Beta-phenylethyl and 8-methylsulphinyloctyl isothiocyanates, constituents of watercress, suppress LPS induced production of nitric oxide and prostaglandin E2 in RAW 264.7 macrophages

Phenethyl isothiocyanate ameliorates liver injuries secondary to inflammatory bowel disease

Inflammatory bowel disease (IBD) is often accompanied by secondary liver injury which further evolves into various hepatobiliary disorders. The pathogenesis of secondary liver injury involves many different mechanisms including inflammation, pyroptosis, oxidative stress, and heat shock response. Here, we tested the effect of administration of phenethyl isothiocyanate (PEITC) on secondary liver injury in DSS-induced IBD mice. PEITC supplementation reversed liver injury as determined by hepatic injury-related parameters and histopathological examinations. Severe hepatic inflammation with IBD, evidenced by ubiquitously distributed activated macrophages, increased secretion of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6), enhanced expression of inflammation-related proteins (iNOS and COX-2), and augmented activation of the TLR4/NF-κB signaling pathway, was inhibited by PEITC treatment. PEITC also prevented IBD-induced increases in pyroptosis and oxidative stress in the liver. In addition, impairments of hepatic heat shock response elicited by IBD were restored by PEITC treatment. Taken together, these results suggested that PEITC may be effective as a therapeutic reagent to attenuate secondary liver injury caused by IBD.

Isothiocyanates in medicine: A comprehensive review on phenylethyl-, allyl-, and benzyl-isothiocyanates

In recent years, isothiocyanates (ITCs), bioactive compounds primarily derived from Brassicaceae vegetables and herbs, have gained significant attention within the biomedical field due to their versatile biological effects. This comprehensive review provides an in-depth exploration of the therapeutic potential and individual biological mechanisms of the three specific ITCs phenylethyl isothiocyanate (PEITC), allyl isothiocyanate (AITC), and benzyl isothiocyanate (BITC), as well as their collective impact within the formulation of ANGOCIN® Anti-Infekt N (Angocin). Angocin comprises horseradish root (Armoracia rusticanae radix, 80 mg) and nasturtium (Tropaeoli majoris herba, 200 mg) and is authorized for treating inflammatory diseases affecting the respiratory and urinary tract. The antimicrobial efficacy of this substance has been confirmed both in vitro and in various clinical trials, with its primary effectiveness attributed to ITCs. PEITC, AITC, and BITC exhibit a wide array of health benefits, including potent anti-inflammatory, antioxidant, and antimicrobial properties, along with noteworthy anticancer potentials. Moreover, we highlight their ability to modulate critical biochemical pathways, such as the nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and signal transducer and activator of transcription (STAT) pathways, shedding light on their involvement in cellular apoptosis and their intricate role to guide immune responses.

Advances in Nrf2 Signaling Pathway by Targeted Nanostructured-Based Drug Delivery Systems

Nanotechnology has gained significant interest in various applications, including sensors and therapeutic agents for targeted disease sites. Several pathological consequences, including cancer, Alzheimer's disease, autoimmune diseases, and many others, are mostly driven by inflammation and Nrf2, and its negative regulator, the E3 ligase adaptor Kelch-like ECH-associated protein 1 (Keap1), plays a crucial role in maintaining redox status, the expression of antioxidant genes, and the inflammatory response. Interestingly, tuning the Nrf2/antioxidant response element (ARE) system can affect immune-metabolic mechanisms. Although many phytochemicals and synthetic drugs exhibited potential therapeutic activities, poor aqueous solubility, low bioavailability, poor tissue penetration, and, consequently, poor specific drug targeting, limit their practical use in clinical applications. Also, the therapeutic use of Nrf2 modulators is hampered in clinical applications by the absence of efficient formulation techniques. Therefore, we should explore the engineering of nanotechnology to modulate the inflammatory response via the Nrf2 signaling pathway. This review will initially examine the role of the Nrf2 signaling pathway in inflammation and oxidative stress-related pathologies. Subsequently, we will also review how custom-designed nanoscale materials encapsulating the Nrf2 activators can interact with biological systems and how this interaction can impact the Nrf2 signaling pathway and its potential outcomes, emphasizing inflammation.

Developing multifunctional crops by engineering Brassicaceae glucosinolate pathways

Glucosinolates (GSLs), found mainly in species of the Brassicaceae family, are one of the most well-studied classes of secondary metabolites. Produced by the action of myrosinase on GSLs, GSL-derived hydrolysis products (GHPs) primarily defend against biotic stress in planta. They also significantly affect the quality of crop products, with a subset of GHPs contributing unique food flavors and multiple therapeutic benefits or causing disagreeable food odors and health risks. Here, we explore the potential of these bioactive functions, which could be exploited for future sustainable agriculture. We first summarize our accumulated understanding of GSL diversity and distribution across representative Brassicaceae species. We then systematically discuss and evaluate the potential of exploited and unutilized genes involved in GSL biosynthesis, transport, and hydrolysis as candidate GSL engineering targets. Benefiting from available information on GSL and GHP functions, we explore options for multifunctional Brassicaceae crop ideotypes to meet future demand for food diversification and sustainable crop production. An integrated roadmap is subsequently proposed to guide ideotype development, in which maximization of beneficial effects and minimization of detrimental effects of GHPs could be combined and associated with various end uses. Based on several use-case examples, we discuss advantages and limitations of available biotechnological approaches that may contribute to effective deployment and could provide novel insights for optimization of future GSL engineering.

Anti-Inflammatory Potential of Brassicaceae-Derived Phytochemicals: In Vitro and In Vivo Evidence for a Putative Role in the Prevention and Treatment of IBD

Inflammatory bowel disease (IBD) is a group of intestinal disorders, of unknown etiology, characterized by chronic inflammation within the gut. They are gradually becoming critical because of the increasing incidence worldwide and improved diagnosis. Due to the important side effects observed during conventional therapy, natural bioactive components are now under intense investigation for the prevention and treatment of chronic illnesses. The Brassicaceae family comprises vegetables widely consumed all over the world. In recent decades, a growing body of literature has reported that extracts from the Brassicaceae family and their purified constituents have anti-inflammatory properties, which has generated interest from both the scientific community and clinicians. In this review, data from the literature are scrutinized and concisely presented demonstrating that Brassicaceae may have anti-IBD potential. The excellent biological activities of Brassicacea are widely attributable to their ability to regulate the levels of inflammatory and oxidant mediators, as well as their capacity for immunomodulatory regulation, maintenance of intestinal barrier integrity and intestinal flora balance. Possible future applications of bioactive-derived compounds from Brassicaceae for promoting intestinal health should be investigated.

Glucosinolates and Omega-3 Fatty Acids from Mustard Seeds: Phytochemistry and Pharmacology

Seeds from mustard (genera Brassica spp. and Sinapsis spp.), are known as a rich source of glucosinolates and omega-3 fatty acids. These compounds are widely known for their health benefits that include reducing inflammation and lowering the risk of cardiovascular diseases and cancer. This review presented a synthesis of published literature from Google Scholar, PubMed, Scopus, Sci Finder, and Web of Science regarding the different glucosinolates and omega-3 fatty acids isolated from mustard seeds. We presented an overview of extraction, isolation, purification, and structure elucidation of glucosinolates from the seeds of mustard plants. Moreover, we presented a compilation of in vitro, in vivo, and clinical studies showing the potential health benefits of glucosinolates and omega-3 fatty acids. Previous studies showed that glucosinolates have antimicrobial, antipain, and anticancer properties while omega-3 fatty acids are useful for their pharmacologic effects against sleep disorders, anxiety, cerebrovascular disease, neurodegenerative disease, hypercholesterolemia, and diabetes. Further studies are needed to investigate other naturally occurring glucosinolates and omega-3 fatty acids, improve and standardize the extraction and isolation methods from mustard seeds, and obtain more clinical evidence on the pharmacological applications of glucosinolates and omega-3 fatty acids from mustard seeds.

