Neuroprotective effects of p-tyrosol after the global cerebral ischemia in rats

Identification of Hub Genes and Pathways of Middle Cerebral Artery Occlusion in Aged Rats Using the Gene Expression Omnibus Database

Stroke remained the leading cause of disability in the world, and the most important non-modifiable risk factor was age. The treatment of stroke for elder patients faced multiple difficulties due to its complicated pathogenesis and mechanism. Therefore, we aimed to identify the potential differentially expressed genes (DEGs) and singnalling pathways for aged people of stroke. To compare the DEGs in the aged rats with or without middle cerebral artery occlusion (MCAO) and to analyse the important genes and the key signaling pathways involved in the development of cerebral ischaemia in aged rats. The Gene Expression Omnibus (GEO) analysis tool was used to analyse the DEGs in the GSE166162 dataset of aged MCAO rats compared with aged sham rats. Differential expression analysis was performed in aged MCAO rats and sham rats using limma. In addition, the 74 DEGs (such as Fam111a, Lcn2, Spp1, Lgals3 and Gpnmb were up-regulated; Egr2, Nr4a3, Arc, Klf4 and Nr4a1 were down-regulated) and potential compounds corresponding to the top 20 core genes in the Protein-Protein Interaction (PPI) network was constructed using the STRING database (version 12.0). Among these 30 compounds, resveratrol, cannabidiol, honokiol, fucoxanthin, oleandrin and tyrosol were significantly enriched. These DEGs were subjected to Gene Ontology (GO) function analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis to determine the most significantly enriched pathway in aged MCAO rats. Moreover, innate immune response, the complement and coagulation cascades signaling pathway, the IL-17 and other signaling pathways were significantly correlated with the aged MCAO rats. Our study indicates that multiple genes and pathological processes involved in the aged people of stroke. The immune response might be the key pathway in the intervention of cerebral infarction in aged people.

An Overview of 1,2,3-triazole-Containing Hybrids and Their Potential Anticholinesterase Activities

Acetylcholine (ACh) neurotransmitter of the cholinergic system in the brain is involved in learning, memory, stress responses, and cognitive functioning. It is hydrolyzed into choline and acetic acid by two key cholinesterase enzymes, viz., acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). A loss or degeneration of cholinergic neurons that leads to a reduction in ACh levels is considered a significant contributing factor in the development of neurodegenerative diseases (NDs) such as Alzheimer's disease (AD). Numerous studies have shown that cholinesterase inhibitors can raise the level of ACh and, therefore, enhance people's quality of life, and, at the very least, it can temporarily lessen the symptoms of NDs. 1,2,3-triazole, a five-membered heterocyclic ring, is a privileged moiety, that is, a central scaffold, and is capable of interacting with a variety of receptors and enzymes to exhibit a broad range of important biological activities. Recently, it has been clubbed with other pharmacophoric fragments/molecules in hope of obtaining potent and selective AChE and/or BuChE inhibitors. The present updated review succinctly summarizes the different synthetic strategies used to synthesize the 1,2,3-triazole moiety. It also highlights the anticholinesterase potential of various 1,2,3-triazole di/trihybrids reported in the past seven years (2015-2022), including a rationale for hybridization and with an emphasis on their structural features for the development and optimization of cholinesterase inhibitors to treat NDs.

Neuroprotective Effects of Rhodiola Sacra on Transient Global Cerebral Ischemia Through Activating AMPK/Nrf2 Pathway in Rats

