Neuroprotective effect of allicin against traumatic brain injury via Akt/endothelial nitric oxide synthase pathway-mediated anti-inflammatory and anti-oxidative activities

Allicin alleviates traumatic brain injury-induced neuroinflammation by enhancing PKC-δ-mediated mitophagy

BACKGROUND

Traumatic brain injury (TBI) leads to neuroinflammation, which is a key contributor to the negative prognosis in TBI patients. Recent evidence indicates that allicin can prevent neuronal injury after TBI. However, whether allicin alleviates neuroinflammation by promoting mitophagy is unclear.

PURPOSE

We investigated the suppressive effects of allicin on neuroinflammation and clarified the role of mitophagy in the underlying mechanism.

STUDY DESIGN/METHODS

The controlled cortical impact (CCI) was employed to effectively mimic TBI in a living system. Cellular mechanical damage was modeled in vitro using a Bv2 cell stretch model. Neuroinflammation was assessed by evaluating levels of TNF-α, IL-1β, IL-6, ROS, IL-4 and IL-10, along with the expression of NLRP3 and TLR4 proteins. RNA-sequence and KEGG analyses revealed allicin-regulated molecular processes in the Bv2 cell stretch model. Immunofluorescence staining was performed to label both the autophagy marker protein LC3 and the outer mitochondrial membrane (OMM) marker COX IV. Lipid MS and lipidomic analyses were used to determine the CL levels in the OMM and IMM. The characteristic bilayer structure of mitochondria was observed using transmission electron microscopy (TEM). PKC-δ expression and phosphorylated phospholipid scramblase-3 (PLS3) levels were detected via western blotting. Stretched Bv2 cells and primary neurons were cocultured to assess the anti-neuroinflammatory effects of allicin. Neuro-rehabilitation was assessed using behavioral experiments such as the rotarod and morris water maze (MWM) tests.

RESULTS

Allicin treatment reduced TNF-α, IL-1β, IL-6, ROS levels, and the expression of NLRP3 and TLR4 proteins in mice with CCI, while IL-4 and IL-10 levels remained unchanged. Additionally, allicin reduced tissue lesions and cell death after CCI. The transcriptomic analysis revealed that mitophagy was important in allicin-related molecular pathways. The translocation of CL from IMM to OMM was facilitated by allicin, as demonstrated by flow cytometry and lipidomic analyses. Importantly, allicin increased PKC-δ expression and PLS3 phosphorylation in the CL-related mitophagy process in both the CCI and Bv2 cell stretch models. These findings suggest that allicin reduces mitophagy-related neuroinflammation and further prevents neuronal injury in vitro. Rottlerin, a selective PKC-δ inhibitor, effectively diminished allicin's capacity to reduce neuroinflammation, correlating with worsened motor function and cognitive abilities. Thus, CCI-induced behavioral deficits were also ameliorated by the administration of allicin via a PKC-δ-related mitophagy.

CONCLUSIONS

This study uncovers a novel mechanism where allicin enhances PKC-δ expression and PLS3 phosphorylation, facilitating CL translocation to the OMM and activating mitophagy, thereby reducing TBI-induced neuroinflammation.

Neuroprotection in traumatic brain injury: effects of alpha-asarone and Acorus calamus extract in mice using weight drop model

Traumatic brain injury (TBI) is a significant public health concern characterized by severe neurological consequences. The management of TBI remains a formidable challenge, necessitating a multifaceted approach aimed at reducing secondary injury and promoting neuroprotection. This study assessed the neuroprotective potential of Alpha-asarone (AA) at 12.5, 25, 50 mg/kg, p.o (phytoconstituent of Acorus calamus) at, and Acorus calamus (AC) extract at 190 mg/kg, p.o in a murine TBI model induced by weight drop method. Blood-Brain Barrier (BBB) permeability and oxidative stress were evaluated on 1st and 3rd day, while Neurological Severity Score (NSS) was assessed on 1st, 3rd, 7th, 14th, and 21st day after TBI. The administration of AA and AC extract at all tested doses demonstrated a dose-dependent restoration of blood-brain barrier (BBB) integrity and oxidative stress markers. Specifically, AA at doses of 25 mg/kg and 50 mg/kg, as well as AC extract at 190 mg/kg, administered orally, exhibited significant effects on BBB integrity and oxidative stress at 1st and 3rd day post-treatment. Furthermore, enhanced neurological outcomes were observed at 14th and 21st day post TBI, evidenced by improved NSS, particularly with the 50 mg/kg dose of AA and the 190 mg/kg dose of AC extract. This research underscores the potential of AA and AC extract as neuroprotective agents. The findings highlight their efficacy in improving BBB integrity, mitigating oxidative stress-induced cellular damage and enhancing neurological impairments following TBI. These results hold promise for the development of innovative neuroprotective therapies and advocate for the exploration of natural compounds as adjunctive interventions in TBI management.

Allicin: a promising modulator of apoptosis and survival signaling in cancer

According to the World Health Organization, cancer is the foremost cause of mortality globally. Various phytochemicals from natural sources have been extensively studied for their anticancer properties. Allicin, a powerful organosulfur compound derived from garlic, exhibits anticancer, antioxidant, anti-inflammatory, antifungal, and antibacterial properties. This review aims to update and evaluate the chemistry, composition, mechanisms of action, and pharmacokinetics Allicin. Allicin has garnered significant attention for its potential role in modulating Fas-FasL, Bcl2-Bax, PI3K-Akt-mTOR, autophagy, and miRNA pathways. At the molecular level, allicin induces the release of cytochrome c from the mitochondria and enhances the activation of caspases-3, -8, and -9. This is accompanied by the simultaneous upregulation of Bax and Fas expression in tumor cells. Allicin can inhibit excessive autophagy by activating the PI3K/Akt/mTOR and MAPK/ERK/mTOR signaling pathways. Allicin-loaded nano-formulations efficiently induce apoptosis in cancer cells while minimizing toxicity to normal cells. Safety and clinical aspects are meticulously scrutinized, providing insights into the tolerability and adverse effects associated with allicin administration, along with an overview of current clinical trials evaluating its therapeutic potential. In conclusion, this review underscores the promising prospects of allicin as a dietary-derived medicinal compound for cancer therapy. It emphasizes the need for further research to elucidate its precise mechanisms of action, optimize delivery strategies, and validate its efficacy in clinical settings.

Ferroptosis: a new antidepressant pharmacological mechanism

The incidence rate of depression, a mental disorder, is steadily increasing and has the potential to become a major global disability factor. Given the complex pathological mechanisms involved in depression, the use of conventional antidepressants may lead to severe complications due to their side effects. Hence, there is a critical need to explore the development of novel antidepressants. Ferroptosis, a newly recognized form of cell death, has been found to be closely linked to the onset of depression. Several studies have indicated that certain active ingredients can ameliorate depression by modulating the ferroptosis signaling pathway. Notably, traditional Chinese medicine (TCM) active ingredients and TCM prescriptions have demonstrated promising antidepressant effects in previous investigations owing to their unique advantages in antidepressant therapy. Building upon these findings, our objective was to review recent relevant research and provide new insights and directions for the development and application of innovative antidepressant strategies.

Therapeutic effect of allicin in a mouse model of intracerebral hemorrhage

Natural compounds with sulfur moiety produce various biological actions that may be beneficial for the therapies of several devastative disorders of the central nervous system. Here we investigated potential therapeutic effect of allicin, an organosulfur compound derived from garlic, in a mouse model of intracerebral hemorrhage (ICH) based on intrastriatal collagenase injection. Daily intraperitoneal administration of allicin (50 mg/kg) from 3 h after induction of ICH afforded neuroprotective effects, as evidenced by the increase of surviving neurons in the hematoma, reduction of axonal transport impairment, and prevention of axon tract injury. In addition, allicin inhibited accumulation of activated microglia/macrophages around the hematoma and infiltration of neutrophils within the hematoma. Allicin also suppressed ICH-induced mRNA upregulation of pro-inflammatory factors such as interleukin 6 and C-X-C motif ligand 2 in the brain, suggesting its anti-inflammatory effect. Moreover, ICH-induced increase of malondialdehyde as well as decrease of total glutathione in the brain was attenuated by allicin. Finally, allicin-treated mice showed better recovery of sensorimotor functions after ICH than vehicle-treated mice. These results indicate that allicin produces a therapeutic effect on ICH pathology via alleviation of neuronal damage, inflammatory responses and oxidative stress in the brain.

