Safranal protects against beta-amyloid peptide-induced cell toxicity in PC12 cells via MAPK and PI3 K pathways

Saffron, a Potential Bridge between Nutrition and Disease Therapeutics: Global Health Challenges and Therapeutic Opportunities

Plants are an important source of essential bioactive compounds that not only have a beneficial role in human health and nutrition but also act as drivers for shaping gut microbiome. However, the mechanism of their functional attributes is not fully understood despite their significance. One such important plant is Crocus sativus, also known as saffron, which possesses huge medicinal, nutritional, and industrial applications like food and cosmetics. The importance of this plant is grossly attributed to its incredible bioactive constituents such as crocins, crocetin, safranal, picrocrocin, and glycosides. These bioactive compounds possess a wide range of therapeutic activities against multiple human ailments. Since a huge number of studies have revealed negative unwanted side effects of modern-day drugs, the scientific communities at the global level are investigating a large number of medicinal plants to explore natural products as the best alternatives. Taken into consideration, the available research findings indicate that saffron has a huge scope to be further explored to establish alternative natural-product-based drugs for health benefits. In this review, we are providing an update on the role of bioactive compounds of saffron as therapeutic agents (human disorders and antimicrobial activity) and its nutritional values. We also highlighted the role of omics and metabolic engineering tools for increasing the content of key saffron bioactive molecules for its mass production. Finally, pre-clinical and clinical studies seem to be necessary to establish its therapeutic potential against human diseases.

Therapeutic potential of saffron in brain disorders: From bench to bedside

Saffron is a spice derived from the flower of Crocus sativus L., which has been used for centuries as a coloring and flavoring agent, as well as a source of medicinal compounds. Saffron contains various bioactive constituents, such as crocin, crocetin, safranal, picrocrocin, and kaempferol, that have shown potential benefits for human health. Among them, crocin is the most abundant and characteristic constituent of saffron, responsible for its bright red color and antioxidant properties. One of the most promising applications of saffron and its constituents is in the prevention and treatment of neurological disorders, such as depression, anxiety, Alzheimer's disease, Parkinson's disease, and other brain disorders. Saffron and its constituents have been reported to exert neuroprotective effects through various mechanisms, such as modulating neurotransmitters, enhancing neurogenesis, reducing neuroinflammation, regulating oxidative stress, activating the Nrf2 signaling pathway, and modulating epigenetic factors. Several clinical and preclinical studies have demonstrated the efficacy and safety of saffron and its constituents in improving cognitive function, mood, and other neurological outcomes. In this review, we summarize the current evidence on the therapeutic potential of saffron and its constituents in neurological disorders, from bench to bedside. We also discuss the challenges and future directions for the development of saffron-based therapies for brain health.

Therapeutic effects of saffron and its components on neurodegenerative diseases

Due to an increase in the number of older people in recent years, neurodegenerative diseases as the most important age-related neurological disorders are considered as a great threat to human health. The treatment strategies for these disorders are symptomatic and there is no known definitive treatment; however, recently, several studies have investigated the effectiveness of some herbs and their components in limiting the progression and treatment of neurodegenerative disorders. In this study, we searched Medline (via PubMed), Scopus, Science Direct, and Google Scholar databases. The keywords used in the search were: saffron [title/abstract] or (saffron compound [title/abstract]) and (neurological disorders [title/abstract]), publication date range (2010-2023), and language (English). After applying inclusion and exclusion criteria, 30 articles remained. Of the 30 articles included in the study, six studies on the treatment of neurodegenerative disorders by saffron and its components were in the clinical trial phase, and 24 studies were in the preclinical phase. Saffron and its compounds can play an important role in inhibiting neuroinflammation and excitotoxic pathways, modulating autophagy and apoptosis, attenuating oxidative damage, and activating defensive antioxidant enzymes, resulting in neuroprotection against neurodegenerative diseases. Therefore, this study aimed to review the studies on the effects of saffron and its compounds on the treatment of neurodegenerative diseases.