Aims: Rhodiola sacra is a widely used pharmaceutical component with multiple functions, including anti-oxidation and anti-inflammation. However, the exact mechanisms involved in neuroprotection against transient global cerebral ischemia (tGCI) remain to be elucidated. Herein, we aim at closing the gap in understanding on whether rhodiola sacra reduces neuronal death in hippocampal CA1 and at demonstrating how rhodiola sacra offers neuroprotection after tGCI. Results: The results show that rhodiola sacra (2.4 g/kg/d by feeding) pretreatment or/and postreatment significantly alleviated neuronal injury, inhibited glial activation, and improved cognitive function in male rats subjected to tGCI. The neuroprotection of prophylaxis with rhodiola sacra is equivalent to that of therapeutics. The binding mode of adenosine monophosphate-activated protein kinase (AMPK) α2-subunit with rhodiola sacra was predicted by molecular docking. Further, rhodiola sacra upregulates phosphorylated AMPK and promotes nuclear translocation of nuclear factor erythroid 2 related factor 2 (Nrf2). In addition, rhodiola sacra increases heme oxygenase-1 (HO-1) expression and activity and reduces malondialdehyde (MDA) content in CA1 after tGCI. However, the neuroprotection of rhodiola sacra is abolished by Nrf2 knockdown with small interfering RNA (siRNA) after tGCI. Similarly, the inhibition of AMPK with Compound C or siRNA against AMPK α2 aggravates neuronal death after tGCI through decreasing nuclear Nrf2 and the expression and activity of HO-1, and by increasing the release of MDA. Innovation and Conclusion: For the first time, this study demonstrates that as a prophylactic or therapeutic agent rhodiola sacra prevents oxidant stress, protects neurons, and improves cognitive function through activating the AMPK/Nrf2 pathway in tGCI rats. Antioxid. Redox Signal. 36, 567-591.

Preclinical Evidence and Possible Mechanisms of Rhodiola rosea L. and Its Components for Ischemic Stroke: A Systematic Review and Meta-Analysis

Background: Rhodiola rosea L. has long been used as traditional medicines in Europe and Asia to treat a variety of common conditions and diseases including Alzheimer's disease, cardiovascular disease, cognitive dysfunctions, cancer, and stroke. Previous studies reported that Rhodiola rosea L. and its components (RRC) improve ischemia stroke in animal models. Here, we conducted a systematic review and meta-analysis for preclinical studies to evaluate the effects of RRC and the probable neuroprotective mechanisms in ischemic stroke. Methods: Studies of RRC on ischemic stroke animal models were searched in seven databases from inception to Oct 2021. The primary measured outcomes included the neural functional deficit score (NFS), infarct volume (IV), brain water content, cell viability, apoptotic cells, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells, B-cell lymphoma-2 (Bcl-2) level and tumor necrosis factor-α (TNF-α) level. The secondary outcome measures were possible mechanisms of RRC for ischemic stroke. All the data were analyzed via RevMan version 5.3. Results: 15 studies involving 345 animals were identified. Methodological quality for each included studies was accessed according to the CAMARADES 10-item checklist. The quality score of studies range from 1 to 7, and the median was 5.53. Pooled preclinical data showed that compared with the controls, RRC could improve NFS (Zea Longa (p < 0.01), modified neurological severity score (mNSS) (p < 0.01), rotarod tests (p < 0.01), IV (p < 0.01), as well as brain edema (p < 0.01). It also can increase cell viability (p < 0.01), Bcl-2 level (p < 0.01) and reduce TNF-α level (p < 0.01), TUNEL-positive cells (p < 0.01), apoptotic cells (p < 0.01). Conclusion: The findings suggested that RRC can improve ischemia stroke. The possible mechanisms of RRC are largely through antioxidant, anti-apoptosis activities, anti-inflammatory, repressing lipid peroxidation, antigliosis, and alleviating the pathological blood brain barrier damage.

Tyrosol improves ovalbumin (OVA)-induced asthma in rat model through prevention of airway inflammation

Asthma is an inflammatory disease that affects many people around the world, especially persons at paediatric age group. The effectiveness of tyrosol, a natural phenolic compound, was examined in the asthma model induced by ovalbumin (OVA). For this purpose, four groups, each consisting of eight rats, were arranged. For 21 days, physiological saline solution was treated to the control group and OVA was treated to the groups of OVA, OVA + dexamethasone (Dexa) and OVA + tyrosol groups, intraperitoneally and through inhalation. Additionally, 0.25 mg/kg Dexa was treated to the OVA + Dexa group and 20 mg/kg tyrosol to the OVA + tyrosol group by oral gavage. Serum, blood, bronchoalveolar lavage fluid (BALF) and lung tissues of the rats were examined. It was observed that MDA level decreased, GSH level and GPx activity increased, and there was no change in CAT activity in lung tissues of the tyrosol treatment groups. It was also observed that NF-κB, TNF-α, IL-4, IL-5, IL-13, IFN-γ and IgE levels decreased compared to the OVA group in lung tissue and serum samples except for serum NF-κB and IL-4. However, no effect on IL-1 β level was observed. In addition, it was determined that tyrosol treatment increased the IL-10 level on both tissue samples. The results of the histopathological investigation of lung tissue showed that tyrosol significantly ameliorated OVA-induced histopathological lesions. Additionally, PAS staining showed that mucus hypersecretion was significantly reduced with the use of tyrosol. In addition, it was determined that the number of eosinophils decreased significantly in blood and BALF samples. The obtained results showed that tyrosol possessed antioxidant and anti-inflammatory features on OVA-induced rats and preserved tissue architecture.

