(2R,3S)-Pinobanksin-3-cinnamate improves cognition and reduces oxidative stress in rats with vascular dementia

Correlation between total phenolic and flavonoid contents and biological activities of 12 ethanolic extracts of Iranian propolis

Propolis is a resinous substance produced by honey bees that is very popular as a natural remedy in traditional medicine. The current research is the first study on the biological properties of ethanolic extracts of propolis (EEP) from several different regions (12) of Iran. Total phenolic and flavonoid contents (TPC and TFC) of Iranian EEPs were variable between 26.59-221.38 mg GAE/g EEP and 4.8-100.03 mg QE/g EEP. The DPPH scavenging assay showed all the studied EEP samples, except for the sample with the lowest TPC and TFC (P6), have suitable antioxidant activity. All the EEPs inhibited both cholinesterase enzymes (acetylcholinesterase: AChE, butyrylcholinesterase: BuChE) but most of them exhibited a distinct selectivity over BuChE. Evaluation of the antibacterial activity of the EEP samples using four pathogenic bacteria (B. cereus, S. aureus, A. baumannii, and P. aeruginosa) demonstrated that the antibacterial properties of propolis are more effective on the gram-positive bacterium. Spearman correlation analysis showed a strong positive correlation between TPC and TFC of the Iranian EEPs and their antioxidant, anticholinesterase, and antibacterial activities. Considering that there is ample evidence of anticholinesterase activity of flavonoids and a significant correlation between the anticholinesterase activity of the studied Iranian EEPs and their total flavonoid content was observed, the interaction of 17 well-known propolis flavonoids with AChE and BuChE was explored using molecular docking. The results indicated that all the flavonoids interact with the active site gorge of both enzymes with high affinity. Summing up, the obtained results suggest that Iranian propolis possesses great potential for further studies.

Unusual Bioactive Compounds with Antioxidant Properties in Adjuvant Therapy Supporting Cognition Impairment in Age-Related Neurodegenerative Disorders

Cognitive function decline is strictly related to age, resulting in the loss of the ability to perform daily behaviors and is a fundamental clinical neurodegeneration symptom. It has been proven that an adequate diet, comprehensive nutrition, and a healthy lifestyle may significantly inhibit neurodegenerative processes, improving cognitive functions. Therefore, intensive research has been conducted on cognitive-enhancing treatment for many years, especially with substances of natural origin. There are several intervention programs aimed at improving cognitive functions in elderly adults. Cognitive functions depend on body weight, food consumed daily, the quality of the intestinal microflora, and the supplements used. The effectiveness in the prevention of dementia is particularly high before the onset of the first symptoms. The impact of diet and nutrition on age-associated cognitive decline is becoming a growing field as a vital factor that may be easily modified, and the effects may be observed on an ongoing basis. The paper presents a review of the latest preclinical and clinical studies on the influence of natural antioxidants on cognitive functions, with particular emphasis on neurodegenerative diseases. Nevertheless, despite the promising research results in animal models, the clinical application of natural compounds will only be possible after solving a few challenges.

NXP031 Improves Cognitive Impairment in a Chronic Cerebral Hypoperfusion-Induced Vascular Dementia Rat Model through Nrf2 Signaling

Vascular dementia (VaD) is a progressive cognitive impairment caused by a reduced blood supply to the brain. Chronic cerebral hypoperfusion (CCH) is one cause of VaD; it induces oxidative stress, neuroinflammation, and blood-brain barrier (BBB) disruption, damaging several brain regions. Vitamin C plays a vital role in preventing oxidative stress-related diseases induced by reactive oxygen species, but it is easily oxidized and loses its antioxidant activity. To overcome this weakness, we have developed a vitamin C/DNA aptamer complex (NXP031) that increases vitamin C's antioxidant efficacy. Aptamers are short single-stranded nucleic acid polymers (DNA or RNA) that can interact with their corresponding target with high affinity. We established an animal model of VaD by permanent bilateral common carotid artery occlusion (BCCAO) in 12 week old Wistar rats. Twelve weeks after BCCAO, we injected NXP031 into the rats intraperitoneally for two weeks at moderate (200 mg/4 mg/kg) and high concentrations (200 mg/20 mg/kg). NXP031 administration alleviates cognitive impairment, microglial activity, and oxidative stress after CCH. NXP031 increased the expression of basal lamina (laminin), endothelial cell (RECA-1, PECAM-1), and pericyte (PDGFRβ); these markers maintain the BBB integrity. We found that NXP031 administration activated the Nrf2-ARE pathway and increased the expression of SOD-1 and GSTO1/2. These results suggest that this new aptamer complex, NXP031, could be a therapeutic intervention in CCH-induced VaD.