Research progress of natural products and their derivatives against Alzheimer's disease

Alzheimer's disease (AD), a persistent neurological dysfunction, has an increasing prevalence with the aging of the world and seriously threatens the health of the elderly. Although there is currently no effective treatment for AD, researchers have not given up, and are committed to exploring the pathogenesis of AD and possible therapeutic drugs. Natural products have attracted considerable attention owing to their unique advantages. One molecule can interact with multiple AD-related targets, thus having the potential to be developed in a multi-target drug. In addition, they are amenable to structural modifications to increase interaction and decrease toxicity. Therefore, natural products and their derivatives that ameliorate pathological changes in AD should be intensively and extensively studied. This review mainly presents research on natural products and their derivatives for the treatment of AD.

Effects of adding poly-histidine tag on stability, antimicrobial activity and safety of recombinant buforin I expressed in periplasmic space of Escherichia coli

The lack of cost-effective methods for producing antimicrobial peptides has made it impossible to use their high potential as a new and powerful class of antimicrobial agents. In recent years, extensive research has been conducted to decrease the cost of recombinant proteins production through microorganisms, transgenic animals, and plants. Well-known genetic and physiological characteristics, short-term proliferation, and ease of manipulation make E. coli expression system a valuable host for recombinant proteins production. Expression in periplasmic space is recommended to reduce the inherently destructive behavior of antimicrobial peptides against the expressing microorganism and to decline susceptibility to proteolytic degradation. In this study, a pET-based expression system was used to express buforin I at E. coli periplasmic space, and its antimicrobial, hemolytic, and cell toxicity activities as well as structural stability were evaluated. The hemolysis activity and cytotoxicity of His-tagged buforin I were negligible and its antimicrobial activity did not show a significant difference compared to synthetic buforin I. In addition, in silico investigating of stability of native and His-tagged buforin I showed that RMSF, RMSD and Rg curves had followed a similar trend during 150 ns simulation. Furthermore, evaluating the modelled structures, FTIR and X-ray methods of both peptides indicated an insignificant structural difference. It was concluded that the recombinant buforin I could be a viable alternative to some currently used antibiotics by successfully expressing it in the pET-based expression system.

Profiling microRNA from peripheral blood mononuclear cells in early-onset familial Alzheimer's disease

MicroRNAs (miRNAs) refer to short in-length, noncoding RNAs that regulate numerous cellular functions by targeting mRNA, and numerous types of research have shown that miRNA is vitalin Alzheimer's disease. For identifying differentially expressed miRNAs in the peripheral blood mononuclear cell (PBMC) of early-onset familial Alzheimer's disease (EOFAD), we conducted this study which might give a reference for potential therapeutic targets or biomarkers for this disease. On the basis of high-throughput sequencing, we screened the miRNAs expression profiles in PBMC regarding both EOFAD patients and healthy controls, and the biological information was analyzed. Compared with the PBMC of healthy controls, 142 miRNAs were differentially expressed in EOFAD patients ( P  < 0.05), including 48 significantly differentially expressed miRNAs, 37 of which were significantly upregulated, including miR-3614-5p, miR-193A-5p, miR-2115-5p, miR-143-3p, etc. and 11 were significantly downregulated, including miR-484, miR-708-5p, miR-205-5p, miR-31-5p, etc. According to biological information analysis, 768 miRNA target genes were differentially expressed, which may be involved in multiple gene functions and cell cycle, cell senescence, and several signaling pathways, including FoxO, MAPK, Ras, mTOR, neurotrophin, etc. There are differential expressions of miRNAs in PBMC of EOFAD patients and controls, revealing their importance in Alzheimer's disease as indicated by co-expression network analysis; this may support basic information for new biomarkers or treatment exploring.

