Induction of detoxifying enzymes by garlic organosulfur compounds through transcription factor Nrf2: effect of chemical structure and stress signals

Emerging Vistas for the Nutraceutical Withania somnifera in Inflammaging

Inflammaging, a coexistence of inflammation and aging, is a persistent, systemic, low-grade inflammation seen in the geriatric population. Various natural compounds have been greatly explored for their potential role in preventing and treating inflammaging. Withania somnifera has been used for thousands of years in traditional medicine as a nutraceutical for its numerous health benefits including regenerative and adaptogenic effects. Recent preclinical and clinical studies on the role of Withania somnifera and its active compounds in treating aging, inflammation, and oxidative stress have shown promise for its use in healthy aging. We discuss the chemistry of Withania somnifera, the etiology of inflammaging and the protective role(s) of Withania somnifera in inflammaging in key organ systems including brain, lung, kidney, and liver as well as the mechanistic underpinning of these effects. Furthermore, we elucidate the beneficial effects of Withania somnifera in oxidative stress/DNA damage, immunomodulation, COVID-19, and the microbiome. We also delineate a putative protein-protein interaction network of key biomarkers modulated by Withania somnifera in inflammaging. In addition, we review the safety/potential toxicity of Withania somnifera as well as global clinical trials on Withania somnifera. Taken together, this is a synthetic review on the beneficial effects of Withania somnifera in inflammaging and highlights the potential of Withania somnifera in improving the health-related quality of life (HRQoL) in the aging population worldwide.

Hydrogen sulfide supplementation as a potential treatment for primary mitochondrial diseases

Primary mitochondrial diseases (PMD) are amongst the most common inborn errors of metabolism causing fatal outcomes within the first decade of life. With marked heterogeneity in both inheritance patterns and physiological manifestations, these conditions present distinct challenges for targeted drug therapy, where effective therapeutic countermeasures remain elusive within the clinic. Hydrogen sulfide (H2S)-based therapeutics may offer a new option for patient treatment, having been proposed as a conserved mitochondrial substrate and post-translational regulator across species, displaying therapeutic effects in age-related mitochondrial dysfunction and neurodegenerative models of mitochondrial disease. H2S can stimulate mitochondrial respiration at sites downstream of common PMD-defective subunits, augmenting energy production, mitochondrial function and reducing cell death. Here, we highlight the primary signalling mechanisms of H2S in mitochondria relevant for PMD and outline key cytoprotective proteins/pathways amenable to post-translational restoration via H2S-mediated persulfidation. The mechanisms proposed here, combined with the advent of potent mitochondria-targeted sulfide delivery molecules, could provide a framework for H2S as a countermeasure for PMD disease progression.

Antioxidant and Anti-Inflammatory Effects of Garlic in Ischemic Stroke: Proposal of a New Mechanism of Protection through Regulation of Neuroplasticity

Stroke represents one of the main causes of death and disability in the world; despite this, pharmacological therapies against stroke remain insufficient. Ischemic stroke is the leading etiology of stroke. Different molecular mechanisms, such as excitotoxicity, oxidative stress, and inflammation, participate in cell death and tissue damage. At a preclinical level, different garlic compounds have been evaluated against these mechanisms. Additionally, there is evidence supporting the participation of garlic compounds in other mechanisms that contribute to brain tissue recovery, such as neuroplasticity. After ischemia, neuroplasticity is activated to recover cognitive and motor function. Some garlic-derived compounds and preparations have shown the ability to promote neuroplasticity under physiological conditions and, more importantly, in cerebral damage models. This work describes damage/repair mechanisms and the importance of garlic as a source of antioxidant and anti-inflammatory agents against damage. Moreover, we examine the less-explored neurotrophic properties of garlic, culminating in proposals and observations based on our review of the available information. The aim of the present study is to propose that garlic compounds and preparations could contribute to the treatment of ischemic stroke through their neurotrophic effects.

Importance of DJ-1 in autophagy regulation and disease

Autophagy is a highly conserved biological process that has evolved across evolution. It can be activated by various external stimuli including oxidative stress, amino acid starvation, infection, and hypoxia. Autophagy is the primary mechanism for preserving cellular homeostasis and is implicated in the regulation of metabolism, cell differentiation, tolerance to starvation conditions, and resistance to aging. As a multifunctional protein, DJ-1 is commonly expressed in vivo and is associated with a variety of biological processes. Its most widely studied role is its function as an oxidative stress sensor that inhibits the production of excessive reactive oxygen species (ROS) in the mitochondria and subsequently the cellular damage caused by oxidative stress. In recent years, many studies have identified DJ-1 as another important factor regulating autophagy; it regulates autophagy in various ways, most commonly by regulating the oxidative stress response. In particular, DJ-1-regulated autophagy is involved in cancer progression and plays a key role in alleviating neurodegenerative diseases(NDS) and defective reperfusion diseases. It could serve as a potential target for the regulation of autophagy and participate in disease treatment as a meaningful modality. Therefore, exploring DJ-1-regulated autophagy could provide new avenues for future disease treatment.

Long term exposure of cigarette smoke condensate (CSC) mediates transcriptomic changes in normal human lung epithelial Beas-2b cells and protection by garlic compounds

Chronic cigarette smoke condensate (CSC) exposure is one of the preventable risk factors in the CS-induced lung cancer. However, understanding the mechanism of cellular transformation induced by CS in the lung remains limited. We investigated the effect of long term exposure of CSC in human normal lung epithelial Beas-2b cells, and chemopreventive mechanism of organosulphur garlic compounds, diallyl sulphide (DAS) and diallyl disulphide (DADS) using Next Generation Sequencing (NGS) transcriptomic analysis. CSC regulated 1077 genes and of these 36 genes are modulated by DAS while 101 genes by DADS. DAS modulated genes like IL1RL1 (interleukin-1 receptor like-1), HSPA-6 (heat shock protein family A, member 6) while DADS demonstrating ADTRP (Androgen-Dependent TFPI Regulating Protein), ANGPT4 (Angiopoietin 4), GFI1 (Growth Factor-Independent 1 Transcriptional Repressor), TBX2 (T-Box Transcription Factor 2), with some common genes like NEURL-1 (Neuralized E3-Ubiquitin Protein Ligase 1), suggesting differential effects between these two garlic compounds. They regulate genes by influencing pathways including HIF-1alpha, STAT-3 and matrix metalloproteases, contributing to the chemoprotective ability of organosulfur garlic compounds against CSC-induced cellular transformation. Taken together, we demonstrated CSC induced global gene expression changes pertaining to cellular transformation which potentially can be delayed with dietary chemopreventive phytochemicals like DS and DADS influencing alterations at the transcriptomic level.

A New Frontier in Studying Dietary Phytochemicals in Cancer and in Health: Metabolic and Epigenetic Reprogramming

Metabolic rewiring and epigenetic reprogramming are closely inter-related, and mutually regulate each other to control cell growth in cancer initiation, promotion, progression, and metastasis. Epigenetics plays a crucial role in regulating normal cellular functions as well as pathological conditions in many diseases, including cancer. Conversely, certain mitochondrial metabolites are considered as essential cofactors and regulators of epigenetic mechanisms. Furthermore, dysregulation of metabolism promotes tumor cell growth and reprograms the cells to produce metabolites and bioenergy needed to support cancer cell proliferation. Hence, metabolic reprogramming which alters the metabolites/epigenetic cofactors, would drive the epigenetic landscape, including DNA methylation and histone modification, that could lead to cancer initiation, promotion, and progression. Recognizing the diverse array of benefits of phytochemicals, they are gaining increasing interest in cancer interception and treatment. One of the significant mechanisms of cancer interception and treatment by phytochemicals is reprogramming of the key metabolic pathways and remodeling of cancer epigenetics. This review focuses on the metabolic remodeling and epigenetics reprogramming in cancer and investigates the potential mechanisms by which phytochemicals can mitigate cancer.