Icariin, an Up-and-Coming Bioactive Compound Against Neurological Diseases: Network Pharmacology-Based Study and Literature Review

Icariin is a biologically active substance in Epimedii herba that is used for the treatment of neurologic disorders. However, a comprehensive analysis of the molecular mechanisms of icariin is lacking. In this review, we present a brief history of the use of icariin for medicinal purposes; describe the active chemical components of Epimedii herba; and examine the evidence from experimental studies that have uncovered molecular targets of icariin in different diseases. We also constructed a protein–protein interaction network and carried out Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analyses to predict the therapeutic actions of icariin in nervous system diseases including Alzheimer disease, Parkinson disease, ischemic stroke, depressive disorder, multiple sclerosis, glioblastoma, and hereditary spastic paraplegias. The results of our analyses can guide future studies on the application of icariin to the treatment of neurologic disorders.

Tyrosol as a Neuroprotector: Strong Effects of a "Weak" Antioxidant

The use of neuroprotective agents for stroke is pathogenetically justified, but the translation of the results of preclinical studies of neuroprotectors into clinical practice has been a noticeable failure. One of the leading reasons for these failures is the one-target mechanism of their activity. p-Tyrosol (Tyr), a biophenol, is present in a variety of natural sources, mainly in foods, such as olive oil and wine. Tyr has a wide spectrum of biological activity: antioxidant, stress-protective, anti-inflammatory, anticancer, cardioprotective, neuroprotective and many others. This review analyzes data on the neuroprotective, antioxidant, anti-inflammatory, anti-apoptotic and other kinds of Tyr activity as well as data on the pharmacokinetics of the substance. The data presented in the review substantiate the acceptability of tyr as the basis for the development of a new neuroprotective drug with multitarget activity for the treatment of ischemic stroke. Tyr is a promising molecule for the development of an effective neuroprotective agent for use in ischemic stroke.

Antioxidant Effects of Salidroside in the Cardiovascular System

Cardiovascular disease is one of the main human health risks, and the incidence is increasing. Salidroside is an important bioactive component of Rhodiola rosea L., which is used to treat Alzheimer's disease, tumor, depression, and other diseases. Recent studies have shown that salidroside has therapeutic effects, to some degree, in cardiovascular diseases via an antioxidative mechanism. However, evidence-based clinical data supporting the effectiveness of salidroside in the treatment of cardiovascular diseases are limited. In this review, we discuss the effects of salidroside on cardiovascular risk factors and cardiovascular diseases and highlight potential antioxidant therapeutic strategies.

Tyrosol 1,2,3-triazole analogues as new acetylcholinesterase (AChE) inhibitors

The present work proposed the preparation of triazolic analogues of tyrosol, a biophenol found in olive oil and whose wide range of bioactivities has been the target of many studies. We obtained fifteen novel tyrosol derivatives and the compounds of the series were later evaluated as acetylcholinesterase (AChE) inhibitors. The study of AChE inhibition is important for the development of new drugs and pesticides, and especially the research for managing Alzheimer's disease. The most active compound, namely 7-({1-[2-(4-hydroxyphenyl)ethyl]-1H-1,2,3-triazol-4-yl}methoxy)-4-methyl-2H-chromen-2-one (30), showed IC₅₀ value of 14.66 ± 2.29 μmol L^-1. Docking experiments corroborated by kinetic assay are suggestive of a competitive inhibition mechanism. Derivatives interacted with amino acids from the AChE active site associated to the development of Alzheimer's disease. The results indicate that the compounds synthesized have a high potential as prototypes for the development of new acetylcholinesterase inhibitors.