Garlic extract enhances bioceramic bone scaffolds through upregulating ALP & BGLAP expression in hMSC-monocyte co-culture

Bone homeostasis is predicated by osteoblast and osteoclast cell cycles where gene expressions are responsible for their differentiation from human mesenchymal stem cells (hMSC) and monocytes, respectively. The pro-osteogenic potential of an hMSC-monocyte co-culture can be measured through complementary DNA (mRNA synthesis) within the nucleus, known as quantitative polymerase chain reaction (qPCR). Through this technique, the effects of garlic extract (allicin) release from calcium phosphate bone scaffolds on gene expression of bone forming and bone remodeling cells was explored. Results show this complex biomaterial system enhances hMSC differentiation through the upregulation of bone-forming proteins. Osteoblastic gene markers alkaline phosphatase (ALP) and osteocalcin (BGLAP), are respectively upregulated by 3-fold and 1.6-fold by day 14. These mature osteoblasts then upregulate the receptor activator of nuclear factor-kB ligand (RANKL) which recruits osteoclast cells, as captured by a nearly 2-fold higher osteoclast expression of tartrate-resistance acid-phosphatase (ACP5). This also activates antagonist osteoprotegerin (OPG) expression in osteoblasts, decreasing osteoclast resorption potential and ACP5 expression by day 21. The pro-osteogenic environment with garlic extract release is further quantified by a 4× increase in phosphatase activity and visibly captured in immunofluorescent tagged confocal images. Also corroborated by enhanced collagen formation in a preliminary in vivo rat distal femur model, this work collectively reveals how garlic extract can enhance bioceramic scaffolds for bone tissue regenerative applications.

Collagen for neural tissue engineering: Materials, strategies, and challenges

Neural tissue engineering (NTE) has made remarkable strides in recent years and holds great promise for treating several devastating neurological disorders. Selecting optimal scaffolding material is crucial for NET design strategies that enable neural and non-neural cell differentiation and axonal growth. Collagen is extensively employed in NTE applications due to the inherent resistance of the nervous system against regeneration, functionalized with neurotrophic factors, antagonists of neural growth inhibitors, and other neural growth-promoting agents. Recent advancements in integrating collagen with manufacturing strategies, such as scaffolding, electrospinning, and 3D bioprinting, provide localized trophic support, guide cell alignment, and protect neural cells from immune activity. This review categorises and analyses collagen-based processing techniques investigated for neural-specific applications, highlighting their strengths and weaknesses in repair, regeneration, and recovery. We also evaluate the potential prospects and challenges of using collagen-based biomaterials in NTE. Overall, this review offers a comprehensive and systematic framework for the rational evaluation and applications of collagen in NTE.

The Pharmacological Activity of Garlic (Allium sativum) in Parkinson's Disease: From Molecular Mechanisms to the Therapeutic Potential

Parkinson's disease (PD), one of the most common neurological diseases worldwide, is mainly characterized neuropathologically by the dopaminergic neurodegeneration in the substantia nigra pars compacta of the brainstem. Genetic and environmental factors contribute to PD pathophysiology through modulation of pleiotropic cellular mechanisms. The currently available treatment options focus only on replenishing dopamine and do not alter disease progression. Interestingly, garlic (Allium sativum), globally famed for its flavor and taste-enhancing properties, has shown protective activity in different PD models. Numerous chemical constituents of garlic, mainly the organosulfur compounds, have been shown to exhibit anti-Parkinsonian effects by targeting oxidative stress, mitochondrial impairment, and neuroinflammation-related signaling. However, despite its therapeutic potential against PD, the major bioactive components of garlic display some stability issues and some adverse effects. In the present review, we explore the therapeutic potential of garlic and its major constituents in PD, the molecular mechanisms responsible for its pharmaceutical activity, and the associated limitations that need to be overcome for its future potential use in clinical practice.

A Systematic Review on Traumatic Brain Injury Pathophysiology and Role of Herbal Medicines in its Management

BACKGROUND

Traumatic brain injury (TBI) is a worldwide problem. Almost about sixtynine million people sustain TBI each year all over the world. Repetitive TBI linked with increased risk of neurodegenerative disorder such as Parkinson, Alzheimer, traumatic encephalopathy. TBI is characterized by primary and secondary injury and exerts a severe impact on cognitive, behavioral, psychological and other health problem. There were various proposed mechanism to understand complex pathophysiology of TBI but still there is a need to explore more about TBI pathophysiology. There are drugs present for the treatment of TBI in the market but there is still need of more drugs to develop for better and effective treatment of TBI, because no single drug is available which reduces the further progression of this injury.

OBJECTIVE

The main aim and objective of structuring this manuscript is to design, develop and gather detailed data regarding about the pathophysiology of TBI and role of medicinal plants in its treatment.

METHOD

This study is a systematic review conducted between January 1995 to June 2021 in which a consultation of scientific articles from indexed periodicals was carried out in Science Direct, United States National Library of Medicine (Pubmed), Google Scholar, Elsvier, Springer and Bentham.

RESULTS

A total of 54 studies were analyzed, on the basis of literature survey in the research area of TBI.

CONCLUSION

Recent studies have shown the potential of medicinal plants and their chemical constituents against TBI therefore, this review targets the detailed information about the pathophysiology of TBI and role of medicinal plants in its treatment.

MLN-4760 Induces Oxidative Stress without Blood Pressure and Behavioural Alterations in SHRs: Roles of Nfe2l2 Gene, Nitric Oxide and Hydrogen Sulfide

Reduced angiotensin 1-7 bioavailability due to inhibition of angiotensin-converting enzyme 2 (ACE2) may contribute to increased mortality in hypertensive individuals during COVID-19. However, effects of ACE2 inhibitor MLN-4760 in brain functions remain unknown. We investigated the selected behavioural and hemodynamic parameters in spontaneously hypertensive rats (SHRs) after a 2-week s.c. infusion of MLN-4760 (dose 1 mg/kg/day). The biochemical and molecular effects of MLN-4760 were investigated in the brainstem and blood plasma. MLN-4760 had no effects on hemodynamic and behavioural parameters. However, MLN-4760 increased plasma hydrogen sulfide (H₂S) level and total nitric oxide (NO) synthase activity and conjugated dienes in the brainstem. Increased NO synthase activity correlated positively with gene expression of Nos3 while plasma H₂S levels correlated positively with gene expressions of H₂S-producing enzymes Mpst, Cth and Cbs. MLN-4760 administration increased gene expression of Ace2, Sod1, Sod2, Gpx4 and Hmox1, which positively correlated with expression of Nfe2l2 gene encoding the redox-sensitive transcription factor NRF2. Collectively, MLN-4760 did not exacerbate pre-existing hypertension and behavioural hyperactivity/anxiety in SHRs. However, MLN-4760-induced oxidative damage in brainstem was associated with activation of NO- and H₂S-mediated compensatory mechanisms and with increased gene expression of antioxidant, NO- and H₂S-producing enzymes that all correlated positively with elevated Nfe2l2 expression.

Current studies and potential future research directions on biological effects and related mechanisms of allicin

Allicin, a thiosulfonate extract from freshly minced garlic, has been reported to have various biological effects on different organs and systems of animals and human. It can reduce oxidative stress, inhibit inflammatory response, resist pathogen infection and regulate intestinal flora. In addition, dozens of studies also demonstrated allicin could reduce blood glucose level, protect cardiovascular system and nervous system, and fight against cancers. Allicin was widely used in disease prevention and health care. However, more investigations on human cohort study are needed to verify the biological or clinical effects of allicin in the future. In this review, we summarized the biological effects of allicin from previous outstanding and valuable studies and provided useful information for future studies on the health effects of allicin.