Nrf2 signaling pathway in trace metal carcinogenesis: A cross-talk between oxidative stress and angiogenesis

A large number of people worldwide are affected by chronic metal exposure, which is known to be associated with different type of malignancies. The mechanisms of metal carcinogenicity are complex in nature, and excessive reactive oxygen species (ROS) generation induced by chronic metal exposure, among the other factors, has been proposed as one of the major mechanisms involved in that process. In tumor cells, ROS buildup may lead to cell death through intrinsic and extrinsic signaling pathways. Furthermore, ROS-mediated redox signaling has a crucial role in angiogenesis, which is recognized as an essential step in tumor progression. There are several redox-modulating pathways and among them, the nuclear factor erythroid2-related factor2 (Nrf2), as a sensor of oxidative or electrophilic stress, has introduced as a master regulator of cellular response against environmental stresses. Activation of Nrf2 signaling induces expression of wide variety of antioxidant and detoxification enzymes genes. Thus, this transcription factor has recently received much attention as a target for cancer chemoprevention. But meanwhile, constitutive Nrf2 activation in cancerous cells may promote cancer progression and resistance to chemotherapy. The current review describes the major underlying mechanisms involved in carcinogenesis of trace metals: copper, silver, and cadmium, with a special focus on the Nrf2 signaling pathway as a crossroad between oxidative stress and angiogenesis.

Effects of bile acids on aflatoxin B1 bioaccumulation, detoxification system, and growth performance of Pacific white shrimp

The potential of bile acids (BAs) to reduce aflatoxin B₁ (AFB₁) residues and toxicity in Litopenaeus vannamei was evaluated. Both juveniles and subadults were treated with 0, 0.05, 0.15 and 0.25 g/kg BAs for 60 days followed by 10-d AFB₁ exposure (2000 μg/kg), and fifteen shrimp (five shrimp were pooled into one sample, n = 3) from each treatment were collected at five time points (30, 60, 63, 66 and 70 d). All parameters were determined using accepted and standard methods with acceptable accuracy (recovery) of 90-110%. Results demonstrated that BAs reduced the AFB₁ residues in shrimp (limit of detection: 0.01 μg/L, relative standard deviation < 10% and recovery: 92.1-96.8%). BAs increased the detoxification of AFB₁ and decreased the levels of oxidative stress products by increasing Phase II and antioxidant systems, avoiding AFB₁-induced deterioration of shrimp meat and health risks to human. The confidence level was 95%.

Redox signaling, mitochondrial metabolism, epigenetics and redox active phytochemicals

Biological redox signaling plays an important role in many diseases. Redox signaling involves reductive and oxidative mechanisms. Oxidative stress occurs when reductive mechanism underwhelms oxidative challenges. Cellular oxidative stress occurs when reactive oxygen/nitrogen species (RO/NS) exceed the cellular reductive/antioxidant capacity. Endogenously produced RO/NS from mitochondrial metabolic citric-acid-cycle coupled with electron-transport-chain or exogenous stimuli trigger cellular signaling events leading to homeostatic response or pathological damage. Recent evidence suggests that RO/NS also modulate epigenetic machinery driving gene expression. RO/NS affect DNA methylation/demethylation, histone acetylation/deacetylation or histone methylation/demethylation. Many health beneficial phytochemicals possess redox capability that counteract RO/NS either by directly scavenging the radicals or via inductive mechanism of cellular defense antioxidant/reductive enzymes. Amazingly, these phytochemicals also possess epigenetic modifying ability. This review summarizes the latest advances on the interactions between redox signaling, mitochondrial metabolism, epigenetics and redox active phytochemicals and the future challenges of integrating these events in human health.

Curculigoside mitigates hepatic ischemia/reperfusion-induced oxidative stress, inflammation, and apoptosis via activation of the Nrf-2/HO-1 pathway

Curculigoside has been shown to decrease oxidative stress and inflammatory reactions in many disorders, but its effects during hepatic ischemia-reperfusion injury (IRI) remain unknown. This research aims to determine the protective role and the potential mechanism of action of curculigoside in hepatic IRI. Here, a well-established rat model of partial warm IRI was constructed; serum ALT/AST and H&E staining were employed to assay the extent of liver injury; the superoxide dismutase, malondialdehyde, IL-6, and TNF-α contents were determined using the corresponding kits; the apoptosis index was evaluated by TUNEL staining; and the expression of Nrf-2, HO-1, and apoptosis-associated proteins was detected by qRT-PCR and Western blotting. The results showed that curculigoside pretreatment effectively mitigated hepatic IRI, as demonstrated by decreases in the levels of serum aminotransferases, hepatocellular necrosis and apoptosis, oxidative stress markers, infiltration of inflammatory cells, and secretion of proinflammatory cytokines. Mechanistically, the expression of Nrf-2 and HO-1 was greatly suppressed by hepatic IRI and reactivated by curculigoside. Furthermore, cotreatment with ML-385, an inhibitor of Nrf-2, counteracted the protective effect of curculigoside against hepatic IRI. The results of our study show that curculigoside plays a protective role in hepatic IRI by inhibiting oxidative stress, inflammation, and apoptosis and that its effects may be associated with activation of the Nrf-2/HO-1 pathway.

A New Insight into an Alternative Therapeutic Approach to Restore Redox Homeostasis and Functional Mitochondria in Neurodegenerative Diseases

Neurodegenerative diseases are accompanied by oxidative stress and mitochondrial dysfunction, leading to a progressive loss of neuronal cells, formation of protein aggregates, and a decrease in cognitive or motor functions. Mitochondrial dysfunction occurs at the early stage of neurodegenerative diseases. Protein aggregates containing oxidatively damaged biomolecules and other misfolded proteins and neuroinflammation have been identified in animal models and patients with neurodegenerative diseases. A variety of neurodegenerative diseases commonly exhibits decreased activity of antioxidant enzymes, lower amounts of antioxidants, and altered cellular signalling. Although several molecules have been approved clinically, there is no known cure for neurodegenerative diseases, though some drugs are focused on improving mitochondrial function. Mitochondrial dysfunction is caused by oxidative damage and impaired cellular signalling, including that of peroxisome proliferator-activated receptor gamma coactivator 1α. Mitochondrial function can also be modulated by mitochondrial biogenesis and the mitochondrial fusion/fission cycle. Mitochondrial biogenesis is regulated mainly by sirtuin 1, NAD⁺, AMP-activated protein kinase, mammalian target of rapamycin, and peroxisome proliferator-activated receptor γ. Altered mitochondrial dynamics, such as increased fission proteins and decreased fusion products, are shown in neurodegenerative diseases. Due to the restrictions of a target-based approach, a phenotype-based approach has been performed to find novel proteins or pathways. Alternatively, plasma membrane redox enzymes improve mitochondrial function without the further production of reactive oxygen species. In addition, inducers of antioxidant response elements can be useful to induce a series of detoxifying enzymes. Thus, redox homeostasis and metabolic regulation can be important therapeutic targets for delaying the progression of neurodegenerative diseases.

