Neuroprotective effects of oleuropein against cognitive dysfunction induced by colchicine in hippocampal CA1 area in rats

Oleuropein Has Modulatory Effects on Systemic Lipopolysaccharide-Induced Neuroinflammation in Male Rats

BACKGROUND

Neuroinflammation induced by systemic inflammation is a risk factor for developing chronic neurologic disorders. Oleuropein (OLE) has antioxidant and anti-inflammatory properties; however, its effect on systemic inflammation-related neuroinflammation is unknown.

OBJECTIVES

This study aimed to determine whether OLE protects against systemic lipopolysaccharide (LPS)-induced neuroinflammation in rats.

METHODS

Six-wk-old Wistar rats were randomly assigned to 1 of the following 5 groups: 1) control, 2) OLE-only, 3) LPS + vehicle, 4) OLE+LPS (O-LPS), and 5) a single-dose OLE + LPS (SO-LPS group). OLE 200 mg/kg or saline as a vehicle was administered via gavage for 7 d. On the seventh day, 2.5 mg/kg LPS was intraperitoneally administered. The rats were decapitated after 24 h of LPS treatment, and serum collection and tissue dissection were performed. The study assessed astrocyte and microglial activation using glial fibrillary acidic protein (GFAP) and CD11b immunohistochemistry, nod-like receptor protein-3, interleukin (IL)-1β, IL-17A, and IL-4 concentrations in prefrontal and hippocampal tissues via enzyme-linked immunosorbent assay, and total antioxidant/oxidant status (TAS/TOS) in serum and tissues via spectrophotometry.

RESULTS

In both the O-LPS and SO-LPS groups, LPS-related activation of microglia and astrocytes was suppressed in the cortex and hippocampus (P < 0.001), excluding cortical astrocyte activation, which was suppressed only in the SO-LPS group (P < 0.001). Hippocampal GFAP immunoreactivity and IL-17A concentrations in the dentate gyrus were higher in the OLE group than those in the control group, but LPS-related increases in these concentrations were suppressed in the O-LPS group. The O-LPS group had higher cortical TAS and IL-4 concentrations.

CONCLUSIONS

OLE suppressed LPS-related astrocyte and microglial activation in the hippocampus and cortex. The OLE-induced increase in cortical IL-4 concentrations indicates the induction of an anti-inflammatory phenotype of microglia. OLE may also modulate astrocyte and IL-17A functions, which could explain its opposing effects on hippocampal GFAP immunoreactivity and IL-17A concentrations when administered with or without LPS.

Olea europaea L-derived secoiridoids: Beneficial health effects and potential therapeutic approaches

Over the years, health challenges have become increasingly complex and global and, at the beginning of the 21st century, chronic diseases, including cardiovascular, neurological, and chronic respiratory diseases, as well as cancer and diabetes, have been identified by World Health Organization as one of the biggest threats to human health. Recently, antimicrobial resistance has also emerged as a growing problem of public health for the management of infectious diseases. In this scenario, the exploration of natural products as supplementation or alternative therapeutic options is acquiring great importance, and, among them, the olive tree, Olea europaea L, specifically leaves, fruits, and oil, has been increasingly investigated for its health promoting properties. Traditionally, these properties have been largely attributed to the high concentration of monounsaturated fatty acids, although, in recent years, beneficial effects have also been associated to other components, particularly polyphenols. Among them, the most interesting group is represented by Olea europaea L secoiridoids, comprising oleuropein, oleocanthal, oleacein, and ligstroside, which display anti-inflammatory, antioxidant, cardioprotective, neuroprotective and anticancer activities. This review provides an overview of the multiple health beneficial effects, the molecular mechanisms, and the potential applications of secoiridoids from Olea europaea L.

Inhibition of TLR4, NF-κB, and INOS pathways mediates ameliorative effect of syringic acid in experimental ulcerative colitis in rats

OBJECTIVE

Numerous therapeutics and pharmacological properties have been reported in syringic acid (SA). In this study, we aimed to evaluate effect of SA in ulcerative colitis (UC) in rats considering effect on TLR4, NF-κB, and INOS pathways.

MATERIALS AND METHODS

48 Wistar rats were randomly designated into six groups (n = 8). UC was induced via intra-rectal administration of 7% acetic acid (0.8 ml). SA at doses of 10, 25, 50 mg/kg was administrated through gavage, and dexamethasone (2 mg/kg) administrated intra-peritoneally for 5 consecutive days. The macroscopic and histopathological damages as well as expression of inflammatory and apoptotic genes along with superoxide dismutase (SOD) and catalase (CAT) activities, total antioxidant capacity (TAC), nitric oxide (NO), and malondialdehyde (MDA) levels in the colon tissue were assessed.

RESULTS

UC led to an increase in the apoptotic and inflammatory genes, NO and MDA levels as well as decrease in TAC level, and SOD and CAT activities (p < 0.05). UC also caused severe damage, edema, inflammation, and necrosis in the colon. SA significantly reduced gene expressions of INOS, TLR4, IL-6, IL-1β, NF-κB, Caspase-3, Caspase-8, and Bax. SA ameliorated negative macroscopic and histopathologic effects of UC. SA significantly reduced MDA and NO levels, and increased TAC level and CAT activity in the colon tissue in comparison to the UC rats without treatment (p < 0.05).

CONCLUSION

SA via attenuation of the TLR4-NF-κB, NF-κB-INOS-NO pathways, oxidative stress, inflammation, and apoptosis of UC in rats.

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Oleuropein Promotes Neural Plasticity and Neuroprotection via PPARα-Dependent and Independent Pathways

Oleuropein (OLE), a main constituent of olives, displays a pleiotropic beneficial dynamic in health and disease; the effects are based mainly on its antioxidant and hypolipidemic properties, and its capacity to protect the myocardium during ischemia. Furthermore, OLE activates the peroxisome proliferator-activated receptor (PPARα) in neurons and astrocytes, providing neuroprotection against noxious biological reactions that are induced following cerebral ischemia. The current study investigated the effect of OLE in the regulation of various neural plasticity indices, emphasizing the role of PPARα. For this purpose, 129/Sv wild-type (WT) and Pparα-null mice were treated with OLE for three weeks. The findings revealed that chronic treatment with OLE up-regulated the brain-derived neurotrophic factor (BDNF) and its receptor TrkB in the prefrontal cortex (PFC) of mice via activation of the ERK1/2, AKT and PKA/CREB signaling pathways. No similar effects were observed in the hippocampus. The OLE-induced effects on BDNF and TrkB appear to be mediated by PPARα, because no similar alterations were observed in the PFC of Pparα-null mice. Notably, OLE did not affect the neurotrophic factors NT3 and NT4/5 in both brain tissues. However, fenofibrate, a selective PPARα agonist, up-regulated BDNF and NT3 in the PFC of mice, whereas the drug induced NT4/5 in both brain sites tested. Interestingly, OLE provided neuroprotection in differentiated human SH-SY5Y cells against β-amyloid and H2O2 toxicity independently from PPARα activation. In conclusion, OLE and similar drugs, acting either as PPARα agonists or via PPARα independent mechanisms, could improve synaptic function/plasticity mainly in the PFC and to a lesser extent in the hippocampus, thus beneficially affecting cognitive functions.