Allicin, an Antioxidant and Neuroprotective Agent, Ameliorates Cognitive Impairment

Allicin (diallylthiosulfinate) is a defense molecule produced by cellular contents of garlic (Allium sativum L.). On tissue damage, the non-proteinogenic amino acid alliin (S-allylcysteine sulfoxide) is converted to allicin in an enzyme-mediated process catalysed by alliinase. Allicin is hydrophobic in nature, can efficiently cross the cellular membranes and behaves as a reactive sulfur species (RSS) inside the cells. It is physiologically active molecule with the ability to oxidise the thiol groups of glutathione and between cysteine residues in proteins. Allicin has shown anticancer, antimicrobial, antioxidant properties and also serves as an efficient therapeutic agent against cardiovascular diseases. In this context, the present review describes allicin as an antioxidant, and neuroprotective molecule that can ameliorate the cognitive abilities in case of neurodegenerative and neuropsychological disorders. As an antioxidant, allicin fights the reactive oxygen species (ROS) by downregulation of NOX (NADPH oxidizing) enzymes, it can directly interact to reduce the cellular levels of different types of ROS produced by a variety of peroxidases. Most of the neuroprotective actions of allicin are mediated via redox-dependent pathways. Allicin inhibits neuroinflammation by suppressing the ROS production, inhibition of TLR4/MyD88/NF-κB, P38 and JNK pathways. As an inhibitor of cholinesterase and (AChE) and butyrylcholinesterase (BuChE) it can be applied to manage the Alzheimer's disease, helps to maintain the balance of neurotransmitters in case of autism spectrum disorder (ASD) and attention deficit hyperactive syndrome (ADHD). In case of acute traumatic spinal cord injury (SCI) allicin protects neuron damage by regulating inflammation, apoptosis and promoting the expression levels of Nrf2 (nuclear factor erythroid 2-related factor 2). Metal induced neurodegeneration can also be attenuated and cognitive abilities of patients suffering from neurological diseases can be ameliorates by allicin administration.

A Pivotal Role of the Nrf2 Signaling Pathway in Spinal Cord Injury: A Prospective Therapeutics Study

The nuclear erythroid 2-related factor 2 (Nrf2) signaling pathway has a main role against oxidative stress and inflammation. Spinal Cord Injury (SCI) leads to the high secretion of inflammatory cytokines and reactive oxygen species, which disturbs nervous system function and regeneration. Several studies have indicated that the activation of the Nrf2 signaling pathway may be effective against inflammation after SCI. The experimental studies have indicated that many chemical and natural agents act as Nrf2 inducer, which inhibits the SCI progression. Thus, the finding of novel Nrf2- inducer anti-inflammatory agents may be a valuable approach in drug discovery. In the present review, we discussed the Nrf2 signal pathway and crosstalk with the NF-κB pathway and also the impact of this pathway on inflammation in animal models of SCI. Furthermore, we discussed the regulation of Nrf2 by several phytochemicals and drugs, as well as their effects on the SCI inhibition. Therefore, the current study presented a new hypothesis of the development of anti-inflammatory agents that mediate the Nrf2 signaling pathway for treating the SCI outcomes.

Anti-Inflammatory Effect of Allicin Associated with Fibrosis in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling. Recent evidence supports that inflammation plays a key role in triggering and maintaining pulmonary vascular remodeling. Recent studies have shown that garlic extract has protective effects in PAH, but the precise role of allicin, a compound derived from garlic, is unknown. Thus, we used allicin to evaluate its effects on inflammation and fibrosis in PAH. Male Wistar rats were divided into three groups: control (CON), monocrotaline (60 mg/kg) (MCT), and MCT plus allicin (16 mg/kg/oral gavage) (MCT + A). Right ventricle (RV) hypertrophy and pulmonary arterial medial wall thickness were determined. IL-1β, IL-6, TNF-α, NFκB p65, Iκβ, TGF-β, and α-SMA were determined by Western blot analysis. In addition, TNF-α and TGF-β were determined by immunohistochemistry, and miR-21-5p and mRNA expressions of Cd68, Bmpr2, and Smad5 were determined by RT-qPCR. Results: Allicin prevented increases in vessel wall thickness due to TNF-α, IL-6, IL-1β, and Cd68 in the lung. In addition, TGF-β, α-SMA, and fibrosis were lower in the MCT + A group compared with the MCT group. In the RV, allicin prevented increases in TNF-α, IL-6, and TGF-β. These observations suggest that, through the modulation of proinflammatory and profibrotic markers in the lung and heart, allicin delays the progression of PAH.

Allicin mitigates hepatic injury following cyclophosphamide administration via activation of Nrf2/ARE pathways and through inhibition of inflammatory and apoptotic machinery

Treatment with anti-neoplastic agents, including cyclophosphamide (CP), is associated with several adverse reactions. Here, we distinguished the potential protective effect of allicin against CP-mediated hepatotoxicity in rats. To assess the effect of allicin, four experimental groups were used, with 7 rats per group, including control, allicin (10 mg/kg), CP (200 mg/kg), and allicin + CP-treated groups. All groups were treated for 10 days. Blood and liver samples were collected for biochemical, molecular, and histological analyses. Treatment with CP led to deformations in the liver tissue that were associated with higher liver function markers (alanine transaminase, aspartate transaminase, and alkaline phosphatase). Additionally, a disturbance in the redox balance was observed after CP exposure, as indicated by increased levels of oxidants, including malondialdehyde and nitric oxide, and the decreased levels of endogenous antioxidants, including glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase, and catalase. At the molecular level, CP treatment resulted in reduced expression of the Nrf2/ARE pathway and other genes related to this pathway, including NAD(P)H quinone dehydrogenase 1 and glutamate-cysteine ligase catalytic subunit. CP also led to a hyper-inflammatory response in hepatic tissue, with increased production of pro-inflammatory cytokines, including tumor necrosis factor-alpha and interlukin-1beta, and upregulation of nitric oxide synthase 2. CP also enhanced the immunoreactivity of the profibrogenic cytokine, transforming growth factor-beta, in liver tissue. Upregulation of caspase 3 and Bcl-2-associated X protein and downregulation of B-cell lymphoma 2 were also observed in response to CP treatment. Treatment with allicin reversed the molecular, biochemical, and histological changes that occurred with CP exposure. These results suggest that allicin can be used in combination with CP to avoid hepatotoxicity.

JM-20 Treatment After Mild Traumatic Brain Injury Reduces Glial Cell Pro-inflammatory Signaling and Behavioral and Cognitive Deficits by Increasing Neurotrophin Expression

Traumatic brain injury (TBI) is considered a public health problem and is often related to motor and cognitive disabilities, besides behavioral and emotional changes that may remain for the rest of the subject's life. Resident astrocytes and microglia are the first cell types to start the inflammatory cascades following TBI. It is widely known that continuous or excessive neuroinflammation may trigger many neuropathologies. Despite the large numbers of TBI cases, there is no effective pharmacological treatment available. This study aimed to investigate the effects of the new hybrid molecule 3-ethoxycarbonyl-2-methyl-4-(2-nitrophenyl)-4,11-dihydro1H-pyrido[2,3-b][1,5]benzodiazepine (JM-20) on TBI outcomes. Male Wistar rats were submitted to a weight drop model of mild TBI and treated with a single dose of JM-20 (8 mg/kg). Twenty-four hours after TBI, JM-20-treated animals showed improvements on locomotor and exploratory activities, and short-term memory deficits induced by TBI improved as well. Brain edema was present in TBI animals and the JM-20 treatment was able to prevent this change. JM-20 was also able to attenuate neuroinflammation cascades by preventing glial cells-microglia and astrocytes-from exacerbated activation, consequently reducing pro-inflammatory cytokine levels (TNF-α and IL-1β). BDNF mRNA level was decreased 24 h after TBI because of neuroinflammation cascades; however, JM-20 restored the levels. JM-20 also increased GDNF and NGF levels. These results support the JM-20 neuroprotective role to treat mild TBI by reducing the initial damage and limiting long-term secondary degeneration after TBI.

Anticancer Effects of Herbal Medicine Compounds and Novel Formulations: a Literature Review

INTRODUCTION

Many agents disrupt the cell cycle and its signaling circuits leading to cancer progress. Cancer therapy is performed by surgery, radiation, and chemical drugs remaining some side effects.

OBJECTIVE

To evaluate the anticancer traits of herbal medicines.

METHODS

We collected previously published data in searching engines (Web of Science, PubMed, Medline, and SCOPUS) by searching key words "herbal medicine," "anticancer effect," "compounds," and "fractions."

