology (GO) analysis, Kyoto gene and genome encyclopedia (KEGG) pathway enrichment and protein-protein interaction (PPI) network were analyzed. The hub genes were calculated by Cytoscape software. Molecular docking and molecular dynamics simulation were used to evaluate and visualize the binding between candidate drugs and key genes. A total of 564 DEGs were screened, and the hub genes were ISG15, STAT1, MX1, IFIT3, IFIT2, RSAD2, IFIT1, IFI44, IFI44L and DDX58. Enrichment terms mainly included response to virus, IFN-γ signaling pathway and virus infection. Diclofenac had good binding effect with IFI44 and IFI44L. Potential drugs may act on key gene targets and then regulate biological pathways such as virus response and IFN-γ-mediated signal pathway, so as to achieve anti-virus, improve immune balance and reduce inflammatory response, and thus play a role in anti-AD.

Ginkgo biloba: A Leaf of Hope in the Fight against Alzheimer's Dementia: Clinical Trial Systematic Review

Alzheimer's disease (AD) is a stealthy and progressive neurological disorder that is a leading cause of dementia in the global elderly population, imposing a significant burden on both the elderly and society. Currently, the condition is treated with medications that alleviate symptoms. Nonetheless, these drugs may not consistently produce the desired results and can cause serious side effects. Hence, there is a vigorous pursuit of alternative options to enhance the quality of life for patients. Ginkgo biloba (GB), an herb with historical use in traditional medicine, contains bioactive compounds such as terpenoids (Ginkgolides A, B, and C), polyphenols, organic acids, and flavonoids (quercetin, kaempferol, and isorhamnetin). These compounds are associated with anti-inflammatory, antioxidant, and neuroprotective properties, making them valuable for cognitive health. A systematic search across three databases using specific keywords-GB in AD and dementia-yielded 1702 documents, leading to the selection of 15 clinical trials for synthesis. In eleven studies, GB extract/EGb 761® was shown to improve cognitive function, neuropsychiatric symptoms, and functional abilities in both dementia types. In four studies, however, there were no significant differences between the GB-treated and placebo groups. Significant improvements were observed in scores obtained from the Mini-Mental State Examination (MMSE), Short Cognitive Performance Test (SKT), and Neuropsychiatric Inventory (NPI). While the majority of synthesized clinical trials show that Ginkgo biloba has promising potential for the treatment of these conditions, more research is needed to determine optimal dosages, effective delivery methods, and appropriate pharmaceutical formulations. Furthermore, a thorough assessment of adverse effects, exploration of long-term use implications, and investigation into potential drug interactions are critical aspects that must be carefully evaluated in future studies.

Ginkgo biloba and Its Chemical Components in the Management of Alzheimer's Disease

The pathogenesis of Alzheimer's disease (AD), a degenerative disease of the central nervous system, remains unclear. The main manifestations of AD include cognitive and behavioral disorders, neuropsychiatric symptoms, neuroinflammation, amyloid plaques, and neurofibrillary tangles. However, current drugs for AD once the dementia stage has been reached only treat symptoms and do not delay progression, and the research and development of targeted drugs for AD have reached a bottleneck. Thus, other treatment options are needed. Bioactive ingredients derived from plants are promising therapeutic agents. Specifically, Ginkgo biloba (Gb) extracts exert anti-oxidant, anticancer, neuroplastic, neurotransmitter-modulating, blood fluidity, and anti-inflammatory effects, offering alternative options in the treatment of cardiovascular, metabolic, and neurodegenerative diseases. The main chemical components of Gb include flavonoids, terpene lactones, proanthocyanidins, organic acids, polysaccharides, and amino acids. Gb and its extracts have shown remarkable therapeutic effects on various neurodegenerative diseases, including AD, with few adverse reactions. Thus, high-quality Gb extracts are a well-established treatment option for AD. In this review, we summarize the insights derived from traditional Chinese medicine, experimental models, and emerging clinical trials on the role of Gb and its chemical components in the treatment of the main clinical manifestations of AD.

Design, Synthesis, and Biological Evaluation of Novel Tetrahydroacridin Hybrids with Sulfur-Inserted Linkers as Potential Multitarget Agents for Alzheimer's Disease

Alzheimer's disease (AD) is a complex neurodegenerative disease that can lead to the loss of cognitive function. The progression of AD is regulated by multiple signaling pathways and their associated targets. Therefore, multitarget strategies theoretically have greater potential for treating AD. In this work, a series of new hybrids were designed and synthesized by the hybridization of tacrine (4, AChE: IC50 = 0.223 μM) with pyrimidone compound 5 (GSK-3β: IC50 = 3 μM) using the cysteamine or cystamine group as the connector. The biological evaluation results demonstrated that most of the compounds exhibited moderate to good inhibitory activities against acetylcholinesterase (AChE) and glycogen synthase kinase 3β (GSK-3β). The optimal compound 18a possessed potent dual AChE/GSK-3β inhibition (AChE: IC50 = 0.047 ± 0.002 μM, GSK-3β: IC50 = 0.930 ± 0.080 μM). Further molecular docking and enzymatic kinetic studies revealed that this compound could occupy both the catalytic anionic site and the peripheral anionic site of AChE. The results also showed a lack of toxicity to SH-SY5Y neuroblastoma cells at concentrations of up to 25 μM. Collectively, this work explored the structure-activity relationships of novel tetrahydroacridin hybrids with sulfur-inserted linkers, providing a reference for the further research and development of new multitarget anti-AD drugs.