Role of chemopreventive phytochemicals in NRF2-mediated redox homeostasis in humans

While functioning as a second messenger in the intracellular signaling, ROS can cause oxidative stress when produced in excess or not neutralized/eliminated properly. Excessive ROS production is implicated in multi-stage carcinogenesis. Our body is equipped with a defense system to cope with constant oxidative stress caused by the external insults, including redox-cycling chemicals, radiation, and microbial infection as well as endogenously generated ROS. The transcription factor, nuclear transcription factor erythroid 2-related factor 2 (NRF2) is a master switch in the cellular antioxidant signaling and plays a vital role in adaptive survival response to ROS-induced oxidative stress. Although NRF2 is transiently activated when cellular redox balance is challenged, this can be overwhelmed by massive oxidative stress. Therefore, it is necessary to maintain the NRF2-mediated antioxidant defense capacity at an optimal level. This review summarizes the natural NRF2 inducers/activators, especially those present in the plant-based diet, in relation to their cancer chemopreventive potential in humans. The molecular mechanisms underlying their stabilization or activation of NRF2 are also discussed.

Diet and Hydrogen Sulfide Production in Mammals

Significance: In recent times, it has emerged that some dietary sulfur compounds can act on mammalian cell signaling systems via their propensity to release hydrogen sulfide (H₂S). H₂S plays important biochemical and physiological roles in the heart, gastrointestinal tract, brain, kidney, and immune systems of mammals. Reduced levels of H₂S in cells and tissues correlate with a spectrum of pathophysiological conditions, including heart disease, diabetes, obesity, and altered immune function. Recent Advances: In the last decade, researchers have now begun to explore the mechanisms by which dietary-derived sulfur compounds, in addition to cysteine, can act as sources of H₂S. This research has led to the identified several compounds, organic sulfides, isothiocyanates, and inorganic sulfur species including sulfate that can act as potential sources of H₂S in mammalian cells and tissues. Critical Issues: We have summarised progress made in the identification of dietary factors that can impact on endogenous H₂S levels in mammals. We also describe current research focused on how some sulfur molecules present in dietary plants, and associated chemical analogues, act as sources of H₂S, and discuss the biological properties of these molecules as studied in a range of in vitro and in vivo systems. Future Directions: The identification of sulfur compounds in edible plants that can act as novel H₂S releasing molecules is intriguing. Research in this area could inform future studies exploring the impact of diet on H₂S levels in mammalian systems. Despite recent progress, additional work is needed to determine the mechanisms by which H₂S is released from these molecules following ingestions of dietary plants in humans, whether the amounts of H₂S produced is of physiological significance following the metabolism of these compounds in vivo, and if diet could be used to manipulated H₂S levels in humans. Importantly, this will lead to a better understanding of the biological significance of H₂S generated from dietary sources, and this information could be used in the development of plant breeding initiatives to increase the levels of H₂S releasing sulfur compounds in crops, or inform dietary intervention strategies that could be used to alter the levels of H₂S in humans.

Cytoprotective Potential of Aged Garlic Extract (AGE) and Its Active Constituent, S-allyl-l-cysteine, in Presence of Carvedilol during Isoproterenol-Induced Myocardial Disturbance and Metabolic Derangements in Rats

This study was conducted to determine the potential interaction of aged garlic extract (AGE) with carvedilol (CAR), as well as to investigate the role of S-allyl-l-cysteine (SAC), an active constituent of AGE, in rats with isoproterenol (ISO)-induced myocardial dysfunction. At the end of three weeks of treatment with AGE (2 and 5 mL/kg) or SAC (13.1 and 32.76 mg/kg), either alone or along with CAR (10 mg/kg) in the respective groups of animals, ISO was administered subcutaneously to induce myocardial damage. Myocardial infarction (MI) diagnostic predictor enzymes, lactate dehydrogenase (LDH) and creatinine kinase (CK-MB), were measured in both serum and heart tissue homogenates (HTH). Superoxide dismutase (SOD), catalase, and thiobarbituric acid reactive species (TBARS) were estimated in HTH. When compared with other groups, the combined therapy of high doses of AGE and SAC given alone or together with CAR caused a significant decrease in serum LDH and CK-MB activities. Further, significant rise in the LDH and CK-MB activities in HTH was noticed in the combined groups of AGE and SAC with CAR. It was also observed that both doses of AGE and SAC significantly increased endogenous antioxidants in HTH. Furthermore, histopathological observations corroborated the biochemical findings. The cytoprotective potential of SAC and AGE were dose-dependent, and SAC was more potent than AGE. The protection offered by aged garlic may be attributed to SAC. Overall, the results indicated that a high dose of AGE and its constituent SAC, when combined with carvedilol, has a synergistic effect in preventing morphological and physiological changes in the myocardium during ISO-induced myocardial damage.

Hepatoprotective Effect of Mixture of Dipropyl Polysulfides in Concanavalin A-Induced Hepatitis

The main biologically active components of plants belonging to the genus Allium, responsible for their biological activities, including anti-inflammatory, antioxidant and immunomodulatory, are organosulfur compounds. The aim of this study was to synthetize the mixture of dipropyl polysulfides (DPPS) and to test their biological activity in acute hepatitis. C57BL/6 mice were administered orally with DPPS 6 h before intravenous injection of Concanavalin A (ConA). Liver inflammation, necrosis and hepatocytes apoptosis were determined by histological analyses. Cytokines in liver tissue were determined by ELISA, expression of adhesive molecules and enzymes by RT PCR, while liver mononuclear cells were analyzed by flow cytometry. DPPS pretreatment significantly attenuated liver inflammation and injury, as evidenced by biochemical and histopathological observations. In DPPS-pretreated mice, messenger RNA levels of adhesion molecules and NADPH oxidase complex were significantly reduced, while the expression of SOD enzymes was enhanced. DPPS pretreatment decreased protein level of inflammatory cytokines and increased percentage of T regulatory cells in the livers of ConA mice. DPPS showed hepatoprotective effects in ConA-induced hepatitis, characterized by attenuation of inflammation and affection of Th17/Treg balance in favor of T regulatory cells and implicating potential therapeutic usage of DPPS mixture in inflammatory liver diseases.

Lipophilic compounds in garlic decrease the toxicity of methylmercury by forming sulfur adducts

Garlic (Allium sativum L.) contains numerous sulfur compounds. We have previously found that reactive sulfur species such as glutathione persulfide, glutathione polysulfide, protein-bound persulfides, and hydrogen sulfide can bind to methylmercury to give bismethylmercury sulfide, which is less toxic than methylmercury. It was not clear, however, whether such reactive sulfur species are present in garlic. The aim of the study presented here was to determine whether garlic contains reactive sulfur species that can bind to methylmercury. We extracted garlic with organic solvents and then performed silica gel column chromatography to separate constituents that could cause bismethylmercury sulfide to form. We found numerous garlic constituents could bind to methylmercury to form bismethylmercury sulfide. A hexane extract of garlic decreased methylmercury cytotoxicity in vitro and body weight loss in mice. The results suggest that ingesting garlic may decrease methylmercury toxicity by causing the formation of sulfur adducts that inhibit adverse reactions.

Natural products improve healthspan in aged mice and rats: A systematic review and meta-analysis

Over the last decades a decrease in mortality has paved the way for late onset pathologies such as cardiovascular, metabolic or neurodegenerative diseases. This evidence has led many researchers to shift their focus from researching ways to extend lifespan to finding ways to increase the number of years spent in good health; "healthspan" is indeed the emerging concept of such quest for ageing without chronic or disabling diseases and dysfunctions. Regular consumption of natural products might improve healthspan, although the mechanisms of action are still poorly understood. Since preclinical studies aimed to assess the efficacy and safety of these compounds are growing, we performed a systematic review and meta-analysis on the effects of natural products on healthspan in mouse and rat models of physiological ageing. Results indicate that natural compounds show robust effects improving stress resistance and cognitive abilities. These promising data call for further studies investigating the underlying mechanisms in more depth.