Quinic acid ameliorates ulcerative colitis in rats, through the inhibition of two TLR4-NF-κB and NF-κB-INOS-NO signaling pathways

OBJECTIVE

In this study, the therapeutic effect of quinic acid (QA), which has anti-inflammatory activity, was investigated on acetic acid-induced colitis in male Wistar rats.

METHODS

Ulcerative colitis (UC) was induced in rats by acetic acid intrarectally, and the protective effects of QA in 10, 30, 60, and 100 mg/kg doses were investigated. Rats were treated for 5 days and their colon tissues were dissected out at the end. Macroscopic and histopathological examinations were performed in colon tissues. Also, the expression of inflammatory and apoptotic genes, including TLR4, IL-1β, INOS, IL-6, TNF-α, NF-κB, Caspase-3, Caspase-8, Bax, and Bcl-2, was measured. Biochemistry indices, such as malondialdehyde (MDA) and nitrite oxide (NO) content, in addition to, total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), and enzymes activities were also assessed.

RESULTS

Colitis increased the levels of MDA and NO, and enhanced the inflammatory and apoptotic gene expressions, while reducing the SOD and CAT enzymes activity, and TAC levels in the colitis rats. Also, results showed that colitis was associated with the infiltration of inflammatory cells, epithelium damage, and edema in colon tissue. QA significantly ameliorated histopathological indices, oxidative stress, inflammation, and apoptosis in colitis rats.

CONCLUSION

QA ameliorated UC through the inhibition of two TLR4-NF-κB and NF-κB-INOS-NO signaling pathways, which results in the reduction of colitis complications, including oxidative stress, inflammation, apoptosis and histopathological injuries in rats. Therefore it can be concluded, that QA exerts its therapeutic effects through antiapoptotic, antioxidant, and anti-inflammatory properties.

The effect of phytoprotectors on the functioning of liver NAD⁺- and NADP⁺-maliс enzymes in rats with alloxan diabetes

The development of experimental alloxan diabetes in rats was accompanied by the increase the activity of liver NAD⁺- and NADP⁺-dependent malic enzymes (ME; NAD⁺-ME, EC 1.1.1.39 and NADP⁺-ME, 1.1.1.40) associated with an increase in the rate of transcription of genes encoding these enzymes. Oral administration of aqueous extracts of Jerusalem artichoke and olive to diabetic rats caused a noticeable decrease in blood glucose, a decrease in the rate of transcription of the studied genes; and a decrease in ME activity towards normal values. Thus, extracts of Jerusalem artichoke and olive can be used as additives to the standard therapy of diabetes mellitus.

Oxidative Stress and Natural Antioxidants: Back and Forth in the Neurological Mechanisms of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by the progressive degeneration of neuronal cells. With the increase in aged population, there is a prevalence of irreversible neurodegenerative changes, causing a significant mental, social, and economic burden globally. The factors contributing to AD are multidimensional, highly complex, and not completely understood. However, it is widely known that aging, neuroinflammation, and excessive production of reactive oxygen species (ROS), along with other free radicals, substantially contribute to oxidative stress and cell death, which are inextricably linked. While oxidative stress is undeniably important in AD, limiting free radicals and ROS levels is an intriguing and potential strategy for deferring the process of neurodegeneration and alleviating associated symptoms. Therapeutic compounds from natural sources have recently become increasingly accepted and have been effectively studied for AD treatment. These phytocompounds are widely available and a multitude of holistic therapeutic efficiencies for treating AD owing to their antioxidant, anti-inflammatory, and biological activities. Some of these compounds also function by stimulating cholinergic neurotransmission, facilitating the suppression of beta-site amyloid precursor protein-cleaving enzyme 1, α-synuclein, and monoamine oxidase proteins, and deterring the occurrence of AD. Additionally, various phenolic, flavonoid, and terpenoid phytocompounds have been extensively described as potential palliative agents for AD progression. Preclinical studies have shown their involvement in modulating the cellular redox balance and minimizing ROS formation, displaying them as antioxidant agents with neuroprotective abilities. This review emphasizes the mechanistic role of natural products in the treatment of AD and discusses the various pathological hypotheses proposed for AD.

Coumaric acid ameliorates experimental colitis in rats through attenuation of oxidative stress, inflammatory response and apoptosis

OBJECTIVE

Due to the high side effects of commonly used drugs and according to the pharmacological properties reported for coumaric acid (CA), this study was designed to determine the impact of CA on acetic acid-induced colitis in rats, considering its possible anti-inflammatory, antioxidant, and anti-apoptotic properties.

MATERIALS AND METHODS

Forty-eight male Wistar rats were divided into 6 equal groups (n = 8). Colitis was induced by acetic acid intrarectally. CA in three different doses (50, 100, and 150 mg/kg) was administrated for 5 days. Finally, the macroscopic and histopathological changes in the colon tissue were examined. The expression of inflammatory and apoptotic genes, including NF-κB, TNF-α, INOS, IL-1β, IL-6, TLR4, Caspase-3, Caspase-8, Bax, Bcl-2 was assessed. In addition, changes in the levels of catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), nitrite, and total antioxidant capacity (TAC) were measured in the colon tissue.

RESULTS

Colitis led to a decrease in TAC and the activity levels of CAT and SOD and an increase in the expression of inflammatory and apoptotic genes, MDA, and nitrite levels in the colon. Colitis was also associated with edema and severe damage to the epithelium, infiltration of inflammatory cells, and the presence of ulcers and necrosis in the colon tissue. CA significantly improved the inflammation, oxidative stress, apoptosis, and histopathological indices caused by acetic acid-induced colitis on the colon.

CONCLUSION

It is concluded that CA probably exerts its positive effects in the management of colitis, through its anti-inflammatory, antioxidant, and anti-apoptotic properties.

Olive Leaf Extract Attenuates Chlorpyrifos-Induced Neuro- and Reproductive Toxicity in Male Albino Rats

Chlorpyrifos (CPF) is a common organophosphorus insecticide. It is associated with negative consequences such as neurotoxicity and reproductive injury. This study aimed to observe the ability of olive leaf extract to attenuate chlorpyrifos toxicity, which induced neuro- and reproductive toxicity in male albino rats. Olive leaf extract (OLE) exhibits potent antioxidant and antiapoptotic properties. Twenty-two mature male rats were divided into four groups: control (saline), CPF (9 mg/kg), OLE (150 mg/kg), and CPF + OLE. Treatment was administered orally for 80 days. The CPF significantly reduced serum sex hormones, sperm counts and motility, high oxidants (MDA), and depleted antioxidants (GSH, SOD, TAC) in the brain and testes homogenate; additionally, it decreased serum AChE and brain neurotransmitters, increased Bax, decreased Bcl-2, and boosted caspase-3 immune expression in neural and testicular cells. Immunological expression of Ki 67 in the cerebrum, cerebellum, choroid plexus, and hippocampus was reduced, and α-SMA in testicular tissue also decreased. Histopathological findings were consistent with the above impacts. OLE co-administration significantly normalized all these abnormalities. OLE showed significant protection against neural and reproductive damage caused by CPF.