Saffron as a promising therapy for diabetes and Alzheimer's disease: mechanistic insights

The prevalence of both Alzheimer's disease (AD) and diabetes mellitus is increasing with the societies' aging and has become an essential social concern worldwide. Accumulation of amyloid plaques and neurofibrillary tangles (NFTs) of tau proteins in the brain are hallmarks of AD. Diabetes is an underlying risk factor for AD. Insulin resistance has been proposed to be involved in amyloid-beta (Aβ) aggregation in the brain. It seems that diabetic conditions can result in AD pathology by setting off a cascade of processes, including inflammation, mitochondrial dysfunction, and ROS and advanced glycation end products (AGEs) synthesis. Due to the several side effects of chemical drugs and their high cost, using herbal medicine has recently attracted attention for the treatment of diabetes and AD. Saffron and its active ingredients have been used for its anti-inflammatory, anti-oxidant, anti-diabetic, and anti-AD properties. Therefore, in the present review paper, we take account of the clinical, in vivo and in vitro evidence regarding the anti-diabetic and anti-AD effects of saffron and discuss the preventive or postponing properties of saffron or its components on AD development via its anti-diabetic effects.

Safranal Treatment Induces Sirt1 Expression and Inhibits Endoplasmic Reticulum Stress in Mouse Chondrocytes and Alleviates Osteoarthritis Progression in a Mouse Model

Osteoarthritis (OA) is an age-related degenerative disease. Oxidative stress (OS) modulates OA pathogenesis by enhancing chondrocyte apoptosis and extracellular matrix (ECM) degeneration via activation of the endoplasmic reticulum (ER) stress. Prior studies revealed that safranal plays a critical role in multiple diseases treatments, but there are no reports on its effect on OA. Therefore, investigating the effect of safranal on OA is needed. As a compound that can lead excessive reactive oxygen species (ROS) accumulation, tert-butyl hydroperoxide (TBHP) was used to induce OS and OS-mediated endoplasmic reticulum (ER) stress for imitating OA in vitro. Besides, the bilateral medial meniscus was removed to induce joint instability and excessive friction of the joint surface to establish destabilization of medial meniscus for imitating the initiation and progression of OA in vivo. We, next, conducted Western blot and RT-PCR analyses to identify biomarkers of the underlying signaling pathway. Our results demonstrated that 30 μM safranal strongly upregulated Sirt1 expression, suppressed TBHP-mediated ER stress, and, in turn, prevented chondrocyte apoptosis and ECM degeneration. Furthermore, compared with the other two classic signaling pathways of ER stress, safranal can inhibit the PERK-eIF2α-CHOP axis at the lower concentration (5 and 15 μM). In vivo, using Safranin O staining, X-ray, immunofluorescence (IF), and immunohistochemical (IHC) staining, we demonstrated that OA progression can be postponed with intraperitoneal injection of 90 and 180 mg/kg safranal in an OA mouse model. Taken together, our analyses revealed that safranal can potentially prevent OA development.

Saffron (Crocus sativus L.): A Source of Nutrients for Health and for the Treatment of Neuropsychiatric and Age-Related Diseases

Saffron (Crocus sativus L.) is a medicinal plant, originally cultivated in the East and Middle East, and later in some Mediterranean countries. Saffron is obtained from the stigmas of the plant. Currently, the use of saffron is undergoing a revival. The medicinal virtues of saffron, its culinary use and its high added value have led to the clarification of its phytochemical profile and its biological and therapeutic characteristics. Saffron is rich in carotenoids and terpenes. The major products of saffron are crocins and crocetin (carotenoids) deriving from zeaxanthin, pirocrocin and safranal, which give it its taste and aroma, respectively. Saffron and its major compounds have powerful antioxidant and anti-inflammatory properties in vitro and in vivo. Anti-tumor properties have also been described. The goal of this review is to present the beneficial effects of saffron and its main constituent molecules on neuropsychiatric diseases (depression, anxiety and schizophrenia) as well as on the most frequent age-related diseases (cardiovascular, ocular and neurodegenerative diseases, as well as sarcopenia). Overall, the phytochemical profile of saffron confers many beneficial virtues on human health and, in particular, on the prevention of age-related diseases, which is a major asset reinforcing the interest for this medicinal plant.