Design of immobilized biocatalyst and optimal conditions for tyrosol β-galactoside production

Tyrosol β-galactoside (TG) is a phenylethanoid glycoside with proven neuroprotective properties. This work deals with its biocatalytic production from tyrosol and lactose using Aspergillus oryzae β-galactosidase in immobilized form. Six commercial carriers were examined to find the optimal biocatalyst. Besides standard biocatalyst performance characteristics, adsorption of the hydrophobic substrate on immobilization carrier matrices was also investigated. The adsorption of tyrosol was significant, but it did not have adverse effects on TG production. On the contrary, TG yield was improved for some biocatalysts. A biocatalyst prepared by covalent binding of β-galactosidase on an epoxy-activated carrier was used for detailed investigation of the effect of reaction conditions on glycoside production. Temperature had a surprisingly weak effect on the overall process rate. A lactose concentration of 0.83 M was found to be optimal to enhance TG formation. The impact of tyrosol concentration was rather complex. This substrate caused inhibition of all reactions. Its concentration had a strong effect on the hydrolysis of lactose and all products. Higher tyrosol concentrations, 30-40 g/L, were favorable as pseudo-equilibrium concentrations of TG and galactooligosaccharide were reached. Repeated batch results revealed excellent operational stability of the biocatalyst.

Salidroside as a potential neuroprotective agent for ischemic stroke: a review of sources, pharmacokinetics, mechanism and safety

Salidroside (Sal) is a bioactive extract principally from traditional herbal medicine such as Rhodiola rosea L., which has been commonly used for hundreds of years in Asia countries. The excellent neuroprotective capacity of Sal has been illuminated in recent studies. This work focused on the source, pharmacokinetics, safety and anti-ischemic stroke (IS) effect of Sal, especially emphasizing its mechanism of action and BBB permeability. Extensive databases, including Pubmed, Web of science (WOS), Google Scholar and China National Knowledge Infrastructure (CNKI), were applied to obtain relevant online literatures. Sal exerts powerful therapeutic effects on IS in experimental models either in vitro or in vivo due to its neuroprotection, with significantly diminishing infarct size, preventing cerebral edema and improving neurological function. Also, the findings suggest the underlying mechanisms involve anti-oxidation, anti-inflammation and anti-apoptosis by regulating multiple signaling pathways and key molecules, such as NF-κB, TNF-α and PI3K/Akt pathway. In pharmacokinetics, although showing a rapid absorption and elimination, bioavailability of Sal is elevated under some non-physiological conditions. The component and its metabolite (tyrosol) are capable of distributing to brain tissue and the later keeps a higher level of concentration. Moreover, Sal scarcely has obvious toxicity or side effects in a variety of animal experiments and clinical trials, but combination of drugs and perinatal use of medicine should be taken more attentions. Finally, as an active ingredient, not only is Sal isolated from diverse plants with limited yield, but also large batches of the products can be harvested by biological and chemical synthesis. With higher efficacy and better safety profiles, Sal could sever as a promising neuroprotectant for preventing and treating IS. Nevertheless, further investigations are still required to explore the pharmacodynamic and pharmacokinetic properties of Sal in the treatment of IS.

Protective Evaluation of Compounds Extracted from Root of Rhodiola rosea L. against Methylglyoxal-Induced Toxicity in a Neuronal Cell Line

Rhodiola rosea L. (R. rosea) is one of the most beneficial medicinal plants and it is studied as an adaptogen. This study aims to evaluate the neuroprotective activity of compounds extracted from the root of R. rosea against methylglyoxal (MG)-induced apoptosis in neuro-2A (N2A) cells. The root of R. rosea was extracted with ethanol and partitioned with water, ethyl acetate, and n-butanol fractions to evaluate acetylcholinesterase (AChE) inhibitory activity and neuroprotective activity. The ethyl acetate fraction exhibited the highest values of AChE inhibitory activity (49.2% ± 3%) and cell viability (50.7% ± 4.8%) for neuroprotection. The structure identification of the most potential fraction (ethyl acetate fraction) revealed 15 compounds, consisting of three tannins, five flavonoids, and seven phenolics by infrared spectroscopy, nuclear magnetic resonance, and mass spectroscopy. All compounds were evaluated for their neuroprotective activity. Salidroside had the most potential neuroprotective activity. Gallic acid and methyl gallate had potential cytotoxicity in N2A cells. This study showed that R. rosea might have potential neuroprotective activities.

