A diet rich in high-glucoraphanin broccoli interacts with genotype to reduce discordance in plasma metabolite profiles by modulating mitochondrial function

Systems Approach to Investigate the Role of Fruit and Vegetable Types on Vascular Function in Pre-Hypertensive Participants: Protocol and Baseline Characteristics of a Randomised Crossover Dietary Intervention

The evidence on the impact of fruits and vegetable types on cardiovascular risk factors remains limited. Specifically, the utilisation of biomarkers to objectively measure dietary compliance and metabolic responses is emerging. This protocol and baseline characteristics of a pilot randomised controlled, crossover, dietary intervention study aimed to examine the effects of citrus fruits, cruciferous vegetables, or common fruits and vegetables on cardiovascular risk factors. A total of 39 volunteers with untreated prehypertension was recruited and consumed a standardised, provided diet with eight daily portions of citrus fruits and cruciferous vegetables, common fruits and vegetables, or a low fruit and vegetable diet (two portions/d, control diet) in a random order for 2 weeks each, separated by a wash-out week. A targeted cohort-based recruitment strategy was utilised and resulted in 74% of participants recruited by re-contacting preselected individuals from two cohort studies with a 15% average enrolment rate. Participants had an average age of 54.4 years (±6.1 years), BMI of 27.9 kg/m2, and BP of 135/81 mmHg and were mainly male (67%). The primary outcome was office blood pressure; secondary outcomes included arterial stiffness, lipid profiles, inflammation, cognitive function, and subjective mood. Biofluids, i.e., 24 h urine, stool, and blood samples, were collected for biomarker measurements with multiple metabolomic platforms and the gut microbial composition, together with traditional dietary biomarkers.

Impact of thermal processing on polyphenols, carotenoids, glucosinolates, and ascorbic acid in fruit and vegetables and their cardiovascular benefits

Bioactive compounds in fruit and vegetables have a positive impact on human health by reducing oxidative stress, inflammation, and the risk of chronic diseases such as cancer, cardiovascular (CV) diseases, and metabolic disorders. However, some fruit and vegetables must be heated before consumption and thermal processes can modify the amount of nutraceuticals, that is, polyphenols, carotenoids, glucosinolates, and ascorbic acid, that can increase or decrease in relation to different factors such as type of processing, temperature, and time but also the plant part (e.g., flower, leaf, tuber, and root) utilized as food. Another important aspect is related to the bioaccessibility and bioavailability of nutraceuticals. Indeed, the key stage of nutraceutical bioefficiency is oral bioavailability, which involves the release of nutraceuticals from fruit and vegetables in gastrointestinal fluids, the solubilization of nutraceuticals and their interaction with other components of gastrointestinal fluids, the absorption of nutraceuticals by the epithelial layer, and the chemical and biochemical transformations into epithelial cells. Several studies have shown that thermal processing can enhance the absorption of nutraceuticals from fruit and vegetable. Once absorbed, they reach the blood vessels and promote multiple biological effects (e.g., antioxidant, anti-inflammatory, antihypertensive, vasoprotective, and cardioprotective). In this review, we described the impact of different thermal processes (such as boiling, steaming and superheated steaming, blanching, and microwaving) on the retention/degradation of bioactive compounds and their health-promoting effects after the intake. We then summarized the impact of heating on the absorption of nutraceuticals and the biological effects promoted by natural compounds in the CV system to provide a comprehensive overview of the potential impact of thermal processing on the CV benefits of fruit and vegetables.

Brassica-derived isothiocyanates as anticancer therapeutic agents and their nanodelivery

The isothiocyanates (ITCs) derived from the precursor glucosinolate molecules present in Brassica vegetables are bioactive organo-sulfur compounds with numerous pharmacologically important properties such as antioxidant, antiinflammatory, antimicrobial, and anticancer. Over the years, ITCs have been the focus of several research investigations associated with cancer treatment. Due to their potent chemo-preventive action, ITCs have been considered to be promising therapeutics for cancer therapy in place of the already existing conventional anticancer drugs. However, their wide spread use at the clinical stage is greatly restricted due to several factors such as low solubility in an aqueous medium, low bioavailability, low stability, and hormetic effect. To overcome these hindrances, nanotechnology can be exploited to develop nano-scale delivery systems that have the potential to enhance stability, and bioavailability and minimize the hermetic effect of ITCs.

Anticancer activity of broccoli, its organosulfur and polyphenolic compounds

The use of natural bioactive constituents from various food sources for anticancer purposes has become increasingly popular worldwide. Broccoli (Brassica oleracea var. italica) is on the top of the consumed vegetables by the masses. Its raw matrix contains a plethora of phytochemicals, such as glucosinolates and phenolic compounds, along with rich amounts of vitamins, and minerals. Consumption of broccoli-derived phytochemicals provides strong antioxidant effects, particularly due to its sulforaphane content, while modulating numerous molecules involved in cell cycle regulation, control of apoptosis, and tuning enzyme activity. Thus, the inclusion of broccoli in the daily diet lowers the susceptibility to developing cancers. Numerous studies have underlined the undisputable role of broccoli in the diet as a chemopreventive raw food, owing to the content in sulforaphane, an isothiocyanate produced as a result of hydrolysis of precursor glucosinolates called glucoraphanin. This review will provide evidence supporting the specific role of fresh florets and sprouts of broccoli and its key bioactive constituents in the prevention and treatment of different cancers; a number of studies carried out in the in vitro and in vivo conditions as well as clinical trials were analyzed.

Effects of nanocarbon solution treatment on the nutrients and glucosinolate metabolism in broccoli

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Nanocarbon application could enhance the total protein in broccoli, directly.

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18.75 L·ha⁻¹ nanocarbon solution greatly increase 22.9 % of glucoraphanin.

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Nanocarbon solution obviously reduces 4 indolic glucosinolate productions.

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Nanocarbon has great great impact on glucosinolate biosynthesis and pathway.

The effects of a nanocarbon solution on the nutrients, glucosinolate metabolism and glucoraphanin pathway in broccoli were investigated. Significant positive linear relationships were observed between the nanocarbon solution and total protein yield, although effects on the soluble sugars, vitamin C and dry matter production were not observed. All nanocarbon solutions significantly increased the glucoraphanin content (p < 0.05), and the 18.75 L·ha⁻¹ nanocarbon solution maximally increased the glucoraphanin content by 22.9 %. However, these treatments also significantly reduced the contents of glucobrassicin, 4-methoxyglucobrassicin, 4-hydroxyglucobrassicin and neoglucobrassicin. Further research demonstrated that the 18.75 L·ha⁻¹ nanocarbon solution significantly upregulated the MAM1, IPMI2, CYP79F1, FMOgs-ox2, AOP2, and TGG1 expression levels, which directly resulted in the accumulation of glucoraphanin and glucoerucin. This study provides insights into the prospective nanotechnological approaches for developing efficient and environmentally friendly nanocarbon solution for use on crops.