Beneficial Health Effects of Glucosinolates-Derived Isothiocyanates on Cardiovascular and Neurodegenerative Diseases

Neurodegenerative diseases (NDDs) and cardiovascular diseases (CVDs) are illnesses that affect the nervous system and heart, all of which are vital to the human body. To maintain health of the human body, vegetable diets serve as a preventive approach and particularly Brassica vegetables have been associated with lower risks of chronic diseases, especially NDDs and CVDs. Interestingly, glucosinolates (GLs) and isothiocyanates (ITCs) are phytochemicals that are mostly found in the Cruciferae family and they have been largely documented as antioxidants contributing to both cardio- and neuroprotective effects. The hydrolytic breakdown of GLs into ITCs such as sulforaphane (SFN), phenylethyl ITC (PEITC), moringin (MG), erucin (ER), and allyl ITC (AITC) has been recognized to exert significant effects with regards to cardio- and neuroprotection. From past in vivo and/or in vitro studies, those phytochemicals have displayed the ability to mitigate the adverse effects of reactive oxidation species (ROS), inflammation, and apoptosis, which are the primary causes of CVDs and NDDs. This review focuses on the protective effects of those GL-derived ITCs, featuring their beneficial effects and the mechanisms behind those effects in CVDs and NDDs.

Combining Human Genetics of Multiple Sclerosis with Oxidative Stress Phenotype for Drug Repositioning

In multiple sclerosis (MS), oxidative stress (OS) is implicated in the neurodegenerative processes that occur from the beginning of the disease. Unchecked OS initiates a vicious circle caused by its crosstalk with inflammation, leading to demyelination, axonal damage and neuronal loss. The failure of MS antioxidant therapies relying on the use of endogenous and natural compounds drives the application of novel approaches to assess target relevance to the disease prior to preclinical testing of new drug candidates. To identify drugs that can act as regulators of intracellular oxidative homeostasis, we applied an in silico approach that links genome-wide MS associations and molecular quantitative trait loci (QTLs) to proteins of the OS pathway. We found 10 drugs with both central nervous system and oral bioavailability, targeting five out of the 21 top-scoring hits, including arginine methyltransferase (CARM1), which was first linked to MS. In particular, the direction of brain expression QTLs for CARM1 and protein kinase MAPK1 enabled us to select BIIB021 and PEITC drugs with the required target modulation. Our study highlights OS-related molecules regulated by functional MS variants that could be targeted by existing drugs as a supplement to the approved disease-modifying treatments.

Lactobacillus plantarum probiotic induces Nrf2-mediated antioxidant signaling and eNOS expression resulting in improvement of myocardial diastolic function

Yorkshire swine were fed standard diet (n = 7) or standard diet containing applesauce rich in caffeic acid with Lactobacillus plantarum (n = 7) for 3 wk. An ameroid constrictor was next placed around the left coronary circumflex artery, and the dietary regimens were continued. At 14 wk, cardiac function, myocardial perfusion, vascular density, and molecular signaling in ischemic myocardium were evaluated. The L. plantarum-applesauce augmented NF-E2-related factor 2 (Nrf2) in the ischemic myocardium and induced Nrf2-regulated antioxidant enzymes heme oxygenase-1 (HO-1), NADPH dehydrogenase quinone 1 (NQO-1), and thioredoxin reductase (TRXR-1). Improved left ventricular diastolic function and decreased myocardial collagen expression were seen in animals receiving the L. plantarum-applesauce supplements. The expression of endothelial nitric oxide synthase (eNOS) was increased in ischemic myocardial tissue of the treatment group, whereas levels of asymmetric dimethyl arginine (ADMA), hypoxia inducible factor 1α (HIF-1α), and phosphorylated MAPK (pMAPK) were decreased. Collateral-dependent myocardial perfusion was unaffected, whereas arteriolar and capillary densities were reduced as determined by α-smooth muscle cell actin and CD31 immunofluorescence in ischemic myocardial tissue. Dietary supplementation with L. plantarum-applesauce is a safe and effective method of enhancing Nrf2-mediated antioxidant signaling cascade in ischemic myocardium. Although this experimental diet was associated with a reduction in hypoxic stimuli, decreased vascular density, and without any change in collateral-dependent perfusion, the net effect of an increase in antioxidant activity and eNOS expression resulted in improvement in diastolic function.NEW & NOTEWORTHY Colonization of the gut microbiome with certain strains of L. Plantarum has been shown to convert caffeic acid readily available in applesauce to 4-vinyl-catechol, a potent activator of the Nrf2 antioxidant defense pathway. In this exciting study, we show that simple dietary supplementation with L. Plantarum-applesauce-mediated Nrf2 activation supports vascular function, ameliorates myocardial ischemic diastolic dysfunction, and upregulates expression of eNOS.

Immunomodulating Effect of the Consumption of Watercress (Nasturtium officinale) on Exercise-Induced Inflammation in Humans

The vegetable watercress (Nasturtium officinale R.Br.) is, besides being a generally nutritious food, a rich source of glucosinolates. Gluconasturtiin, the predominant glucosinolate in watercress, has been shown to have several health beneficial properties through its bioactive breakdown product phenethyl isothiocyanate. Little is known about the immunoregulatory effects of watercress. Moreover, anti-inflammatory effects have mostly been shown in in vitro or in animal models. Hence, we conducted a proof-of-concept study to investigate the effects of watercress on the human immune system. In a cross-over intervention study, 19 healthy subjects (26.5 ± 4.3 years; 14 males, 5 females) were given a single dose (85 g) of fresh self-grown watercress or a control meal. Two hours later, a 30 min high-intensity workout was conducted to promote exercise-induced inflammation. Blood samples were drawn before, 5 min after, and 3 h after the exercise unit. Inflammatory blood markers (IL-1β, IL-6, IL-10, TNF-α, MCP-1, MMP-9) were analyzed in whole blood cultures after ex vivo immune cell stimulation via lipopolysaccharides. A mild pro-inflammatory reaction was observed after watercress consumption indicated by an increase in IL-1β, IL-6, and TNF-α, whereas the immune response was more pronounced for both pro-inflammatory and anti-inflammatory markers (IL-1β, IL-6, IL-10, TNF-α) after the exercise unit compared to the control meal. During the recovery phase, watercress consumption led to a stronger anti-inflammatory downregulation of the pro-inflammatory cytokines IL-6 and TNF-α. In conclusion, we propose that watercress causes a stronger pro-inflammatory response and anti-inflammatory counter-regulation during and after exercise. The clinical relevance of these changes should be verified in future studies.