Antioxidant activity of organic sulfides from fresh Allium macrostemon Bunge and their protective effects against oxidative stress in Caenorhabditis elegans

Long-stamen chive (Allium macrostemon Bunge; AMB), which is prevalent in the Wuling Mountain area of China, is a characteristic food of the nation. In the study, we evaluated the as-yet-unknown nutritional value and antioxidant activity of fresh AMB. The free amino acid content, volatile components, and free radical-scavenging capacity of isolated organic sulfides were analyzed to evaluate the qualitative and physiological properties of fresh AMB. The plant was found to be rich in free essential amino acids and contain multiple flavor-imparting amino acids. The organic sulfides showed an apparent free radical-scavenging activity in vitro. Furthermore, these sulfides alleviated oxidative stress in Caenorhabditis elegans. Notably, the organic sulfides isolated from AMB enhanced the activities of superoxide dismutase, catalase, and glutathione peroxidase; improved motility; and extended the lifespan in oxidative stress-affected nematodes. In conclusion, our study indicates that AMB is a nutritious vegetable with potential to be developed as a functional food. PRACTICAL APPLICATIONS: Long-stamen chive is a wild edible vegetable belonging to the genus Allium (A. macrostemon Bunge; AMB). However, its quality and physiological properties have not been comprehensively investigated. Herein, we analyzed the free amino acid content, composition of volatile compounds, and potential antioxidative properties of AMB. Our results indicated that AMB is rich in essential amino acids, making it a highly nutritious food. Further analysis indicated that AMB contains a high proportion of organic sulfides, which have been previously been shown to have antioxidative properties. Together, our findings indicate that AMB contains important bioactive components and can be developed as a functional food or health supplement. Furthermore, our findings will enhance public awareness regarding this wild resource and provide new directions for the research and development of natural products derived from it.

Naturally Derived Heme-Oxygenase 1 Inducers and Their Therapeutic Application to Immune-Mediated Diseases

Heme oxygenase (HO) is the primary antioxidant enzyme involved in heme group degradation. A variety of stimuli triggers the expression of the inducible HO-1 isoform, which is modulated by its substrate and cellular stressors. A major anti-inflammatory role has been assigned to the HO-1 activity. Therefore, in recent years HO-1 induction has been employed as an approach to treating several disorders displaying some immune alterations components, such as exacerbated inflammation or self-reactivity. Many natural compounds have shown to be effective inductors of HO-1 without cytotoxic effects; among them, most are chemicals present in plants used as food, flavoring, and medicine. Here we discuss some naturally derived compounds involved in HO-1 induction, their impact in the immune response modulation, and the beneficial effect in diverse autoimmune disorders. We conclude that the use of some compounds from natural sources able to induce HO-1 is an attractive lifestyle toward promoting human health. This review opens a new outlook on the investigation of naturally derived HO-1 inducers, mainly concerning autoimmunity.

Activation of Nrf2/AREs-mediated antioxidant signalling, and suppression of profibrotic TGF-β1/Smad3 pathway: a promising therapeutic strategy for hepatic fibrosis - A review

Hepatic fibrosis (HF) is a wound-healing response that occurs during chronic liver injury and features by an excessive accumulation of extracellular matrix (ECM) components. Activation of hepatic stellate cell (HSC), the leading effector in HF, is responsible for overproduction of ECM. It has been documented that transforming growth factor-β1 (TGF-β1) stimulates superfluous accumulation of ECM and triggers HSCs activation mainly via canonical Smad-dependent pathway. Also, the pro-fibrogenic TGF-β1 is correlated with generation of reactive oxygen species (ROS) and inhibition of antioxidant mechanisms. Moreover, involvement of oxidative stress (OS) can be clearly elucidated as a fundamental event in liver fibrogenesis. Nuclear factor erythroid 2-related factor 2-antioxidant response elements (Nrf2-AREs) pathway, a group of OS-mediated transcription factors with diverse downstream targets, is associated with the induction of diverse detoxifying enzymes and the most pivotal endogenous antioxidative system. More specifically, Nrf2-AREs pathway has recently assigned as a new therapeutic target for cure of HF. The overall goal of this review will focus on recent findings about activation of Nrf2-AREs-mediated antioxidant and suppression of profibrotic TGF-β1/Smad3 pathway in the liver, providing an overview of recent advances in transcriptional repressors that dislocated during HF formation, and highlighting possible novel therapeutic targets for liver fibrosis.

Garlic and its Active Compounds: A Potential Candidate in The Prevention of Cancer by Modulating Various Cell Signalling Pathways

BACKGROUND

Cancer is a multi-factorial disease including alterations in the cell signalling pathways. Currently, several drugs are in use to treat cancer but such drugs show negative side effects on normal cells and cause severe toxicity.

METHODS

The current research is mainly focused on medicinal plants with potential therapeutic efficacy in the treatment of cancer without any adverse effects on normal cells. In this regard, garlic and its active compounds including diallyl sulfide, diallyl trisulfide, ajoene, and allicin have been established to suppress the growth of cancer and killing of cancer cells.

RESULT

The review focuses on garlic and its active compounds chemopreventive effect through modulating various cell signalling pathways. Additionally, garlic and its active compound were established to induce cell cycle arrest at the G0/G1 phase and G2/M phases in cancer cells, increase the expression of tumor suppressor genes, inhibit the angiogenesis process, induction of apoptosis and modulation of various other genetic pathways.

CONCLUSION

This review sketches the diverse chemopreventive activities of garlic and their active ingredients in the management of cancer mainly focusing on cell signalling pathways.

Impact of Antioxidant Natural Compounds on the Thyroid Gland and Implication of the Keap1/Nrf2 Signaling Pathway

BACKGROUND

Natural compounds with potential antioxidant properties have been used in the form of food supplements or extracts with the intent to prevent or treat various diseases. Many of these compounds can activate the cytoprotective Nrf2 pathway. Besides, some of them are known to impact the thyroid gland, often with potential side-effects, but in other instances, with potential utility in the treatment of thyroid disorders.

OBJECTIVE

In view of recent data regarding the multiple roles of Nrf2 in the thyroid, this review summarizes the current bibliography on natural compounds that can have an effect on thyroid gland physiology and pathophysiology, and it discusses the potential implication of the Nrf2 system in the respective mechanisms.

METHODS & RESULTS

Literature searches for articles from 1950 to 2018 were performed in PubMed and Google Scholar using relevant keywords about phytochemicals, Nrf2 and thyroid. Natural substances were categorized into phenolic compounds, sulfur-containing compounds, quinones, terpenoids, or under the general category of plant extracts. For individual compounds in each category, respective data were summarized, as derived from in vitro (cell lines), preclinical (animal models) and clinical studies. The main emerging themes were as follows: phenolic compounds often showed potential to affect the production of thyroid hormones; sulfur-containing compounds impacted the pathogenesis of goiter and the proliferation of thyroid cancer cells; while quinones and terpenoids modified Nrf2 signaling in thyroid cell lines.

CONCLUSION

Natural compounds that modify the activity of the Nrf2 pathway should be evaluated carefully, not only for their potential to be used as therapeutic agents for thyroid disorders, but also for their thyroidal safety when used for the prevention and treatment of non-thyroidal diseases.