The effect of Brassica vegetables on blood glucose levels and lipid profiles in adults. A systematic review and meta-analysis

Previous studies on the effect of Brassica vegetables on blood glucose and lipid profile have reported inconclusive findings. Due to the high prevalence of glucose and lipid metabolism disorders and their importance as predictors of chronic diseases, the present meta-analysis was performed to clarify the effect of Brassica vegetables on blood glucose and lipid profile. A systematic search of the databases of PubMed, Scopus, and Cochran Library was performed up to October 2020. All randomized controlled trials (RCTs) that examined the effect of Brassica vegetables on blood glucose and lipid profile were included in the study. The search results were limited to English-language publications. Finally, nine RCTs, including 548 participants, were selected for the present study. Pooled analysis indicated a significant reduction in total cholesterol (TC) (SMD = -0.28, 95%CI: 0.48 to 0.08; p = 0.005) following Brassica vegetables consumption. Overall, Brassica vegetables had no significant impact on serum levels of triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fasting blood sugar, and glycated hemoglobin. Consumption of Brassica vegetables had a statistically significant effect on TC concentration. However, further high-quality studies are needed to firmly establish the clinical efficacy of these plants.

Characterisation of the Introgression of Brassica villosa Genome Into Broccoli to Enhance Methionine-Derived Glucosinolates and Associated Health Benefits

Broccoli cultivars that have enhanced accumulation of methionine-derived glucosinolates have been developed through the introgression of a novel allele of the MYB28 transcription factor from the wild species Brassica villosa. Through a novel k-mer approach, we characterised the extent of the introgression of unique B. villosa genome sequences into high glucosinolate broccoli genotypes. RNAseq analyses indicated that the introgression of the B. villosa MYB28 C2 allele resulted in the enhanced expression of the MYB28 transcription factor, and modified expression of genes associated with sulphate absorption and reduction, and methionine and glucosinolate biosynthesis when compared to standard broccoli. A adenine-thymine (AT) short tandem repeat (STR) was identified within the 5' untranslated region (UTR) B. villosa MYB28 allele that was absent from two divergent cultivated forms of Brassica oleracea, which may underpin the enhanced expression of B. villosa MYB28.

Bioavailability Study of Isothiocyanates and Other Bioactive Compounds of Brassica oleracea L. var. Italica Boiled or Steamed: Functional Food or Dietary Supplement?

The levels of bioactive compounds in broccoli and their bioavailability following broccoli intake can be affected by the cooking procedures used for vegetable preparation. In the present pilot study, we compared the human plasma bioavailability of antioxidant compounds (β-carotene, lutein and isothiocyanate) and of phylloquinone (vitamin K) on seven volunteers before and after the administration of boiled and steamed broccoli. Moreover, plasma isothiocyanate (ITCs) levels were also evaluated after the administration of a single dose of BroccoMax^®, a dietary supplement containing GLSs with active myrosinase. Steam-cooking has been demonstrated to promote higher plasma bioavailability in ITCs than boiling (AUC_STEAMED = 417.4; AUC_BOILED = 175.3) and is comparable to that reached following the intake of BroccoMax^®, a supplement containing glucoraphanin and active myrosinase (AUC = 450.1). However, the impact of boiling and steaming treatment on plasma bioavailability of lipophilic antioxidants (lutein and β-carotene) and of phylloquinone was comparable. The lutein and β-carotene plasma levels did not change after administration of steamed or boiled broccoli. Conversely, both treatments led to a similar increase of phylloquinone plasma levels. Considering the antioxidant action and the potential chemopreventive activity of ITCs, steaming treatments can be considered the most suitable cooking method to promote the health benefits of broccoli in the diet.

An Overview of Registered Clinical Trials on Glucosinolates and Human Health: The Current Situation

Epidemiological studies suggest a potential role of glucosinolates (GSLs) and isothiocyanates on human health. However, evidence from intervention studies, due to heterogeneity in features of study design, duration, participants, food or food components administered, and outcomes analyzed, is still insufficient. The current review aims to provide an overview of the trials on GSLs and GSL-rich foods registered over the last 20 years with the intention to summarize the main topics and results, but also the existing gaps that still need to be covered. Studies were collected by using ClinicalTrials.gov and the International Standard Randomized Controlled Trial Number (ISRCTN) registry. A total of 87 registered trials were identified with which most of them were performed by using extracts or pure compounds (n = 60) while few were conducted with GSL-rich foods (n = 27). In detail, sulforaphane was the most investigated compound, while broccoli was the most frequent food tested in the trials. The majority of the studies assessed the health effects of GSLs focusing on outcomes related to cancer and cognitive function, even if the current findings are not univocal. Emerging topics also included the study of GSLs and gut microbiota interaction and impact on skin health. Further attention was also drawn to the bioavailability of GSLs and/or derivatives from foods, extracts, and single compounds by also considering the contribution of the different genetic polymorphisms. In conclusion, although considerable efforts have been made to study GSLs and GSL-rich foods, further studies are necessary to provide evidence-based research and to corroborate the findings obtained. The interindividual response due to genetic polymorphisms should be further investigated in order to explore the contribution to the overall beneficial effect.

A Scoping Review of the Application of Metabolomics in Nutrition Research: The Literature Survey 2000-2019

Nutrimetabolomics is an emerging field in nutrition research, and it is expected to play a significant role in deciphering the interaction between diet and health. Through the development of omics technology over the last two decades, the definition of food and nutrition has changed from sources of energy and major/micro-nutrients to an essential exposure factor that determines health risks. Furthermore, this new approach has enabled nutrition research to identify dietary biomarkers and to deepen the understanding of metabolic dynamics and the impacts on health risks. However, so far, candidate markers identified by metabolomics have not been clinically applied and more efforts should be made to validate those. To help nutrition researchers better understand the potential of its application, this scoping review outlined the historical transition, recent focuses, and future prospects of the new realm, based on trends in the number of human research articles from the early stage of 2000 to the present of 2019 by searching the Medical Literature Analysis and Retrieval System Online (MEDLINE). Among them, objective dietary assessment, metabolic profiling, and health risk prediction were positioned as three of the principal applications. The continued growth will enable nutrimetabolomics research to contribute to personalized nutrition in the future.

Sulforaphane enhances long-term potentiation and ameliorate scopolamine-induced memory impairment

Increases in human life expectancy have led to increases in the prevalence of senile dementia and neurodegenerative diseases. This is a major problem because there are no curative treatments for these diseases, and patients with unmanaged cognitive and neurodegenerative symptoms experience many social problems. Sulforaphane is a type of organosulfur compound known as an isothiocyanate. It is derived from glucoraphanin, a compound found in cruciferous vegetables such as broccoli, brussels sprouts, and cabbages, via an enzymatic reaction that is triggered by plant damage (e.g., chewing). Sulforaphane exhibits activity against cancer, inflammation, depression, and severe cardiac diseases. It can also alleviate oxidative stress and neural dysfunction in the brain. However, there is insufficient knowledge about the electrophysiological and behavioral basis of the effects of sulforaphane on learning and memory. Therefore, we evaluated whether acute sulforaphane administration affected long-term potentiation (LTP) in organotypic cultured rat hippocampal tissues. We also measured the effect of sulforaphane on the performance of three behavioral tests, the Y-maze test, the passive avoidance test, and the Morris water maze, which assess short-term memory, avoidance memory, and short and long-term spatial memory, respectively. We found that sulforaphane increased the total field excitatory postsynaptic potential (fEPSP) in a dose-dependent manner after high frequency stimulation and attenuated scopolamine-induced interference of the fEPSP in the hippocampal CA1 area. Sulforaphane also restored cognitive function and inhibited memory impairment as indicated by the alleviation of the negative neurological effects of scopolamine, i.e, a lowered ratio of spontaneous alternation in the Y-maze, a reduced step-through latency in the passive avoidance test, and an increased navigation time in the Morris water maze. These results indicate that sulforaphane can effectively prevent the attenuation of LTP and cognitive abilities induced by cholinergic and muscarinic receptor blockade. Further research is warranted to explore the potential therapeutic and prophylactic utility of sulforaphane for improving learning and memory, especially in those suffering from neurodegenerative disorders.