Salidroside inhibits migration and invasion of poorly differentiated thyroid cancer cells

Background

No effective treatment is currently available for poorly differentiated thyroid cancer which is resistant to radioiodine, especially with migration and invasion. A great number of researches have revealed the anticancer effects of salidroside, but none have studied the effects of salidroside on thyroid cancer. This study aimed to investigate the effect of salidroside on migration and invasion of poorly differentiated thyroid cancer cells.

Methods

The effects of salidroside on migration, invasion and apoptosis of poorly differentiated thyroid cancer WRO cells and normal thyroid follicular epithelial Nthy‐ori 3‐1 cells were measured by wound‐healing assay, transwell migration/invasion assay and flow cytometry, respectively. The expression levels of MMP2 and MMP9 at RNA and protein levels in WRO cells were detected by qRT‐PCR and western blot. The phosphorylation levels of Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3) and the apoptosis‐related protein levels of Bax, cleaved caspase 3 and Bcl‐2 were assessed by western blot.

Results

Salidroside significantly suppressed migration/invasion and induced apoptosis in poorly differentiated thyroid cancer WRO cells. We further illustrated that salidroside significantly inhibited expressions of MMP2 and MMP9 at mRNA and protein levels and the phosphorylation activation of JAK2/STAT3 in WRO cells. In addition, salidroside increased expressions of pro‐apoptotic factors (Bax and cleaved caspase 3) and decreased expression of anti‐apoptotic factor (Bcl‐2) significantly in WRO cells.

Conclusion

The present study demonstrates that salidroside inhibits migration and invasion of WRO cells (a kind of poorly differentiated cancer cell line) significantly, which might be via suppressing JAK2‐STAT3 signaling pathway.

Protective Effects of a New C-Jun N-terminal Kinase Inhibitor in the Model of Global Cerebral Ischemia in Rats

c-Jun N-terminal kinase (JNK) is activated by various brain insults and is implicated in neuronal injury triggered by reperfusion-induced oxidative stress. Some JNK inhibitors demonstrated neuroprotective potential in various models, including cerebral ischemia/reperfusion injury. The objective of the present work was to study the neuroprotective activity of a new specific JNK inhibitor, IQ-1S (11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt), in the model of global cerebral ischemia (GCI) in rats compared with citicoline (cytidine-5'-diphosphocholine), a drug approved for the treatment of acute ischemic stroke and to search for pleiotropic mechanisms of neuroprotective effects of IQ-1S. The experiments were performed in a rat model of ischemic stroke with three-vessel occlusion (model of 3VO) affecting the brachiocephalic artery, the left subclavian artery, and the left common carotid artery. After 7-min episode of GCI in rats, 25% of animals died, whereas survived animals had severe neurological deficit at days 1, 3, and 5 after GCI. At day 5 after GCI, we observing massive loss of pyramidal neurons in the hippocampal CA1 area, increase in lipid peroxidation products in the brain tissue, and decrease in local cerebral blood flow (LCBF) in the parietal cortex. Moreover, blood hyperviscosity syndrome and endothelial dysfunction were found after GCI. Administration of IQ-1S (intragastrically at a dose 50 mg/kg daily for 5 days) was associated with neuroprotective effect comparable with the effect of citicoline (intraperitoneal at a dose of 500 mg/kg, daily for 5 days).The neuroprotective effect was accompanied by a decrease in the number of animals with severe neurological deficit, an increase in the number of animals with moderate degree of neurological deficit compared with control GCI group, and an increase in the number of unaltered neurons in the hippocampal CA1 area along with a significant decrease in the number of neurons with irreversible morphological damage. In rats with IQ-1S administration, the LCBF was significantly higher (by 60%) compared with that in the GCI control. Treatment with IQ-1S also decreases blood viscosity and endothelial dysfunction. A concentration-dependent decrease (IC50 = 0.8 ± 0.3 μM) of tone in isolated carotid arterial rings constricted with phenylephrine was observed after IQ-1S application in vitro. We also found that IQ-1S decreased the intensity of the lipid peroxidation in the brain tissue in rats with GCI. 2.2-Diphenyl-1-picrylhydrazyl scavenging for IQ-1S in acetonitrile and acetone exceeded the corresponding values for ionol, a known antioxidant. Overall, these results suggest that the neuroprotective properties of IQ-1S may be mediated by improvement of cerebral microcirculation due to the enhanced vasorelaxation, beneficial effects on blood viscosity, attenuation of the endothelial dysfunction, and antioxidant/antiradical IQ-1S activity.