RESULTS

Herbal medicines have unraveled anticancer effects mostly through cancer cells apoptosis via blocking NF-κB pathway by curcumin and terpenoides; CD95 signaling and enhancement of CD95L expression by resveratrol; and inhibiting tyrosine kinas, angiogenesis, and cell cycle arrest in G2/M phase by β-lapachone-genistein and cytochrome-c release into the cytosol and caspase-9 activation by biocalein and quercetin. Additionally, impeding cell cycle in the G1 phase in ovarian cancer cells by 7-hydroxystaurosporine, immune cells enrichment (neutrophils and NK cells activation by Viscum album L., T cells and NK cells activation and cytokines such as tumor necrosis factor release by Ganoderma lucidum and microRNAs regulation (by Sinomeniumacutum, shikonin, Oleaeuropaea, curcumin and ginseng). These effects have implications for proper cancer cells elimination. It has been revealed that cytotoxic effects of herbal compounds (mostly those secondary metabolites) have exerted anticancer properties against several cancer cell lines. In addition, targeting microRNAs, nanoparticle-assisted herbal synergism, and novel drug delivery systems and combination chemotherapies have also emerged exerting higher efficacies for specific cell targeting as novel cancer therapy approaches.

CONCLUSION

Considering side effects, toxicity, and higher costs of common cancer therapy approaches, application of novel herbal medicine-based therapies will confer promising insights for health outcomes.

Light-To-Moderate Raw Garlic Consumption Frequency Is Inversely Associated With Thickened Carotid Intima-Media Thickness: A Population-Based Study

Background: Previous animal and clinical studies have reported beneficial effects of garlic preparations on carotid intima-media thickness (cIMT). However, no epidemiological study has yet investigated the association between dietary raw garlic consumption and cIMT in the general population. The objective of this study was investigating the association between dietary raw garlic consumption and thickened cIMT in Chinese adults. Methods: This cross-sectional study used data from the Tianjin Chronic Low-grade Systemic Inflammation and Health Cohort Study. A total of 4,329 general adults from 2015 to 2017 were included in this study. Frequency of consumption of raw garlic was summarized as four categories for analysis: < 1 time/week, 1 time/week, 2-3 times/week, ≥4 times/week with a validated food frequency questionnaire. The thickened cIMT was defined as common carotid artery IMT ≥ 1.0 mm or a carotid bifurcation IMT ≥ 1.2 mm by ultrasonography. Multivariable logistic regression analysis was used to examine the association between frequency of raw garlic consumption and thickened cIMT. Results: The prevalence of thickened cIMT is 22.9% among these participants. The adjusted odds ratios (95% confidence intervals) associated with the different frequencies were 1.00 (reference) for < 1 time/week, 0.74 (0.59, 0.94) for 1 time/week, 0.71 (0.55, 0.92) for 2-3 times/week, and 0.94 (0.71, 1.25) for ≥ 4 times/week. Conclusions: Light-to-moderate raw garlic consumption was inversely associated with thickened cIMT, whereas greater raw garlic consumption (i.e., ≥4 times/week) was not associated with thickened cIMT. Future longitudinal studies should be conducted to test these findings.

Nitric oxide and the brain. Part 2: Effects following neonatal brain injury-friend or foe?

Nitric oxide (NO) has critical roles in a wide variety of key biologic functions and has intricate transport mechanisms for delivery to key distal tissues under normal conditions. However, NO also plays important roles during disease processes, such as hypoxia-ischemia, asphyxia, neuro-inflammation, and retinopathy of prematurity. The effects of exogenous NO on the developing neonatal brain remain controversial. Inhaled NO (iNO) can be neuroprotective or toxic depending on a variety of factors, including cellular redox state, underlying disease processes, duration of treatment, and dose. This review identifies key gaps in knowledge that should prompt further investigation into the possible role of iNO as a therapeutic agent after injury to the brain. IMPACT: NO is a key signal mediator in the neonatal brain with neuroprotective and neurotoxic properties. iNO, a commonly used medication, has significant effects on the neonatal brain. Dosing, duration, and timing of administration of iNO can affect the developing brain. This review article summarizes the roles of NO in association with various disease processes that impact neonates, such as brain hypoxia-ischemia, asphyxia, retinopathy of prematurity, and neuroinflammation. The impact of this review is that it clearly describes gaps in knowledge, and makes the case for further, targeted studies in each of the identified areas.

Herb-Derived Products: Natural Tools to Delay and Counteract Stem Cell Senescence

Cellular senescence plays a very important role in organismal aging increasing with age and in age-related diseases (ARDs). This process involves physiological, structural, biochemical, and molecular changes of cells, leading to a characteristic trait referred to "senescence-associated secretory phenotype (SASP)." In particular, with aging, stem cells (SCs) in situ exhibit a diminished capacity of self-renewal and show a decline in their functionality. The identification of interventions able to prevent the accumulation of senescent SCs in the organism or to pretreat cultured multipotent mesenchymal stromal cells (MSCs) prior to employing them for cell therapy is a main purpose of medical research. Many approaches have been investigated and resulted effective to prevent or counteract SC senescence in humans, as well as other animal models. In this work, we have reviewed the chance of using a number of herb-derived products as novel tools in the treatment of cell senescence, highlighting the efficacy of these agents, often still far from being clearly understood.

Immunomodulatory effect of diallyl sulfide on experimentally-induced benign prostate hyperplasia via the suppression of CD4+T/IL-17 and TGF-β1/ERK pathways

Benign prostatic hyperplasia (BPH) is a nonmalignant enlargement of the prostate common in older men. Diallyl sulfide (DAS), a major component of garlic, has been reported to possess antioxidant, anti-inflammatory, and antiproliferative effects. However, the underlying protective immunomodulatory mechanism of DAS on BPH remains vague. Herein, experimental BPH was induced in rats by daily subcutaneous injection of testosterone propionate (TP) (3 mg/kg, s.c.) for 4 weeks. In parallel, finasteride (Fin) (5 mg/kg, p.o) or DAS (50 mg/kg, p.o.) was administered orally during BPH induction. TP-induced histological alterations and the immune-inflammatory cascade. On the other hand, DAS or Fin administration alleviated all abnormalities induced testosterone. Fin and DAS administration markedly reduced prostate weight by 53% with Fin, and by 60% with DAS. Moreover, serum testosterone and DHT were reduced by 55% and 52%, respectively, with Fin and by 68% and 75%, respectively, with DAS, in concordance with decreased protein expression of androgen receptor (AR), and prostate-specific antigen (PSA). Furthermore, both regime lessen immune-inflammatory milieu, as evidenced by decrease CD4+ T-cells protein expression and associated inflammatory cytokines. Concomitantly, Fin and DAS exhibited marked mitigation in insulin-like growth factor-1 (IGF-1), transforming growth factor-beta1 (TGF-β1), and phosphorylated extracellular signal-regulated kinase (ERK1/2) signaling. Besides alleviating oxidative stress by 53% and 68% in prostatic MDA and by 27% and 7% in prostatic iNOS with Fin and DAS, respectively. In conclusion, this work highlighted a potential therapeutic approach of DAS as a dietary preventive agent against BPH via its anti-inflammatory and immunomodulatory effect along with suppression of the ERK pathway.

Allicin pharmacology: Common molecular mechanisms against neuroinflammation and cardiovascular diseases

According to investigations in phytomedicine and ethnopharmacology, the therapeutic properties of garlic (Allium sativum) have been described by ancestral cultures. Notwithstanding, it is of particular concern to elucidate the molecular mechanisms underlying this millenary empirical knowledge. Allicin (S-allyl prop-2-ene-1-sulfinothioate), a thioester of sulfenic acid, is one of the main bioactive compounds present in garlic, and it is responsible for the particular aroma of the spice. The pharmacological attributes of allicin integrate a broad spectrum of properties (e.g., anti-inflammatory, immunomodulatory, antibiotic, antifungal, antiparasitic, antioxidant, nephroprotective, neuroprotective, cardioprotective, and anti-tumoral activities, among others). The primary goal of the present article is to review and clarify the common molecular mechanisms by which allicin and its derivates molecules may perform its therapeutic effects on cardiovascular diseases and neuroinflammatory processes. The intricate interface connecting the cardiovascular and nervous systems suggests that the impairment of one organ could contribute to the dysfunction of the other. Allicin might target the cornerstone of the pathological processes underlying cardiovascular and neuroinflammatory disorders, like inflammation, renin-angiotensin-aldosterone system (RAAS) hyperactivation, oxidative stress, and mitochondrial dysfunction. Indeed, the current evidence suggests that allicin improves mitochondrial function by enhancing the expression of HSP70 and NRF2, decreasing RAAS activation, and promoting mitochondrial fusion processes. Finally, allicin represents an attractive therapeutic alternative targeting the complex interaction between cardiovascular and neuroinflammatory disorders.