Eruca sativa Mill. seed extract promotes anti-obesity and hypoglycemic effects in mice fed with a high-fat diet

Obesity is currently considered a major source of morbidity, with dramatic complications on health status and life expectancy. Several studies demonstrated the positive effects of Brassicaceae vegetables on obesity and related diseases, partially attributing these beneficial properties to glucosinolates and their derivatives isothiocyanates. Recently, isothiocyanates have been described as a hydrogen sulfide (H₂ S)-releasing moiety, suggesting that H₂ S may be at least in part responsible for the beneficial effects of Brassicaceae. In this work, the metabolic effects of an extract obtained from Eruca sativa Mill. seeds (E.S., Brassicaceae), containing high levels of glucoerucin, were evaluated in an experimental model of obesity. Male balb/c mice were fed for 10 weeks with standard (Std) diet or high fat (HF) diet supplemented with E.S. E.S. significantly contained the body weight gain in this obesity model, improving also glucose homeostasis. Interestingly, lower values of white adipose tissue mass and a significant reduction of adipocytes size were also observed. Moreover, E.S. enhanced the adipocytes metabolism, improving the citrate synthase activity and reduced triglyceride levels in mice fed with HF diet. Taken together, these results suggest that E.S. is endowed with an interesting translational and nutraceutical value in the prevention of metabolic disorders, suggesting that H₂ S could be a key player.

Fruit and vegetable consumption and cardiovascular diseases among Jordanians: a case-control study

OBJECTIVES

Fruit and vegetable intake has been reported as one of the significant protective factors against the development of cardiovascular diseases (CVD). This study aimed to assess the possible preventive effect of fruit and vegetable consumption on developing CVD.

METHODS

A total of 398 participants (205 cases and 193 controls) referred for elective coronary angiography with clinical suspicion of coronary artery disease to Prince Hamza Hospital in Amman were enrolled in this case-control study. Dietary data were collected separately from each patient using interview-based food frequency questionnaire.

RESULTS

The findings of the present study revealed that a total consumption of 3 servings of vegetable per day decreased significantly the risk of CVD to about 54% (OR = 0.46, 95% CI: 0.22-0.97, p = 0.033). Consumption of banana was found to reduce the risk of CVD to about 44% and 62% when consuming 1-2 and 3-6 servings/week, respectively, with p-value for trend 0.004. For the vegetables, the consumption of grape leaves and stuffed vegetables in general was significantly associated with lower risk of CVD. Increasing cauliflower consumption of 1-2 servings per week decreased CVD risk to about 37% (OR = 0.63, 95% CI: 0.38-0.98). Consuming up to 3-6 servings per week of mixed vegetables (OR = 0.10, 95% CI: 0.01-0.83) and onion (OR = 0.42, 95% CI: 0.22-0.80) revealed an inverse association with CVD development.

CONCLUSIONS

Adding to the present evidence, consumption of some fruits and vegetables could be considered as preventive factor against developing CVD. However, the association of consuming vegetables with preventing CVD was higher than the fruit consumption.

Current Landscape of NRF2 Biomarkers in Clinical Trials

The transcription factor NF-E2 p45-related factor 2 (NRF2; encoded by NFE2L2) plays a critical role in the maintenance of cellular redox and metabolic homeostasis, as well as the regulation of inflammation and cellular detoxication pathways. The contribution of the NRF2 pathway to organismal homeostasis is seen in many studies using cell lines and animal models, raising intense attention towards targeting its clinical promise. Over the last three decades, an expanding number of clinical studies have examined NRF2 inducers targeting an ever-widening range of diseases. Full understanding of the pharmacokinetic and pharmacodynamic properties of drug candidates rely partly on the identification, validation, and use of biomarkers to optimize clinical applications. This review focuses on results from clinical trials with four agents known to target NRF2 signaling in preclinical studies (dimethyl fumarate, bardoxolone methyl, oltipraz, and sulforaphane), and evaluates the successes and limitations of biomarkers focused on expression of NRF2 target genes and others, inflammation and oxidative stress biomarkers, carcinogen metabolism and adduct biomarkers in unavoidably exposed populations, and targeted and untargeted metabolomics. While no biomarkers excel at defining pharmacodynamic actions in this setting, it is clear that these four lead clinical compounds do touch the NRF2 pathway in humans.

Metabolic pathway engineering: Perspectives and applications

BACKGROUND

Metabolic engineering aims at contriving microbes as biocatalysts for enhanced and cost-effective production of countless secondary metabolites. These secondary metabolites can be treated as the resources of industrial chemicals, pharmaceuticals and fuels. Plants are also crucial targets for metabolic engineers to produce necessary secondary metabolites. Metabolic engineering of both microorganism and plants also contributes towards drug discovery. In order to implement advanced metabolic engineering techniques efficiently, metabolic engineers should have detailed knowledge about cell physiology and metabolism. Principle behind methodologies: Genome-scale mathematical models of integrated metabolic, signal transduction, gene regulatory and protein-protein interaction networks along with experimental validation can provide such knowledge in this context. Incorporation of omics data into these models is crucial in the case of drug discovery. Inverse metabolic engineering and metabolic control analysis (MCA) can help in developing such models. Artificial intelligence methodology can also be applied for efficient and accurate metabolic engineering.

CONCLUSION

In this review, we discuss, at the beginning, the perspectives of metabolic engineering and its application on microorganism and plant leading to drug discovery. At the end, we elaborate why inverse metabolic engineering and MCA are closely related to modern metabolic engineering. In addition, some crucial steps ensuring efficient and optimal metabolic engineering strategies have been discussed. Moreover, we explore the use of genomics data for the activation of silent metabolic clusters and how it can be integrated with metabolic engineering. Finally, we exhibit a few applications of artificial intelligence to metabolic engineering.

Profiling of Endogenous and Gut Microbial Metabolites to Indicate Metabotype-Specific Dietary Responses: A Systematic Review

Upon dietary exposure, the endogenous metabolism responds to the diet-derived nutrients and bioactive compounds, such as phytochemicals. However, the responses vary remarkably due to the interplay with other dietary components, lifestyle exposures, and intrinsic factors, which lead to differences in endogenous regulatory metabolism. These physiological processes are evidenced as a signature profile composed of various metabolites constituting metabolic phenotypes, or metabotypes. The metabolic profiling of biological samples following dietary intake hence would provide information about diet-that is, as the intake biomarkers and the ongoing physiological reactions triggered by this intake-thereby enable evaluation of the metabolic basis required to distinguish the different metabotypes. The capacity of nontargeted metabolomics to also encompass the unprecedented metabolite species has enabled the profiling of multiple metabolites and the corresponding metabotypes with a single analysis, decoding the complex interplay between diet, other relevant factors, and health. In this systematic review, we screened 345 articles published in English in January 2007-July 2018, which applied the metabolomics approach to profile the changes of endogenous metabolites in the blood related to dietary interventions, either derived by metabolism of gut microbiota or the human host. We excluded all the compounds that were directly derived from diet, and also the dietary interventions focusing on supplementation with individual compounds. After the removal of less relevant studies and assessment of eligibility, 49 articles were included in this review. First, we mention the contribution of individual factors, either modifiable or nonmodifiable factors, in shaping metabolic profile. Then, how different aspects of the diet would affect the metabolic profiles are disentangled. Next, the classes of endogenous metabolites altered following included dietary interventions are listed. We also discuss the current challenges in the field, along with future research opportunities.