A Narrative Review on Therapeutic Potentials of Watercress in Human Disorders

Watercress (WC) is an aquatic vegetable that belongs to the Brassicaceae family, and it often grows near water. In traditional medicine, WC is a known remedy for hypercholesterolemia, hyperglycemia, hypertension, arthritis, bronchitis, diuresis, odontalgia, and scurvy. It also acts as an antiestrogenic and can be used as a nutritional supplement. It has been reported that these therapeutic effects are due to primary metabolites such as isothiocyanates, glucosinolates, polyphenols (flavonoids, phenolic acids, and proanthocyanidins), vitamins (B₁, B₂, B₃, B₆, E, and C), terpenes (including carotenoids), and bioelements which exist in this plant. Many pharmacological studies confirm the antioxidant, antibacterial, anticancer, antipsoriatic, anti-inflammatory, cardioprotective, renoprotective, hepatoprotective, and antigenotoxicity effects of WC. The consumption of WC extract can be useful in reducing the complications of hypercholesterolemia and hyperglycemia. Furthermore, the extract of WC could markedly augment the antioxidant enzymes such as superoxide dismutase and catalase activity. Interestingly, consumption of food rich in polyphenols such as WC extract can help reduce oxidative stress, DNA damage, and cancer susceptibility. Several studies also showed that WC extract significantly reduced liver injury as a result of cholestatic hepatic injury, gamma radiation, arsenic, and acetaminophen-induced hepatotoxicity. In this review, the researchers focus on the phytochemical and biochemical characterizations of WC and its therapeutic effects in the treatment of human diseases.

An Overview of Nrf2 Signaling Pathway and Its Role in Inflammation

Inflammation is a key driver in many pathological conditions such as allergy, cancer, Alzheimer’s disease, and many others, and the current state of available drugs prompted researchers to explore new therapeutic targets. In this context, accumulating evidence indicates that the transcription factor Nrf2 plays a pivotal role controlling the expression of antioxidant genes that ultimately exert anti-inflammatory functions. Nrf2 and its principal negative regulator, the E3 ligase adaptor Kelch-like ECH- associated protein 1 (Keap1), play a central role in the maintenance of intracellular redox homeostasis and regulation of inflammation. Interestingly, Nrf2 is proved to contribute to the regulation of the heme oxygenase-1 (HO-1) axis, which is a potent anti-inflammatory target. Recent studies showed a connection between the Nrf2/antioxidant response element (ARE) system and the expression of inflammatory mediators, NF-κB pathway and macrophage metabolism. This suggests a new strategy for designing chemical agents as modulators of Nrf2 dependent pathways to target the immune response. Therefore, the present review will examine the relationship between Nrf2 signaling and the inflammation as well as possible approaches for the therapeutic modulation of this pathway.

Local/traditional uses, secondary metabolites and biological activities of Mashua (Tropaeolum tuberosum Ruíz & Pavón)

ETHNOPHARMACOLOGICAL RELEVANCE

Tropaeolum tuberosum Ruíz & Pavón (Tropaeolaceae). Sim (commonly called Mashua) is an indigenous plant that has medicinal values for various ethnic groups of the regions of the Andes mountain range of South America, which use it for the treatment of diseases venereal, lung and skin; for the healing of internal and external wounds; and as an analgesic for kidney and bladder pain.

AIM OF THE REVIEW

We critically summarised the current evidence on the botanic characterisation and distribution, ethnopharmacology, secondary metabolites, pharmacological activities, qualitative and quantitative analysis, and toxicology of T. tuberosum.

MATERIALS AND METHODS

The relevant information on T. tuberosum was gathered from worldwide accepted scientific databases via electronic search (Google scholar, Elsevier, SciFinder, ScienceDirect, PubMed, SpringerLink, Web of Science, Scopus, Wiley Online, Mendeley, Scielo and Dialnet electronic databases). Information was also obtained from the literature and books as well as PhD and MSc dissertations. Plant names were validated by 'The Plant List' (www.theplantlist.org).

RESULTS

T. tuberosum has diverse uses in local and popular medicine, specifically for relieving pain and infections in humans. Regarding its biological activities, polar extracts (aqueous, hydroalcoholic) and isolated compounds from the tubers have exhibited a wide range of in vitro and in vivo pharmacological effects, including antibacterial, antioxidant, anti-inflammatory activities. Quantitative analysis (e.g., NMR, HPLC, GC-MS) indicated the presence of a set of secondary metabolites, including hydroxybenzoic acids, tannins, flavanols, anthocyanins, glucosinolates, isothiocyanates, phytosterols, fatty acids and alkamides in the tubers of T. tuberosum. Likewise, glucosinolates have been identified in the seeds and isothiocyanates have been detected in leaves, flowers and seeds.

CONCLUSIONS

T. tuberosum has been tested for various biological activities and the extracts (tubers in particular) demonstrated a promising potential as an antibacterial, antioxidant, anti-inflammatory and inhibitors of benign prostatic hyperplasia. A lack of alignment between the ethno-medicinal uses and existing biological screenings was observed, indicating the need to explore its potential for the treatment against respiratory affections, urinary affections and blood diseases. Likewise, it is necessary to analyse deeply the relationship that exists between the different tuber colours of T. tuberosum and its use for the treatment of certain diseases. Validation of clinical studies of the antibacterial, antioxidant/anti-inflammatory, anti-spermatogenic activities and as inhibitors of benign prostatic hyperplasia is required. Moreover, studies on the toxicity, bioavailability, and pharmacokinetics, in addition to clinical trials, are indispensable for assessing the safety and efficacy of the active metabolites or extracts obtained from T. tuberosum. Other areas that need investigation are the development of future applications based on their active metabolites, such as neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, Huntington's disease). Finally, the work purposes to motivate other research groups to carry out a series of scientific studies that can fill the gaps that exist with respect to Mashua properties, and thus be able to change the focus of T. tuberosum (Mashua) that currently has in the consumer society.

Efficacy of isothiocyanate-based compounds on different forms of persistent pain

Purpose

Current pharmacotherapy for persistent pain related to neuropathy or articular diseases is unsatisfactory, due to the large number of unresponsive patients and side effects. Isothiocyanates (ITCs) are a class of natural or synthetic compounds characterized by the general formula R–NCS. ITCs show antihyperalgesic effects in models of central and peripheral nervous tissue injury and anti-inflammatory properties. The pharmacodynamics are strictly related to the release of the gasotransmitter hydrogen sulfide (H₂S) from their moiety. In particular, phenyl ITC (PITC) and 3-carboxyphenyl ITC (3C-PITC) exhibit interesting slow H₂S-release properties suitable for treating painful pathology. The aim of the present work was to evaluate the efficacy of PITC and 3C-PITC against mechanical hyperalgesia and spontaneous pain induced by nerve injury and osteoarthritis.

Methods

Nerve injury and osteoarthritis were induced in rats by ligation of the sciatic nerve (chronic constriction injury) and intra-articular injection of monoiodoacetate, respectively. Behavioral tests were performed 14 days after damage induction.

Results

Single subcutaneous administrations of PITC, 3C-PITC (4.43 and 13.31 µmol kg⁻¹, respectively) were able to completely reverse hypersensitivity to noxious stimuli in both models of neuropathic and osteoarticular pain. The effect of ITCs was compared with that of NaHS, the prototypical H₂S donor, showing similar efficacy and higher potency. ITCs and NaHS also reduced spontaneous pain.

Conclusion

ITCs offer a promising novel approach to counteract persistent, drug-resistant painful pathology.