The increased effective connectivity from left middle occipital gyrus to right medial septum/diagonal bands in AD patients after donepezil intervention

Introduction

Donepezil enhances the function of cholinergic nerves by increasing the concentration of acetylcholine, thereby improving clinical symptoms in patients with Alzheimer's disease (AD). However, the neural mechanisms of how donepezil modulates the effective connectivity (EC) network of cholinergic system in AD patients remain unknown. We speculated that the effective network of the cholinergic system changes in AD patients after donepezil intervention.

Methods

We employed resting-state functional magnetic resonance imaging and Granger causality analysis approach to explore changes in the effective connectivity network of the basal forebrain in AD patients before and after donepezil intervention. This study included 32 participants, including 16 healthy controls (HCs) and 16 AD patients. In a 3T MRI scanner, the 16 AD patients were scanned before and after the donepezil intervention. To compare EC differences between the three groups of participants, ANOVA and post-hoc t-tests analysis were employed.

Results

Compared to baseline status, AD patients after donepezil intervention had an increased EC from left middle occipital gyrus to right medial septum/diagonal bands. Compared to HCs, AD patients after donepezil intervention had an increased EC from right inferior frontal gyrus/orbit part to right medial septum/diagonal bands, AD patients before donepezil intervention had a reduced EC from right precuneus to right medial septum/diagonal bands. A significant positive correlation was found between EC values in right precuneus and Mini-Mental State Examination in pre-intervention AD patients (r = 0.7338, p = 0.0012).

Discussion

Our study showed that effective connectivity of brain regions associated with the default mode network in the cholinergic pathway was enhanced after donepezil intervention. The results of this study will help us to better understand the neural mechanisms of donepezil intervention in AD and to find clinical targets for intervention.

Mitochondrial Targeting against Alzheimer's Disease: Lessons from Hibernation

Alzheimer's disease (AD) is the most common cause of dementia worldwide and yet remains without effective therapy. Amongst the many proposed causes of AD, the mitochondrial cascade hypothesis is gaining attention. Accumulating evidence shows that mitochondrial dysfunction is a driving force behind synaptic dysfunction and cognitive decline in AD patients. However, therapies targeting the mitochondria in AD have proven unsuccessful so far, and out-of-the-box options, such as hibernation-derived mitochondrial mechanisms, may provide valuable new insights. Hibernators uniquely and rapidly alternate between suppression and re-activation of the mitochondria while maintaining a sufficient energy supply and without acquiring ROS damage. Here, we briefly give an overview of mitochondrial dysfunction in AD, how it affects synaptic function, and why mitochondrial targeting in AD has remained unsuccessful so far. We then discuss mitochondria in hibernation and daily torpor in mice, covering current advancements in hibernation-derived mitochondrial targeting strategies. We conclude with new ideas on how hibernation-derived dual mitochondrial targeting of both the ATP and ROS pathways may boost mitochondrial health and induce local synaptic protein translation to increase synaptic function and plasticity. Further exploration of these mechanisms may provide more effective treatment options for AD in the future.

The effect of single and repeated doses of rivastigmine on gastric myoelectric activity in experimental pigs

BACKGROUND

Rivastigmine is a pseudo-irreversible cholinesterase inhibitor used for therapy of Alzheimer's disease and non-Alzheimer dementia syndromes. In humans, rivastigmine can cause significant gastrointestinal side effects that can limit its clinical use. The aim of this study was to assess the impact of rivastigmine on gastric motor function by means of electrogastrography (EGG) in experimental pigs.

METHODS

Six experimental adult female pigs (Sus scrofa f. domestica, hybrids of Czech White and Landrace breeds; 3-month-old; mean weight 30.7 ± 1.2 kg) were enrolled into the study twice and created two experimental groups. In group A, a single intragastric dose of 6 mg rivastigmine hydrogen tartate was administered in the morning to fasting pigs before EGG recording. In group B, rivastigmine was administered to overnight fasting animals in a dietary bolus in the morning for 7 days (6 mg per day). On day 8, an intragastric dose of 12 mg rivastigmine was given in the morning to fasting pigs before EGG. EGG recording was accomplished by means of an EGG standalone system. Recordings from both groups were evaluated in dominant frequency and EGG power (areas of amplitudes).

RESULTS

In total, 1,980 one-minute EGG intervals were evaluated. In group A, basal EGG power (median 1290.5; interquartile range 736.5-2330 μV2) was significantly higher in comparison with the power of intervals T6 (882; 577-1375; p = 0.001) and T10 (992.5; 385-2859; p = 0.032). In group B, the dominant frequency increased significantly from basal values (1.97 ± 1.57 cycles per minute) to intervals T9 (3.26 ± 2.16; p < 0.001) and T10 (2.14 ± 1.16; p = 0.012), respectively. In group B, basal EGG power (median 1030.5; interquartile range 549-5093) was significantly higher in comparison with the power of intervals T7 (692.5; 434-1476; p = 0.002) and T8 (799; 435-1463 μV2; p = 0.004).