Allicin ameliorates obesity comorbid depressive-like behaviors: involvement of the oxidative stress, mitochondrial function, autophagy, insulin resistance and NOX/Nrf2 imbalance in mice

The increased prevalence of obesity has been a major medical and public health problem in the past decades. In obese status, insulin resistance and sustained oxidative stress damage might give rise to behavioral deficits. The anti-obesity and anti-oxidant effects of allicin have been previously reported in peripheral tissues. In the present study, the functions and mechanisms of allicin involved in the prevention of high-fat diet (HFD)-induced depressive-like behaviors were investigated to better understand the pharmacological activities of allicin. Obese mice (five weeks of age) were treated with allicin (50, 100, and 200 mg/kg) by gavage for 15 weeks and behavioral test (sucrose preference, open field, and tail suspension) were performed. Furthermore, markers of oxidative stress, mitochondrial function, autophagy, and insulin resistance were measured in the hippocampal tissue. Finally, the levels of NADPH oxidase (NOX2, NOX4) and the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway were evaluated in the hippocampus. The body weight, metabolic disorders, and depressive-like behaviors in obese mice were ameliorated by allicin. The depressive-like behaviors presented in the obese mice were accompanied by remarkably excessive reactive oxygen species (ROS) production and oxidative stress, damaged mitochondrial function, imbalanced autophagy, and enhanced insulin resistance in the hippocampus. We found that allicin improved the above undesirable effects in the obese mice. Furthermore, allicin significantly decreased NOX2 and NOX4 levels and activated the Nrf2 pathway. Allicin attenuated depressive-like behaviors triggered by long-term HFD consumption by inhibiting ROS production and oxidative stress, improving mitochondrial function, regulating autophagy, and reducing insulin resistance in the hippocampus via optimization of NOX/Nrf2 imbalance.

Allicin alleviates lead-induced hematopoietic stem cell aging by up-regulating PKM2

Hematopoietic stem cells (HSCs) aging is associated with hematopoietic dysfunction and diseases. Our previous study showed that lead exposure induced a functional decline in HSCs. Allicin, a chemical extracted from the garlic (Allium sativum L.), has been reported to have antioxidative and anti-inflammatory effects. However, the biological activities of allicin on lead-induced toxicity, especially in the hematopoietic system, remain unclear. Here, we found that lead exposure elicited aging phenotypes in HSCs, including perturbed cell quiescence, disabled self-renewal function and colony-forming ability, and myeloid-biased differentiation, all of which contributed to significant hematopoietic disorders in mice. Intragastric administration of allicin substantially ameliorated lead-induced HSCs aging phenotypes in vivo. Lead exposure induced a peroxide condition in HSCs leading to DNA damage, which reduced expression of the glycolytic enzyme pyruvate kinase M2 isoform (PKM2), a phenotype which was significantly ameliorated by allicin treatment. These findings suggested that allicin alleviated lead-induced HSCs aging by up-regulating PKM2 expression; thus, it could be a natural herb for preventing lead toxicity.

Medicinal plants in traumatic brain injury: Neuroprotective mechanisms revisited

Traumatic brain injury (TBI) is the most prevalent health problem affecting all age groups, and leads to many secondary problems in other organs especially kidneys, gastrointestinal tract, and heart function. In this review, the search terms were TBI, fluid percussion injury, cold injury, weight drop impact acceleration injury, lateral fluid percussion, cortical impact injury, and blast injury. Studies with Actaea racemosa, Artemisia annua, Aframomum melegueta, Carthamus tinctorius, Cinnamomum zeylanicum, Crocus sativus, Cnidium monnieri, Curcuma longa, Gastrodia elata, Malva sylvestris, Da Chuanxiong Formula, Erigeron breviscapus, Panax ginseng, Salvia tomentosa, Satureja khuzistanica, Nigella sativa, Drynaria fortune, Dracaena cochinchinensis, Polygonum cuspidatum, Rosmarinus officinalis, Rheum tanguticum, Centella asiatica, and Curcuma zedoaria show a significant decrease in neuronal injury by different mechanisms such as increasing superoxide dismutase and catalase activities, suppressing nuclear factor kappa B (NF-κB), interleukin 1 (IL-1), glial fibrillary acidic protein, and IL-6 expression. The aim of this study was to evaluate the neuroprotective effects of medicinal plants in central nervous system pathologies by reviewing the available literature.

Endoplasmic Reticulum Stress and Unfolded Protein Response Pathways Involved in the Health-Promoting Effects of Allicin on the Jejunum

Intestinal endoplasmic reticulum stress (ERS) triggered by adverse factors disturbs the normal function of the intestine. Allicin has been reported to promote intestinal health and development. In the present study, we established in vivo (35-day-old weaned piglets, 4-week-old mice) and in vitro (IPEC-J2 cell line) ERS models to explore the possible mechanisms by which allicin may benefit intestinal health. This study revealed the following: (1) allicin supplementation improved intestinal morphological indices and ameliorated mild ERS in the jejunum of the weaned piglets; (2) allicin supplementation decreased cellular reactive oxygen species and upregulated the XBP-1s signaling pathways in IPEC-J2 cells; (3) allicin supplementation reduced the prolonged ERS-mediated apoptosis of IPEC-J2 cells and in the jejunal tissues of the KM mice; (4) allicin supplementation enhanced the intercellular junction protein levels of jejunal cells by alleviating the prolonged ERS. These novel findings suggest that eating garlic could alleviate some intestinal malfunctions associated with ERS.

The nephroprotective effects of allicin and ascorbic acid against cisplatin-induced toxicity in rats

Cisplatin (CDDP) may induce nephrotoxicity through oxidative stress, DNA damage, and inflammation. This study was performed to evaluate the antioxidant and anti-inflammatory effects of allicin and ascorbic acid (AA) and investigate the nephroprotective efficacy of their combination against CDDP-induced intoxication. Rats were divided into seven groups: control, allicin (10 mg/kg for 14 days), AA (20 mg/kg for 14 days), CDDP (7 mg/kg as a single dose on the seventh experimental day), CDDP-allicin, CDDP-AA, and CDDP-allicin-AA (at the aforementioned doses). The administration of CDDP induced marked body weight loss and renal damage, manifested by significant increases (p < 0.05) in serum creatinine, urea, and uric acid levels and significant reductions in serum Na, Ca, and phosphorus concentrations, in addition to severe alterations in serum and renal tissue levels of tumor necrosis factor-α in comparison with control rats. Moreover, CDDP-intoxicated rats exhibited significantly (p < 0.05) higher lipid peroxidation, as well as lower levels of reduced glutathione and activities of glutathione peroxidase, superoxide dismutase, and catalase enzymes in the renal tissue, compared with control rats. The administration of allicin or AA significantly reduced (p < 0.05) the CDDP-induced changes in all the aforementioned parameters. Interestingly, allicin achieved comparable nephroprotection to AA in most assessed parameters; however, the restoration of normal serum and renal tissue concentrations of these parameters was more frequent in the CDDP-AA group. In conclusion, both allicin and AA showed significant nephroprotective effects against CDDP intoxication and their combination exhibited better protection than either agent alone. These results are probably mediated by their antioxidant and anti-inflammatory activities.

Diallyl Trisulfide can induce fibroblast-like synovial apoptosis and has a therapeutic effect on collagen-induced arthritis in mice via blocking NF-κB and Wnt pathways

BACKGROUND

Diallyl Trisulfide (DATS) is an organosulfur compound extracted from garlic bulb, and exerts cardioprotective, anti-inflammatory, antioxidant, antimicrobial and anticancer effects. But its role in the pathogenesis of rheumatoid arthritis (RA) is unknown. Here we explored the influence of DATS on human fibroblast-like synoviocytes (FLS) isolated from RA patients and a mouse model of collagen-induced arthritis (CIA) and the underlying mechanism.

METHODS

RA-FLS were cultured and treated with different concentrations of DATS. The CCK8 assay was used to assess cell proliferation while cell apoptosis was detected by flow cytometry and western blot. The IL-8, IL-6 and IL-1β levels were determined using RT-qPCR and ELISA assay. The expression of proteins of the NF-κB and Wnt pathways were measured using western blot. Furthermore, the effect of DATS was also explored in vivo using the collagen-induced arthritis mouse model. The Th17/Treg pattern obtain from cells of spleen of collagen-induced arthritis mouse model was detected by flow cytometry.