HO-1 Induction by Selaginella tamariscina Extract Inhibits Inflammatory Response in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

Selaginella Herba is the dried, aerial part of Selaginella tamariscina (P.Beauv.) Spring and has been used to treat amenorrhea, abdominal pain, headaches, and hematuria in Korea. However, scientific evidence regarding the anti-inflammatory activity and action mechanism of Selaginella tamariscina is lacking. Thus, the present study was performed to investigate the anti-inflammatory and antioxidant activities of Selaginella tamariscina ethanol extract (STE) against lipopolysaccharide (LPS)-induced inflammatory responses and identify the molecular mechanism responsible. STE was prepared by heating in 70% ethanol and its quality was confirmed by HPLC. STE dose-dependently inhibited the productions of inflammatory mediators (NO and PGE₂) and proinflammatory cytokines (IL-1β and IL-6) in LPS-stimulated RAW 264.7 cells. STE markedly suppressed the phosphorylations of MAPKs, IκB-α, and NF-κB and the nuclear translocation of NF-κB induced by LPS stimulation. In addition, STE exhibited good free radical scavenging activity and prevented ROS generation by LPS. STE also upregulated the expression of Nrf2 and HO-1 and promoted the nuclear translocation of Nrf2. Taken together, STE was found to have anti-inflammatory and antioxidant effects on RAW 264.7 macrophages and the mechanism appeared to involve the MAPK, NF-κB, and Nrf2/HO-1 signaling pathways. These results suggest that STE might be useful for preventing or treating inflammatory diseases and provide scientific evidence that supports the developments of herbal prescriptions or novel natural products.

Protective Effect of Glucosinolates Hydrolytic Products in Neurodegenerative Diseases (NDDs)

Crucifer vegetables, Brassicaceae and other species of the order Brassicales, e.g., Moringaceae that are commonly consumed as spice and food, have been reported to have potential benefits for the treatment and prevention of several health disorders. Though epidemiologically inconclusive, investigations have shown that consumption of those vegetables may result in reducing and preventing the risks associated with neurodegenerative disease development and may also exert other biological protections in humans. The neuroprotective effects of these vegetables have been ascribed to their secondary metabolites, glucosinolates (GLs), and their related hydrolytic products, isothiocyanates (ITCs) that are largely investigated for their various medicinal effects. Extensive pre-clinical studies have revealed more than a few molecular mechanisms of action elucidating multiple biological effects of GLs hydrolytic products. This review summarizes the most significant and up-to-date in vitro and in vivo neuroprotective actions of sulforaphane (SFN), moringin (MG), phenethyl isothiocyanate (PEITC), 6-(methylsulfinyl) hexyl isothiocyanate (6-MSITC) and erucin (ER) in neurodegenerative diseases.

Chemoprevention with isothiocyanates - From bench to bedside

Isothiocyanates (ITCs) are naturally occurring hydrolization products from glucosinolates (GLSs) in brassicaceae and in epidemiological studies their intake has been weakly to moderately inversely correlated with the risk of colorectal cancer, prostate cancer and lung cancer. Numerous preclinical studies demonstrate chemopreventive mode of actions of ITCs, mainly related to a.) detoxification (induction of phase II enzymes), b.) anti-inflammatory properties by down-regulation of NFkappaB activity, c.) cyclin-mediated cell cycle arrest and d.) epigenetic modulation by inhibition of histone deacetylase activity. First prospective clinical trials were promising in patients with risk of prostate cancer recurrence. The glutathione-S-transferase gene expression seems to play a major role in the individual susceptibility towards ITCs. Safety issues are widely unclear and should be more addressed in future studies because ITCs can, in low concentrations, compromise the function of human immune cells and might impair genome stability.

Brassica-Derived Plant Bioactives as Modulators of Chemopreventive and Inflammatory Signaling Pathways

A high consumption of vegetables belonging to the Brassicaceae family has been related to a lower incidence of chronic diseases including different kinds of cancer. These beneficial effects of, e.g., broccoli, cabbage or rocket (arugula) intake have been mainly dedicated to the sulfur-containing glucosinolates (GLSs)-secondary plant compounds nearly exclusively present in Brassicaceae-and in particular to their bioactive breakdown products including isothiocyanates (ITCs). Overall, the current literature indicate that selected Brassica-derived ITCs exhibit health-promoting effects in vitro, as well as in laboratory mice in vivo. Some studies suggest anti-carcinogenic and anti-inflammatory properties for ITCs which may be communicated through an activation of the redox-sensitive transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) that controls the expression of antioxidant and phase II enzymes. Furthermore, it has been shown that ITCs are able to significantly ameliorate a severe inflammatory phenotype in colitic mice in vivo. As there are studies available suggesting an epigenetic mode of action for Brassica-derived phytochemicals, the conduction of further studies would be recommendable to investigate if the beneficial effects of these compounds also persist during an irregular consumption pattern.

Nrf2 signaling pathway: Pivotal roles in inflammation

Inflammation is the most common feature of many chronic diseases and complications, while playing critical roles in carcinogenesis. Several studies have demonstrated that Nrf2 contributes to the anti-inflammatory process by orchestrating the recruitment of inflammatory cells and regulating gene expression through the antioxidant response element (ARE). The Keap1 (Kelch-like ECH-associated protein)/Nrf2 (NF-E2 p45-related factor 2)/ARE signaling pathway mainly regulates anti-inflammatory gene expression and inhibits the progression of inflammation. Therefore, the identification of new Nrf2-dependent anti-inflammatory phytochemicals has become a key point in drug discovery. In this review, we discuss the members of the Keap1/Nrf2/ARE signal pathway and its downstream genes, the effects of this pathway on animal models of inflammatory diseases, and crosstalk with the NF-κB pathway. In addition we also discuss about the regulation of NLRP3 inflammasome by Nrf2. Besides this, we summarize the current scenario of the development of anti-inflammatory phytochemicals and others that mediate the Nrf2/ARE signaling pathway.

Isothiocyanates Are Promising Compounds against Oxidative Stress, Neuroinflammation and Cell Death that May Benefit Neurodegeneration in Parkinson's Disease

Parkinson’s disease (PD) is recognized as the second most common neurodegenerative disorder and is characterized by a slow and progressive degeneration of dopaminergic neurons in the substantia nigra. Despite intensive research, the mechanisms involved in neuronal loss are not completely understood yet; however, misfolded proteins, oxidative stress, excitotoxicity and inflammation play a pivotal role in the progression of the pathology. Neuroinflammation may have a greater function in PD pathogenesis than initially believed, taking part in the cascade of events that leads to neuronal death. To date, no efficient therapy, able to arrest or slow down PD, is available. In this context, the need to find novel strategies to counteract neurodegenerative progression by influencing diseases’ pathogenesis is becoming increasingly clear. Isothiocyanates (ITCs) have already shown interesting properties in detoxification, inflammation, apoptosis and cell cycle regulation through the induction of phase I and phase II enzyme systems. Moreover, ITCs may be able to modulate several key points in oxidative and inflammatory evolution. In view of these considerations, the aim of the present review is to describe ITCs as pleiotropic compounds capable of preventing and modulating the evolution of PD.

Sulforaphane protects against acrolein-induced oxidative stress and inflammatory responses: modulation of Nrf-2 and COX-2 expression

INTRODUCTION

Acrolein (2-propenal) is a reactive α, β-unsaturated aldehyde which causes a health hazard to humans. The present study focused on determining the protection offered by sulforaphane against acrolein-induced damage in peripheral blood mononuclear cells (PBMC).

MATERIAL AND METHODS

Acrolein-induced oxidative stress was determined through evaluating the levels of reactive oxygen species, protein carbonyl and sulfhydryl content, thiobarbituric acid reactive species, total oxidant status and antioxidant status (total antioxidant capacity, glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase activity). Also, Nrf-2 expression levels were determined using western blot analysis. Acrolein-induced inflammation was determined through analyzing expression of cyclooxygenase-2 by western blot and PGE2 levels by ELISA. The protection offered by sulforaphane against acrolein-induced oxidative stress and inflammation was studied.