Brassicaphenanthrene A from Brassica rapa protects HT22 neuronal cells through the regulation of Nrf2‑mediated heme oxygenase‑1 expression

Brain cell damage that results from oxidative toxicity contributes to neuronal degeneration. The transcription factor nuclear factor‑E2‑related factor 2 (Nrf2) regulates the expression of heme oxygenase (HO)‑1 and glutathione (GSH), and serves a key role in the pathogenesis of neurological diseases. Brassica rapa is a turnip that is unique to Ganghwa County, and is used mainly for making kimchi, a traditional Korean food. In the current study, brassicaphenanthrene A (BrPA) from B. rapa was demonstrated to exhibit protective effects against neurotoxicity induced by glutamate via Nrf2‑mediated HO‑1 expression. Similarly, BrPA increased the expression of cellular glutathione and glutamine‑cysteine ligase genes. Furthermore, BrPA caused the nuclear translocation of Nrf2 and increased antioxidant response element (ARE) promoter activity. Nrf2 also mediated HO‑1 induction by BrPA through the PI3K/Akt and JNK regulatory pathways. The results of the present study indicated the neuroprotective effect of BrPA, a natural food component from B. rapa.

An Appraisal of Developments in Allium Sulfur Chemistry: Expanding the Pharmacopeia of Garlic

Alliums and allied plant species are rich sources of sulfur compounds that have effects on vascular homeostasis and the control of metabolic systems linked to nutrient metabolism in mammals. In view of the multiple biological effects ascribed to these sulfur molecules, researchers are now using these compounds as inspiration for the synthesis and development of novel sulfur-based therapeutics. This research has led to the chemical synthesis and biological assessment of a diverse array of sulfur compounds representative of derivatives of S-alkenyl-l-cysteine sulfoxides, thiosulfinates, ajoene molecules, sulfides, and S-allylcysteine. Many of these synthetic derivatives have potent antimicrobial and anticancer properties when tested in preclinical models of disease. Therefore, the current review provides an overview of advances in the development and biological assessment of synthetic analogs of allium-derived sulfur compounds.

S-1-propenylmercaptocysteine protects murine hepatocytes against oxidative stress via persulfidation of Keap1 and activation of Nrf2

The onion-derived metabolite, S-1-propenylmercaptocysteine (CySSPe), protects against oxidative stress and exhibits anti-inflammatory effects by modulating cellular redox homeostasis. We sought to establish whether CySSPe activates nuclear factor erythroid 2-related factor 2 (Nrf2) and whether activation of Nrf2 by CySSPe involves modification of the Kelch-like ECH-associated protein-1 (Keap1) to manifest these effects. We found that CySSPe stabilized Nrf2 protein and facilitated nuclear translocation to induce expression of antioxidant enzymes, including NQO1, HO-1, and GCL. Moreover, CySSPe attenuated tert-butyl hydroperoxide-induced cytotoxicity and dose-dependently inhibited reactive oxygen species production. Silencing experiments using Nrf2-siRNA confirmed that CySSPe conferred protection against oxidative stress by activating Nrf2. CySSPe enhanced cellular pool of reduced glutathione (GSH) and improved GSH:GSSG ratio. Pretreatment of cells with l-buthionine-S,R-sulfoximine (BSO) confirmed that CySSPe increases de novo synthesis of GSH by upregulating expression of the GSH-synthesizing enzyme GCL. Treatment of cells with CySSPe elevated hydrogen sulfide (H₂S) production. Inhibition of H₂S-synthesizing enzymes, cystathionine-gamma-lyase (CSE) and cystathionine-beta-synthase (CBS), by pretreating cells with propargylglycine (PAG) and oxyaminoacetic acid (AOAA) revealed that H₂S production was partially dependent on a CSE/CBS-catalyzed β-elimination reaction with CySSPe that likely produced 1-propenyl persulfide (RSSH). Depleting cells of their GSH pool by exposure to BSO and diethylmaleate attenuated H₂S production, suggesting a GSH-dependent formation of H₂S, likely via the reduction of RSSH by GSH. Finally, treatment of cells with CySSPe persulfidated Keap1, which may be the mechanism involved for the stabilization of Nrf2 by CySSPe. Taken together, our results showed that attenuation of oxidative stress by CySSPe is associated with its ability to produce H₂S or RSSH, which persulfidates Keap1 and activates Nrf2 signaling. This study provides insights on the potential of CySSPe as an onion-derived dietary agent that modulates redox homeostasis and combats oxidative stress.

Diallyl Trisulfide Protects Rat Brain Tissue against the Damage Induced by Ischemia-Reperfusion through the Nrf2 Pathway

Stroke is a public health problem due to its high mortality and disability rates; despite these, the pharmacological treatments are limited. Oxidative stress plays an important role in cerebral damage in stroke and the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) confers protection against oxidative stress. Different compounds, such as diallyl trisulfide (DATS), have the ability to activate Nrf2. DATS protects against the damage induced in oxygen-glucose deprivation in neuronal cells; however, in in vivo models of cerebral ischemia, DATS has not been evaluated. Male Wistar rats were subjected to 1 h of ischemia and seven days of reperfusion and the protective effect of DATS was evaluated. DATS administration (IR + DATS) decreased the infarct area and brain damage in the striatum and cortex; improved neurological function; decreased malondialdehyde and metalloproteinase-9 levels; increased Nrf2 activation in the cortex and the expression of superoxide dismutase 1 (SOD1) in the nucleus, SOD2 and glutathione S-transferase (GST) in the striatum and cortex; and increased the activity of catalase (CAT) in the striatum and glutathione peroxidase (GPx) in the cortex. Our results demonstrate the protective effect of DATS in an in vivo model of cerebral ischemia that involves Nrf2 activation.

Plasma membrane redox enzymes: new therapeutic targets for neurodegenerative diseases

Mitochondrial dysfunction caused by oxidative stress appears at early stages of aging and age-related diseases. Plasma membrane redox enzymes act in a compensatory manner to decrease oxidative stress and supply reductive capacity to ensure cell survival. Plasma membrane redox enzymes transfer electrons from NAD(P)H to oxidized ubiquinone and α-tocopherol, resulting in inhibition of further oxidative damage. Plasma membrane redox enzymes and their partners are affected by aging, leading to progression of neurodegenerative disease pathogenesis. Up-regulating plasma membrane redox enzymes via calorie restriction and phytochemicals make cells more resistant to oxidative damage under stress conditions by maintaining redox homeostasis and improving mitochondrial function. Investigation into plasma membrane redox enzymes can provide mechanistic details underlying the relationships between plasma membrane redox enzymes and mitochondrial complexes and provide a good therapeutic target for prevention and delay of neurodegenerative disorders.

Role of Nrf2 and Its Activators in Respiratory Diseases

Transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a major regulator of antioxidant response element- (ARE-) driven cytoprotective protein expression. The activation of Nrf2 signaling plays an essential role in preventing cells and tissues from injury induced by oxidative stress. Under the unstressed conditions, natural inhibitor of Nrf2, Kelch-like ECH-associated protein 1 (Keap1), traps Nrf2 in the cytoplasm and promotes the degradation of Nrf2 by the 26S proteasome. Nevertheless, stresses including highly oxidative microenvironments, impair the ability of Keap1 to target Nrf2 for ubiquitination and degradation, and induce newly synthesized Nrf2 to translocate to the nucleus to bind with ARE. Due to constant exposure to external environments, including diverse pollutants and other oxidants, the redox balance maintained by Nrf2 is fairly important to the airways. To date, researchers have discovered that Nrf2 deletion results in high susceptibility and severity of insults in various models of respiratory diseases, including bronchopulmonary dysplasia (BPD), respiratory infections, acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), asthma, idiopathic pulmonary fibrosis (IPF), and lung cancer. Conversely, Nrf2 activation confers protective effects on these lung disorders. In the present review, we summarize Nrf2 involvement in the pathogenesis of the above respiratory diseases that have been identified by experimental models and human studies and describe the protective effects of Nrf2 inducers on these diseases.