Nutraceutical Interventions for Post-Traumatic Stress Disorder in Animal Models: A Focus on the Hypothalamic–Pituitary–Adrenal Axis

Post-traumatic stress disorder (PTSD) occurs after exposure to traumatic events and is characterized by overwhelming fear and anxiety. Disturbances in the hypothalamic–pituitary–adrenal (HPA) axis are involved in the pathogenesis of mood disorders, including anxiety, PTSD, and major depressive disorders. Studies have demonstrated the relationship between the HPA axis response and stress vulnerability, indicating that the HPA axis regulates the immune system, fear memory, and neurotransmission. The selective serotonin reuptake inhibitors (SSRIs), sertraline and paroxetine, are the only drugs that have been approved by the United States Food and Drug Administration for the treatment of PTSD. However, SSRIs require long treatment times and are associated with lower response and remission rates; therefore, additional pharmacological interventions are required. Complementary and alternative medicine therapies ameliorate HPA axis disturbances through regulation of gut dysbiosis, insomnia, chronic stress, and depression. We have described the cellular and molecular mechanisms through which the HPA axis is involved in PTSD pathogenesis and have evaluated the potential of herbal medicines for PTSD treatment. Herbal medicines could comprise a good therapeutic strategy for HPA axis regulation and can simultaneously improve PTSD-related symptoms. Finally, herbal medicines may lead to novel biologically driven approaches for the treatment and prevention of PTSD.

The Risk of Hippocampal Metastasis and the Associated High-Risk Factors in 411 Patients With Brain Metastases

Background and Aims

To retrospectively analyze the incidence of hippocampal metastasis and the associated high-risk factors in patients with brain metastases and evaluate the safety of hippocampal avoidance whole-brain radiation therapy (HA-WBRT).

Methods

We retrospectively analyzed the data of patients with brain metastases diagnosed by contrast-enhanced cranial Magnetic resonance imaging (MRI) at the First Hospital of Lanzhou University from 2017 to 2020. The boundaries of the hippocampus, hippocampus + 5 mm area, hippocampus + 10 mm area, and hippocampus + 20 mm area were delineated, and the distances from the brain metastases to the hippocampus were measured. Univariate and multivariate logistic regressions were adopted to analyze the high-risk factors of hippocampal metastasis.

Results

A total of 3,375 brain metastases in 411 patients were included in the analysis. The metastasis rates in the hippocampus and surrounding areas of the entire group were as follows: 7.3% (30/411) in the hippocampus, 16.5% (68/411) in the hippocampus + 5 mm area, 23.8% (98/411) in the hippocampus + 10 mm area, and 36.5% (150/411) in the hippocampus + 20 mm area. Univariate logistic regression showed that the pathological type, the number of metastases, the maximum diameter of metastases, and the volume of brain metastases were all correlated with hippocampal metastasis. Multivariate logistic regression showed that the pathological type, the number of metastases, and the total volume of metastases were correlated with hippocampal metastasis.

Conclusion

The pathological type, the number of metastases, and the total volume of metastases are the high-risk factors associated with hippocampal metastasis. Small cell lung cancer (SCLC) has a significantly higher rate of hippocampal metastasis than other tumor types. The greater the number and total volume of metastases, the more likely the hippocampal metastasis. For patients with SCLC or a greater number and total volume of brain metastases, the implementation of HA-WBRT may bring a higher risk of tumor recurrence.

Potential benefit of olive leaf extract in cervical spondylotic myelopathy model

Introduction

Cervical spondylosis is the most common cause of myelopathy in the cervical due to chronic compression of the spinal cord in patients aged 55 years or older. Recent studies suggest that olive extracts suppress inflammation and reduce stress oxidative injury. The purpose of this study was to determine the potential neuroprotective effects of olive leaf extract (OLE) in an experimental cervical spondylotic myelopathy model.

Methods

This study was divided into 6 groups; Control Negative (Sham-Operated) Group, Control Positive 1 & 2 (early chronic and chronic), Treatment Groups 1, 2 & 3 (prophylactic, concomitant & late). Olive leaf extract (OLE) give 350 mg/kg BW and spinal cord sample was taken at the compression level C5. Histopathological assessment and immunohistochemistry of Amyloid-β, p-Tau, TDP-43 dan CD-68 dan evaluation of functional motoric outcome was done before animals were terminated.

Results

Chronic spinal cord compression increased the expression of Amyloid-β, p-Tau, TDP-43 dan CD-68. OLE 350 mg/kg BW decreased the expression of these biomarkers and increased functional motoric outcome, especially as prophylactic dan concomitant treatment.

Discussion

These findings indicate that OLE may be effective in protecting cervical spondylotic myelopathy.

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Cervical Spondylotic Myelopathy.

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Spine.

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Amyloid-β.

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p-Tau.

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TDP-43.

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CD-68.

Protective effect of olive leaves phenolic compounds against neurodegenerative disorders: Promising alternative for Alzheimer and Parkinson diseases modulation

The main objective of this work was to review literature on compounds extracted from olive tree leaves, such as simple phenols (hydroxytyrosol) and flavonoids (Apigenin, apigenin-7-O-glucoside, luteolin.) and their diverse pharmacological activities as antioxidant, antimicrobial, anti-viral, anti-obesity, anti-inflammatory and neuroprotective properties. In addition, the study discussed the key mechanisms underlying their neuroprotective effects. This study adopted an approach of collecting data through the databases provided by ScienceDirect, SCOPUS, MEDLINE, PubMed and Google Scholar. This review revealed that there was an agreement on the great impact of olive tree leaves phenolic compounds on many metabolic syndromes as well as on the most prevalent neurodegenerative diseases such as Alzheimer and Parkinson. These findings would be of great importance for the use of olive tree leaves extracts as a food supplement and/or a source of drugs for many diseases. In addition, this review would of great help to beginning researchers in the field since it would offer them a general overview of the studies undertaken in the last two decades on the topic.

Toxic Substance-induced Hippocampal Neurodegeneration in Rodents as Model of Alzheimer’s Dementia

BACKGROUND: Alzheimer’s Dementia (AD) cases are increasing with the global elderly population. To study the part of the brain affected by AD, animal models for hippocampal degeneration are still necessary to better understand AD pathogenesis and develop treatment and prevention measures. AIM: This study was a systematic review of toxic substance-induced animal models of AD using the Morris Water Maze method in determining hippocampal-related memory impairment. Our aim was reviewing the methods of AD induction using toxic substances in laboratory rodents and evaluating the report of the AD biomarkers reported in the models. METHODS: Data were obtained from articles in the PubMed database, then compiled, categorized, and analyzed. Eighty studies published in the past 5 years were included for analysis. RESULTS AND DISCUSSION: The most widely used method was intracerebroventricular injection of amyloid-β _substances. However, some less technically challenging techniques using oral or intraperitoneal administration of other toxic substances also produce successful models. Instead of hippocampal neurodegeneration, many studies detected biomarkers of the AD pathological process while some reported inflammation, oxidative stress, neurotrophic factors, and changes of cholinergic activity. Female animals were underrepresented despite a high incidence of AD in women. CONCLUSION: Toxic substances may be used to develop AD animal models characterized with appropriate AD pathological markers. Characterization of methods with the most easy-handling techniques and more studies in female animal models should be encouraged.

Response surface methodology optimised solvothermal system enables an efficient extraction of echinacoside and oleuropein from Syringa pubescens Turcz

INTRODUCTION

Syringa pubescens Turcz. was reported to be abundant in the Funiu Mountains of Henan Province and can be used to treat hepatitis and cirrhosis. In order to develop and utilise the resource, a fast and simple technique to extract bioactive compounds is needed.