Impact of Glucoraphanin-Mediated Activation of Nrf2 on Non-Alcoholic Fatty Liver Disease with a Focus on Mitochondrial Dysfunction

Non-alcoholic fatty liver disease (NAFLD) is a common disease in Western nations and ranges in severity from steatosis to steatohepatitis (NASH). NAFLD is a genetic-environmental-metabolic stress-related disease of unclear pathogenesis. NAFLD is triggered by caloric overconsumption and physical inactivity, which lead to insulin resistance and oxidative stress. A growing body of evidence indicates that mitochondrial dysfunction plays a critical role in the pathogenesis of NAFLD. Mitochondrial dysfunction not only promotes fat accumulation, but also leads to generation of reactive oxygen species (ROS) and lipid peroxidation, resulting in oxidative stress in hepatocytes. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important modulator of antioxidant signaling that serves as a primary cellular defense against the cytotoxic effects of oxidative stress. The pharmacological induction of Nrf2 ameliorates obesity-associated insulin resistance and NAFLD in a mouse model. Sulforaphane and its precursor glucoraphanin are derived from broccoli sprouts and are the most potent natural Nrf2 inducers—they may protect mitochondrial function, thus suppressing the development of NASH. In this review, we briefly describe the role of mitochondrial dysfunction in the pathogenesis of NASH and the effects of glucoraphanin on its development.

Crosstalk between mitochondrial metabolism and oxidoreductive homeostasis: a new perspective for understanding the effects of bioactive dietary compounds

Mitochondria play an important role in a number of fundamental cellular processes, including energy production, biosynthetic pathways and cellular oxidoreductive homeostasis (redox status), and their dysfunction can lead to numerous pathophysiological consequences. As the biochemical mechanisms orchestrating mitochondrial metabolism and redox homeostasis are functionally linked, mitochondria have been identified as a potential therapeutic target. Consequently, considerable effort has been made to evaluate the efficacy of natural compounds that modulate mitochondrial function. Molecules produced by plants (for example, polyphenols and isothiocyanates) have been shown to modulate mitochondrial metabolism/biogenesis and redox status; however, despite the existence of a functional link, few studies have considered the combined efficacy of these mitochondrial functions. The present review provides a complete overview of the molecular pathways involved in modulating mitochondrial metabolism/biogenesis and redox status. Crosstalk between these critical mechanisms is also discussed, whilst major data from the literature regarding their antioxidant abilities are described and critically analysed. We also provide a summary of recent evidence regarding the ability of several plant-derived compounds to target these mitochondrial functions. An in-depth understanding of the functional link between mitochondrial metabolism/biogenesis and redox status could facilitate the analysis of the biological effects of natural compounds as well as the development of new therapeutic approaches.

Broccoli or Sulforaphane: Is It the Source or Dose That Matters?

There is robust epidemiological evidence for the beneficial effects of broccoli consumption on health, many of them clearly mediated by the isothiocyanate sulforaphane. Present in the plant as its precursor, glucoraphanin, sulforaphane is formed through the actions of myrosinase, a β-thioglucosidase present in either the plant tissue or the mammalian microbiome. Since first isolated from broccoli and demonstrated to have cancer chemoprotective properties in rats in the early 1990s, over 3000 publications have described its efficacy in rodent disease models, underlying mechanisms of action or, to date, over 50 clinical trials examining pharmacokinetics, pharmacodynamics and disease mitigation. This review evaluates the current state of knowledge regarding the relationships between formulation (e.g., plants, sprouts, beverages, supplements), bioavailability and efficacy, and the doses of glucoraphanin and/or sulforaphane that have been used in pre-clinical and clinical studies. We pay special attention to the challenges for better integration of animal model and clinical studies, particularly with regard to selection of dose and route of administration. More effort is required to elucidate underlying mechanisms of action and to develop and validate biomarkers of pharmacodynamic action in humans. A sobering lesson is that changes in approach will be required to implement a public health paradigm for dispensing benefit across all spectrums of the global population.

Relation of Fruits and Vegetables with Major Cardiometabolic Risk Factors, Markers of Oxidation, and Inflammation

Noncommunicable diseases (NCDs) are considered to be the leading cause of death worldwide. Inadequate fruit and vegetable intake have been recognized as a risk factor for almost all NCDs (type 2 diabetes mellitus, cancer, and cardiovascular and neurodegenerative diseases). The main aim of this review is to examine the possible protective effect that fruit and vegetable consumption or their bioactive compounds may have on the development of NCDs such as atherosclerosis. The accumulated evidence on the protective effects of adequate consumption of fruits and vegetables in some cases, or the lack of evidence in others, are summarized in the present review. The main conclusion of this review is that well-designed, large-scale, long-term studies are needed to truly understand the role fruit and vegetable consumption or their bioactive compounds have in atherosclerosis.

The potential use of l-sulforaphane for the treatment of chronic inflammatory diseases: A review of the clinical evidence

According to the World Health Organisation, 70% of all deaths globally can be attributed to chronic inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease, respiratory conditions, cardiovascular diseases, diabetes and cancer. Chronic inflammation has a significant impact on the quality of life of affected individuals with an increased risk of developing other chronic inflammatory diseases. Given the limitations of current pharmaceuticals, there is an intense research interest in identifying novel dietary interventions that can regulate and alleviate inflammation. A diet rich in cruciferous vegetables has been extensively studied for its immediate and long-term health benefits, particularly in the context of cardiovascular disease and cancer. Cruciferous vegetables contain the precursor glucoraphanin, which is hydrolysed upon consumption to form l-sulforaphane (LSF), the primary active compound that mediates potential cardio-protective and anti-carcinogenic effects. LSF has been shown to have beneficial effects in vitro and in animal studies through its classical antioxidant and anti-inflammatory properties, and more recently its chromatin modifying effects. This review discusses the clinical evidence to date in relation to the use of LSF in the context of chronic inflammatory diseases as well as provide key mechanistic insights for these effects.

Intake of glucosinolates and risk of coronary heart disease in three large prospective cohorts of US men and women

Importance

Glucosinolates, a group of phytochemicals abundant in cruciferous vegetables, may have cardioprotective properties. However, no prospective study has evaluated the association of intake of glucosinolates with the risk of coronary heart disease (CHD).

Objective

The objective of the study was to evaluate the association between the intake of glucosinolates and incident CHD in US men and women.

Design

Prospective longitudinal cohort study.

Setting

Health professionals in the USA.

Participants

We followed 74,241 women in the Nurses’ Health Study (NHS; 1984–2012), 94,163 women in the NHSII (1991–2013), and 42,170 men in the Health Professionals Follow-Up Study (1986–2012), who were free of cardiovascular disease and cancer at baseline.

Exposure

Glucosinolate intake was assessed using validated semi-quantitative food frequency questionnaires at baseline and updated every 2–4 years during follow-up.

Main outcome measures

Incident cases of CHD were confirmed by medical record review.