Enoxacin Exerts Anti-Tumor Effects Against Prostate Cancer Through Inducing Apoptosis

Background:

Prostate cancer is the most commonly diagnosed cancer and second leading cause of cancer death in men. Enoxacin, a third-generation fluoroquinolone antibiotic, was found with anti-proliferative effects against many cancer types. This study was to further investigate its effects against prostate cancer and explore the underlying molecular mechanisms.

Methods:

PC-3 cells were treated with Enoxacin at different concentrations. Tumor model was established by subcutaneously injecting PC-3 cells into nude mice. MTT assay was used to detect cell viability. ELISA assay, Annexin V/PI staining and TUNEL assay were used to detect apoptosis. RT-qPCR and western blot were used to detect the gene and protein expression, respectively.

Results:

Our data showed that Enoxacin inhibited PC-3 cell proliferation and induced the apoptosis through up-regulating the expression of pro-apoptotic proteins, while down-regulating expression levels of anti-apoptotic proteins. Moreover, Enoxacin increased the gene and protein expression of the autophagy and endoplasmic reticulum stress markers. Treating tumor-bearing mice with Enoxacin significantly inhibited tumor growth in xenograft tumor model.

Conclusion:

Our results suggested that Enoxacin could be developed as a potential anti-tumor agent against prostate carcinoma.

Pharmacological Treatment of Vascular Dementia: A Molecular Mechanism Perspective

Vascular dementia (VaD) is a neurodegenerative disease, with cognitive dysfunction attributable to cerebrovascular factors. At present, it is the second most frequently occurring type of dementia in older adults (after Alzheimer's disease). The underlying etiology of VaD has not been completely elucidated, which limits its management. Currently, there are no approved standard treatments for VaD. The drugs used in VaD are only suitable for symptomatic treatment and cannot prevent or reduce the occurrence and progression of VaD. This review summarizes the current status of pharmacological treatment for VaD, from the perspective of the molecular mechanisms specified in various pathogenic hypotheses, including oxidative stress, the central cholinergic system, neuroinflammation, neuronal apoptosis, and synaptic plasticity. As VaD is a chronic cerebrovascular disease with multifactorial etiology, combined therapy, targeting multiple pathophysiological factors, may be the future trend in VaD.

Targeting Transcription Factor Nrf2 (Nuclear Factor Erythroid 2-Related Factor 2) for the Intervention of Vascular Cognitive Impairment and Dementia

Vascular cognitive impairment and dementia (VCID) is an age-related, mild to severe mental disability due to a broad panel of cerebrovascular disorders. Its pathobiology involves neurovascular dysfunction, blood-brain barrier disruption, white matter damage, microRNAs, oxidative stress, neuroinflammation, and gut microbiota alterations, etc. Nrf2 (Nuclear factor erythroid 2-related factor 2) is the master regulator of redox status and controls the transcription of a panel of antioxidative and anti-inflammatory genes. By interacting with NF-κB (nuclear factor-κB), Nrf2 also fine-tunes the cellular oxidative and inflammatory balance. Aging is associated with Nrf2 dysfunction, and increasing evidence has proved the role of Nrf2 in mitigating the VCID process. Based on VCID pathobiologies and Nrf2 studies from VCID and other brain diseases, we point out several hypothetical Nrf2 targets for VCID management, including restoration of endothelial function and neurovascular coupling, preservation of blood-brain barrier integrity, reduction of amyloidopathy, promoting white matter integrity, and mitigating oxidative stress and neuroinflammation. Collectively, the Nrf2 pathway could be a promising direction for future VCID research. Targeting Nrf2 would shed light on VCID managing strategies.