OBJECTIVES

Our aims were to provide an extraction technique of glycosides from S. pubescens and study the antioxidant activity of this material.

METHODS

Box-Behnken design (BBD) was employed with three factors at three levels. The process parameters such as ethanol concentration (X₁ ), temperature (X₂ ), and solvent-solid ratio (X₃ ) could significantly influence efficiency and yield of target compounds. High-performance liquid chromatography (HPLC) was used to determine the content of glycosides. DPPH (α,α-diphenyl-β-picrylhydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and reducing power were used to evaluate the antioxidant activity of S. pubescens extract.

RESULTS

The optimal parameters for the maximal extraction yield were obtained with ethanol concentration of 68%, temperature of 89°C, solvent-solid ratio of 46 mL/g, and time of 20 min. The S. pubescens extract showed strong antioxidant properties in vitro.

CONCLUSION

The findings indicated the potential application of solvothermal extraction method to extract bioactive compounds from S. pubescens Turcz. Furthermore, the S. pubescens extract could be used as an important resource of antioxidant activity.

Natural products as pharmacological modulators of mitochondrial dysfunctions for the treatments of Alzheimer's disease: A comprehensive review

Alzheimer's disease (AD) is the most common progressive neurodegenerative disorder characterized by neuronal loss and cognitive impairment that harshly affect the elderly individuals. Currently, the available anti-AD pharmacological approaches are purely symptomatic to alleviate AD symptoms, and the curative effects of novel anti-AD drugs focused on Aβ target are disappointing. Hence, there is a tremendous need to adjust AD therapeutic targets and discover novel anti-AD agents. In AD, mitochondrial dysfunction gradually triggers neuronal death from different aspects and worsens the occurrence and progress of AD. Consequently, it has been proposed that the intervention of impaired mitochondria represents an attractive breakthrough point for AD treatments. Due to chemical diversity, poly-pharmacological activities, few adverse effects and multiple targeting, natural products (NPs) have been identified as a valuable treasure for drug discovery and development. Multiple lines of studies have scientifically proven that NPs display ameliorative benefits in AD treatment in relation to mitochondrial dysfunction. This review surveys the complicated implications for mitochondrial dysregulation and AD, and then summarizes the potentials of NPs and their underlying molecular mechanisms against AD via reducing or improving mitochondrial dysfunction. It is expected that this work may open the window to speed up the development of innovative anti-AD drugs originated from NPs and improve upcoming AD therapeutics.

The potential neuroprotective roles of olive leaf extract in an epilepsy rat model induced by kainic acid

BACKGROUND AND PURPOSE

Epilepsy is recognized as a chronic neurologic disease. Increasing evidence has addressed the antioxidant and anti-inflammatory roles of olive leaf extract (OLE) in neurodegenerative diseases. So, the current study aimed to investigate the neuroprotective roles of OLE in epilepsy.

EXPERIMENTAL APPROACH

Forty rats were divided into 4 groups including a control group, sham group, kainic acid (KA) group, and KA + OLE group. KA (4 μg/rat) was injected intrahippocampal, and OLE (300 mg/kg) was orally administrated for 4 weeks. Animals were sacrificed, and their hippocampi were isolated. KA- induced seizure activity was recorded. Oxidative stress index was assessed by measuring its indicators including malondialdehyde (MDA), nitrite, nitrate, and glutathione (GSH) as well as the catalase (CAT) activity. The supernatant concentration of tumor necrosis factor-α (TNF-α) and the apoptosis rate in neurons were measured.

FINDINGS/RESULTS

Treatment with OLE significantly reduced the seizure score. OLE decreased oxidative stress index by reducing the concentration of MDA, nitrite, and nitrate as well as increasing the level of GSH. OLE had a significant anti-apoptotic effect on neurons. However, CAT activity and the level of TNF-α were not affected.

CONCLUSION AND IMPLICATIONS

Our findings indicated neuroprotective properties of OLE, which is mainly mediated by its antioxidant and anti-apoptotic effects, therefore, could be considered as a valuable therapeutic supplement for epilepsy.

Antihyperlipidemic, Antihyperglycemic, and Liver Function Protection of Olea europaea var. Meski Stone and Seed Extracts: LC-ESI-HRMS-Based Composition Analysis

Methanol and methanol/water extracts of olive stones and seeds from Olea europaea var. meski were analyzed by reversed-phase high-performance liquid chromatography (HPLC) with diode array detection and mass spectrometry (LC-MS/MS). A total of 28 metabolites were identified; among them are hydroxycinnamic acid derivatives, phenolic alcohols, flavonoids and flavonoid glucosides, secoiridoids, and terpenes. All the extracts were screened for the inhibitory effect of key enzymes related to diabetes and obesity, such as α-amylase and lipase. An in vitro study revealed that Olea meski stone ethanol (MSE) and methanol (MSM) extracts and Olea meski seed ethanol (MSE1) and methanol (MSM1) extracts exert an inhibitory action against lipase and α-amylase. The most potent activity was observed in the StM extract with IC₅₀ equal to 0.19 mg/ml against DPPH oxidation, 1.04 mg/ml against α-amylase, and 2.13 mg/ml against lipase. In HFFD rats, the findings indicated that the increase of body weight, LDL, TC, and glucose levels and then the decrease in HDL-C were significantly suppressed in the MSM-treated group than those in HFFD rats. Moreover, the MSM extract exhibited a prominent selective inhibitory effect against intestinal lipase and α-amylase activities. The MSM extract was also able to protect the liver-kidney functions efficiently, which was evidenced by biochemicals and histological studies.

Oleuropein Improved Post Cerebral Stroke Cognitive Function by Promoting Histone Acetylation and Phosphorylation of cAMP Response Element-Binding Protein in MCAO Rats

Background:

Post-stroke cognitive impairment (PSCI) is commonest clinical disorder in which peripheral cholinergic activity is important. Oleuropein (OLP) is polyphenol is present in olive oil. Here we evaluated the effect of OLP in cognitive dysfunction rats in post cerebral stroke model.

Methods:

The post cerebral stroke cognitive dysfunction PSD rat model was created by occlusion of transient middle cerebral artery. The rats were divided into 6 groups named, Sham + Vehicle, Sham + OLP (50 mg/kg), PSD rats + Vehicle, PSD rats + OLP (20, 50 or 100 mg/kg). The spatial learning was assessed by Morris water maze (MWM). The expression of choline acetyltransferase (ChAT), acetylcholine (ACH), extent of histone acetylation and phosphorylation of cAMP response element-binding protein (CREB) were evaluated by Western blot assay and immunofluorescence staining.

Results:

Treatment of OLP at various doses showed higher number of spontaneous and rewarded alterations and lesser percentage bias compared to vehicle treated PSD rats. OLP resulted in decreased levels of ChAT and ACH, whereas the degree of histone acetylation and phosphorylation of CREB improved in dose dependent pattern.

Conclusion:

treatment of OLP improved PSCI via increasing the phosphorylation of CREB and histone acetylation, thus attenuating cholinergic activity.