Results

During 4,824,001 person-years of follow-up, 8,010 cases of CHD were identified in the three cohorts. After adjustment for major lifestyle and dietary risk factors of CHD, weak but significantly positive associations were observed for glucosinolates with CHD risk when comparing the top with bottom quintiles (hazard ratio [HR]:1.09; 95% CI: 1.01, 1.17; P_trend<0.001). Higher intakes of three major subtypes of glucosinolates were consistently associated with a higher CHD risk, although the association for indolylglucosinolate did not achieve statistical significance. Regarding cruciferous vegetable intake, participants who consumed one or more servings per week of Brussels sprouts (HR: 1.16; 95% CI: 1.06, 1.26; P<0.001) and cabbage (HR: 1.09; 95% CI: 1.02, 1.17; P=0.009) had a significantly higher CHD risk than those who consumed these cruciferous vegetables less than once per month.

Conclusion and relevance

In these three prospective cohort studies, dietary glucosinolate intake was associated with a slightly higher risk of CHD in US adults. These results warrant replications in further studies including biomarker-based studies. Further studies are needed to confirm these findings and elucidate mechanistic pathways that may underlie these associations.

Potential effects of sulforaphane to fight obesity

Obesity is linked to the onset of many diseases such as diabetes mellitus, cardiovascular diseases and cancer, among others. The prevalence of obesity nearly doubled worldwide between 1980 and 2014. Simultaneously, in the last decade, the effects of sulforaphane as a potential treatment for obesity have been investigated, with promising results. Fruits and vegetables and their processed agri-food co-products are good sources of natural health-promoting compounds. Brassica crops are among the most produced crops in the world and are a good source of glucoraphanin, which, following hydrolysis, releases sulforaphane. The Brassicaceae family generates large amounts of co-products with no intended use, causing negative economic and environmental impact. Valorization of these co-products could be achieved through their exploitation for the extraction of bioactive compounds such as sulforaphane. However, the extraction process still needs further improvement for its economic feasibility. This article reviews the potential effects of sulforaphane in the treatment of obesity, linked to the relevance of giving Brassica co-products added value, which is of key importance for the competitiveness of farmers and the agri-food industry. © 2018 Society of Chemical Industry.

Dietary glucosinolates and risk of type 2 diabetes in 3 prospective cohort studies

Background

Glucosinolates are a group of phytochemicals that are abundant in cruciferous vegetables and precursors of the potentially chemopreventive isothiocyanates. Isothiocyanates may reduce oxidative stress and inflammation, but little is known regarding the association between glucosinolate intake and risk of type 2 diabetes (T2D).

Objective

To evaluate the association between the intake of glucosinolates and the incidence of T2D in US men and women.

Design

This prospective cohort study investigated 200,907 women and men [71,256 women from the Nurses' Health Study (NHS; 1984-2012), 88,293 women from the NHS II (1991-2013), and 41,358 men from the Health Professionals Follow-Up Study (1986-2012)] who were free of diabetes, cardiovascular disease, and cancer at baseline. Diet was assessed using validated semiquantitative food frequency questionnaires. Self-reported T2D incidence was confirmed by a supplementary questionnaire.

Results

During follow-up in the 3 cohorts, we accumulated 4,303,750 person-years and 16,567 incident cases of T2D. After adjustment for major lifestyle and dietary risk factors for T2D, participants in the highest quintile of total glucosinolate intake had a 19% higher risk (95% CI: 13%, 25%; Ptrend < 0.001) of T2D than did those in the lowest quintile. The intake of 3 major glucosinolate subtypes was consistently and significantly associated with T2D risk, with pooled HRs ranging from 1.13 to 1.18 (all Ptrend < 0.001). A significant association was also observed between total cruciferous vegetable consumption and T2D (HR: 1.16; 95% CI :1.07, 1.25; Ptrend < 0.001). These associations persisted in subgroups defined by demographic, lifestyle, and other dietary factors.

Conclusions

Dietary glucosinolate intake was associated with a moderately higher risk of T2D in US adults. These results need to be replicated in further investigations, including biomarker-based studies. Mechanistic research is also needed to understand the relation between exposures to glucosinolates, isothiocyanates, and other metabolites with T2D risk. This trial was registered at clinicaltrials.gov as NCT03366532.

Reconstructing Biosynthetic Pathway of the Plant-Derived Cancer Chemopreventive-Precursor Glucoraphanin in Escherichia coli

Epidemiological data confirmed a strong correlation between regular consumption of cruciferous vegetables and lower cancer risk. This cancer preventive property is mainly attributed to the glucosinolate products, such as glucoraphanin found in broccoli that is derived from methionine. Here we report the first successful reconstruction of the complete biosynthetic pathway of glucoraphanin from methionine in Escherichia coli via gene selection, pathway design, and protein engineering. We used branched-chain amino transferase 3 to catalyze two transamination steps to ensure the purity of precursor molecules and used cysteine as a sulfur donor to simplify the synthesis pathway. Two chimeric cytochrome P450 enzymes were engineered and expressed in E. coli functionally. The original plant C-S lyase was replaced by the Neurospora crassa hercynylcysteine sulfoxide lyase. Other pathway enzymes were successfully mined from Arabidopsis thaliana, Brassica rapa, and Brassica oleracea. Biosynthesis of glucoraphanin upon coexpression of the optimized enzymes in vivo was confirmed by liquid chromatography-tandem mass spectrometry analysis. No other glucosinolate analogues (except for glucoiberin) were identified that could facilitate the downstream purification processes. Production of glucoraphanin in this study laid the foundation for microbial production of such health-beneficial glucosinolates in a large-scale.

miRNA processing gene polymorphisms, blood DNA methylation age and long-term ambient PM2.5 exposure in elderly men

AIM

We tested whether genetic variation in miRNA processing genes modified the association of PM2.5 with DNA methylation (DNAm) age.

PATIENTS & METHODS

We conducted a repeated measures study based on 552 participants from the Normative Aging Study with multiple visits between 2000 and 2011 (n = 940 visits). Address-level 1-year PM2.5 exposures were estimated using the GEOS-chem model. DNAm-age and a panel of 14 SNPs in miRNA processing genes were measured from participant blood samples.

RESULTS & CONCLUSION

In fully adjusted linear mixed-effects models, having at least one copy of the minor rs4961280 [AGO2] allele was associated with a lower DNAm-age (β = -1.13; 95% CI: -2.26 to -0.002). However, the association of PM2.5 with DNAm-age was significantly (Pinteraction  = 0.01) weaker in homozygous carriers of the major rs4961280 [AGO2] allele (β = 0.38; 95% CI: -0.20 to 0.96) when compared with all other participants (β = 1.58; 95% CI: 0.76 to 2.39). Our results suggest that miRNA processing impacts DNAm-age relationships. Graphical abstract: miRNA processing AGO2 polymorphism (rs4961280) modifies the association of long-term ambient fine particle exposure with blood DNA methylation age [Formula: see text] The graph depicts lines from a fully adjusted linear regression model with fine particle exposure levels ranging from the tenth to the ninetieth percentile, all other continuous variables held constant at their means, and all other categorical variables held at their most frequent level.

KEAP1 and Done? Targeting the NRF2 Pathway with Sulforaphane

BACKGROUND

Since the re-discovery of sulforaphane in 1992 and the recognition of the bioactivity of this phytochemical, many studies have examined its mode of action in cells, animals and humans. Broccoli, especially as young sprouts, is a rich source of sulforaphane and broccoli-based preparations are now used in clinical studies probing efficacy in health preservation and disease mitigation. Many putative cellular targets are affected by sulforaphane although only one, KEAP1-NRF2 signaling, can be considered a validated target at this time. The transcription factor NRF2 is a master regulator of cell survival responses to endogenous and exogenous stressors.

