Biomarkers of Dietary Polyphenols in Cancer Studies: Current Evidence and Beyond

Strategies of Elicitation to Enhance Bioactive Compound Content in Edible Plant Sprouts: A Bibliometric Study

Vegetable sprouts are a food source that presents high content of bioactive compounds which can also be enhanced through elicitation mechanisms. To better understand the scientific production and research trends on this topic, a bibliometric analysis by means of the Web of Science database was carried out. The results showed significant growth in research on the elicitation of edible plants sprouts. The three most productive journals were the Journal of Agricultural and Food Chemistry, followed by Food Chemistry and LWT-Food Science and Technology. The co-occurrence of keyword analysis of the different authors showed that the main research topics in this domain were 'germination', 'antioxidant activity', 'sprouts', 'glucosinolates' and 'phenolics'. The countries with the highest number of scientific publications were China, followed by India and USA. The productivity patterns of the authors conformed to Lotka's law. This study provides an overview of research on elicitation to enrich bioactive compounds in sprouts, and the need to review and update the trends on this subject.

Mass spectrometry-based metabolomics for the discovery of candidate markers of flavonoid and polyphenolic intake in adults

Robust biological markers of dietary exposure are essential in improving the understanding of the link between diet and health outcomes. Polyphenolic compounds, including flavonoids, have been proposed to mitigate the risk of chronic diseases where oxidative stress and inflammation play a central role. Biomarkers can provide objective measurement of the levels of polyphenolic compounds. In this study, we provide methodology to identify potential candidate markers of polyphenol intake in human serum. Seventeen participants from the UK arm of the Global Allergy and Asthma Network of Excellence (GA²LEN) had their dietary intake estimated using a validated food frequency questionnaire, and serum samples were assessed using mass spectrometry to identify potential candidate markers. 144 features were assigned identities, of these we identified four biologically relevant compounds (rhamnazin 3-rutinoside, 2-galloyl-1,4-galactarolactone methyl ester, 2″,32″-di-O-p-coumaroylafzelin and cyclocommunin), which were significantly increased in the serum of participants with high predicted level of fruit and vegetable intake. 2-galloyl-1,4-galactarolactone methyl ester was strongly correlated with total flavonoids (r = 0.62; P = 0.005), flavan-3-ols (r = 0.67; P = 0.002) as well as with other four subclasses. Rhamnazin 3-rutinoside showed strong correlation with pro-anthocyanidins (r = 0.68; P = 0.001), flavones (r = 0.62; P = 0.005). Our results suggest that serum profiling for these compounds might be an effective way of establishing the relative intake of flavonoids and could contribute to improve the accuracy of epidemiological methods to ascertain flavonoid intake.

The Relationship between Dietary Polyphenol Intakes and Urinary Polyphenol Concentrations in Adults Prescribed a High Vegetable and Fruit Diet

Urinary polyphenol metabolites are potential biomarkers of dietary polyphenol intake. The current study aims to evaluate associations between total diet, vegetable and fruit polyphenol intakes with urinary polyphenol metabolite concentrations in a sample of adults prescribed a diet rich in vegetables and fruit. Thirty-four participants completed a 10-week pre-post study. Participants were asked to consume Australian recommended daily vegetable and fruit serves and attend measurement sessions at baseline and at weeks 2 and 10. Two 24-h diet recalls were collected at each time-point and polyphenol intakes were calculated using the Phenol-Explorer database. Spot urine samples, collected at each time-point, were analyzed for 15 polyphenol metabolites using liquid chromatography-mass spectroscopy. Spearman’s correlation analyzes assessed the strength of relationships between urinary and dietary polyphenols. Linear mixed models were used to investigate relationships between polyphenol excretion and intake. Total urinary polyphenols were significantly correlated with total polyphenol intakes at week 10 (r_s = 0.47) and fruit polyphenols at week 2 (r_s = 0.38). Hippuric acid was significantly correlated with vegetable polyphenols at baseline (r_s = 0.39). Relationships were identified between individual polyphenol metabolites and vegetable and fruit polyphenols. Linear mixed model analyzes identified that for every 1 mg increase in polyphenol intakes, urinary polyphenol excretion increased by 16.3 nmol/g creatinine. Although the majority of relationships were not sufficiently strong or consistent at different time-points, promising relationships were observed between total urinary polyphenols and total polyphenol intakes, and hippuric acid and vegetable polyphenols.

Polyphenol-Enriched Extracts from Trapa acornis Husks Inhibit Her2-Positive SK-BR-3 Breast Cancer Cell Proliferation and In Vivo Tumor Angiogenesis

The study aimed to investigate the antitumor effects of Trapa acornis husks (TAH) extract on SK-BR-3 cells of Her2-positive breast cancer. The bioactive compounds of TAH extracts were analyzed qualitatively and quantitatively by Ultra-Performance Liquid Chromatography/Mass Spectrometry (UPLC-MS)/high-performance liquid chromatographic system (HPLC). The effects of TAH extracts on cell proliferation, cell cycle, and apoptosis of SK-BR-3 cells were determined by CCK-8 and flow cytometry. Besides, the In Vivo antitumor effect of TAH extracts was detected. UPLC-MS/HPLC showed that the main bioactive compounds of TAH were gallic acid and galloylglucose derivatives. TAH extracts significantly inhibited the proliferation of SK-BR-3 cells in a dose- and time-dependent manner (P < 0.01). With the increase of TAH extracts concentration, cells in G2/M stage were increased and cell apoptosis was significantly increased. Immunohistochemical analysis showed that TAH extracts can significantly reduce the positive expression rate of Ki67 and Factor VIII index in tumor tissues. The mRNA expression levels of VEGF, MMP2, MMP9, and uPA were reduced after TAH extracts intervention (P < 0.01). TAH extracts also decreased the protein expression of p-Her2, p-ERK1/2, VEGF, MMP2, MMP9, and uPA (P < 0.01). In conclusion, polyphenol-enriched extracts from TAH might inhibit breast cancer cell proliferation and In Vivo tumor angiogenesis.