Therapeutic Effects of Oleuropein in Improving Seizure, Oxidative Stress and Cognitive Disorder in Pentylenetetrazole Kindling Model of Epilepsy in Mice

Prolonged epileptic seizures are the cause of neuronal death and brain damage. Lesions in different regions of the brain can lead to memory loss and cognitive disorders. It is therefore essential to seek out new neuroprotective drugs. Our aim was to investigate the therapeutic effects of oleuropein in improving seizure, oxidative stress, and cognitive disorder in pentylenetetrazole (PTZ) kindling model of epilepsy in mice. Mice were randomized to four groups; negative control group intraperitoneally receiving PTZ for 10 days, oleuropein group receiving oleuropein (20 mg/kg) 30 min before PTZ administration, positive control group receiving diazepam 30 min before PTZ administration and flumazenil group receiving flumazenil and then oleuropein 30 min before PTZ administration. Epilepsy severity was investigated after final administration of PTZ. Then hippocampal tissues were removed and stored at -70 °C until measurements of the interleukin-1 (IL-1) and glutamate transporter 1 (GLT-1) gene expression were conducted. Oleuropein treatment caused a significant increase in seizure latency and a significant decrease in total frequencies of head ticks, head and upper limbs seizures, the whole body seizures, frequent spinning and jumping and tonic seizures in PTZ receiving mice. IL-1 expression decreased in oleuropein group and GLT-1 levels did not change significantly in this group. Oleuropein treatment caused significant improvement of passive avoidance memory in PTZ receiving mice in shuttle box. Oleuropein can decrease PTZ-induced seizures and memory disorders due to its antioxidant and anti-inflammatory properties and is thus recommended to be used for production of anti-epileptic drugs.

Neuroprotective effects of Fraxinus angustifolia Vahl. bark extract against Alzheimer's disease

Alzheimer disease's (AD) is a neurodegenerative disease induced by amyloid-β (Aβ) aggregation and accumulation of neurotoxic metals in the brain. Fraxinus angustifolia Vahl. (Oleaceae) is a Mediterranean plant traditionally used to treat several human problems as nervous system problems. This study aimed to evaluate the neuroprotective effects of F. angustifolia Vahl. bark extract (FAB) in vitro and in vivo against Aβ-aggregation and aluminium induced-neurotoxicity in mice. FAB was characterized by colorimetric methods and its individual compounds were identified and quantified by LC-MS. First, the neuroprotective effect of FAB was evaluated against Aβ_25-35-aggregation where it was directly incubated with Aβ_25-35 and the kinetic of aggregation was measured by spectrophotometer at 200 nm. Then, the extract was tested against Aβ_25-35-induced cytotoxicity on PC12 cells and the cells viability was determined by MTT test. On the other hand, FAB (0.01-0.5 mg/mL) was tested against aluminium-activated lipid peroxidation in mice synaptosomal membranes, and in vivo against aluminium-caused neurotoxicity in male N.M.R.I. (Naval Medical Research Institute) mice; this test consisted of daily co-administration of the extract with Al for 60 days. At the end of the treatment, behavioral and memory tests (locomotor activity, black and white and Morris water maze tests) and histological analysis were realized. The identification and quantification of FAB phenolics revealed the presence of different phenolic classes with high concentration of phenylethanoids and hydroxycoumarins. FAB showed a high Aβ_25-35 anti-aggregative effect and a dose dependent protective effect on PC12 cells. The extract also demonstrated a significant inhibition of lipid peroxidation and was found to prevent the Al harmful effects where it significantly increased the locomotor activity, decreased the anxiety, improved memory and reduced histological alterations. In conclusion, FAB is rich of bioactive compounds that gave it the ability to inhibit Aβ-aggregation and Al-caused neurotoxicity in mice.

Hydroxytyrosol Promotes Proliferation of Human Schwann Cells: An In Vitro Study

Recent advances in phytomedicine have explored some potential candidates for nerve regeneration, including hydroxytyrosol (HT). This study was undertaken to explore the potential effects of HT on human Schwann cells' proliferation. Methods: The primary human Schwann cell (hSC) was characterized, and the proliferation rate of hSC supplemented with various concentrations of HT was determined via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle analysis and protein expression of glial fibrillary acidic protein (GFAP) and p75 nerve growth factor receptor (p75 NGFR) were evaluated via the immunofluorescence technique. Results: In vitro culture of hSCs revealed spindle-like, bipolar morphology with the expression of specific markers of hSC. Hydroxytyrosol at 10 and 20 ng/mL significantly increased the proliferation of hSCs by 30.12 ± 5.9% and 47.8 ± 6.7% compared to control (p < 0.05). Cell cycle analysis showed that HT-treated hSCs have a higher proliferation index (16.2 ± 0.2%) than the control (12.4 ± 0.4%) (p < 0.01). In addition, HT significantly increased the protein expression of GFAP and p75NGFR (p < 0.05). Conclusion: HT stimulates the proliferation of hSCs in vitro, indicated by a significant increase in the hSC proliferation index and protein expression of hSCs' proliferation markers, namely p75 NGFR and GFAP.

Effects of Hypericum scabrum extract on dentate gyrus synaptic plasticity in high fat diet-fed rats

High-fat diet (HFD) can induce deficits in neural function, oxidative stress, and decrease hippocampal neurogenesis. Hypericum (H.) scabrum extract (Ext) contains compounds that could treat neurological disorders. This study aimed to examine the neuroprotective impacts of the H. scabrum Ext on hippocampal synaptic plasticity in rats that were fed HFD. Fifty-four male Wistar rats (220 ± 10 g) were randomly arranged in six groups: (1) HFD group; (2) HFD + Ext300 group; (3) HFD + Ext100 group; (4) Control group; (5) Ext 300 mg/kg group; (6) Ext 100 mg/kg group. These protocols were administrated for 3 months. After this stage, a stimulating electrode was implanted in the perforant pathway (PP), and a bipolar recording electrode was embedded into the dentate gyrus (DG). Long-term potentiation (LTP) was provoked by high-frequency stimulation (HFS) of the PP. Field excitatory postsynaptic potentials (EPSP) and population spikes (PS) were recorded at 5, 30, and 60 min after HFS. The HFD group exhibited a large and significant decrease in their PS amplitude and EPSP slope as compared to the control and extract groups. In reverse, H. scabrum administration in the HFD + Ext rats reversed the effect of HFD on the PS amplitude and EPSP slope. The results of the study support that H. scabrum Ext can inhibit diminished synaptic plasticity caused by the HFD. These effects are probably due to the extreme antioxidant impacts of the Ext and its capability to scavenge free radicals.

The Impact of Natural Compounds on S-Shaped Aβ42 Fibril: From Molecular Docking to Biophysical Characterization

The pursuit for effective strategies inhibiting the amyloidogenic process in neurodegenerative disorders, such as Alzheimer’s disease (AD), remains one of the main unsolved issues, and only a few drugs have demonstrated to delay the degeneration of the cognitive system. Moreover, most therapies induce severe side effects and are not effective at all stages of the illness. The need to find novel and reliable drugs appears therefore of primary importance. In this context, natural compounds have shown interesting beneficial effects on the onset and progression of neurodegenerative diseases, exhibiting a great inhibitory activity on the formation of amyloid aggregates and proving to be effective in many preclinical and clinical studies. However, their inhibitory mechanism is still unclear. In this work, ensemble docking and molecular dynamics simulations on S-shaped Aβ₄₂ fibrils have been carried out to evaluate the influence of several natural compounds on amyloid conformational behaviour. A deep understanding of the interaction mechanisms between natural compounds and Aβ aggregates may play a key role to pave the way for design, discovery and optimization strategies toward an efficient destabilization of toxic amyloid assemblies.