RESULTS

Our results showed that DATS could decrease cell viability and introduce apoptosis in RA-FLS. Furthermore, DATS significantly attenuated the production of key inflammatory cytokines induced by RA-FLS cells following treatment with tumor necrosis α (TNF-α) at a concentration of 100 μM or higher. This was due to its inhibitory effect on the NF-κB and Wnt pathway signaling in RA-FLS. Additionally, DATS decreased the production of inflammatory cytokines and regulated the immune function by restoring the balance between Th17 and Treg in CIA mouse model.

CONCLUSIONS

In conclusion, DATS may serve as a potential curative agent for RA.

Herbal medicine as an auspicious therapeutic approach for the eradication of Helicobacter pylori infection: A concise review

Helicobacter pylori (H. pylori) causes gastric mucosa inflammation and gastric cancer mostly via several virulence factors. Induction of proinflammatory pathways plays a crucial role in chronic inflammation, gastric carcinoma, and H. pylori pathogenesis. Herbal medicines (HMs) are nontoxic, inexpensive, and mostly anti-inflammatory reminding meticulous emphasis on the elimination of H. pylori and gastric cancer. Several HM has exerted paramount anti-H. pylori traits. In addition, they exert anti-inflammatory effects through several cellular circuits such as inhibition of 5'-adenosine monophosphate-activated protein kinase, nuclear factor-κB, and activator protein-1 pathway activation leading to the inhibition of proinflammatory cytokines (interleukin 1α [IL-1α], IL-1β, IL-6, IL-8, IL-12, interferon γ, and tumor necrosis factor-α) expression. Furthermore, they inhibit nitrous oxide release and COX-2 and iNOS activity. The apoptosis induction in Th1 and Th17-polarized lymphocytes and M2-macrophagic polarization and STAT6 activation has also been exhibited. Thus, their exact consumable amount has not been revealed, and clinical trials are needed to achieve optimal concentration and their pharmacokinetics. In the aspect of bioavailability, solubility, absorption, and metabolism of herbal compounds, nanocarriers such as poly lactideco-glycolide-based loading and related formulations are helpful. Noticeably, combined therapies accompanied by probiotics can also be examined for better clearance of gastric mucosa. In addition, downregulation of inflammatory microRNAs (miRNAs) by HMs and upregulation of those anti-inflammatory miRNAs is proposed to protect the gastric mucosa. Thus there is anticipation that in near future HM-based formulations and proper delivery systems are possibly applicable against gastric cancer or other ailments because of H. pylori.

Allicin attenuates early brain injury after experimental subarachnoid hemorrhage in rats

Early Brain Injury, rather than Cerebral Vasospasm, has been demonstrated to be more important for patients with Subarachnoid hemorrhage. It is considered that allicin can make sense in a wide range of pharmacological areas and can be taken as a therapeutic method in many pathologic situations. We have explored the potential effect of allicin and possible mechanisms in Early Brain Injury after Experimental Subarachnoid Hemorrhage in Rats. With therapy (70 mg/kg Allicin, rather than 30 mg/kg) 30 min post SAH, groups showed better neurological scores in 24 h. Significant differences could be found in body weight ratio between the SAH + vehicle groups and SAH + Allicin groups. Treatment with 70 mg/kg, not 30 mg/kg, Allicin significantly reduced brain edema and EB extravasation in 24 h after SAH. Assessments in 24 h after SAH showed that treatment with 70 mg/kg Allicin in 30 min after SAH significantly restrained the expression of cleaved caspase-3, mitigated the severity of neuronal degeneration, decreased the proportion of apoptotic neurons and the elevated MDA levels, and increased the suppressed GSH and SOD levels. We demonstrated for the first time that Allicin extenuated brain edema and blood-brain barrier dysfunction, improved neurological outcomes by the suppression of apoptosis and oxidative stress damage after SAH in experimental models, which may shade new light on the treatments of SAH.

Allicin attenuated chronic social defeat stress induced depressive-like behaviors through suppression of NLRP3 inflammasome

Allicin, one of the main biologically active compounds derived from garlic, was previously reported to possess multiple pharmacological activities. Whether allicin protected against chronic social defeat stress (CSDS) induced depressive-like behaviors remained unknown. Thus, our present study for the first time investigated the potential antidepressant effects and the mechanisms of allicin on the CSDS mice model. Thirty minutes before social defeat stress, allicin (2, 10, 50 mg/kg) was treated by intraperitoneal injection. The duration times of CSDS model establishment and allicin intervene were 10 days. Subsequently, the force swimming test (FST), social interaction test (SIT), and sucrose preference test (SPT) were applied for behavioral assessments. The levels of inflammation mediators were determined by commercial ELISA kits. The concentration of iron was tested, and relative protein expressions were measured by western blot. Oxidative stress and apoptosis markers were also detected by commercial kits and western blot. The behavioral defects induced by social defeat stress were obviously improved by allicin. Microglia activation, as well as inflammatory cytokines elevation in the hippocampus of CSDS also down-regulated by administration of allicin. Furthermore, content of iron and protein expressions of key components in iron metabolism were remarkably aberrant changed in the CSDS mice hippocampus, meanwhile, allicin ameliorated this phenomenon. Allicin decreased the production of reactive oxygen species (ROS), malondialdehyde (MDA), and protein carbonyl, and the protein expression of NOX4, as well as up-regulated the activities of superoxide dismutase (SOD) and Nrf2/HO-1 pathway. In addition, allicin attenuated the enhanced neuronal apoptosis. Finally, allicin supplementation inhibited the Nucleotide-binding oligomerization domain containing 3 (NLRP3) inflammasome hyperactivity, and the expressions of inflammasome components, such as ACS, caspase-1, and IL-1β in the hippocampus of CSDS mice. Allicin attenuated depressive-like behaviors of CSDS mice through reducing neuroinflammation, ameliorating iron abnromal accumulation, balacing oxidative stress, and attenuation neuronal apoptosis in the hippocampus via suppression of NLRP3 inflammasome.

Diallyl trisulfide regulates rat colonic smooth muscle contractions by inhibiting L-type calcium channel currents

Diallyl trisulfide (DATS) is an active organosulfide component of allicin and has several beneficial effects, including antimicrobial, antioxidant, cardioprotective and anticancer effects. Few studies have shown the modulatory effect of DATS on L-type calcium channels in rat colonic smooth muscle cells and colonic motility. To investigate the modulatory effect of DATS on L-type calcium channels in rat colonic smooth muscle and colonic contraction, L-type calcium channel currents were recorded, and colonic contractility in longitudinal and circular smooth muscle strips was measured. DATS attenuated L-type calcium channel currents without affecting steady-state activation or inactivation kinetics and inhibited the spontaneous contractions of both longitudinal and circular smooth muscle strips dose-dependently. In conclusion, DATS has an inhibitory effect on the contractions of colonic muscle strips that is related to its regulation of L-type calcium channels.

Antioxidant therapies in traumatic brain injury: a review

Oxidative stress constitute one of the commonest mechanism of the secondary injury contributing to neuronal death in traumatic brain injury cases. The oxidative stress induced secondary injury blockade may be considered as to be a good alternative to improve the outcome of traumatic brain injury (TBI) treatment. Due to absence of definitive therapy of traumatic brain injury has forced researcher to utilize unconventional therapies and its roles investigated in the improvement of management and outcome in recent year. Antioxidant therapies are proven effective in many preclinical studies and encouraging results and the role of antioxidant mediaction may act as further advancement in the traumatic brain injury management it may represent aonr of newer moadlaity in neurosurgical aramamentorium, this kind of therapy could be a good alternative or adjuct to the previously established neuroprotection agents in TBI.

Suppression of cortical TRPM7 protein attenuates oxidative damage after traumatic brain injury via Akt/endothelial nitric oxide synthase pathway

Neuronal death after traumatic brain injury (TBI) is a complex process resulting from a combination of factors, many of which are still unknown. Transient receptor potential melastatin 7 (TRPM7) is a transient receptor potential channel that has been demonstrated to mediate ischemic and traumatic neuronal injury in vitro. In the present study, TRPM7 was suppressed in the rat cerebral cortex by intracortical injections of viral vectors bearing shRNA specific for TRPM7 to investigate its potential role in an in vivo TBI model. We found that TRPM7 suppression significantly reduced brain edema, brain contusion volume and motor functional deficits, which was sustained for at least 2 weeks after the insult. These protective effects were accompanied by inhibited apoptosis in injured cortex. Also, TRPM7 suppression attenuated lipid peroxidation, decreased the expression of protein carbonyl, and preserved the endogenous antioxidant enzyme activities. The results of western blot analysis showed that TRPM7 suppression markedly increased the phosphorylation of Akt and endothelial nitric oxide synthase (eNOS). In addition, blocking Akt/eNOS pathway activation by the specific inhibitor LY294002 (LY, 10 μL, 10 mmol/L) or L-NIO (0.5 mg/kg) partially reversed the protective effects of TRPM7 suppression and its anti-oxidative activities. Taken together, these findings demonstrated that regional inhibition of TRPM7 in cerebral cortex exerts neuroprotective effects against TBI through activation of Akt/eNOS pathway. Thus, TRPM7 might represent a potential drug development target for the treatment of TBI.