Buforin I an alternative to conventional antibiotics: Evaluation of the antimicrobial properties, stability, and safety

Cationic antimicrobial peptides are being developed as a promising class of antimicrobial sub-stances. The introduction of a new antibiotic component requires a comprehensive study of its properties so that it can be relied upon to continue laboratory procedures and clinical trials on laboratory animals or human volunteers. Antimicrobial activity of buforin I was evaluated against 15 of the most important pathogenic bacterial and fungal strains. This was followed by assessing anti-biofilm activity, time-dependent inhibitory, thermal stability, plas-ma stability, hemolysis, and cytotoxic activities. The range of obtained MICs was between 4 and 16 μg/mL. The most resistant and most sensitive microbial strains were S. salivarius and C. perfringens, respectively. Buforin I not only inhibited biofilm formation, but also showed a high biofilm radiation activity. Buforin I was stable in human plasma and also at different temperatures including 40, 60, and 80 °C. Although no significant anti-cancer properties were observed for buforin I, the lack of cytotoxicity as well as the lack of hemolytic activity confirm its safety. The high therapeutic index indicated that buforin I has a considerable pharmaceutical potential and can be a reasonable candidate to replace antibiotics or administered in combination with antibiotics to increase the effectiveness as well as reduce the dose of antibiotics.

Delineation of Neuroprotective Effects and Possible Benefits of AntioxidantsTherapy for the Treatment of Alzheimer's Diseases by Targeting Mitochondrial-Derived Reactive Oxygen Species: Bench to Bedside

Alzheimer's disease (AD) is considered the sixth leading cause of death in elderly patients and is characterized by progressive neuronal degeneration and impairment in memory, language, etc. AD is characterized by the deposition of senile plaque, accumulation of fibrils, and neurofibrillary tangles (NFTs) which are responsible for neuronal degeneration. Amyloid-β (Aβ) plays a key role in the process of neuronal degeneration in the case of AD. It has been reported that Aβ is responsible for the production of reactive oxygen species (ROS), depletion of endogenous antioxidants, increase in intracellular Ca²⁺ which further increases mitochondria dysfunctions, oxidative stress, release of pro-apoptotic factors, neuronal apoptosis, etc. Thus, oxidative stress plays a key role in the pathogenesis of AD. Antioxidants are compounds that have the ability to counteract the oxidative damage conferred by ROS. Therefore, the antioxidant therapy may provide benefits and halt the progress of AD to advance stages by counteracting neuronal degeneration. However, despite the beneficial effects imposed by the antioxidants, the findings from the clinical studies suggested inconsistent results which might be due to poor study design, selection of the wrong antioxidant, inability of the molecule to cross the blood-brain barrier (BBB), treatment in the advanced state of disease, etc. The present review insights into the neuroprotective effects and limitations of the antioxidant therapy for the treatment of AD by targeting mitochondrial-derived ROS. This particular article will certainly help the researchers to search new avenues for the treatment of AD by utilizing mitochondrial-derived ROS-targeted antioxidant therapies.

Safranal Alleviated OVA-Induced Asthma Model and Inhibits Mast Cell Activation

Introduction

Asthma is a chronic and recurring airway disease, which related to mast cell activation. Many compounds derived from Chinese herbal medicine has promising effects on stabilizing mast cells and decreasing inflammatory mediator production. Safranal, one of the active compounds from Crocus sativus, shows many anti-inflammatory properties. In this study, we evaluated the effect of safranal in ovalbumin (OVA)-induced asthma model. Furthermore, we investigate the effectiveness of safranal on stabilizing mast cell and inhibiting the production of inflammatory mediators in passive systemic anaphylaxis (PSA) model.