The effect of epigallocatechin-3-gallate on morphine-induced memory impairments in rat: EGCG effects on morphine neurotoxicity

AIM OF STUDY

This investigation evaluated the capacity of epigallocatechin-3-gallate (EGCG) as the main polyphenolic compound in the green tea extract against memory impairment and neurotoxicity in morphine-treated rats.

METHODS

To measure the EGCG effect (5 and 50 mg/kg, i.p., co-treated with morphine) on spatial learning and memory of morphine-administrated male Wistar rats (45 mg/kg, s.c., 4 weeks), the Morris water maze test was used. Some apoptotic protein levels (Bax, Bcl-2, and cleaved caspase 3) were evaluated in the hippocampus tissue by the Western blot test. Also, oxidative stress status (malondialdehyde level, glutathione peroxidase, and superoxide dismutase activity) was measured in hippocampus tissue.

RESULTS

The data presented that EGCG treatment (50 mg/kg) inhibited the morphine-induced memory deficits in rats. Also, EGCG administration reduced the apoptosis and oxidative stress in the hippocampus of morphine-treated rats.

CONCLUSIONS

Our data indicate that EGCG can improve memory in morphine-treated rats. Molecular mechanisms underlying the detected effects could be related to the prevention of apoptosis and oxidative stress in the hippocampus of morphine-treated rats.

Chromatin modification by olive phenolics: In silico molecular docking studies utilising the phenolic groups categorised in the OliveNet™ database against lysine specific demethylase enzymes

Extra virgin olive oil is the principal source of dietary fat in the Mediterranean diet and is considered to have beneficial health effects. There is evidence to suggest that the phenolic compounds within Olea europaea have the ability to inhibit lysine-specific demethylase 1 (LSD1). This is an epigenetic enzyme that removes methyl groups from histone proteins and regulates gene transcription. Conversely, SET domain-containing protein 7 (SETD7) has opposing enzymatic activity and is a histone methyltransferase. Due to the involvement of these proteins in a number of pathological processes, including cancer and diabetes, further research needs to be conducted into the way in which they can be targeted. A large number of phenolic compounds (>200) have been identified in Olea europaea. To help expedite the discovery of promising lead compounds, in this study, in silico molecular docking methods were used to investigate the molecular binding properties of the phenolic compounds obtained from the OliveNet™ database to LSD1 and its variants, LSD2, and SETD7. Numerous Olea europaea phenolic compounds were predicted to bind to the epigenetic enzymes and several had stronger binding affinities than the LSD1 and SETD7 positive control inhibitors. The protein-ligand interactions of the phenolic compounds were also compared to known inhibitors and the molecular docking results suggest that the flavonoids, secoiridoids and glucosides may bind particularly strongly to the epigenetic regulators. Overall, several ligands were identified as lead compounds from this research and their potential inhibitory activity could be validated further in the laboratory.

The effect of oleuropein on unilateral ureteral obstruction induced-kidney injury in rats: the role of oxidative stress, inflammation and apoptosis

Unilateral ureteral obstruction (UUO) induces kidney injury. Oleuropein as a major compound of olive leaves modulates the inflammatory parameters and decreases oxidative stress. Accordingly, we evaluate the renoprotective effect of oleuropein against 3-day UUO rats. Forty rats were randomly divided into five groups (n = 8) including control, UUO and UUO + oleuropein groups (50, 100 and 200 mg/kg). UUO model was induced by left ureter ligation and continued for 3-day. Rats were treated synchronic daily for 3-day, then mean arterial pressure (MAP), renal perfusion pressure (RPP), renal blood flow (RBF), serum creatinine level, and also superoxide dismutase (SOD), glutathione peroxidase (GPx) activity levels and malondialdehyde (MDA) concentration (in the obstructed kidney) were measured. The western blotting method was applied to evaluate the Bax, Bcl-2, cleaved caspase-3 and TNF-α proteins expression level. The hematoxylin and eosin method was applied to evaluate the kidney tissue damage score (KTDS). UUO significantly increased RVR, KTDS, and MDA, cleaved caspase-3, Bax, serum creatinine and TNF-α protein levels (P < 0.05), and also significantly decreased RBF, SOD, and GPx and Bcl-2 protein expression levels (P < 0.001) in the obstructed kidney and oleuropein (200 mg/kg) significantly ameliorated the changes induced by UUO. Our findings showed that oleuropein has a renoprotective effect against 3-day UUO. The mechanisms underlying the observed effects may be related to its antioxidative stress, anti-apoptotic, and anti-inflammatory effects.

Effect of oleuropein on morphine-induced hippocampus neurotoxicity and memory impairments in rats

Oleuropein, as an olive leaf extract antioxidant polyphenol, has been reported to be a free radical scavenger. This study was done to investigate the effects of oleuropein, against morphine-induced hippocampus neurotoxicity and memory impairment in rats. The Morris water maze (MWM) test was used to assess the effect of oleuropein (5, 15, and 30 mg/kg, i.p., co-administrated with morphine) on spatial learning and memory of male Wistar rats which were treated with morphine sulfate (45 mg/kg, s.c., 4 weeks). In order to evaluate the cleaved caspase-3, Bax, and Bcl2 protein expression (as biochemical markers of apoptosis) in CA1 area of hippocampus tissue, the western blot test was used. Also, to evaluate the oxidative stress status of hippocampus CA1 area tissue, the malondialdehyde (MDA) level, superoxide dismutase (SOD) activity, and glutathione peroxidase (GPx) activity were assessed. The data showed that oleuropein treatment (15 and 30 mg/kg) improves the spatial learning and memory impairments in morphine-treated animals. Also, oleuropein treatment decreased the apoptosis and oxidative stress levels in the hippocampus CA1 area of morphine-treated rats. Oleuropein can prevent the spatial learning and memory impairments in morphine-treated rats. Molecular mechanisms underlying the observed effects could be at least partially related to the inhibition of neuronal apoptosis and oxidative stress in the hippocampus CA1 area of morphine-treated rats.

Natural Compounds for Alzheimer's Disease Therapy: A Systematic Review of Preclinical and Clinical Studies

Alzheimer's Disease (AD) is a neurodegenerative disorder related with the increase of age and it is the main cause of dementia in the world. AD affects cognitive functions, such as memory, with an intensity that leads to several functional losses. The continuous increase of AD incidence demands for an urgent development of effective therapeutic strategies. Despite the extensive research on this disease, only a few drugs able to delay the progression of the disease are currently available. In the last years, several compounds with pharmacological activities isolated from plants, animals and microorganisms, revealed to have beneficial effects for the treatment of AD, targeting different pathological mechanisms. Thus, a wide range of natural compounds may play a relevant role in the prevention of AD and have proven to be efficient in different preclinical and clinical studies. This work aims to review the natural compounds that until this date were described as having significant benefits for this neurological disease, focusing on studies that present clinical trials.