RESULTS

Acrolein showed a significant (p < 0.001) increase in the levels of oxidative stress parameters and down-regulated Nrf-2 expression. Acrolein-induced inflammation was observed through upregulation (p < 0.001) of COX-2 and PGE2 levels. Pretreatment with sulforaphane enhanced the antioxidant status through upregulating Nrf-2 expression (p < 0.001) in PBMC. Acrolein-induced inflammation was significantly inhibited through suppression of COX-2 (p < 0.001) and PGE2 levels (p < 0.001).

CONCLUSIONS

The present study provides clear evidence that pre-treatment with sulforaphane completely restored the antioxidant status and prevented inflammatory responses mediated by acrolein. Thus the protection offered by sulforaphane against acrolein-induced damage in PBMC is attributed to its anti-oxidant and anti-inflammatory potential.

Pharmacokinetics, Tissue Distribution, and Anti-Lipogenic/Adipogenic Effects of Allyl-Isothiocyanate Metabolites

Allyl-isothiocyanate (AITC) is an organosulfur phytochemical found in abundance in common cruciferous vegetables such as mustard, wasabi, and cabbage. Although AITC is metabolized primarily through the mercapturic acid pathway, its exact pharmacokinetics remains undefined and the biological function of AITC metabolites is still largely unknown. In this study, we evaluated the inhibitory effects of AITC metabolites on lipid accumulation in vitro and elucidated the pharmacokinetics and tissue distribution of AITC metabolites in rats. We found that AITC metabolites generally conjugate with glutathione (GSH) or N-acetylcysteine (NAC) and are distributed in most organs and tissues. Pharmacokinetic analysis showed a rapid uptake and complete metabolism of AITC following oral administration to rats. Although AITC has been reported to exhibit anti-tumor activity in bladder cancer, the potential bioactivity of its metabolites has not been explored. We found that GSH-AITC and NAC-AITC effectively inhibit adipogenic differentiation of 3T3-L1 preadipocytes and suppress expression of PPAR-γ, C/EBPα, and FAS, which are up-regulated during adipogenesis. GSH-AITC and NAC-AITC also suppressed oleic acid-induced lipid accumulation and lipogenesis in hepatocytes. Our findings suggest that AITC is almost completely metabolized in the liver and rapidly excreted in urine through the mercapturic acid pathway following administration in rats. AITC metabolites may exert anti-obesity effects through suppression of adipogenesis or lipogenesis.

Chemical and biochemical mechanisms underlying the cardioprotective roles of dietary organopolysulfides

Foods that are rich in organosulfides are highly regarded for their broad range of functions in disease prevention and health promotion since ancient time yet modern scientific study, particularly clinical studies could not agree with traditional wisdom. One of the complexities is due to the labile nature of organosulfides, which are often transformed to different structures depending on the processing conditions. The recent evidence on polysulfides as H₂S donors may open up a new avenue for establishing structure and health promotion activity relationship. To put this development into perspective, we carried out a review on the recent progress on the chemistry and biochemistry of organopolysulfides with emphasis on their cardioprotective property. First, we briefly surveyed the foods that are rich in polysulfides and their structural diversity. This is followed by in-depth discussion on the chemical transformations of polysulfides under various processing conditions. We further reviewed the potential action mechanisms of polysulfides in cardioprotection through: (a) hydrogen sulfide releasing activity; (b) radical scavenging activity; and (c) activity in enzyme inhibition and intervention of gene regulation pathways. Based on the literature trend, we can conclude that the emerging concept of organopolysulfides as naturally occurring H₂S donors is intriguing and warrants further research to establish the structure and activity relationship of the organopolysulfides as H₂S donors.

Nrf2 knockout attenuates the anti-inflammatory effects of phenethyl isothiocyanate and curcumin

The role of phytochemicals in preventive and therapeutic medicine is a major area of scientific research. Several studies have illustrated the mechanistic roles of phytochemicals in Nrf2 transcriptional activation. The present study aims to examine the importance of the transcription factor Nrf2 by treating peritoneal macrophages from Nrf2^+/+ and Nrf2^–/– mice ex vivo with phenethyl isothiocyanate (PEITC) and curcumin (CUR). The peritoneal macrophages were pretreated with the drugs and challenged with lipopolysaccharides (LPSs) alone and in combination with PEITC or CUR to assess their anti-inflammatory and antioxidative effects based on gene and protein expression in the treated cells. LPS treatment resulted in an increase in the expression of inflammatory markers such as cycloxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in both Nrf2^+/+ and Nrf2^–/– macrophages, detected by quantitative polymerase chain reaction (qPCR). Nrf2^+/+ macrophages treated with PEITC and CUR exhibited a significant decrease in the expression of these anti-inflammatory genes along with an increase in the expression of hemeoxygenase-1 (HO-1), which is an antioxidative stress gene downstream of the Nrf2 transcription factor battery. Although there was no significant decrease in the expression of the anti-inflammatory genes or an increase in HO-1 expression in Nrf2^–/– macrophages treated with either PEITC or CUR, there was a significant decrease in the protein expression of COX-2 and an increase in the expression of HO-1 in Nrf2^+/+ macrophages treated with PEITC compared to that with CUR treatment. No significant changes were observed in the macrophages from knockout animals. Additionally, there was a significant decrease in LPS-induced IL-6 and TNF-α production following PEITC treatment compared with that following CUR in Nrf2^+/+ macrophages, whereas no change was observed in the macrophages from knockout animals. The results from qPCR, western blot, and ELISA analyses in macrophages from Nrf2^+/+ and Nrf2 ^–/– mice indicate that Nrf2 plays an important role in the anti-inflammatory and antioxidative effects of PEITC and CUR, as observed by their decreased activities in Nrf2^–/– macrophages.

Glucosinolates, myrosinase hydrolysis products, and flavonols found in rocket (Eruca sativa and Diplotaxis tenuifolia)

Rocket species have been shown to have very high concentrations of glucosinolates and flavonols, which have numerous positive health benefits with regular consumption. This review highlights how breeders and processors of rocket species can utilize genomic and phytochemical research to improve varieties and enhance the nutritive benefits to consumers. Plant breeders are increasingly looking to new technologies such as HPLC, UPLC, LC-MS, and GC-MS to screen populations for their phytochemical content to inform plant selections. This paper collates the research that has been conducted to date in rocket and summarizes all glucosinolate and flavonol compounds identified in the species. The paper emphasizes the importance of the broad screening of populations for phytochemicals and myrosinase degradation products, as well as unique traits that may be found in underutilized gene bank resources. This review also stresses that collaboration with industrial partners is becoming essential for long-term plant breeding goals through research.

Health promoting effects of brassica-derived phytochemicals: from chemopreventive and anti-inflammatory activities to epigenetic regulation

A high intake of brassica vegetables may be associated with a decreased chronic disease risk. Health promoting effects of Brassicaceae have been partly attributed to glucosinolates and in particular to their hydrolyzation products including isothiocyanates. In vitro and in vivo studies suggest a chemopreventive activity of isothiocyanates through the redox-sensitive transcription factor Nrf2. Furthermore, studies in cultured cells, in laboratory rodents, and also in humans support an anti-inflammatory effect of brassica-derived phytochemicals. However, the underlying mechanisms of how these compounds mediate their health promoting effects are yet not fully understood. Recent findings suggest that brassica-derived compounds are regulators of epigenetic mechanisms. It has been shown that isothiocyanates may inhibit histone deacetylase transferases and DNA-methyltransferases in cultured cells. Only a few papers have dealt with the effect of brassica-derived compounds on epigenetic mechanisms in laboratory animals, whereas data in humans are currently lacking. The present review aims to summarize the current knowledge regarding the biological activities of brassica-derived phytochemicals regarding chemopreventive, anti-inflammatory, and epigenetic pathways.