Methods

OVA-induced asthma and PSA model were used to evaluate the effect of safranal in vivo. Lung tissues were collected for H&E, TB, IHC, and PAS staining. ELISA were used to determine level of IgE and chemokines (IL-4, IL-5, TNF-α, and IFN-γ). RNA sequencing was used to uncovers genes that safranal regulate. Bone marrow-derived mast cells (BMMCs) were used to investigate the inhibitory effect and mechanism of safranal. Cytokine production (IL-6, TNF-α, and LTC₄) and NF-κB and MAPKs signaling pathway were assessed.

Results

Safranal reduced the level of serum IgE, the number of mast cells in lung tissue were decreased and Th1/Th2 cytokine levels were normalized in OVA-induced asthma model. Furthermore, safranal inhibited BMMCs degranulation and inhibited the production of LTC₄, IL-6, and TNF-α. Safranal inhibits NF-κB and MAPKs pathway protein phosphorylation and decreases NF-κB p65, AP-1 nuclear translocation. In the PSA model, safranal reduced the levels of histamine and LTC₄ in serum.

Conclusions

Safranal alleviates OVA-induced asthma, inhibits mast cell activation and PSA reaction. The possible mechanism occurs through the inhibition of the MAPKs and NF-κB pathways.

The role of Safranal and saffron stigma extracts in oxidative stress, diseases and photoaging: A systematic review

Reactive oxygen species (ROS) are produced as a result of various environmental factors and cellular metabolism reactions creating oxidative stress. The reversible oxidative modification on proteins such as cysteine oxidation may be useful and can play positive role. ROS generated offer some benefits such as cellular signalling and tissue repair when present in low concentration. However, most of the times, these reactive species cause detrimental effects to cell components which leads to various pathological conditions which causes or aggravates diseases due to oxidative stress. The degenerative diseases due to oxidative stress are diabetes, cardiovascular diseases, epilepsy, cancer and aging. Antioxidants are the compounds which scavenge these free radicals and hence neutralize their effects. Research has enabled the use of natural antioxidants as therapeutic agent in the treatment of diseases. Safranal is one such natural agent which is a major volatile component of saffron. Saffron, Red gold is the most expensive spice found in limited region of the planet and is also reported to be used in traditional systems of medicine. Chemically, safranal is a monoterpene aldehyde possessing a sweet fragrance. While exploring for the photoprotective properties of safranal, we learnt about the immense antioxidant potential of safranal. Investigation by various research groups established safranal as an anti-inflammatory, antidepressant, anxiolytic, antiasthamatic, antihypertensive, anticonvulsant, anticancer and antitussive and antigenotoxic agent. It has brought researchers over the world to explore the antioxidant benefits of saffron for human health. In the present paper, potential of safranal and its related molecules as radical scavenger in combating oxidative stress, diseased conditions is collated and the underlying mechanisms have been explained. Various cell lines and animal models used for study of Safranal have been discussed.

Curcumin Efficacy in a Serum/Glucose Deprivation-Induced Neuronal PC12 Injury Model

BACKGROUND

Glucose/serum deprivation (GSD), has been used for understanding molecular mechanisms of neuronal damage during ischemia. It has been suggested that curcumin may improve neurodegenerative diseases.

AIM

In this study, the protective effects of curcumin and its underlying mechanisms were investigated in PC12 cells upon GSD-induced stress.

METHODS

PC12 cells were cultured in DMEM overnight and then incubated in GSD condition for either 6 or 12h. GSD-treated cells were pretreated with various concentrations of curcumin (10, 20, and 40 μM) for 5h. The cell viability, apoptosis, reactive oxygen species (ROS) level, oxidative stress, expression of apoptosis-related genes, and IL-6 were determined.

RESULTS

Curcumin increased cell viability and caused an anti-apoptotic effect in PC12 cells exposed for 12h to GSD . Curcumin also increased antioxidant enzyme expression, suppressed lipid peroxidation, and decreased interleukin-6 secretion in PC12 cells subjected to GSD. In addition, pretreatment with curcumin down-regulated pro-apoptotic (Bax), and up-regulated antiapoptotic (Bcl2) mediators.