Distribution of metastasis in the brain in relation to the hippocampus: a retrospective single-center analysis of 565 metastases in 116 patients

OBJECTIVE

To examine the distribution of brain metastases (BM) in relation to the hippocampus, so as to determine the risk of metastasis in the hippocampus, and thus provide experimental evidence for the hippocampal avoidance (HA) in patients with BM during radiotherapy.

METHODS

(1) For the retrospective analysis of 116 patients diagnosed with malignancies, confirmed as BM, from December 2014 to December 2016 at the First Affiliated Hospital of Bengbu Medical College. We obtained the T1-weighted, postcontrast axial, sagittal, and coronal Magnetic Resonance imaging (MRI) images f the patients, in supine position, using the head restraints and head thermoplastic masks to adjust the positioning, with computed tomography (CT) positioning scan ranging from the head to the mandible (layer thickness: 3 mm). CT and MRI images were fused on a Philips Pinnacle v9.8 treatment planning system;(2) Every metastasis of the 565 metastases was contoured;(3) hippocampus were contoured, and hippocampus with 5 mm expansion envelopes were analyzed;(4) Using the SPSS 16.0 software, we analyzed the relation between the distribution and age, sex, Karnofsky performance status (KPS), primary site, aggregate volume of intracranial metastases and the whole brain. The data were analyzed using a binary logistic regression analysis method, with two-sided P < 0.05 for statistical significance.

RESULTS

In this study, we recruited 116 patients with 565 metastases. Among them, 1.7% (n = 2) had metastases in the hippocampus, and 11.2% (n = 13) had metastases within 5 mm of the hippocampus, of which more than half were patients with non-small cell lung cancer (n = 7). Using a binary logistic regression to analyze the relation between the metastases located within 5 mm of the hippocampus and age (P = 0.395), sex (P = 0.139), KPS (P = 0.724), primary site (P = 0.894), aggregate volume of intracranial metastases (p = 0.093) and the whole brain (p = 0.998), and none of them showed statistically significant difference between them and the metastases location (P>0.05).

CONCLUSION

This study showed a low risk for the perihippocampal metastases (PHM) and no significant correlation between PHM and age, sex, KPS, primary site, aggregate volume of intracranial metastases and the whole brain. Accordingly, it is may be acceptable to avoid the perihippocampal region during whole brain radiotherapy.

Pharma-Nutritional Properties of Olive Oil Phenols. Transfer of New Findings to Human Nutrition

The Mediterranean diet has been long associated with improved cardiovascular prognosis, chemoprevention, and lower incidence of neurodegeneration. Of the multiple components of this diet, olive oil stands out because its use has historically been limited to the Mediterranean basin. The health benefits of olive oil and some of its components are being rapidly decoded. In this paper we review the most recent pharma-nutritional investigations on olive oil biophenols and their health effects, chiefly focusing on recent findings that elucidate their molecular mechanisms of action.

Oleuropein reduces anxiety-like responses by activating of serotonergic and neuropeptide Y (NPY)-ergic systems in a rat model of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a stress-related mental disorder caused by traumatic experiences. This psychopathological response to traumatic stressors induces anxiety in rats. Oleuropein (OLE), a major compound in olive leaves, reportedly possesses several pharmacological properties, including anti-cancer, anti-diabetic, and anti-atherosclerotic and neuropsychiatric activities. However, the anxiolytic-like effects of OLE and its mechanism of action in PTSD are unclear. The present study used several behavioral tests to examine the effects of OLE on symptoms of anxiety in rats after a single prolonged stress (SPS) exposure by inhibiting the hypothalamic-pituitary-adrenal axis. Male Sprague Dawley rats received OLE (10, 50 and 70 mg/kg, i.p., once daily) for 14 days after SPS exposure. Daily OLE (70 mg/kg) administration significantly increased the number and duration of open arm visits in the elevated plus maze (EPM) test, reduced the anxiety index and grooming behavior in the EPM test, and increased the time spent and number of central zone crossings in the open field test. OLE also blocked the SPS-induced decrease in hippocampal serotonin and neuropeptide Y expression in hippocampus. These findings suggest that OLE has anxiolytic-like effects on behavioral and biochemical symptoms similar to those observed in patients with PTSD.

Oleuropein and rutin protect against 6-OHDA-induced neurotoxicity in PC12 cells through modulation of mitochondrial function and unfolded protein response

Parkinson’s disease (PD) is a highly prevalent neurodegenerative disorder, often associated with oxidative stress-induced transcriptional changes in dopaminergic neurons. Phenolic antioxidants, oleuropein (OLE) and rutin (RUT) have attracted a great interest due to their potential to counteract oxidative protein aggregation and toxicity. This study aimed at examining the effects of OLE and RUT against 6-OHDA-induced stress response in rat pheochromocytoma cells. When differentiated PC12 cells were exposed to oxidative stress composer 6-OHDA (100 μM, 8 h), a decreased mitochondrial membrane potential (ΔΨm) was observed along with a significant loss of cell viability and apoptotic nuclear changes. Exposure to 6-OHDA resulted in unfolded protein response (UPR) in differentiated PC12 cells as evidenced by an increased level of endoplasmic reticulum (ER)-localized transmembrane signal transducer IRE1α, adaptive response proteins ATF-4 and proapoptotic transcription factor CHOP. OLE or RUT pretreatment (24 h) at low doses (1–50 μM) protected the differentiated PC12 cells from 6-OHDA-induced cytotoxicity as assessed by increased viability, improved ΔΨm and inhibited apoptosis, whereas relatively high doses of OLE or RUT (>50 μM) inhibited cell growth and proliferation, indicating a typical hormetic effect. In hormetic doses, OLE and RUT up-regulated 6-OHDA-induced increase in IRE1α, ATF-4 and inhibited CHOP, PERK, BIP and PDI. 6-OHDA-activated XBP1 splicing was also inhibited by OLE or RUT. The presented results suggest that neuroprotection against 6-OHDA-induced oxidative toxicity may be attributable to neurohormetic effects of OLE or RUT at low doses through regulating mitochondrial functions, controlling persistent protein misfolding, activating and/or amplificating the adaptive response-related signaling pathways, leading to UPR prosurvival output.

The neuroprotective effects of hydro-alcoholic extract of olive (Olea europaea L.) leaf on rotenone-induced Parkinson's disease in rat

Parkinson's disease (PD) is an age-related disease in which dopaminergic neurons in the nigrostriatal pathway are destroyed, resulting in movement and behavioral problems. Oxidative stress and the generation of reactive oxygen species play key roles in neurodegenerative diseases, such as PD. Rotenone (ROT) is a common pesticide that induces oxidative stress. Olive leaves extract (OLE) has antioxidant and neuroprotective effects. Thus, the aim of this study was to investigate the neuroprotective effects of OLE on ROT-induced oxidative stress in the midbrain of a rat model of PD. Ninety-six Wistar rats were randomly divided into the following 6 groups (n = 16 rats/group): Control, Sham, ROT, and 3 ROT + OLE (75, 150, and 300 mg/kg/daily) groups. ROT (2.5 mg/kg/48 h) was injected subcutaneously, and vehicle or OLE was orally administered for 30 days. The animals were then sacrificed, and their brains were removed. Biochemical measures, including the levels of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and malondialdehyde (MDA), and the number of tyrosine hydroxylase (TH)-positive neurons were determined, and behavioral (rotarod and hanging) tests were conducted. The balance and muscle strength of the OLE (150 and 300 mg/kg)-treated groups were significantly improved. Treatment with OLE prevented the increases in the levels of MDA, significantly improved the SOD, CAT, and GPx levels in the midbrain, and prevented the depletion of the TH-positive neurons. These findings suggested that OLE has neuroprotective properties and that it might be useful for preventing the death of dopaminergic neurons in patients with PD.