CONCLUSIONS

Both single as well as repeated intragastric administration of rivastigmine hydrogen tartrate caused a significant decrease of EGG power (areas of amplitudes) in experimental pigs. EGG power may serve as an indirect indicator of gastric motor competence. These findings might provide a possible explanation of rivastigmine-associated dyspepsia in humans.

[Cerebrolysin in the treatment of cognitive impairment]

Cognitive impairment is one of the most important problems of modern health care. Currently, according to WHO, more than 55 million people worldwide are living with dementia. Dementia is one of the leading causes of disability and addiction among older people worldwide. Even more significant is the number of patients with mild cognitive impairment who have an increased risk of progression to dementia compared to people of the same age without cognitive impairment. The number of patients with cognitive impairment has also increased due to the consequences of COVID-19. It is necessary to use drugs that not only improve cognitive functions, but also slow down their progression. One of these drugs is cerebrolysin, the effectiveness of which has been confirmed in various types of cognitive impairment. Cerebrolysin, being a preparation from the brain of a pig, belongs to the group of biological drugs. In the production of Cerebrolysin very strict measures are taken to comply with the technology, which ensures the quality and identity of the product from batch to batch. The experience of many years of clinical use of Cerebrolysin testifies not only to its high efficiency, but also to its safety. It should be taken into account that similar substances can be developed in relation to biological products - biosimilars or biosimilars, which can be considered comparable only in case of equivalent pharmacokinetic parameters, efficacy and safety.

Nosustrophine: An Epinutraceutical Bioproduct with Effects on DNA Methylation, Histone Acetylation and Sirtuin Expression in Alzheimer's Disease

Alzheimer's disease (AD), the most common cause of dementia, causes irreversible memory loss and cognitive deficits. Current AD drugs do not significantly improve cognitive function or cure the disease. Novel bioproducts are promising options for treating a variety of diseases, including neurodegenerative disorders. Targeting the epigenetic apparatus with bioactive compounds (epidrugs) may aid AD prevention treatment. The aims of this study were to determine the composition of a porcine brain-derived extract Nosustrophine, and whether treating young and older trigenic AD mice produced targeted epigenetic and neuroprotective effects against neurodegeneration. Nosustrophine regulated AD-related APOE and PSEN2 gene expression in young and older APP/BIN1/COPS5 mice, inflammation-related (NOS3 and COX-2) gene expression in 3-4-month-old mice only, global (5mC)- and de novo DNA methylation (DNMT3a), HDAC3 expression and HDAC activity in 3-4-month-old mice; and SIRT1 expression and acetylated histone H3 protein levels in 8-9-month-old mice. Mass spectrometric analysis of Nosustrophine extracts revealed the presence of adenosylhomocysteinase, an enzyme implicated in DNA methylation, and nicotinamide phosphoribosyltransferase, which produces the NAD+ precursor, enhancing SIRT1 activity. Our findings show that Nosustrophine exerts substantial epigenetic effects against AD-related neurodegeneration and establishes Nosustrophine as a novel nutraceutical bioproduct with epigenetic properties (epinutraceutical) that may be therapeutically effective for prevention and early treatment for AD-related neurodegeneration.

Pharmacotherapy of Alzheimer's disease: an overview of systematic reviews

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disease and the most common cause of dementia. In this umbrella systematic review (SR), we summarized the efficacy of different pharmacological interventions in improving cognitive function in patients with AD.

METHODS

A systematic search was performed through the PubMed, Scopus, Embase, and Cochrane databases for SRs of studies assessing the efficacy of pharmacological interventions versus placebo in improving cognitive function in AD or mild cognitive impairment due to AD. The risk of bias (RoB) was assessed using the Risk of Bias in SRs (ROBIS) tool.

RESULTS

Out of 1748 articles found through the database survey, 33 SR articles were included. These studies assessed effects of immunotherapy, cholinesterase inhibitors (ChEIs), memantine, statins, lithium, nonsteroidal anti-inflammatory drugs (NSAIDs), antidiabetic agents, Cerebrolysin, RAS-targeting antihypertensive drugs (ARBs and ACEIs), psychostimulants, glycogen synthase kinase 3 (GSK-3) inhibitors, melatonin, and herbal medications on cognitive function in AD patients. There was no notable overall RoB in 18 studies (54.5%), the RoB in 14 studies (42.4%) was high, and in one study (3.0%) it was unclear.

CONCLUSIONS

The use of ChEIs, including rivastigmine, galantamine, and donepezil, as well as memantine has demonstrated a positive impact on improving cognitive outcomes of AD patients, but no considerable effects were found for immunotherapies. Melatonin, statins, antihypertensive drugs, antidiabetic agents, Cerebrolysin, psychostimulants, and some herbal drugs such as Danggui-Shaoyao-San and Ginkgo biloba seem to be effective in improving cognitive function of AD patients, but the evidence in this regard is limited.