Novel molecular mechanisms for the adaptogenic effects of herbal extracts on isolated brain cells using systems biology

INTRODUCTION

Adaptogens are natural compounds or plant extracts that increase adaptability and survival of organisms under stress. Adaptogens stimulate cellular and organismal defense systems by activating intracellular and extracellular signaling pathways and expression of stress-activated proteins and neuropeptides. The effects adaptogens on mediators of adaptive stress response and longevity signaling pathways have been reported, but their stress-protective mechanisms are still not fully understood.

AIM OF THE STUDY

The aim of this study was to identify key molecular mechanisms of adaptogenic plants traditionally used to treat stress and aging-related disorders, i.e., Rhodiola rosea, Eleutherococcus senticosus, Withania somnifera, Rhaponticum carthamoides, and Bryonia alba.

MATERIALS AND METHODS

To investigate the underlying molecular mechanisms of adaptogens, we conducted RNA sequencing to profile gene expression alterations in T98G neuroglia cells upon treatment of adaptogens and analyzed the relevance of deregulated genes to adaptive stress-response signaling pathways using in silico pathway analysis software.

RESULTS AND DISCUSSION

At least 88 of the 3516 genes regulated by adaptogens were closely associated with adaptive stress response and adaptive stress-response signaling pathways (ASRSPs), including neuronal signaling related to corticotropin-releasing hormone, cAMP-mediated, protein kinase A, and CREB; pathways related to signaling involving CXCR4, melatonin, nitric oxide synthase, GP6, Gαs, MAPK, neuroinflammation, neuropathic pain, opioids, renin-angiotensin, AMPK, calcium, and synapses; and pathways associated with dendritic cell maturation and G-coupled protein receptor-mediated nutrient sensing in enteroendocrine cells. All samples tested showed significant effects on the expression of genes encoding neurohormones CRH, GNRH, UCN, G-protein-coupled and other transmembrane receptors TLR9, PRLR, CHRNE, GP1BA, PLXNA4, a ligand-dependent nuclear receptor RORA, transmembrane channels, transcription regulators FOS, FOXO6, SCX, STAT5A, ZFPM2, ZNF396, ZNF467, protein kinases MAPK10, MAPK13, MERTK, FLT1, PRKCH, ROS1, TTN), phosphatases PTPRD, PTPRR, peptidases, metabolic enzymes, a chaperone (HSPA6), and other proteins, all of which modulate numerous life processes, playing key roles in several canonical pathways involved in defense response and regulation of homeostasis in organisms. It is for the first time we report that the molecular mechanism of actions of melatonin and plant adaptogens are alike, all adaptogens tested activated the melatonin signaling pathway by acting through two G-protein-coupled membrane receptors MT1 and MT2 and upregulation of the ligand-specific nuclear receptor RORA, which plays a role in intellectual disability, neurological disorders, retinopathy, hypertension, dyslipidemia, and cancer, which are common in aging. Furthermore, melatonin activated adaptive signaling pathways and upregulated expression of UCN, GNRH1, TLR9, GP1BA, PLXNA4, CHRM4, GPR19, VIPR2, RORA, STAT5A, ZFPM2, ZNF396, FLT1, MAPK10, MERTK, PRKCH, and TTN, which were commonly regulated by all adaptogens tested. We conclude that melatonin is an adaptation hormone playing an important role in regulation of homeostasis. Adaptogens presumably worked as eustressors ("stress-vaccines") to activate the cellular adaptive system by inducing the expression of ASRSPs, which then reciprocally protected cells from damage caused by distress. Functional investigation by interactive pathways analysis demonstrated that adaptogens activated ASRSPs associated with stress-induced and aging-related disorders such as chronic inflammation, cardiovascular health, neurodegenerative cognitive impairment, metabolic disorders, and cancer.

CONCLUSION

This study has elucidated the genome-wide effects of several adaptogenic herbal extracts in brain cells culture. These data highlight the consistent activation of ASRSPs by adaptogens in T98G neuroglia cells. The extracts affected many genes playing key roles in modulation of adaptive homeostasis, indicating their ability to modify gene expression to prevent stress-induced and aging-related disorders. Overall, this study provides a comprehensive look at the molecular mechanisms by which adaptogens exerts stress-protective effects.

Redox Modulation at Work: Natural Phytoprotective Polysulfanes From Alliums Based on Redox-Active Sulfur

Purpose of review

This article provides a brief overview of natural phytoprotective products of allium with a special focus on the therapeutic potential of diallyl polysulfanes from garlic, their molecular targets and their fate in the living organisms. A comprehensive overview of antimicrobial and anticancer properties of published literature is presented for the reader to understand the effective concentrations of polysulfanes and their sensitivity towards different human pathogenic microbes, fungi, and cancer cell lines.

Recent findings

The article finds polysulfanes potentials as new generation novel antibiotics and chemo preventive agent. The effective dose rates of polysulfanes for antimicrobial properties are in the range of 0.5-40 mg/L and for anticancer 20-100 μM. The molecular targets for these redox modulators are mainly cellular thiols as well as inhibition and/or activation of certain cellular proteins in cancer cell lines.

Summary

Antimicrobial and anticancer activities of polysulfanes published in the literature indicate that with further development, they could be promising candidates for cancer prevention due to their selectivity towards abnormal cells.

Targeting Nrf-2 is a promising intervention approach for the prevention of ethanol-induced liver disease

Alcoholic liver disease (ALD) remains to be a worldwide health problem. It is generally accepted that oxidative stress plays critical roles in the pathogenesis of ALD, and antioxidant therapy represents a logical strategy for the prevention and treatment of ALD. Nuclear factor erythroid-derived 2-like 2 (NFE2L2 or Nrf-2) is essential for the antioxidant responsive element (ARE)-mediated induction of endogenous antioxidant enzymes such as heme oxygenase 1 (HO-1) and glutamate-cysteine ligase [GCL, the rate-limiting enzyme in the synthesis of glutathione (GSH)]. Activation of Nrf-2 pathway by genetic manipulation or pharmacological agents has been demonstrated to provide protection against ALD, which suggests that targeting Nrf-2 may be a promising approach for the prevention and treatment of ALD. Herein, we review the relevant literature about the potential hepatoprotective roles of Nrf-2 activation against ALD.

Induction of Apoptosis in Human Papillary-Thyroid-Carcinoma BCPAP Cells by Diallyl Trisulfide through Activation of the MAPK Signaling Pathway

This study aimed to elucidate the potential effects of diallyl trisulfide (DATS) on human papillary-thyroid-carcinoma BCPAP cells and its underlying mechanisms. DATS is an organosulfur compound derived from garlic. In this study, we demonstrated that compared with the solvent control, DATS treatment at concentrations of 5, 10, and 20 μΜ decreased cell survival rates of BCPAP cells to 84.51 ± 2.67, 57.16 ± 1.18, and 41.22 ± 1.19% respectively. DATS also caused cell-cycle arrest at G0/G1 phase, and the proportion of cells arrested in G0/G1 phase rose from 68.8 ± 8.38 to 80.4 ± 8.38%, which eventually resulted in cell apoptosis through a mitochondrial apoptotic pathway in BCPAP cells. Further evidence showed that DATS activated ERK, JNK, and p38, members of the MAPK family. Moreover, ERK and JNK inhibitors partially reversed apoptosis in BCPAP cells induced by DATS treatment. Taken together, our results demonstrated that DATS exerted an apoptosis-inducing effect on papillary-thyroid-cancer cells via activation of the MAPK signaling pathway, which shed light on a prospective therapeutic target for thyroid-cancer treatment.