SCOPE AND APPROACH

This review summarizes the chemical biology of sulforaphane as an inducer of NRF2 signaling and efficacy as an inhibitor of carcinogenesis. It also provides a summary of the current findings from clinical trials using a suite of broccoli sprout preparations on a series of short-term endpoints reflecting a diversity of molecular actions.

KEY FINDINGS AND CONCLUSIONS

Sulforaphane, as a pure chemical, protects against chemical-induced skin, oral, stomach, colon, lung and bladder carcinogenesis and in genetic models of colon and prostate carcinogenesis. In many of these settings the antitumorigenic efficacy of sulforaphane is dampened in Nrf2-disrupted animals. Broccoli preparations rich in glucoraphanin or sulforaphane exert demonstrable pharmacodynamic action in over a score of clinical trials. Measures of NRF2 pathway response and function are serving as guideposts for the optimization of dose, schedule and formulation as clinical trials with broccoli-based preparations become more commonplace and more rigorous in design and implementation.

Enhancement Of Glucosinolate and Isothiocyanate Profiles in Brassicaceae Crops: Addressing Challenges in Breeding for Cultivation, Storage, and Consumer-Related Traits

Glucosinolates (GSLs) and isothiocyanates (ITCs) produced by Brassicaceae plants are popular targets for analysis due to the health benefits associated with them. Breeders aim to increase the concentrations in commercial varieties; however, there are few examples of this. The most well-known is Beneforté broccoli, which has increased glucoraphanin/sulforaphane concentrations compared to those of conventional varieties. It was developed through traditional breeding methods with considerations for processing, consumption, and health made throughout this process. Many studies presented in the literature do not take a holistic approach, and key points about breeding, cultivation methods, postharvest storage, sensory attributes, and consumer preferences are not properly taken into account. In this review, we draw together data for multiple species and address how such factors can influence GSL profiles. We encourage researchers and institutions to engage with industry and consumers to produce research that can be utilized in the improvement of Brassicaceae crops.

Naringenin Attenuates H2O2-Induced Mitochondrial Dysfunction by an Nrf2-Dependent Mechanism in SH-SY5Y Cells

Mitochondria are the major site of ATP production in mammalian cells. Furthermore, these organelles are a source and a target of reactive oxygen species (ROS), such as radical anion superoxide (O₂^-·) and hydrogen peroxide (H₂O₂). The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is the master regulator of the mammalian redox biology and controls the expression of antioxidant and phase II detoxifying enzymes in several cell types. Naringenin (NGN, 5,7-dihydroxy-2-(4-hydroxyphenyl)-2,3-dihydrochromen-4-one), a flavanone, exhibits cytoprotective effects by acting as an antioxidant and anti-inflammatory agent. NGN is a potent activator of Nrf2. Nonetheless, it was not examine yet whether NGN would induce mitochondrial protection in cells under redox stress. Therefore, we investigate here whether Nrf2 would be involved in the mitochondrial protection elicited by NGN in SH-SY5Y cells exposed to H₂O₂. We observed that a pretreatment with NGN at 80 µM for 2 h reduced the levels of lipid peroxidation, protein carbonylation, and protein nitration in the membranes of mitochondria obtained from H₂O₂-treated SH-SY5Y cells. Additionally, NGN prevented the H₂O₂-induced impairment in the function of the enzymes aconitase, α-ketoglutarate dehydrogenase, and succinate dehydrogenase. The activites of the complexes I and V, as well as the production of ATP, were restored by NGN. NGN also suppressed the H₂O₂-induced mitochondria-related apoptosis. Interestingly, NGN promoted an increase in the levels of both total and mitochondrial glutathione (GSH). Silencing of Nrf2 abolished the protective effects induced by NGN. Overall, NGN induced mitochondrial protection by an Nrf2-dependent mechanism in H₂O₂-treated SH-SY5Y cells.

Antioxidant dietary approach in treatment of fatty liver: New insights and updates

Non-alcoholic fatty liver disease (NAFLD) is a common clinicopathological condition, encompassing a range of conditions caused by lipid deposition within liver cells. To date, no approved drugs are available for the treatment of NAFLD, despite the fact that it represents a serious and growing clinical problem in the Western world. Identification of the molecular mechanisms leading to NAFLD-related fat accumulation, mitochondrial dysfunction and oxidative balance impairment facilitates the development of specific interventions aimed at preventing the progression of hepatic steatosis. In this review, we focus our attention on the role of dysfunctions in mitochondrial bioenergetics in the pathogenesis of fatty liver. Major data from the literature about the mitochondrial targeting of some antioxidant molecules as a potential treatment for hepatic steatosis are described and critically analysed. There is ample evidence of the positive effects of several classes of antioxidants, such as polyphenols (i.e., resveratrol, quercetin, coumestrol, anthocyanins, epigallocatechin gallate and curcumin), carotenoids (i.e., lycopene, astaxanthin and fucoxanthin) and glucosinolates (i.e., glucoraphanin, sulforaphane, sinigrin and allyl-isothiocyanate), on the reversion of fatty liver. Although the mechanism of action is not yet fully elucidated, in some cases an indirect interaction with mitochondrial metabolism is expected. We believe that such knowledge will eventually translate into the development of novel therapeutic approaches for fatty liver.

Isothiocyanates are detected in human synovial fluid following broccoli consumption and can affect the tissues of the knee joint

Osteoarthritis is a major cause of disability and there is no current pharmaceutical treatment which can prevent the disease or slow its progression. Dietary advice or supplementation is clearly an attractive option since it has low toxicity and ease of implementation on a population level. We have previously demonstrated that sulforaphane, a dietary isothiocyanate derived from its glucosinolate precursor which is found in broccoli, can prevent cartilage destruction in cells, in in vitro and in vivo models of osteoarthritis. As the next phase of this research, we enrolled 40 patients with knee osteoarthritis undergoing total knee replacement into a proof-of-principle trial. Patients were randomised to either a low or high glucosinolate diet for 14 days prior to surgery. We detected ITCs in the synovial fluid of the high glucosinolate group, but not the low glucosinolate group. This was mirrored by an increase in ITCs and specifically sulforaphane in the plasma. Proteomic analysis of synovial fluid showed significantly distinct profiles between groups with 125 differentially expressed proteins. The functional consequence of this diet will now be tested in a clinical trial.

The multifaceted role of Nrf2 in mitochondrial function

The transcription factor nuclear factor erythroid 2 p45-related factor 2 (Nrf2) is the master regulator of the cellular redox homeostasis. Nrf2 target genes comprise of a large network of antioxidant enzymes, proteins involved in xenobiotic detoxification, repair and removal of damaged proteins, inhibition of inflammation, as well as other transcription factors. In recent years it has emerged that as part of its role as a regulator of cytoprotective gene expression, Nrf2 impacts mitochondrial function. Increased Nrf2 activity defends against mitochondrial toxins. Reduced glutathione, the principal small molecule antioxidant in the mammalian cell and a product of several of the downstream target genes of Nrf2, counterbalances mitochondrial ROS production. The function of Nrf2 is suppressed in mitochondria-related disorders, such as Parkinson's disease and Friedrich's ataxia. Studies using isolated mitochondria and cultured cells have demonstrated that Nrf2 deficiency leads to impaired mitochondrial fatty acid oxidation, respiration and ATP production. Small molecule activators of Nrf2 support mitochondrial integrity by promoting mitophagy and conferring resistance to oxidative stress-mediated permeability transition. Excitingly, recent studies have shown that Nrf2 also affects mitochondrial function in stem cells with implications for stem cell self-renewal, cardiomyocyte regeneration, and neural stem/progenitor cell survival.