Pharmacological activation of Nrf2 promotes wound healing

Wound repair and regeneration is a complex orchestrated process, comprising several phases interconnecting various cellular events and triggering multiple intracellular molecular pathways in damaged cells and tissues. In several metabolic disorders including diabetes mellitus, delay in wound healing due to elevated levels of cellular stress poses a key challenge. Several therapeutic wound dressing materials and strategies including hyperbaric oxygen therapy and negative pressure wound therapy have been developed to accelerate repair and restore cellular homeostasis at the wound site. Further, tremendous progress has been made in identification of transcriptional regulators involved in the process of wound healing. Nuclear factor erythroid 2-related factor 2 (Nrf2), a redox sensitive transcription factor, is the key regulator of intracellular redox homeostasis which induces the expression of cytoprotective genes and increases the production of antioxidants that scavenge free radicals. Activators of Nrf2 have been reported to combat oxidative stress and enhance the process of wound healing in several pathophysiological conditions, including diabetes and its complications such as diabetic foot ulcer, and chronic kidney disease, and diabetic nephropathy. Several bioactive compounds have been reported to reduce cellular stress, and thus accelerate cell proliferation, neovascularization results in repairing damaged tissues by the activation of the transcription factor, Nrf2. This review is focused on the strategies for diabetic wound healing and the highlights the role of bioactive compounds that activate the Nrf2 signaling and revitalize the cellular and molecular mechanism in the chronic wound niche, regulate and restore redox homeostasis thereby promoting wound repair and regeneration.

Ephedrine causes retinal damage in SD rats associating with JAK2/STAT3 pathway

PURPOSE

Ephedrine has various side effects in the cardiovascular and nervous systems. However, the cellular mechanism of toxicity remains unknown, specifically on the retina. This study was to investigate effects of ephedrine on the retina and explore the underlying mechanisms.

METHODS

Sprague Dawley rats were treated with ephedrine (n = 10) or saline (n = 10) by oral gavage for seven days. The retinal morphology was evaluated by Toluidine blue staining. Apoptosis-related markers were detected in the retinal lysate. Enzyme-linked immunosorbent assays were used to measure neurotransmitters and oxidative stress markers. Real-time PCR and western blot were used to measure gene and protein expression, respectively.

RESULTS

Our results demonstrated that ephedrine induced apoptosis in the retina, increased dopamine level as well as oxidative stress, and down-regulated the Jak2/Stat3 gene expression as well as protein expression of p-JAK2/p-STAT3.

CONCLUSIONS

Our study indicated that ephedrine treatment caused retinal damage in SD rats, which may be associated with the JAK2/STAT3 pathway.

(Z)-7,4′-Dimethoxy-6-hydroxy-aurone- 4-O-β-glucopyranoside alleviates cerebral ischemia-reperfusion injury in rats associating with the regulation of JAK1/STAT1 signaling pathway

Inflammatory responses have been demonstrated to contribute to the neuronal death following cerebral ischemia. This study was to investigate the repairing effects and potential mechanisms of (Z)-7,4′-dimethoxy-6-hydroxy-aurone-4-O-β-glucopyranoside (DHAG), a compound with neuroprotective effects, on cerebral ischemia-reperfusion (I/R) injury in rats. Cerebral I/R model was established with middle cerebral artery occlusion method in Sprague Dawley rats and then rats were treated with DHAG (1 and 2 mg/kg) for 7 days. The volume of cerebral infarction was detected by triphenyltetrazolium chloride staining. The apoptosis in ischemic brain tissues was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Oxidative stress markers and inflammatory factors were detected by enzyme-linked immunosorbent assay. Protein expression was detected by Western blot. DHAG treatment significantly alleviated the cerebral I/R injury and decreased apoptosis in brain tissues. Moreover, DHAG treatment significantly inhibited oxidative stress and reduced inflammatory responses, associating with decreasing the protein expression of phosphorylated Janus kinase 1/phosphorylated signal transducer and transcriptional activator 1. These results demonstrated neuroprotective properties of DHAG and highlighted it as a potential therapeutic agent against injury of cerebral IR.

Therapeutic Effects of Salidroside on Cognitive Ability in Rats with Experimental Vascular Dementia

We examined the effects of salidroside on cognition in rats with vascular dementia and explored the mechanisms of its neuroprotective effects. Sprague-Dawley rats (n=60) were randomly subdivided into 3 equal groups: controls, untreated rats with vascular dementia, and rats with vascular dementia treated with salidroside (30 mg/kg for 8 weeks). Vascular dementia was provoked by bilateral occlusion of the common carotid arteries. The cognitive function was tested in the Morris water maze. Oxidation stress was assessed by the levels of superoxide dismutase and malondialdehyde assayed with standard biochemical kits. Expressions of proteins p38, p-p38, and caspase-3 were assessed by Western blotting. In untreated rats with vascular dementia, the cognitive function degraded in parallel with a decrease in superoxide dismutase, malondialdehyde accumulation, and activation the expression of p-p38 and caspase-3. Salidroside treatment significantly improved the cognitive functions in rats with vascular dementia and diminished adverse shifts in the levels of superoxide dismutase and malondialdehyde as well as the changes in the expression of p-p38 and caspase-3 in comparison with similar changes in untreated rats. Moreover, salidroside improved spatial learning and memory in rats with vascular dementia. The therapeutic effect of salidroside is probably based on its antioxidant effects and inhibition of caspase-3-mediated apoptosis via suppression of p38 MAPK signaling pathway.