Garlic and Gaseous Mediators

Garlic (Allium sativum) and allied plant species are rich sources of sulfur compounds. Major roles for garlic and its sulfur constituents include the regulation of vascular homeostasis and the control of metabolic systems linked to nutrient metabolism. Recent studies have indicated that some of these sulfur compounds, such as diallyl trisulfide (DATS), alter the levels of gaseous signalling molecules including nitric oxide (NO), hydrogen sulfide (H₂S), and perhaps carbon monoxide (CO) in mammalian tissues. These gases are important in cellular processes associated with the cardiovascular system, inflammation, and neurological functions. Importantly, these studies build on the known biological effects of garlic and associated sulfur constituents. This review highlights our current understanding of the health benefits attributed to edible plants like garlic.

Protective and Restorative Effects of Nutrients and Phytochemicals

Intoroduction:

Dietary intake fundamentally provides reintegration of energy and essential nutrients to human organisms. However, its qualitative and quantitative composition strongly affects individual’s health, possibly being either a preventive or a risk factor. It was shown that nutritional status resulting from long-term exposition to specific diet formulations can outstandingly reduce incidences of most common and most important diseases of the developed world, such as cardiovascular and neoplastic diseases. Diet formulations result from different food combinations which bring specific nutrient molecules. Numerous molecules, mostly but not exclusively from vegetal foods, have been characterized among nutritional components as being particularly responsible for diet capabilities to exert risk reduction. These “bioactive nutrients” are able to produce effects which go beyond basic reintegration tasks, i.e. energetic and/or structural, but are specifically pharmacologically active within pathophysiological pathways related to many diseases, being able to selectively affect processes such as cell proliferation, apoptosis, inflammation, differentiation, angiogenesis, DNA repair and carcinogens activation.

Conclusion:

The present review was aimed to know the molecular mechanisms and pathways of activity of bioactive molecules; which will firstly allow search for optimal food composition and intake, and then use them as possible therapeutical targets and/or diagnostics. Also, the present review discussed the therapeutic effect of both nutrients and phytochemicals.

DADLE improves hepatic ischemia/reperfusion injury in mice via activation of the Nrf2/HO‑1 pathway

Hepatic ischemia/reperfusion (I/R) injury is a common pathophysiological process that occurs following liver surgery, which is associated with oxidative stress, and can cause acute liver injury and lead to liver failure. Recently, the development of drugs for the prevention of hepatic I/R injury has garnered interest in the field of liver protection research. Previous studies have demonstrated that [D‑Ala2, D‑Leu5]‑Enkephalin (DADLE) exerts protective effects against hepatic I/R injury. To further clarify the specific mechanism underlying the effects of DADLE on hepatic I/R injury, the present study aimed to observe the effects of various doses of DADLE on hepatic I/R injury in mice. The results indicated that DADLE, at a concentration of 5 mg/kg, significantly reduced the levels of alanine aminotransferase and aspartate aminotransferase in the serum, and the levels of malondialdehyde in the liver homogenate. Conversely, the levels of glutathione, catalase and superoxide dismutase in the liver homogenate were increased. In addition, DADLE was able to promote nuclear factor, erythroid 2 like 2 (Nrf2) nuclear translocation and upregulate the expression of heme oxygenase (HO)‑1, which is a factor downstream of Nrf2, thus improving hepatic I/R injury in mice. In conclusion, the present study demonstrated that DADLE was able to significantly improve hepatic I/R injury in mice, and the specific mechanism may be associated with the Nrf2/HO‑1 signaling pathway.

Applications of Lawesson's reagent in the synthesis of naturally occurring steroids and terpenoids

Steroids and terpenoids are among the most biologically significant classes of natural products possessing a variety of biological activities. The replacement of one or more oxygen atoms in a steroid or terpenoid molecule by a heteroatom affects the chemical properties of that particular steroid or terpenoid, and that replacement often results in alterations of its biological properties, which is sometimes valuable. One possible modification is the thionation that could have some influence on such activity. Among the various thionating reagents, Lawesson's reagent was found to be most suitable and showed versatile properties, including chemoselectivity and functional group tolerance. In this review, we present the role of Lawesson's reagent in the synthesis of thioanalogues of natural steroids and terpenoids.

Diallyl trisulfide, a garlic polysulfide protects against As-induced renal oxidative nephrotoxicity, apoptosis and inflammation in rats by activating the Nrf2/ARE signaling pathway

BACKGROUND

Arsenic (As) contamination is an extremely dangerous global environmental problem as it can enter into the food chain and become bio-accumulated, endangering human health. Chronic As intoxication leads to undesirable toxic effects in various organ systems of the body, especially the kidney. Diallyl trisulfide (DATS) is an organosulfur compound which has been widely known for its uses as antibacterial, antitumorogenic, antioxidant agent and has been also reported to have anti-apoptotic and anti-inflammatory properties.

PURPOSE

In the present work, we intend to investigate the protective role of DATS, a garlic organosulfur compound in preventing the As-induced oxidative stress mediated renal injury in rats. Study design The activity of DATS to antagonize As-induced renal oxidative toxicity was analyzed using rats as an in vivo model.

METHODS

We investigated the nephroprotective effect of DATS on As treated rats by performing various serological, biochemical, molecular and histological studies. The activation of Nrf2 was investigated using western blot.

RESULTS

The data showed that As exposure significantly increased the serum and urine nephritic, oxidative stress, apoptosis and inflammatory markers in the renal tissue of rats. As intoxication also decreased the antioxidant status of the renal tissue along with the disturbances in the membrane bound ATPases. As nephrotoxicity was further confirmed with the altered morphological and ultrastructural changes in the renal tissue. Conversely, the DATS pre-administration effectively recuperate the altered renal variables by As, which has been further supported by the histological and ultrastructural observations. This counteraction was achieved partially via the activation of Nrf2-ARE pathway through the activation of Akt.

CONCLUSION

These findings explicate the prospective use of DATS as a promising organosulfur compound against As-induced renal oxidative dysfunction in rats.

Dietary Bioactive Diallyl Trisulfide in Cancer Prevention and Treatment

Bioactive dietary agents have been shown to regulate multiple cancer hallmark pathways. Epidemiologic studies have linked consumption of Allium vegetables, such as garlic and onions, to decreased incidence of cancer. Diallyl trisulfide (DATS), a bioactive compound derived from Allium vegetables, has been investigated as an anti-cancer and chemopreventive agent. Preclinical studies provide ample evidence that DATS regulates multiple cancer hallmark pathways including cell cycle, apoptosis, angiogenesis, invasion, and metastasis. DATS has been shown to arrest cancer cells at multiple stages of the cell cycle with the G2/M arrest being the most widely reported. Additionally, increased pro-apoptotic capacity as a result of regulating intrinsic and extrinsic apoptotic pathway components has been widely reported following DATS treatment. Invasion, migration, and angiogenesis represent emerging targets of DATS and support its anti-cancer properties. This review summarizes DATS mechanisms of action as an anti-cancer and chemopreventive agent. These studies provide rationale for future investigation into its use as a cancer chemopreventive agent.