Inhibition of TNF-α production in LPS-activated THP-1 monocytic cells by the crude extracts of seven Bhutanese medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

Seven studied medicinal plants; Aconitum laciniatum, Ajania nubigena, Codonopsis bhutanica, Corydalis crispa, Corydalis dubia, Meconopsis simplicifolia and Pleurospermum amabile, are currently used in the Bhutanese Traditional Medicine (BTM) for the management of different types of disorders including the diseases that bore relevance to various inflammatory conditions.

AIMS OF THE STUDY

This study aimed to evaluate the inhibition of TNF-α production in LPS-activated THP-1 monocytic cells by the crude extracts of seven selected Bhutanese medicinal plants. It is expected to; (a) generate a scientific basis for their use in the BTM and (b) form a basis for prioritization of the seven plants for further phytochemical and anti-inflammatory studies.

MATERIALS AND METHODS

Seven plants were selected using an ethno-directed bio-rational approach and their crude extracts were prepared using four different solvents (methanol, hexane, dichloromethane and chloroform). The TNF-α inhibitory activity of these extracts was determined by cytokine-specific sandwich quantitative enzyme-linked immunosorbent assays (ELISAs). The results were quantified statistically and the statistical significance were evaluated by GraphPad Prism version 5.01 using Student's t-test with one-tailed distribution. A p-value ≤0.05 was considered statistically significant.

RESULTS

Of the seven plants studied, the crude extracts of six of them inhibited the production of pro-inflammatory cytokine, TNF-α in LPS-activated THP-1 monocytic cells. Amongst the six plants, Corydalis crispa gave the best inhibitory activity followed by Pleurospermum amabile, Ajania nubigena, Corydalis dubia, Meconopsis simplicifolia and Codonopsis bhutanica. Of the 13 extracts that exhibited statistically significant TNF-α inhibitory activity (p<0.05; p<0.01), five of them showed very strong inhibition when compared to the DMSO control and RPMI media.

CONCLUSIONS

Six medicinal plants studied here showed promising TNF-α inhibitory activity. These findings rationalize the traditional use of these selected medicinal plants in the BTM as an individual plant or in combination with other ingredients for the treatment of disorders bearing relevance to the inflammatory conditions. The results forms a good preliminary basis for the prioritization of candidate plant species for an in-depth phytochemical study and anti-inflammatory activity screening of the pure compounds contained within those seven plants.

The multicomponent medication lymphomyosot improves the outcome of experimental lymphedema

BACKGROUND

Secondary lymphedema is a life-long disease of painful tissue swelling that often follows axillary lymph node dissection to treat breast cancer. It is hypothesized that poor lymphatic regeneration across the obstructive scar tissue during the wound healing process may predispose the tissue to swell at a later date. Treatment for lymphedema remains suboptimal and is in most cases palliative. The purpose of this study was to evaluate the ability of Lymphomyosot to treat tissue swelling and promote lymphangiogenesis in experimental models of murine lymphedema.

METHODS

Experimental models of mouse lymphedema were injected with varied amounts of Lymphomyosot and saline as control. Measurements of tail swelling and wound closure were taken and compared amongst the groups. Three separate groups of mice were analyzed for lymphatic capillary migration, lymphatic vessel regeneration, and macrophage recruitment.

RESULTS

Lymphomyosot significantly reduced swelling and increased the rate of surgical wound closure. Lymphomyosot did not increase the migration of lymph capillaries in a mouse tail skin regeneration model or regeneration of lymph vessels following murine axillary lymph node dissection.

CONCLUSIONS

Lymphomyosot may act through inflammatory and wound repair pathways to reduce experimental lymphedema. Its ability to regulate inflammation as well as assist in tissue repair and extracellular formation may allow for the production of a scar-free matrix bridge through which migrating cells and accumulated interstitial fluid can freely spread.

Ginsenoside Rd inhibits the expressions of iNOS and COX-2 by suppressing NF-κB in LPS-stimulated RAW264.7 cells and mouse liver

Ginsenoside Rd is a primary constituent of the ginseng rhizome and has been shown to participate in the regulation of diabetes and in tumor formation. Reports also show that ginsenoside Rd exerts anti-oxidative effects by activating anti-oxidant enzymes. Treatment with ginsenoside Rd decreased nitric oxide and prostaglandin E₂ (PGE₂) in lipopolysaccharides (LPS)-challenged RAW264.7 cells and in ICR mouse livers (5 mg/kg LPS; LPS + ginsenoside Rd [2, 10, and 50 mg/kg]). Furthermore, these decreases were associated with the down-regulations of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 and of nuclear factor (NF)-κB activity in vitro and in vivo. Our results indicate that ginsenoside Rd treatment decreases; 1) nitric oxide production (40% inhibition); 2) PGE₂ synthesis (69% to 93% inhibition); 3) NF-κB activity; and 4) the NF-κB-regulated expressions of iNOS and COX-2. Taken together, our results suggest that the anti-inflammatory effects of ginsenoside Rd are due to the down-regulation of NF-κB and the consequent expressional suppressions of iNOS and COX-2.

Phenethylisothiocyanate alters site- and promoter-specific histone tail modifications in cancer cells

Site-specific histone modifications are important epigenetic regulators of gene expression. As deregulation of genes often results in complex disorders, corrective modulation of site-specific histone marks could be a powerful therapeutic or disease-preventive strategy. However, such modulation by dietary compounds and the resulting impact on disease risk remain relatively unexplored. Here we examined phenethylisothiocyanate (PEITC), a common dietary compound derived from cruciferous vegetables with known chemopreventive properties under experimental conditions, as a possible modulator of histone modifications in human colon cancer cells. The present study reports novel, dynamic, site-specific chemical changes to histone H3 in a gene-promoter-specific manner, associated with PEITC exposure in human colon tumor-derived SW480 epithelial cells. In addition, PEITC attenuated cell proliferation in a concentration- and time-dependent manner, likely mediated by caspase-dependent apoptotic signalling. The effects of PEITC on histone modifications and gene expression changes were achieved at low, non-cytotoxic concentrations, in contrast to the higher concentrations necessary to halt cancer cell proliferation. Increased understanding of specific epigenetic alterations by dietary compounds may provide improved chemopreventive strategies for reducing the healthcare burden of cancer and other human diseases.

Phenethyl isothiocyanate regulates inflammation through suppression of the TRIF-dependent signaling pathway of Toll-like receptors

AIMS

The aim of this study was to evaluate the therapeutic potential of the phenethyl isothiocyanate (PEITC) in Toll-like receptor (TLR) signaling pathways.

MAIN METHODS

To evaluate the cytotoxic nature of PEITC in RAW 264.7 cells, cytotoxicity was determined using the MTS cell viability assay. RAW264.7 cells were transfected with a nuclear factor-κB (NF-κB), interferon β (IFNβ) PRDIII-I, or interferon inducible protein-10 (IP-10) luciferase plasmid and then luciferase enzyme activities were determined by luciferase assay. The expression of inducible nitric oxide synthase (iNOS) and phosphorylation of interferon regulatory factor 3 (IRF3) were determined by Western blotting. The levels of IP-10 were determined with culture medium by using an IP-10 enzyme-linked immunosorbent assay (ELISA) kit.

KEY FINDINGS

PEITC suppressed the activation of IRF3 and the expression of IP-10 induced by lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (poly[I:C]).