Lysergic acid diethylamide causes mouse retinal damage by up-regulating p-JAK1/p-STAT1

Purpose: Lysergic acid diethylamide (LSD) is a powerful hallucinogen with high potential for abuse. There is far less known about its effects on the retina, especially the underlying mechanisms. This study was to investigate the acute toxicity of LSD on the retina of C57 mice and its mechanisms of action.Methods: C57 mice were treated with LSD at progressively increasing doses (0.2-1.2 mg/kg) intraperitoneally two times daily for 5 days, mice treated with saline served as negative control. Electroretinography (ERG) was used to test the function of the retina. Toluidine blue staining was used to detect the morphology of the retina. Enzyme-linked immunosorbent assay (ELISA) was used to measure the apoptosis-related factors. Real-time PCR and western blot techniques were used to measure expression changes of genes and proteins, respectively.Results: LSD treatment caused retinal damage, as shown by a decrease in ERG response and the loss of photoreceptor cells. LSD treatment also increased apoptosis through up-regulating the expression of p-JAK1/p-STAT1.Conclusions: Our study indicated that intraperitoneal administration of LSD-induced retinal damage of C57 mice, at least partially through regulating the JAK/STAT pathway.

D-allose alleviates ischemia/reperfusion (I/R) injury in skin flap via MKP-1

Background

D-allose was promising in the protection of ischemia/reperfusion (I/R) injury. We intended to investigate the function of D-allose in skin flap of rat followed by the injury of I/R and whether ERK signal pathway was involved in.

Methods

The back flap of Wistar rats was picked up with a vascular bundle of the lateral chest wall. I/R model was made by the venous clamp for 6 h. Rats received D-allose and PD-98059, the inhibitor of ERK1/2, 30 min before modeling. Morphology of tissue was observed by HE staining. Nitric oxide (NO), myeloperoxidase (MPO), malondialdehyde (MDA) and superoxide dismutase (SOD) levels in skin flap were determined by ELISA kits. mRNA and protein levels were determined by qPCR and Western blot respectively.

Results

D-allose alleviated the condition of pathological changes and raised the survival rate of skin flap injured by I/R. Moreover, D-allose suppressed NO, MPO and MDA while elevated SOD levels during I/R status. Furthermore, D-allose decreased MCP-1, TNF-α, IL-1β and IL-6 levels in skin flap injured by I/R. In addition, D-allose inhibited MKP-1 expression and activated ERK1/2 pathway in skin flap injured by I/R. PD-98059 partially counteracted D-allose effects on I/R injury.

Conclusions

D-allose exerted its protective function via inhibiting MKP-1expression and further activated ERK1/2 pathway to suppress the progress of oxidative stress, inflammation and necrosis, contributing to the survival of skin flap injured by I/R. Thus, D-allose was promising in the transplantation of skin flap.

Effects of resveratrol on learning and memory in rats with vascular dementia

The purpose of the present study was to study the effects of resveratrol on cognitive function in rats with vascular dementia and to investigate the molecular mechanisms of its neuroprotective effects. Forty-five SD rats were randomly divided into 3 groups: The control group (Con group, n=15), the model group (VD group, n=15) and the resveratrol-treated VD group (Res group, n=15). The VD rats (the VD group and the Res group) were generated by bilateral common carotid artery occlusion. The rats in the Res group received daily resveratrol treatment intraperitoneally for 4 weeks. Cognitive function was tested using the Morris water maze test. The levels of SOD and MDA (oxidative stress indicators) were detected by ELISA kits. The protein expression of Bax, Bcl-2 and caspase-3 was detected by western blotting. Compared with the rats in the Con group, the rats in the VD group exhibited decreased cognitive function, significantly increased hippocampal content of MDA, Bax and caspase-3 (P<0.05), and significantly reduced hippocampal expression of SOD and Bcl-2 (P<0.05). Compared with the rats in the VD group, the rats in the Res group exhibited increased cognitive ability, reduced hippocampal content of MDA, Bax and caspase-3 (P<0.05), and increased hippocampal expression of SOD and Bcl-2 (P<0.05). Resveratrol treatment significantly improved the spatial learning and memory of the VD rats. The mechanism associated with the neuroprotective effects of resveratrol may be closely related to the inhibition of the apoptosis pathway and oxidative stress injury.