CONCLUSION

Curcumin mitigates many of the adverse effects of ischemia, and therefore, should be considered as an adjunct therapy in ischemic patients.

Safranal protects against ischemia-induced PC12 cell injury through inhibiting oxidative stress and apoptosis

Safranal, isolated from saffron (Crocus sativus L.), is known to possesses neuroprotective effects. In this study, the neuroprotective potential of safranal against PC12 cell injury triggered by ischemia/reperfusion was investigated. PC12 cells were pretreated with safranal at concentration ranges of 10-160 μM for 2 h and then deprived from oxygen-glucose-serum for 6 h, followed by reoxygenation for 24 h (OGD condition). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), 2,7-dichlorofluorescin diacetate (DCF-DA), and comet assays were used to measure the extent of cellular viability, reactive oxygen substances (ROS), and DNA damage, respectively. Also, propidium iodide (PI) flow cytometry assay and western blotting of bax, bcl-2, and cleaved caspase-3 were performed for assessment of apoptosis. OGD exposure reduced the cell viability and increased intracellular ROS production, oxidative DNA damage, and apoptosis, in comparison with untreated control cells. Pretreatment with safranal (40 and 160 μM) significantly attenuated OGD-induced PC12 cell death, oxidative damage, and apoptosis. Furthermore, safranal markedly reduced the overexpression of bax/bcl-2 ratio and active caspase-3 following OGD (p < 0.05). The present findings indicated that safranal protects against OGD-induced neurotoxicity via modulating of oxidative and apoptotic responses.Graphical abstract The schematic representation of the mode of action of safranal against PC12 cells death induced by oxygen-glucose-serum deprivation and reoxygenation (OGD-R).

Neuroprotective Potency of Saffron Against Neuropsychiatric Diseases, Neurodegenerative Diseases, and Other Brain Disorders: From Bench to Bedside

The increasing morbidity rates of brain disorders and conditions such as anxiety, depression, Alzheimer’s disease, and Parkinson’s disease have become a severe problem in recent years. Although researchers have spent considerable time studying these diseases and reported many positive outcomes, there still are limited drugs available for their treatment. As a common traditional Chinese medicine (TCM), saffron was employed to treat depression and some other inflammatory diseases in ancient China due to its antioxidant, anti-inflammatory, and antidepressant properties. In modern times, saffron and its constituents have been utilized, alone and in TCM formulas, to treat neuropsychiatric and neurodegenerative diseases. In this review, we mainly focus on recent clinical and preclinical trials of brain disorders in which saffron was applied, and summarize the neuroprotective properties of saffron and its constituents from chemical, pharmacokinetic, and pharmacological perspectives. We discuss the properties of saffron and its constituents, as well as their applications for treating brain disorders; we hope that this review will serve as a comprehensive reference for studies aimed at developing therapeutic drugs based on saffron.

Non-polyphenolic natural inhibitors of amyloid aggregation

Protein misfolding diseases (PMDs) are chronic and progressive, with no effective therapy so far. Aggregation and misfolding of amyloidogenic proteins are closely associated with the onset and progression of PMDs, such as amyloid-β (Aβ) in Alzheimer's disease, α-Synuclein (α-Syn) in Parkinson's disease and human islet amyloid polypeptide (hIAPP) in type 2 diabetes. Inhibiting toxic aggregation of amyloidogenic proteins is regarded as a promising therapeutic approach in PMDs. The past decade has witnessed the rapid progresses of this field, dozens of inhibitors have been screened and verified in vitro and in vivo, demonstrating inhibitory effects against the aggregation and misfolding of amyloidogenic proteins, together with beneficial effects. Natural products are major sources of small molecule amyloid inhibitors, a number of natural derived compounds have been identified with great bioactivities and translational prospects. Here, we review the non-polyphenolic natural inhibitors that potentially applicable for PMDs treatment, along with their working mechanisms. Future directions are proposed for the development and clinical applications of these inhibitors.