The role of Nrf2-Keap1 axis in colorectal cancer, progression, and chemoresistance

Colorectal cancer is the third common cancer after lung and genital cancers worldwide with more than 1.2 million new cases diagnosed annually. Although extensive progress has been made in the treatment of colorectal cancer, finding novel targets for early diagnosis and effective treatment of these patients is an urgent need. Nuclear factor-erythroid 2-kelch-like ECH-associated protein 1 signaling pathway plays a key role in protecting cells from the damage of intracellular oxidative stress and extracellular oxidizing agents. Nuclear factor-erythroid 2 is a transcription factor that creates intracellular redox homeostasis via transcriptional activity and interaction with kelch-like ECH-associated protein 1. Furthermore, it contributes to survival and chemoresistance of colorectal cancer cells which is mediated by overexpression of cytoprotective and multidrug resistance genes. In this review, the dual role of nuclear factor-erythroid 2 signaling in induction of colorectal cancer cell survival and death as well as the possibility of targeting nuclear factor-erythroid 2-kelch-like ECH-associated protein 1 axis as an advanced strategy in prevention and effective treatment of colorectal cancer patients have been discussed.

Pikuni-Blackfeet traditional medicine: Neuroprotective activities of medicinal plants used to treat Parkinson's disease-related symptoms

ETHNOPHARMACOLOGICAL RELEVANCE

Parkinson's disease (PD) is a multifactorial neurodegenerative disorder affecting 5% of the population over the age of 85 years. Current treatments primarily involve dopamine replacement therapy, which leads to temporary relief of motor symptoms but fails to slow the underlying neurodegeneration. Thus, there is a need for safe PD therapies with neuroprotective activity. In this study, we analyzed contemporary herbal medicinal practices used by members of the Pikuni-Blackfeet tribe from Western Montana to treat PD-related symptoms, in an effort to identify medicinal plants that are affordable to traditional communities and accessible to larger populations.

AIM OF THE STUDY

The aims of this study were to (i) identify medicinal plants used by the Pikuni-Blackfeet tribe to treat individuals with symptoms related to PD or other CNS disorders, and (ii) characterize a subset of the identified plants in terms of antioxidant and neuroprotective activities in cellular models of PD.

MATERIALS AND METHODS

Interviews of healers and local people were carried out on the Blackfeet Indian reservation. Plant samples were collected, and water extracts were produced for subsequent analysis. A subset of botanical extracts was tested for the ability to induce activation of the Nrf2-mediated transcriptional response and to protect against neurotoxicity elicited by the PD-related toxins rotenone and paraquat.

RESULTS

The ethnopharmacological interviews resulted in the documentation of 26 medicinal plants used to treat various ailments and diseases, including symptoms related to PD. Seven botanical extracts (out of a total of 10 extracts tested) showed activation of Nrf2-mediated transcriptional activity in primary cortical astrocytes. Extracts prepared from Allium sativum cloves, Trifolium pratense flowers, and Amelanchier arborea berries exhibited neuroprotective activity against toxicity elicited by rotenone, whereas only the extracts prepared from Allium sativum and Amelanchier arborea alleviated PQ-induced dopaminergic cell death.

CONCLUSIONS

Our findings highlight the potential clinical utility of plants used for medicinal purposes over generations by the Pikuni-Blackfeet people, and they shed light on mechanisms by which the plant extracts could slow neurodegeneration in PD.

Angiopoietin-like protein 4 potentiates DATS-induced inhibition of proliferation, migration, and invasion of bladder cancer EJ cells; involvement of G2/M-phase cell cycle arrest, signaling pathways, and transcription factors-mediated MMP-9 expression

Background: Diallyl trisulfide (DATS), a bioactive sulfur compound in garlic, has been highlighted due to its strong anti-carcinogenic activity.

Objective: The current study investigated the molecular mechanism of garlic-derived DATS in cancer cells. Additionally, we explored possible molecular markers to monitoring clinical responses to DATS-based chemotherapy.

Design: EJ bladder carcinoma cells were treated with different concentration of DATS. Molecular changes including differentially expressed genes in EJ cells were examined using immunoblot, FACS cell cycle analysis, migration and invasion assays, electrophoresis mobility shift assay (EMSA), microarray, and bioinformatics analysis.

Results: DATS inhibited EJ cell growth via G₂/M-phase cell cycle arrest. ATM-CHK2-Cdc25c-p21WAF1-Cdc2 signaling cascade, MAPKs, and AKT were associated with the DATS-mediated growth inhibition of EJ cells. DATS-induced inhibition of migration and invasion was correlated with down-regulated MMP-9 via reduced activation of AP-1, Sp-1, and NF-κB. Through microarray gene expression analysis, ANGPTL4, PLCXD1, and MMP3 were identified as candidates of molecular targets of DATS. Introduction of each gene to EJ cells revealed that ANGPTL4 was associated with the DATS-induced inhibition of cell growth, migration, and invasion.

Conclusions: ANGPTL4 regulates DATS-mediated inhibition of proliferation, migration, and invasion of EJ cells, and thus, has potential as a prognostic marker for bladder cancer patients.

Mediterranean diet and inflammaging within the hormesis paradigm

A coherent set of epidemiological data shows that the Mediterranean diet has beneficial effects capable of preventing a variety of age-related diseases in which low-grade, chronic inflammation/inflammaging plays a major role, but the underpinning mechanism(s) is/are still unclear. It is suggested here that the Mediterranean diet can be conceptualized as a form of chronic hormetic stress, similar to what has been proposed regarding calorie restriction, the most thoroughly studied nutritional intervention. Data on the presence in key Mediterranean foods of a variety of compounds capable of exerting hormetic effects are summarized, and the mechanistic role of the nuclear factor erythroid 2 pathway is highlighted. Within this conceptual framework, particular attention has been devoted to the neurohormetic and neuroprotective properties of the Mediterranean diet, as well as to its ability to maintain an optimal balance between pro- and anti-inflammaging. Finally, the European Commission-funded project NU-AGE is discussed because it addresses a number of variables not commonly taken into consideration, such as age, sex, and ethnicity/genetics, that can modulate the hormetic effect of the Mediterranean diet.

Evaluation of the antioxidant properties of carexanes in AGS cells transfected with the Helicobacter pylori's protein HspB

Naturally derived compounds represent a potential source of pharmacologically active drugs able to contrast different diseases, including gastric cancer, a multifactorial disease, in which the important role played by H. pylori infection has been demonstrated. Carexanes, stilbene derivatives, isolated from plants of the Carex distachya Desf., are unusual secondary metabolites with a tetracyclic skeleton arising from a cyclization of prenylstilbenoid precursors. In this study we firstly showed the ability of three purified carexanes CxB, CxG, and CxI to enhance the antioxidant response of AGS cells and to contrast the effect of the H. pylori's protein HspB. Among them CxI was the molecule that best modified the expression of genes involved in the antioxidant response. In particular, CxI was able to reduce Keap-1 gene expression and induce NQO1 gene expression, both at 4 and 24 h in AGS cells, as showed by real time PCR. Nrf2 induction was evident only at 24 h. Interestingly, the effect of CxI was stronger in HspB-transfected AGS cells, where Keap-1 gene expression was nearly abrogated. Finally, we demonstrated that CxI was able to reduce also COX-2 gene expression in HspB-transfected AGS cells, compared with untreated HspB-transfected cells, both at 4 and 24 h. This study first report that carexanes might represent candidate molecules able to contrast the deleterious effect of HspB protein but also to reduce the inflammatory process induced by H. pylori infection.