Allicin protects against H2O2-induced apoptosis of PC12 cells via the mitochondrial pathway

Allicin is a major bioactive ingredient of garlic and has a broad range of biological activities. Allicin has been reported to protect against cell apoptosis induced by H₂O₂ in human umbilical vein endothelial cells. The present study evaluated the neuroprotective effect of allicin on the H₂O₂-induced apoptosis of rat pheochromocytoma PC12 cells in vitro and explored the underlying mechanism involved. PC12 cells were incubated with increasing concentrations of allicin and the toxic effect of allicin was measured by MTT assay. The cells were pretreated for 24 h with low dose (L-), medium dose (M-) and high dose (H-) of allicin, followed by exposure to 200 µM H₂O₂ for 2 h, and the cell viability was examined by MTT assay. In addition, cell apoptosis rate was analyzed by Annexin V-FITC/PI assay, while intracellular reactive oxygen species (ROS) and mitochondrial transmembrane potential (∆ψm) were measured by flow cytometry. Bcl-2, Bax, cleaved-caspase-3 and cytochrome c (Cyt C) in the mitochondria were also examined by western blotting. The results demonstrated that 0.01 µg/ml (L-allicin), 0.1 µg/ml (M-allicin) and 1 µg/ml (H-allicin) were non-toxic doses of allicin. Furthermore, H₂O₂ reduced cell viability, promoted cell apoptosis, induced ROS production and decreased ∆ψm. However, allicin treatment reversed the effect of H₂O₂ in a dose-dependent manner. It was also observed that H₂O₂ exposure significantly decreased Bcl-2 and mitochondrial Cyt C, while it increased Bax and cleaved-caspase-3, which were attenuated by allicin pretreatment. The results revealed that allicin protected PC12 cells from H₂O₂-induced cell apoptosis via the mitochondrial pathway, suggesting the potential neuroprotective effect of allicin against neurological diseases.

Neuroprotective Effects of Aged Garlic Extract on Cognitive Dysfunction and Neuroinflammation Induced by β-Amyloid in Rats

Neuroinflammation is pathological evidence of Alzheimer's disease (AD) that likely starts as a host defense response to the damaging effects of the β-amyloid (Aβ) deposits in the brain. The activation of microglia may promote the neurodegenerative process through the release of proinflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNFα), which may lead to neuronal damage and eventual death. Aged garlic extract (AGE) has been reported to have multiple biological activities, including anti-inflammatory effects. Therefore, the objective of this study was to investigate the effect of AGE on Aβ (1-42)-induced cognitive dysfunction and neuroinflammation. Adult male Wistar rats were given AGE (125, 250, and 500 mg/kg BW, body weight), orally administered, daily for 56 days. They were then injected with 1 μL of aggregated Aβ (1-42) into the lateral ventricles; bilaterally. Seven days later, their recognition memory was evaluated using a novel object recognition (NOR) test. Then the rats were sacrificed to investigate the alteration of microglia cells, IL-1β and TNFα in the cerebral cortex and hippocampus. The results indicated that AGE at doses of 250 and 500 mg/kg BW significantly improved short-term recognition memory in cognitively impaired rats. In addition, AGE significantly minimized the inflammatory response by reducing the activation of microglia and IL-1β to the levels found in the control, which is similar to the results found in Celebrex-treated rats. In conclusion, AGE may be useful for improving the short-term recognition memory and relieve the neuroinflammation in Aβ-induced rats.

σ1-Receptor Agonism Protects against Renal Ischemia-Reperfusion Injury

Mechanisms of renal ischemia-reperfusion injury remain unresolved, and effective therapies are lacking. We previously showed that dehydroepiandrosterone protects against renal ischemia-reperfusion injury in male rats. Here, we investigated the potential role of σ1-receptor activation in mediating this protection. In rats, pretreatment with either dehydroepiandrosterone or fluvoxamine, a high-affinity σ1-receptor agonist, improved survival, renal function and structure, and the inflammatory response after sublethal renal ischemia-reperfusion injury. In human proximal tubular epithelial cells, stimulation by fluvoxamine or oxidative stress caused the σ1-receptor to translocate from the endoplasmic reticulum to the cytosol and nucleus. Fluvoxamine stimulation in these cells also activated nitric oxide production that was blocked by σ1-receptor knockdown or Akt inhibition. Similarly, in the postischemic rat kidney, σ1-receptor activation by fluvoxamine triggered the Akt-nitric oxide synthase signaling pathway, resulting in time- and isoform-specific endothelial and neuronal nitric oxide synthase activation and nitric oxide production. Concurrently, intravital two-photon imaging revealed prompt peritubular vasodilation after fluvoxamine treatment, which was blocked by the σ1-receptor antagonist or various nitric oxide synthase blockers. In conclusion, in this rat model of ischemia-reperfusion injury, σ1-receptor agonists improved postischemic survival and renal function via activation of Akt-mediated nitric oxide signaling in the kidney. Thus, σ1-receptor activation might provide a therapeutic option for renoprotective therapy.

Natural Compounds as a Therapeutic Intervention following Traumatic Brain Injury: The Role of Phytochemicals

There has been a tremendous focus on the discovery and development of neuroprotective agents that might have clinical relevance following traumatic brain injury (TBI). This type of brain injury is very complex and is divided into two major components. The first component, a primary injury, occurs at the time of impact and is the result of the mechanical insult itself. This primary injury is thought to be irreversible and resistant to most treatments. A second component or secondary brain injury, is defined as cellular damage that is not immediately obvious after trauma, but that develops after a delay of minutes, hours, or even days. This injury appears to be amenable to treatment. Because of the complexity of the secondary injury, any type of therapeutic intervention needs to be multi-faceted and have the ability to simultaneously modulate different cellular changes. Because of diverse pharmaceutical interactions, combinations of different drugs do not work well in concert and result in adverse physiological conditions. Research has begun to investigate the possibility of using natural compounds as a therapeutic intervention following TBI. These compounds normally have very low toxicity and have reduced interactions with other pharmaceuticals. In addition, many natural compounds have the potential to target numerous different components of the secondary injury. Here, we review 33 different plant-derived natural compounds, phytochemicals, which have been investigated in experimental animal models of TBI. Some of these phytochemicals appear to have potential as possible therapeutic interventions to offset key components of the secondary injury cascade. However, not all studies have used the same scientific rigor, and one should be cautious in the interpretation of studies using naturally occurring phytochemical in TBI research.

MicroRNA-126 suppresses inflammation in endothelial cells under hyperglycemic condition by targeting HMGB1

MicroRNA-126(miR-126) targets involved in inflammation need to be identified. In this study, we aim to investigate whether high-mobility group box 1(HMGB1), an inflammation-related gene, is the target of miR-126 in diabetic vascular endothelium. The diabetic apoE^-/- mice model, a classical diabetic atherosclerosis model, was established. The aorta of diabetic apoE^-/- mice showed decrease of miR-126 and elevation of HMGB1 and inflammation. Next, we employed several in vitro experiments to address the role of miRNA-126 on the regulation of HMGB1 in endothelial cells under hyperglycemic and inflammatory conditions. Manipulation of miRNA levels in human umbilical vein endothelial cells (HUVECs) was achieved by transfecting cells with miR-126 mimic and antagomir. Overexpression of miR-126 could decrease the expression of downstream components of HMGB1 including TNF-α, ROS, and NADPH oxidase activity in HUVECs under hyperglycemic condition. Nevertheless, such phenomenon was completely reversed by miR-126 antagomir. The expression of HMGB1 protein rather than HMGB1 mRNA was down-regulated after transfection with miR-126 mimic, which indicated the modulation of HMGB1 mediated by miR-126 was at the posttranslational level. Luciferase reporter assay confirmed the 3'-UTR of HMGB1 gene was a direct target of miR-126. Western blot analysis also indicated that overexpression of miR-126 contributed to the elevation of p-eNOS, eNOS and p-AKT expressions, respectively. In summary, our findings suggest that miR-126 may suppress inflammation and ROS production in endothelial cells treated by high glucose through modulating the expression of HMGB1. Our study provides a novel pathogenic link between dysregulated miRNA expression and inflammation in diabetic vascular endothelium.