Iridoids and Other Monoterpenes in the Alzheimer's Brain: Recent Development and Future Prospects

Iridoids are a class of monoterpenoid compounds constructed from 10-carbon skeleton of isoprene building units. These compounds in their aglycones and glycosylated forms exist in nature to contribute to mechanisms related to plant defenses and diverse plant-animal interactions. Recent studies have also shown that iridoids and other structurally related monoterpenes display a vast array of pharmacological effects that make them potential modulators of the Alzheimer’s disease (AD). This review critically evaluates the therapeutic potential of these natural products by assessing key in vitro and in vivo data published in the scientific literature. Mechanistic approach of scrutiny addressing their effects in the Alzheimer’s brain including the τ-protein phosphorylation signaling, amyloid beta (Aβ) formation, aggregation, toxicity and clearance along with various effects from antioxidant to antiinflammatory mechanisms are discussed. The drug likeness of these compounds and future prospects to consider in their development as potential leads are addressed.

Fraxinus: A Plant with Versatile Pharmacological and Biological Activities

Fraxinus, a member of the Oleaceae family, commonly known as ash tree is found in northeast Asia, north America, east and western France, China, northern areas of Pakistan, India, and Afghanistan. Chemical constituents of Fraxinus plant include various secoiridoids, phenylethanoids, flavonoids, coumarins, and lignans; therefore, it is considered as a plant with versatile biological and pharmacological activities. Its tremendous range of pharmacotherapeutic properties has been well documented including anticancer, anti-inflammatory, antioxidant, antimicrobial, and neuroprotective. In addition, its bioactive phytochemicals and secondary metabolites can be effectively used in cosmetic industry and as a competent antiaging agent. Fraxinus presents pharmacological effectiveness by targeting the novel targets in several pathological conditions, which provide a spacious therapeutic time window. Our aim is to update the scientific research community with recent endeavors with specifically highlighting the mechanism of action in different diseases. This potentially efficacious pharmacological drug candidate should be used for new drug discovery in future. This review suggests that this plant has extremely important medicinal utilization but further supporting studies and scientific experimentations are mandatory to determine its specific intracellular targets and site of action to completely figure out its pharmacological applications.

Bioactivity of Olive Oil Phenols in Neuroprotection

Neurological disorders such as stroke, Alzheimer’s and Parkinson’s diseases are associated with high morbidity and mortality, and few or no effective options are available for their treatment. These disorders share common pathological characteristics like the induction of oxidative stress, abnormal protein aggregation, perturbed Ca²⁺ homeostasis, excitotoxicity, inflammation and apoptosis. A large body of evidence supports the beneficial effects of the Mediterranean diet in preventing neurodegeneration. As the Mediterranean diet is characterized by a high consumption of extra-virgin olive oil it has been hypothesized that olive oil, and in particular its phenols, could be responsible for the beneficial effect of the Mediterranean diet. This review provides an updated vision of the beneficial properties of olive oil and olive oil phenols in preventing/counteracting both acute and chronic neurodegenerative diseases.

Effect of oleuropein on cognitive deficits and changes in hippocampal brain-derived neurotrophic factor and cytokine expression in a rat model of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a condition that develops after an individual has experienced a major trauma. This psychopathological response to traumatic stressors induces learning and memory deficits in rats. Oleuropein (OLE), a major compound in olive leaves, has been reported to possess several pharmacological properties, including anti-cancer, anti-diabetic, anti-atherosclerotic and neuroprotective activities. However, the cognitive effects of OLE and its mechanism of action have remained unclear in PTSD. In this study, we examined whether OLE improved spatial cognitive impairment induced in rats following single prolonged stress (SPS), an animal model of PTSD. Male rats were treated intraperitoneally (i.p.) with vehicle or various doses of OLE for 14 consecutive days after the SPS procedure. The SPS procedure resulted in cognitive impairment in the object recognition task and the Morris water maze test, which was reversed by OLE (100 mg/kg, i.p). Additionally, as assessed by immunohistochemistry and reverse transcription-polymerase chain reaction analysis, the administration of OLE significantly alleviated memory-associated decreases in the levels of brain-derived neurotrophic factor and cAMP response element-binding protein and mRNA in the hippocampus. Together, these findings suggest that OLE attenuated SPS-induced cognitive impairment significantly by inhibiting the expression of pro-inflammatory mediators in the rat brain. Thus, OLE reversed several behavioral impairments triggered by the traumatic stress of SPS and might be a potential useful therapeutic intervention for PTSD.

Relationship between cognitive function and regulation of cerebral blood flow

Ageing is the primary risk factor for cognitive deterioration. Given that the cerebral blood flow (CBF) or regulation of cerebral circulation is attenuated in the elderly, it could be expected that ageing-induced cognitive deterioration may be affected by a decrease in CBF as a result of brain ischemia and energy depletion. CBF regulation associated with cerebral metabolism thus likely plays an important role in the preservation of cognitive function. However, in some specific conditions (e.g. during exercise), change in CBF does not synchronize with that of cerebral metabolism. Our recent study demonstrated that cognitive function was more strongly affected by changes in cerebral metabolism than by changes in CBF during exercise. Therefore, it remains unclear how an alteration in CBF or its regulation affects cognitive function. In this review, I summarize current knowledge on previous investigations providing the possibility of an interaction between regulation of CBF or cerebral metabolism and cognitive function.

Protective effects of oleuropein against renal injury oxidative damage in alloxan-induced diabetic rats; a histological and biochemical study

Background:

Oleuropein is a potent antioxidant and free-radical scavenger with antiinflammatory properties.

Objectives:

In the present study, we evaluated the protective effects of oleuropein on myeloperoxidase (MPO) activity, nitrite, urea, creatinine and glomerulosclerosis in alloxan-induced type 1 diabetic rats.

Materials and Methods:

Thirty Sprague-Dawley male rats were randomly divided into 3 groups: group 1 as control; group 2 as untreated diabetic; and group 3 as treated with oleuropein 15 mg/kg i.p daily. Diabetes was induced in the second and third groups by subcutaneous alloxan injection. After 48 days, the animals were anaesthetized and then the livers and kidneys were removed immediately and used fresh or kept frozen until MPO activity analysis. Blood samples were also collected before sacrificing to measure nitrite, urea, and creatinine. Kidney paraffin sections were prepared to estimate glomerular volume, leukocyte infiltration, and glomerulosclerosis.

Results:

Oleuropein significantly decreased leukocyte infiltration and glomerulosclerosis in the treated group compared with the diabetic untreated group. Oleuropein significantly decreased the levels of urea, nitrite, and creatinine in the treated group compared with the diabetic untreated group. Moreover, oleuropein significantly decreased MPO activity in the treated group compared with the diabetic untreated group.

Conclusions:

Oleuropein has antioxidative and antiatherogenic activities and exerts beneficial effects on inflammation and kidney function test and decreases diabetic complication in diabetic rats.