Analysis and Quantification of Glucosinolates

Recent advances in liquid chromatography and mass spectrometry have made it possible to increase the throughput of phytochemical analyses at high sensitivity. These improvements have made it more feasible to monitor metabolic processes at the metabolite level. Glucosinolates, the primary defense compounds in the model plant Arabidopsis thaliana, in particular, have gained increasing attention as model compounds for quantitative genetics and metabolic regulation. Depending on the plant species, tissue, glucosinolate content, complexity of the glucosinolate profile, and, most importantly, the overall purpose of the experiment, different choices need to be made regarding the methods of extraction and analysis. In this chapter, we describe different approaches for the analysis of glucosinolates and highlight advantages, disadvantages, and technical pitfalls. © 2016 by John Wiley & Sons, Inc.

Optimization of Engineered Production of the Glucoraphanin Precursor Dihomomethionine in Nicotiana benthamiana

Glucosinolates are natural products characteristic of the Brassicales order, which include vegetables such as cabbages and the model plant Arabidopsis thaliana. Glucoraphanin is the major glucosinolate in broccoli and associated with the health-promoting effects of broccoli consumption. Toward our goal of creating a rich source of glucoraphanin for dietary supplements, we have previously reported the feasibility of engineering glucoraphanin in Nicotiana benthamiana through transient expression of glucoraphanin biosynthetic genes from A. thaliana (Mikkelsen et al., 2010). As side-products, we obtained fivefold to eightfold higher levels of chain-elongated leucine-derived glucosinolates, not found in the native plant. Here, we investigated two different strategies to improve engineering of the methionine chain elongation part of the glucoraphanin pathway in N. benthamiana: (1) coexpression of the large subunit (LSU1) of the heterodimeric isopropylmalate isomerase and (2) coexpression of BAT5 transporter for efficient transfer of intermediates across the chloroplast membrane. We succeeded in raising dihomomethionine (DHM) levels to a maximum of 432 nmol g⁻¹ fresh weight that is equivalent to a ninefold increase compared to the highest production of this intermediate, as previously reported (Mikkelsen et al., 2010). The increased DHM production without increasing leucine-derived side-product levels provides new metabolic engineering strategies for improved glucoraphanin production in a heterologous host.

The impact of food structure on taste and digestibility

The current knowledge on how food structures relate to perception is discussed.

The emerging role of Nrf2 in mitochondrial function

The transcription factor NF-E2 p45-related factor 2 (Nrf2; gene name NFE2L2) allows adaptation and survival under conditions of stress by regulating the gene expression of diverse networks of cytoprotective proteins, including antioxidant, anti-inflammatory, and detoxification enzymes as well as proteins that assist in the repair or removal of damaged macromolecules. Nrf2 has a crucial role in the maintenance of cellular redox homeostasis by regulating the biosynthesis, utilization, and regeneration of glutathione, thioredoxin, and NADPH and by controlling the production of reactive oxygen species by mitochondria and NADPH oxidase. Under homeostatic conditions, Nrf2 affects the mitochondrial membrane potential, fatty acid oxidation, availability of substrates (NADH and FADH2/succinate) for respiration, and ATP synthesis. Under conditions of stress or growth factor stimulation, activation of Nrf2 counteracts the increased reactive oxygen species production in mitochondria via transcriptional upregulation of uncoupling protein 3 and influences mitochondrial biogenesis by maintaining the levels of nuclear respiratory factor 1 and peroxisome proliferator-activated receptor γ coactivator 1α, as well as by promoting purine nucleotide biosynthesis. Pharmacological Nrf2 activators, such as the naturally occurring isothiocyanate sulforaphane, inhibit oxidant-mediated opening of the mitochondrial permeability transition pore and mitochondrial swelling. Curiously, a synthetic 1,4-diphenyl-1,2,3-triazole compound, originally designed as an Nrf2 activator, was found to promote mitophagy, thereby contributing to the overall mitochondrial homeostasis. Thus, Nrf2 is a prominent player in supporting the structural and functional integrity of the mitochondria, and this role is particularly crucial under conditions of stress.

The spatiotemporal regulation of the Keap1-Nrf2 pathway and its importance in cellular bioenergetics

The Kelch-like ECH associated protein 1 (Keap1)–NF-E2 p45-related factor 2 (Nrf2) pathway regulates networks of proteins that protect against the cumulative damage of oxidants, electrophiles and misfolded proteins. The interaction between transcription factor Nrf2 and its main negative cytoplasmic regulator Keap1 follows a cycle whereby the protein complex sequentially adopts two conformations: ‘open’, in which Nrf2 binds to one monomer of Keap1, followed by ‘closed’, in which Nrf2 interacts with both members of the Keap1 dimer. Electrophiles and oxidants (inducers) are recognized by cysteine sensors within Keap1, disrupting its ability to target Nrf2 for ubiquitination and degradation. Consequently, the protein complex accumulates in the ‘closed’ conformation, free Keap1 is not regenerated and newly synthesized Nrf2 is stabilized to activate target-gene transcription. The prevailing view of the Keap1–Nrf2 pathway, for which there exists a wealth of experimental evidence, is that it lies at the heart of cellular defence, playing crucial roles in adaptation and survival under conditions of stress. More recently, the significance of Nrf2 in intermediary metabolism and mitochondrial physiology has also been recognized, adding another layer of cytoprotection to the repertoire of functions of Nrf2. One way by which Nrf2 influences mitochondrial activity is through increasing the availability of substrates (NADH and FADH₂) for respiration. Another way is through accelerating fatty acid oxidation (FAO). These findings reinforce the reciprocal relationship between oxidative phosphorylation and the cellular redox state, and highlight the key role of Nrf2 in regulating this balance.

Untargeted Metabolomics Reveals Predominant Alterations in Lipid Metabolism Following Light Exposure in Broccoli Sprouts

The consumption of vegetables belonging to the family Brassicaceae (e.g., broccoli and cauliflower) is linked to a reduced incidence of cancer and cardiovascular diseases. The molecular composition of such plants is strongly affected by growing conditions. Here we developed an unbiased metabolomics approach to investigate the effect of light and dark exposure on the metabolome of broccoli sprouts and we applied such an approach to provide a bird’s-eye view of the overall metabolic response after light exposure. Broccoli seeds were germinated and grown hydroponically for five days in total darkness or with a light/dark photoperiod (16 h light/8 h dark cycle). We used an ultra-performance liquid-chromatography system coupled to an ion-mobility, time-of-flight mass spectrometer to profile the large array of metabolites present in the sprouts. Differences at the metabolite level between groups were analyzed using multivariate statistical analyses, including principal component analysis and correlation analysis. Altered metabolites were identified by searching publicly available and in-house databases. Metabolite pathway analyses were used to support the identification of subtle but significant changes among groups of related metabolites that may have gone unnoticed with conventional approaches. Besides the chlorophyll pathway, light exposure activated the biosynthesis and metabolism of sterol lipids, prenol lipids, and polyunsaturated lipids, which are essential for the photosynthetic machinery. Our results also revealed that light exposure increased the levels of polyketides, including flavonoids, and oxylipins, which play essential roles in the plant’s developmental processes and defense mechanism against herbivores. This study highlights the significant contribution of light exposure to the ultimate metabolic phenotype, which might affect the cellular physiology and nutritional value of broccoli sprouts. Furthermore, this study highlights the potential of an unbiased omics approach for the comprehensive study of the metabolism.