Role of phytochemicals as nutraceuticals for cognitive functions affected in ageing

Cognitive decline can occur with normal ageing and in age-related brain disorders, such as mild cognitive impairment and dementia, including Alzheimer's disease, with limited pharmacological therapies available. Other approaches to reduce cognitive decline are urgently needed, and so, the role of dietary interventions or nutraceuticals has received much attention in this respect. In this review, we examine the evidence for dietary plants and their chemical constituents as nutraceuticals, relevant to both cognitive decline in normal ageing and in dementia. Pharmacological (in vitro and in vivo), clinical and epidemiological evidence is assessed for both frequently consumed plants and their dietary forms, including tea, coffee, cocoa (chocolate), red wine, grapes, citrus and other fruits; in addition to plants used less frequently in certain diets and those that cross the blurred boundaries between foods, nutraceuticals and medicinal plants. For the latter, turmeric, saffron, sage, rosemary and lemon balm are examples of those discussed. LINKED ARTICLES: This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc.

Safranal, an active ingredient of saffron, attenuates cognitive deficits in amyloid β-induced rat model of Alzheimer's disease: underlying mechanisms

Alzheimer's disease (AD) is the most prevalent neurodegenerative amyloid disorder with progressive deterioration of cognitive and memory skills. Despite many efforts, no decisive therapy yet exists for AD. Safranal is the active constituent of saffron essential oil with antioxidant, anti-inflammatory, and anti-apoptotic properties. In this study, the possible beneficial effect of safranal on cognitive deficits was evaluated in a rat model of AD induced by intrahippocampal amyloid beta (Aβ_1-40). Safranal was daily given p.o. (0.025, 0.1, and 0.2 ml/kg) post-surgery for 1 week and finally learning and memory were evaluated in addition to assessment of the involvement of oxidative stress, inflammation, and apoptosis. Findings showed that safranal treatment of amyloid β-microinjected rats dose-dependently improved cognition in Y-maze, novel-object discrimination, passive avoidance, and 8-arm radial arm maze tasks. Besides, safranal attenuated hippocampal level of malondialdehyde (MDA), reactive oxygen species (ROS), protein carbonyl, interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor α (TNFα), nuclear factor-kappa B (NF-kB), apoptotic biomarkers including caspase 3 and DNA fragmentation, glial fibrillary acidic protein (GFAP), myeloperoxidase (MPO), and acetylcholinesterase (AChE) activity and improved superoxide dismutase (SOD) activity and mitochondrial membrane potential (MMP) with no significant effect on nitrite, catalase activity, and glutathione (GSH). Furthermore, safranal prevented CA1 neuronal loss due to amyloid β_1-40. In summary, safranal treatment of intrahippocampal amyloid beta_1-40-microinjected rats could prevent learning and memory decline via neuronal protection and at a molecular level through amelioration of apoptosis, oxidative stress, inflammation, cholinesterase activity, neutrophil infiltration, and also by preservation of mitochondrial integrity.

The role of hydrogen in Alzheimer's disease

Alzheimer’s disease is one of the most common neurodegenerative diseases in the elderly. It is often manifested as learning and memory impairment, cognitive function decline, normal social and emotional disorders. However, for this high-risk common disease, there is currently no effective treatment, which has plagued many clinicians. As a new type of medical therapeutic gas, hydrogen has attracted much attention recently. As a recognized reducing gas, hydrogen has shown great anti-oxidative stress and anti-inflammatory effect in many cerebral disease models. It can ameliorate neuronal damage, maintain the number of neurons, prolong the lifespan of neurons, and ultimately inhibit disease progression. Therefore, the role and mechanism of hydrogen in the pathological process of Alzheimer’s disease will be discussed in this paper.