Cinnamon, a promising prospect towards Alzheimer's disease

Over the last decades, an exponential increase of efforts concerning the treatment of Alzheimer's disease (AD) has been practiced. Phytochemicals preparations have a millenary background to combat various pathological conditions. Various cinnamon species and their biologically active ingredients have renewed the interest towards the treatment of patients with mild-to-moderate AD through the inhibition of tau protein aggregation and prevention of the formation and accumulation of amyloid-β peptides into the neurotoxic oligomeric inclusions, both of which are considered to be the AD trademarks. In this review, we presented comprehensive data on the interactions of a number of cinnamon polyphenols (PPs) with oxidative stress and pro-inflammatory signaling pathways in the brain. In addition, we discussed the potential association between AD and diabetes mellitus (DM), vis-à-vis the effluence of cinnamon PPs. Further, an upcoming prospect of AD epigenetic pathophysiological conditions and cinnamon has been sighted. Data was retrieved from the scientific databases such as PubMed database of the National Library of Medicine, Scopus and Google Scholar without any time limitation. The extract of cinnamon efficiently inhibits tau accumulations, Aβ aggregation and toxicity in vivo and in vitro models. Indeed, cinnamon possesses neuroprotective effects interfering multiple oxidative stress and pro-inflammatory pathways. Besides, cinnamon modulates endothelial functions and attenuates the vascular cell adhesion molecules. Cinnamon PPs may induce AD epigenetic modifications. Cinnamon and in particular, cinnamaldehyde seem to be effective and safe approaches for treatment and prevention of AD onset and/or progression. However, further molecular and translational research studies as well as prolonged clinical trials are required to establish the therapeutic safety and efficacy in different cinnamon spp.

Neopterin acts as an endogenous cognitive enhancer

Neopterin is found at increased levels in biological fluids from individuals with inflammatory disorders. The biological role of this pteridine remains undefined; however, due to its capacity to increase hemeoxygenase-1 content, it has been proposed as a protective agent during cellular stress. Therefore, we investigated the effects of neopterin on motor, emotional and memory functions. To address this question, neopterin (0.4 and/or 4pmol) was injected intracerebroventricularly before or after the training sessions of step-down inhibitory avoidance and fear conditioning tasks, respectively. Memory-related behaviors were assessed in Swiss and C57BL/6 mice, as well as in Wistar rats. Moreover, the putative effects of neopterin on motor and anxiety-related parameters were addressed in the open field and elevated plus-maze tasks. The effects of neopterin on cognitive performance were also investigated after intraperitoneal lipopolysaccharide (LPS) administration (0.33mg/kg) in interleukin-10 knockout mice (IL-10(-/-)). It was consistently observed across rodent species that neopterin facilitated aversive memory acquisition by increasing the latency to step-down in the inhibitory avoidance task. This effect was related to a reduced threshold to generate the hippocampal long-term potentiation (LTP) process, and reduced IL-6 brain levels after the LPS challenge. However, neopterin administration after acquisition did not alter the consolidation of fear memories, neither motor nor anxiety-related parameters. Altogether, neopterin facilitated cognitive processes, probably by inducing an antioxidant/anti-inflammatory state, and by facilitating LTP generation. To our knowledge, this is the first evidence showing the cognitive enhancer property of neopterin.

Rannasangpei Is a Therapeutic Agent in the Treatment of Vascular Dementia

Rannasangpei (RSNP) is used as a therapeutic agent in the treatment of cardiovascular diseases, neurological disorders, and neurodegeneration in China; however, its potential use in the treatment of vascular dementia (VD) was unclear. In this study, our aim was to examine the neuroprotective effect of RSNP in a VD rat model, which was induced by permanent bilateral common carotid artery occlusion (2VO). Four-week administration with two doses of RSNP was investigated in our study. Severe cognitive deficit in the VD model, which was confirmed in Morris water maze (MWM) test, was significantly restored by the administration of RSNP. ELISA revealed that the treatments with both doses of RSNP could reinstate the cholinergic activity in the VD animals by elevating the production of choline acetyltransferase (ChAT) and reducing the acetylcholinesterase (AChE); the treatment of RSNP could also reboot the level of superoxide dismutase (SOD) and decrease malondialdehyde (MDA). Moreover, Western blot and quantitative PCR (Q-PCR) results indicated that the RSNP could suppress the apoptosis in the hippocampus of the VD animals by increasing the expression ratio of B-cell lymphoma-2 (Bcl-2) to Bcl-2-associated X protein (Bax). These results suggested that RSNP might be a therapeutic agent in the treatment of vascular dementia in the future.