Peripheral Inflammatory Markers and Antioxidant Response during the Post-Acute and Chronic Phase after Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is a mechanical insult to the brain caused by external forces and associated with inflammation and oxidative stress. The patients may show different profiles of neurological recovery and a combination of oxidative damage and inflammatory processes can affect their courses. It is known that an overexpression of cytokines can be seen in peripheral blood in the early hours/days after the injury, but little is known about the weeks and months encompassing the post-acute and chronic phases. In addition, no information is available about the antioxidant responses mediated by the major enzymes that regulate reactive oxygen species levels: superoxide dismutase, catalase, peroxidases, and GSH-related enzymes. This study investigates the 6-month trends of inflammatory markers and antioxidant responses in 22 severe TBI patients with prolonged disorders of consciousness, consecutively recruited in a dedicated neurorehabilitation facility. Patients with a high degree of neurological impairment often show an uncertain outcome. In addition, the profiles of plasma activities were related to the neurological recovery after 12 months. Venous peripheral blood samples were taken blindly as soon as clinical signs and laboratory markers confirmed the absence of infections, 3 and 6 months later. The clinical and neuropsychological assessment continued up to 12 months. Nineteen patients completed the follow-up. In the chronic phase, persistent high plasma levels of cytokines can interfere with cognitive functioning and higher post-acute levels of cytokines [interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL1b, IL6] are associated with poorer cognitive recoveries 12 months later. Moreover, higher IFN-γ, higher TNF-α, and lower glutathione peroxidase activity are associated with greater disability. The results add evidence of persistent inflammatory response, provide information about long-term imbalance of antioxidant activity, and suggest that the over-production of cytokines and the alteration of the redox homeostasis in the post-acute phase might adversely affect the neurological and functional recovery. Inflammatory and antioxidant activity markers might offer a feasible way to highlight some of the processes opposing recovery after a severe TBI.

Low-Molecular-Weight Fucoidan Attenuates Mitochondrial Dysfunction and Improves Neurological Outcome After Traumatic Brain Injury in Aged Mice: Involvement of Sirt3

Traumatic brain injury (TBI) is a leading cause of death and long-term disability. Fucoidan, a sulfated polysaccharide extracted from brown algae, possesses potent anti-oxidative and anti-inflammatory effects. Considering TBI happens frequently in adults, especially in aged individuals, we herein sought to define the protective effects of low-molecular-weight fucoidan (LMWF) in the aged mice. 16- to 18-month-old mice administered with LMWF (1-50 mg/kg) or vehicle were subjected to TBI using a controlled cortical impact (CCI) model. LMWF at the doses of 10 and 50 mg/kg significantly reduced both cortical and hippocampal lesion volume. This protection was associated with reduced neuronal apoptosis, as evidenced by TUNEL staining. Importantly, LMWF was effective even when administered up to 4 h after TBI. Treatment with LMWF improved long-term neurobehavioral outcomes, including sensorimotor function, and hippocampus-associated spatial learning and memory. In addition, LMWF significantly suppressed protein carbonyl, lipid peroxidation, reactive oxygen species (ROS) generation, as well as mitochondrial dysfunction, which was evidenced by mitochondrial cytochrome c release and collapse of mitochondrial membrane potential (MMP). To evaluate the underlying molecular mechanisms, the expression of sirtuin 3 (Sirt3) was detected by RT-PCR and Western blot. The results showed that TBI significantly increased the expression of Sirt3, which was further elevated by LMWF treatment. Knockdown of Sirt3 using intracerebroventricular injection of small interfering RNA (siRNA) partially prevented the therapeutic effects of LMWF. Collectively, these findings demonstrated that LMWF exerts neuroprotection against TBI in the aged brain, which may be associated with the attenuation of mitochondrial dysfunction through Sirt3 activation.

Comparison of Anti-Oxidant and Anti-Inflammatory Effects between Fresh and Aged Black Garlic Extracts

Numerous studies have demonstrated that aged black garlic (ABG) has strong anti-oxidant activity. Little is known however regarding the anti-inflammatory activity of ABG. This study was performed to identify and compare the anti-oxidant and anti-inflammatory effects of ABG extract (ABGE) with those of fresh raw garlic (FRG) extract (FRGE). In addition, we investigated which components are responsible for the observed effects. Hydrogen peroxide (H2O2) and lipopolysaccharide (LPS) were used as a pro-oxidant and pro-inflammatory stressor, respectively. ABGE showed high ABTS and DPPH radical scavenging activities and low ROS generation in RAW264.7 cells compared with FRGE. However, inhibition of cyclooxygenase-2 and 5-lipooxygenase activities by FRGE was stronger than that by ABGE. FRGE reduced PGE₂, NO, IL-6, IL-1β, LTD₄, and LTE₄ production in LPS-activated RAW264.7 cells more than did ABGE. The combination of FRGE and sugar (galactose, glucose, fructose, or sucrose), which is more abundant in ABGE than in FRGE, decreased the anti-inflammatory activity compared with FRGE. FRGE-induced inhibition of NF-κB activation and pro-inflammatory gene expression was blocked by combination with sugars. The lower anti-inflammatory activity in ABGE than FRGE could result from the presence of sugars. Our results suggest that ABGE might be helpful for the treatment of diseases mediated predominantly by ROS.

Neuroprotective effect of allicin in a rat model of acute spinal cord injury

AIMS

This study aims to investigate the effect of allicin on motor functions and histopathologic changes after spinal cord injury and the mechanism underlying its neuroprotective effects.

MAIN METHODS

The motor function of rats was evaluated with the Basso, Beattie, and Bresna test. Histopathologic changes were evaluated by hematoxylin and eosin and Nissl staining. Spinal cord oxidative stress markers were determined by measuring glutathione and malondialdehyde content and superoxide dismutase activity using commercial kits. Inflammatory factors were determined by measuring tumor necrosis factor-α, interleukin-1β and interleukin-6 using ELISA assay. Apoptosis was examined using TUNEL staining. The effect of allicin on Nrf2 protein levels and localization was assessed using immunofluorescence staining and Western blotting analysis.

KEY FINDINGS

Results demonstrated that allicin accelerated the motor functional recovery and protected neuron damage against spinal cord injury (SCI). SCI-induced oxidative stress, inflammatory response and cell apoptosis in the spinal cord were also prevented by allicin. In addition, we observed that SCI increased Nrf2 nuclear expression, and allicin treatment further increased Nrf2 nuclear translocation in neurons and astrocytes. siRNA-mediated Nrf2 gene knockdown completely blocked the effect of allicin on spinal cord tissue.

SIGNIFICANCE

Our finding suggests that allicin promotes the recovery of motor function after SCI in rats, and this effect may be related to its anti-oxidant, anti-inflammatory and anti-apoptotic effects. Allicin mediated Nrf2 nuclear translocation may be involved in the protective effect as well.

Allium sativum L. Improves Visual Memory and Attention in Healthy Human Volunteers

Studies have shown that Allium sativum L. (AS) protects amyloid-beta peptide-induced apoptosis, prevents oxidative insults to neurons and synapses, and thus prevent Alzheimer's disease progression in experimental animals. However, there is no experimental evidence in human regarding its putative role in memory and cognition. We have studied the effect of AS consumption by healthy human volunteers on visual memory, verbal memory, attention, and executive function in comparison to control subjects taking placebo. The study was conducted over five weeks and twenty volunteers of both genders were recruited and divided randomly into two groups: A (AS) and B (placebo). Both groups participated in the 6 computerized neuropsychological tests of the Cambridge Neuropsychological Test Automated Battery (CANTAB) twice: at the beginning and after five weeks of the study. We found statistically significant difference (p < 0.05) in several parameters of visual memory and attention due to AS ingestion. We also found statistically nonsignificant (p > 0.05) beneficial effects on verbal memory and executive function within a short period of time among the volunteers. Study for a longer period of time with patients suffering from neurodegenerative diseases might yield more relevant results regarding the potential therapeutic role of AS.