Diet rich in high glucoraphanin broccoli reduces plasma LDL cholesterol: Evidence from randomised controlled trials

SCOPE

Cruciferous-rich diets have been associated with reduction in plasma LDL-cholesterol (LDL-C), which may be due to the action of isothiocyanates derived from glucosinolates that accumulate in these vegetables. This study tests the hypothesis that a diet rich in high glucoraphanin (HG) broccoli will reduce plasma LDL-C.

METHODS AND RESULTS

One hundred and thirty volunteers were recruited to two independent double-blind, randomly allocated parallel dietary intervention studies, and were assigned to consume either 400 g standard broccoli or 400 g HG broccoli per week for 12 weeks. Plasma lipids were quantified before and after the intervention. In study 1 (37 volunteers), the HG broccoli diet reduced plasma LDL-C by 7.1% (95% CI: -1.8%, -12.3%, p = 0.011), whereas standard broccoli reduced LDL-C by 1.8% (95% CI +3.9%, -7.5%, ns). In study 2 (93 volunteers), the HG broccoli diet resulted in a reduction of 5.1% (95% CI: -2.1%, -8.1%, p = 0.001), whereas standard broccoli reduced LDL-C by 2.5% (95% CI: +0.8%, -5.7%, ns). When data from the two studies were combined the reduction in LDL-C by the HG broccoli was significantly greater than standard broccoli (p = 0.031).

CONCLUSION

Evidence from two independent human studies indicates that consumption of high glucoraphanin broccoli significantly reduces plasma LDL-C.

Specific glucosinolate analysis reveals variable levels of epimeric glucobarbarins, dietary precursors of 5-phenyloxazolidine-2-thiones, in watercress types with contrasting chromosome numbers

Watercress obtained in food stores in the United States contained significant levels of epiglucobarbarin [(R)-2-hydroxy-2-phenylethylglucosinolate] and low levels of the 2S-epimer glucobarbarin identified by an HPLC+NMR+MS/MS approach. Typical combined levels were 4-7 μmol/g dry wt. The hydrolysis product, 5-phenyloxazolidine-2-thione (barbarin), was detected at similar levels as the precursor glucosinolates after autolysis of fresh watercress in water. Fragmentation patterns in MS(2) of reference desulfoglucosinolates were side chain specific and suitable for routine identification. Watercress was of two main glucosinolate chemotypes: Material from U.S. food stores had a complex profile including glucobarbarins, gluconasturtiin, indole glucosinolates and high levels (6-28 μmol/g dry wt.) of long-chain methylsulfinylalkyl and methylthioalkyl glucosinolates. Material from European food stores had a simple profile dominated by gluconasturtiin, with low levels of epiglucobarbarin and moderate levels of indole glucosinolates. Some wild U.S. material was similar to the U.S. food store type. Both types were found to be Nasturtium officinale by floral parts morphology. Cytological analysis of one U.S. food store accession indicated that it represented a chromosome-doubled variant within N. officinale. The nutritional consequences and invasive potential of the U.S. food store chemotype are discussed.

Sulforaphane and prostate cancer interception

Whereas much attention is focused on distinguishing newly diagnosed prostate cancers that will progress to become aggressive forms of the disease from those that will remain indolent, it is also appropriate to explore therapeutic and lifestyle interventions to reduce the risk of progression. Diets rich in broccoli have been associated with a reduction in risk of progression, which has been attributed to the compound sulforaphane. Although the mode of action of sulforaphane has been extensively studied in cell and animal models and a multiple of mechanisms that could underpin its protective effects have been proposed, recent evidence from human intervention studies suggests that sulforaphane is involved in a complex interplay between redox status and metabolism to result in a tissue environment that does not favour prostate cancer progression.

Key applications of plant metabolic engineering

Great strides have been made in plant metabolic engineering over the last two decades, with notable success stories including Golden rice. Here, we discuss the field's progress in addressing four long-standing challenges: creating plants that satisfy their own nitrogen requirement, so reducing or eliminating the need for nitrogen fertilizer; enhancing the nutrient content of crop plants; engineering biofuel feed stocks that harbor easy-to-access fermentable saccharides by incorporating self-destructing lignin; and increasing photosynthetic efficiency. We also look to the future at emerging areas of research in this field.

Epigenetic-based immune intervention for rheumatic diseases

Rheumatic disease is a large spectrum of heterogeneous conditions affecting the loco-motor system including joints, muscles, connective tissues, and soft tissues around the joints and bones. Many rheumatic diseases have an element of autoimmunity including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Aberrant epigenetic regulation of gene expression is emerging as a major factor within rheumatic disease, and indicates potential new therapeutic avenues of approach to these debilitating conditions. Understanding the precise role of epigenetics in the development and treatment of rheumatic diseases particularly those which have an associated autoimmune element may be important for the long-term management of such conditions.

The Nrf2 regulatory network provides an interface between redox and intermediary metabolism

Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2, also called Nfe2l2) is a transcription factor that regulates the cellular redox status. Nrf2 is controlled through a complex transcriptional/epigenetic and post-translational network that ensures its activity increases during redox perturbation, inflammation, growth factor stimulation and nutrient/energy fluxes, thereby enabling the factor to orchestrate adaptive responses to diverse forms of stress. Besides mediating stress-stimulated induction of antioxidant and detoxification genes, Nrf2 contributes to adaptation by upregulating the repair and degradation of damaged macromolecules, and by modulating intermediary metabolism. In the latter case, Nrf2 inhibits lipogenesis, supports β-oxidation of fatty acids, facilitates flux through the pentose phosphate pathway, and increases NADPH regeneration and purine biosynthesis; these observations suggest Nrf2 directs metabolic reprogramming during stress.

Nrf2 affects the efficiency of mitochondrial fatty acid oxidation

Transcription factor Nrf2 (NF-E2 p45-related factor 2) regulates the cellular redox homoeostasis and cytoprotective responses, allowing adaptation and survival under conditions of stress. The significance of Nrf2 in intermediary metabolism is also beginning to be recognized. Thus this transcription factor negatively affects fatty acid synthesis. However, the effect of Nrf2 on fatty acid oxidation is currently unknown. In the present paper, we report that the mitochondrial oxidation of long-chain (palmitic) and short-chain (hexanoic) fatty acids is depressed in the absence of Nrf2 and accelerated when Nrf2 is constitutively active. Addition of fatty acids stimulates respiration in heart and liver mitochondria isolated from wild-type mice. This effect is significantly weaker when Nrf2 is deleted, whereas it is stronger when Nrf2 activity is constitutively high. In the absence of glucose, addition of fatty acids differentially affects the production of ATP in mouse embryonic fibroblasts from wild-type, Nrf2-knockout and Keap1 (Kelch-like ECH-associated protein 1)-knockout mice. In acute tissue slices, the rate of regeneration of FADH2 is reduced when Nrf2 is absent. This metabolic role of Nrf2 on fatty acid oxidation has implications for chronic disease conditions including cancer, metabolic syndrome and neurodegeneration.