SIGNIFICANCE

TLRs play an important role in the induction of innate immune responses for host defense against invading microbial pathogens. PEITC found in cruciferous vegetables has an effect on treatment of many chronic diseases. Our results suggest that beneficial effects of PEITC on chronic inflammatory diseases are mediated through modulation of Toll-interleukin-1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent signaling pathway of TLRs.

The complex effects of the slow-releasing hydrogen sulfide donor GYY4137 in a model of acute joint inflammation and in human cartilage cells

The role of hydrogen sulfide (H₂S) in inflammation remains unclear with both pro- and anti-inflammatory actions of this gas described. We have now assessed the effect of GYY4137 (a slow-releasing H₂S donor) on lipopolysaccharide (LPS)-evoked release of inflammatory mediators from human synoviocytes (HFLS) and articular chondrocytes (HAC) in vitro. We have also examined the effect of GYY4137 in a complete Freund's adjuvant (CFA) model of acute joint inflammation in the mouse. GYY4137 (0.1–0.5 mM) decreased LPS-induced production of nitrite (NO₂⁻), PGE₂, TNF-α and IL-6 from HFLS and HAC, reduced the levels and catalytic activity of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and reduced LPS-induced NF-κB activation in vitro. Using recombinant human enzymes, GYY4137 inhibited the activity of COX-2, iNOS and TNF-α converting enzyme (TACE). In the CFA-treated mouse, GYY4137 (50 mg/kg, i.p.) injected 1 hr prior to CFA increased knee joint swelling while an anti-inflammatory effect, as demonstrated by reduced synovial fluid myeloperoxidase (MPO) and N-acetyl-β-D-glucosaminidase (NAG) activity and decreased TNF-α, IL-1β, IL-6 and IL-8 concentration, was apparent when GYY4137 was injected 6 hrs after CFA. GYY4137 was also anti-inflammatory when given 18 hrs after CFA. Thus, although GYY4137 consistently reduced the generation of pro-inflammatory mediators from human joint cells in vitro, its effect on acute joint inflammation in vivo depended on the timing of administration.

Isothiocyanates inhibit psoriasis-related proinflammatory factors in human skin

OBJECTIVE

4-Methylthiobutylisothiocyanate (MTBI), the main rocket (Eruca sativa) seed isothiocyanate (ITC), and its oxidized form, sulforaphane (SFN), were assessed for their potential effects on psoriasis-related factors.

METHODS

MTBI and SFN were evaluated for their effect on mRNA expression and cytokine secretion in vitro in human monocytes and macrophage-like cells and ex vivo in topically treated inflamed human skin. In addition, they were assayed in vivo for morphological changes in topically treated psoriasiform human skin in severe-combined immunodeficient (SCID) mice.

RESULTS

MTBI and SFN contributed to the prevention of inflammation development and reduced ongoing inflammation by downregulating lipopolysaccharide (LPS)-induced mRNA expression of the psoriasis-related cytokines, interleukin (IL)-12/23p40 (25-58 %), tumor necrosis factor (TNF)-α (15-37 %) and IL-6 (25-71 %), in human macrophage-like cells. In monocytes, they tended to act additively on cytokine mRNA and reduced IL-12/23p40 (51 %) secretion. In an ex-vivo inflamed human skin organ culture, MTBI (1 μg/ml) reduced the secretion of IL-1 (39 %) and IL-6 (32 %). Moreover, 2/8 and 3/8 of the MTBI- and SFN-treated psoriasiform SCID mice, respectively, recovered partially or entirely from the psoriasiform process.

CONCLUSIONS

Results from these models indicate the potential of rocket seed ITCs as biological agents in the therapy of psoriasis and inflammation-related skin diseases.

Natural isothiocyanates: genotoxic potential versus chemoprevention

Isothiocyanates, occurring in many dietary cruciferous vegetables, show interesting chemopreventive activities against several chronic-degenerative diseases, including cancer, cardiovascular diseases, neurodegeneration, diabetes. The electrophilic carbon residue in the isothiocyanate moiety reacts with biological nucleophiles and modification of proteins is recognized as a key mechanism underlying the biological activity of isothiocyanates. The nuclear factor-erythroid-2-related factor 2 system, which orchestrates the expression of a wide array of antioxidant genes, plays a role in the protective effect of isothiocyanates against almost all the pathological conditions reported above. Recent emerging findings suggest a further common mechanism. Chronic inflammation plays a central role in many human diseases and isothiocyanates inhibit the activity of many inflammation components, suppress cyclooxygenase 2, and irreversibly inactivate the macrophage migration inhibitory factor. Due to their electrophilic reactivity, some isothiocyanates are able to form adducts with DNA and induce gene mutations and chromosomal aberrations. DNA damage has been demonstrated to be involved in the pathogenesis of various chronic-degenerative diseases of epidemiological relevance. Thus, the genotoxicity of the isothiocyanates should be carefully considered. In addition, the dose-response relationship for genotoxic compounds does not suggest evidence of a threshold. Thus, chemicals that are genotoxic pose a greater potential risk to humans than non-genotoxic compounds. Dietary consumption levels of isothiocyanates appear to be several orders of magnitude lower than the doses used in the genotoxicity studies and thus it is highly unlikely that such toxicities would occur in humans. However, the beneficial properties of isothiocyanates stimulated an increase of dietary supplements and functional foods with highly enriched isothiocyanate concentrations on the market. Whether such concentrations may exert a potential health risk cannot be excluded with certainty and an accurate evaluation of the toxicological profile of isothiocyanates should be prompted before any major increase in their consumption be recommended or their clinical use suggested.

Proteins as binding targets of isothiocyanates in cancer prevention

Isothiocyanates are versatile cancer-preventive compounds. Evidence from animal studies indicates that the anticarcinogenic activities of ITCs involve all the major stages of tumor growth: initiation, promotion and progression. Epidemiological studies have also shown that dietary intake of ITCs is associated with reduced risk of certain human cancers. A number of mechanisms have been proposed for the chemopreventive activities of ITCs. To identify the molecular targets of ITCs is a first step to understand the molecular mechanisms of ITCs. Studies in recent years have shown that the covalent binding to certain protein targets by ITCs seems to play an important role in ITC-induced apoptosis and cell growth inhibition and other cellular effects. The knowledge gained from these studies may be used to guide future design and screen of better and more efficacious compounds. In this review, we intend to cover all potential protein targets of ITCs so far studied and summarize what are known about their binding sites and the potential biological consequences. In the end, we also offer discussions to shed light onto the relationship between protein binding and reactive oxygen species generation by ITCs.

Inhibition of lipopolysaccharide-induced cyclooxygenase-2 and inducible nitric oxide synthase expression by 4-[(2'-O-acetyl-α-L-rhamnosyloxy)benzyl]isothiocyanate from Moringa oleifera

Moringa oleifera Lamarck is commonly consumed for nutritional or medicinal properties. We recently reported the isolation and structure elucidation of novel bioactive phenolic glycosides, including 4-[(2'-O-acetyl-α-L-rhamnosyloxy)benzyl]isothiocyanate (RBITC), which was found to suppress inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production in lipopolysaccharide-stimulated RAW 264.7 mouse macrophage cells. Inhibitors of proteins such as cyclooxygenase-2 (COX-2) and iNOS are potential antiinflammatory and cancer chemopreventive agents. The inhibitory activity of RBITC on NO production (IC(50) = 0.96 ± 0.23 μM) was greater than that mediated by other well-known isothiocyanates such as sulforaphane (IC(50) = 2.86 ± 0.39 μM) and benzyl isothiocyanate (IC(50) = 2.08 ± 0.28 μM). RBITC inhibited expression of COX-2 and iNOS at both the protein and mRNA levels. Major upstream signaling pathways involved mitogen-activated protein kinases and nuclear factor-κB (NF-κB). RBITC inhibited phosphorylation of extracellular signal-regulated kinase and stress-activated protein kinase, as well as ubiquitin-dependent degradation of inhibitor κBα (IκBα). In accordance with IκBα degradation, nuclear accumulation of NF-κB and subsequent binding to NF-κB cis-acting element was attenuated by treatment with RBITC. These data suggest RBITC should be included in the dietary armamentarium of isothiocyanates potentially capable of mediating antiinflammatory or cancer chemopreventive activity.