Energetic and Structural Properties of Two Phenolic Antioxidants: Tyrosol and Hydroxytyrosol

Theoretical and experimental studies on the energetic, structural and some other relevant physicochemical properties of the antioxidant tyrosol (1), hydroxytyrosol (1OH) molecules and the corresponding radicals 1_rad^• and 1O_rad^• are reported in this work. The experimental values of the gas-phase enthalpy of formation, Δ_f H_m⁰(g), in kJ·mol^-1, of 1 (-302.4 ± 3.4) and 1OH (-486.3 ± 4.1) have been determined. Quantum chemical calculations, at DFT (M05-2X) and composite ab initio G3 and G4 levels of theory, provided results that served to (i) confirm the excellent consistency of the experimental measurements performed, (ii) establish that the stabilizing effect of H-bond of hydroxyethyl chain and aromatic ring (OH···π interaction) is smaller in radicals than in parent molecules, (iii) deduce-combining experimental data in isodesmic reactions-Δ_f H_m⁰(g) of radicals 1_rad^• (-152.3 ± 4.4 kJ·mol^-1) and 1O_rad^• (-370.6 ± 3.8 kJ·mol^-1), (iv) estimate a reliable O-H bond dissociation enthalpy, BDE of 1 (368.1 ± 5.6 kJ·mol^-1) and of 1OH (333.7 ± 5.6 kJ·mol^-1), and (v) corroborate-using "BDE criteria"-than 1OH is a more effective antioxidant than 1.

Influence of salidroside, a neuroactive compound of Rhodiola rosea L., on alcohol tolerance development in rats

Introduction: In recent years, the search for potential neuroprotective properties of salidroside and its ability to influence the activity of nervous system become the subject of intense studies of many research groups. None of these studies, however, include an attempt to determine the effect of salidroside on the course of alcohol tolerance in vivo.

Objective: The aim of this study was to investigate the ability of salidroside to inhibit the development of alcohol tolerance in rats, determining whether the effect of its action may occur in a dose-dependent manner, reducing both metabolic and central tolerance without affecting body temperature in control rats.

Methods: Male Wistar rats were injected daily with ethanol at a dose of 3 g/kg for 9 consecutive days to produce ethanol tolerance. Salidroside in two doses (4.5 mg/kg and 45 mg/kg b.w.) or vehiculum was administered orally. On the 1st, 3rd, 5th and 8th day a hypothermic effect of ethanol was measured, while the loss of righting reflex procedure was performed on the 2nd, 4th, 6th and 7th day. On the 9th day rats were treated with salidroside, sacrificed 1 h after ethanol injections and blood was collected for blood-ethanol concentration measurement.

Results: Salidroside at a dose of 45 mg/kg inhibited the development of tolerance to hypothermic and sedative effects of ethanol, whereas insignificant elevation of blood-ethanol concentration was observed. The dose of 4.5 mg/kg b.w. had minimal effect, only small inhibition of tolerance to hypothermic action was observed. Salidroside affected neither body mass growth nor body temperature in non-alcoholic (control) rats.

Conclusions: Results of the study indicate that salidroside at a dose of 45 mg/kg inhibited the development of tolerance to the hypothermic effect of ethanol. Observed inhibition of tolerance to the sedative effect of ethanol seems to be associated with salidroside influence on the central nervous system. A comprehensive explanation of the abovementioned observations requires further pharmacological and pharmacodynamic studies.