The effect of hydrogen sulfide donors on lipopolysaccharide-induced formation of inflammatory mediators in macrophages

The role of hydrogen sulfide (H(2)S) in inflammation is controversial, with both pro- and antiinflammatory effects documented. Many studies have used simple sulfide salts as the source of H(2)S, which give a rapid bolus of H(2)S in aqueous solutions and thus do not accurately reflect the enzymatic generation of H(2)S. We therefore compared the effects of sodium hydrosulfide and a novel slow-releasing H(2)S donor (GYY4137) on the release of pro- and antiinflammatory mediators in lipopolysaccharide (LPS)-treated murine RAW264.7 macrophages. For the first time, we show that GYY4137 significantly and concentration-dependently inhibits LPS-induced release of proinflammatory mediators such as IL-1beta, IL-6, TNF-alpha, nitric oxide (*NO), and PGE(2) but increased the synthesis of the antiinflammatory chemokine IL-10 through NF-kappaB/ATF-2/HSP-27-dependent pathways. In contrast, NaHS elicited a biphasic effect on proinflammatory mediators and, at high concentrations, increased the synthesis of IL-1beta, IL-6, NO, PGE(2) and TNF-alpha. This study clearly shows that the effects of H(2)S on the inflammatory process are complex and dependent not only on H(2)S concentration but also on the rate of H(2)S generation. This study may also explain some of the apparent discrepancies in the literature regarding the pro- versus antiinflammatory role of H(2)S.

Dietary phenethylisothiocyanate attenuates bowel inflammation in mice

Background

Phenethylisothiocyanate (PEITC) is produced by Brassica food plants. PEO is a PEITC Essential Oil containing >95% natural PEITC. PEITC is known to produce various health benefits but its effect in alleviation of ulcerative colitis signs is unknown.

Results

In two efficacy studies (acute and chronic) oral administration of PEO was effective at remitting acute and chronic signs of ulcerative colitis (UC) in mice. Disease activity, histology and biochemical characteristics were measured in the treated animals and were compared with appropriate controls. PEO treatment significantly improved body weights and stool consistency as well as decreased intestinal bleeding. PEO treatment also reduced mucosal inflammation, depletion of goblet cells and infiltration of inflammatory cells. Attenuation of proinflammatory interleukin1β production was observed in the colons of PEO-treated animals. Expression analyses were also carried out for immune function related genes, transcription factors and cytokines in lipopolysaccharide-activated mouse macrophage cells. PEO likely affects an intricate network of immune signaling genes including a novel concentration dependent reduction of total cellular Signal Transducer and Activator of Transcription 1 (STAT1) as well as nuclear phosphorylated-STAT1 (activated form of STAT1). A PEO-concentration dependent decrease of mRNA of C-X-C motif ligand 10 (a STAT1 responsive chemokine) and Interleukin 6 were also observed.

Conclusions

PEO might be a promising candidate to develop as a treatment for ulcerative colitis patients. The disease attenuation by PEO is likely associated with suppression of activation of STAT1 transcription and inhibition of pro-inflammatory cytokines.

Suppression of inflammatory mediators by cruciferous vegetable-derived indole-3-carbinol and phenylethyl isothiocyanate in lipopolysaccharide-activated macrophages

This study was aimed to examine the effects of indole-3-carbinol (I3C) and beta-phenylethyl isothiocyanate (PEITC), bioactive components present in cruciferous vegetable, on the production of inflammatory mediators, including nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10), in lipopolysaccharide- (LPS-) stimulated RAW 264.7 macrophages. Possible mechanisms of the NO-inhibitory effects were also explored. The results indicated that I3C and PEITC inhibited NO production, and this suppression was associated with decreased production of TNF-alpha and IL-10 by activated macrophages. In addition, I3C suppressed NO production even after the inducible nitric oxide synthase (iNOS) protein had been produced, but such an inhibitory effect was not observed in cells treated with PEITC. Furthermore, both compounds reduced the NO contents generated from an NO donor in a cell-free condition, suggesting that the increased NO clearance may have contributed to the NO-inhibitory effects. In summary, both I3C and PEITC possessed antiinflammatory effects by inhibiting the productions of NO, TNF-alpha, and IL-10, although the NO-inhibitory effects may have involved in different mechanisms.

Molecular targets of dietary phenethyl isothiocyanate and sulforaphane for cancer chemoprevention

Development of cancer is a long-term and multistep process which comprises initiation, progression, and promotion stages of carcinogenesis. Conceivably, it can be targeted and interrupted along these different stages. In this context, many naturally occurring dietary compounds from our daily consumption of fruits and vegetables have been shown to possess cancer preventive effects. Phenethyl isothiocyanate (PEITC) and sulforaphane (SFN) are two of the most widely investigated isothiocyanates from the crucifers. Both have been found to be very potent chemopreventive agents in numerous animal carcinogenesis models as well as cell culture models. They exert their chemopreventive effects through regulation of diverse molecular mechanisms. In this review, we will discuss the molecular targets of PEITC and SFN potentially involved in cancer chemoprevention. These include the regulation of drug-metabolizing enzymes phase I cytochrome P450s and phase II metabolizing enzymes. In addition, the signaling pathways including Nrf2-Keap 1, anti-inflammatory NFkappaB, apoptosis, and cell cycle arrest as well as some receptors will also be discussed. Furthermore, we will also discuss the similarities and their potential differences in the regulation of these molecular targets by PEITC and SFN.

Potential skin antiinflammatory effects of 4-methylthiobutylisothiocyanate (MTBI) isolated from rocket (Eruca sativa) seeds

Isothiocyanates (ITCs), which are organosulfur compounds present in cruciferous vegetables, have anticarcinogenic, antiinflammatory, and antiproliferative activities. These biological activities, and the knowledge that rocket seed (Eruca sativa) extract is used in skin disorders in traditional Middle Eastern medicine, led to the isolation and assessment of 4-methylthiobutylisothiocyanate (MTBI), the major ITC in rocket seeds, for its potential in the prevention of inflammatory skin diseases, such as psoriasis. MTBI was found to depress the growth of activated keratinocytes and to arrest the activated THP-1 monocytes in the G2 stage. Both MTBI and its oxidized derivative sulforaphane (SFN), which was found in the rocket seed at a low concentration, downregulated the expression of the proinflammatory genes, tumor necrosis factor (TNF)-alpha and interleukin (IL)-12/23 p40, as well as that of intercellular adhesion molecule-1, in activated THP-1 cells. These results demonstrate that MTBI may deter the inflammation process, as has been reported for SFN. Furthermore, pretreatment with MTBI hindered the induction of the inflammatory state in the THP-1 cells, as shown by the inhibition of cytokine mRNA expression of IL-1beta, IL-12/23 p40, and TNF-alpha. Overall, our results imply that MTBI may represent a new family of natural compounds possessing significant skin inflammation-preventive activities.