Research trends in food chemistry: A bibliometric review of its 40 years anniversary (1976-2016)

This study presents a general bibliometric overview of the major scientific developments that have been published in Food Chemistry, since its first issue (1976). The bibliometric data were retrieved from the scopus database. The review identifies the most cited, productive authors, and the leading institutions and countries of the journal, based on bibliometric indicators. The research hot spots in the period from 1976 to 2016 were identified by using the visualization of similarities software (Vosviewer), and the graphical mapping of the authors was developed to visualize networks between authors. A total of 20,050 publications was analysed and the most influential subjects covered by the journal were identified. Topics related to the antioxidant components of foods and the analytical quantification of contaminants or components of food were identified as being most relevant.The bibliometric analyses indicate a significant evolution of the journal in terms of publications, scientometric performance and themes covered.

Androgen receptor and soy isoflavones in prostate cancer

Androgens and androgen receptor (AR) play a critical role not only in normal prostate development, but also in prostate cancer. For that reason, androgen deprivation therapy (ADT) is the primary treatment for prostate cancer. However, the majority of patients develop castration-resistant prostate cancer, which eventually leads to mortality. Novel therapeutic approaches, including dietary changes, have been explored. Soy isoflavones have become a focus of interest because of their positive health benefits on numerous diseases, particularly hormone-related cancers, including prostate and breast cancers. An important strategy for the prevention and/or treatment of prostate cancer might thus be the action of soy isoflavones on the AR signaling pathway. The current review article provides a detailed overview of the anticancer potential of soy isoflavones (genistein, daidzein and glycitein), as mediated by their effect on AR.

Long-term treatment with green tea polyphenols modifies the gut microbiome of female sprague-dawley rats

Green tea polyphenols (GTP) have been shown to exert a spectrum of health benefits to animals and humans. It is plausible that the beneficial effects of GTP are a result of its interaction with the gut microbiota. This study evaluated the effect of long-term treatment with GTP on the gut microbiota of experimental rats and the potential linkage between changes of the gut microbiota with the beneficial effects of GTP. Six-month-old Sprague-Dawley rats were randomly allocated into three dosing regimens (0, 0.5%, and 1.5% of GTP) and followed for 6 months. At the end of month 3 or month 6, half of the animals from each group were sacrificed and their colon contents were collected for microbiome analysis using 16S ribosomal RNA and shotgun metagenomic community sequencing. GTP treatment significantly decreased the biodiversity and modified the microbial community in a dose-dependent manner; similar patterns were observed at both sampling times. Multiple operational taxonomic units and phylotypes were modified: the phylotypes Bacteroidetes and Oscillospira, previously linked to the lean phenotype in human and animal studies, were enriched; and Peptostreptococcaceae previously linked to colorectal cancer phenotype was depleted in GTP treated groups in a dose-dependent manner. Several microbial gene orthologs were modified, among which genes related to energy production and conversion were consistently enriched in samples from month 6 in a dose-dependent manner. This study showed that long-term treatment with GTP induced a dose-dependent modification of the gut microbiome in experimental rats, which might be linked to beneficial effects of GTP.

An emerging trend in functional foods for the prevention of cardiovascular disease and diabetes: Marine algal polyphenols

Marine macroalgae are gaining recognition among the scientific community as a significant source of functional food ingredients. Due to the harsh environments in which macroalgae survive, they produce unique bioactive compounds that are not found in terrestrial plants. Polyphenols are the predominant bioactive compound in brown algae and are accountable for the majority of its biological activity. Phlorotannins are a type of polyphenol that are unique to marine sources and have exhibited protective effects against hyperglycemia, hyperlipidemia, inflammation and oxidative stress, known risk factors for cardiovascular disease and diabetic complications, in cell culture, animal studies and some human studies. This review updates the information on marine polyphenols, with a particular focus on phlorotannins and their potential health benefits in relation to the prevention and treatment of risk factors for type 2 diabetes and cardiovascular diseases.

Polyphenolic Phytochemicals in Cancer Prevention and Therapy: Bioavailability versus Bioefficacy

Natural polyphenols are organic chemicals which contain phenol units in their structures. They show antitumor properties. However, a key problem is their short half-life and low bioavailability under in vivo conditions. Still, definitively demonstrating the human benefits of isolated polyphenolic compounds (alone or in combination) using modern scientific methodology has proved challenging. The most common discrepancy between experimental and clinical observations is the use of nonphysiologically relevant concentrations of polyphenols in mechanistic studies. Thus, it remains highly controversial how applicable underlying mechanisms are with bioavailable concentrations and biological half-life. The present Perspective analyses proposed antitumor mechanisms, in vivo reported antitumor effects, and possible mechanisms that may explain discrepancies between bioavailability and bioefficacy. Polyphenol metabolism and possible toxic side effects are also considered. Our main conclusion emphasizes that these natural molecules (and their chemical derivatives) indeed can be very useful, not only as cancer chemopreventive agents but also in oncotherapy.

The role of lifestyle characteristics on prostate cancer progression in two active surveillance cohorts

BACKGROUND

Although much research has examined the relationship between lifestyle and prostate cancer (PCa) risk, few studies focus on the relationship between lifestyle and PCa progression. The present study examines this relationship among men initially diagnosed with low- to intermediate-risk PCa and managed with active surveillance (AS).

METHODS

Men enrolled in two separate AS programs were recruited for this study. Data regarding clinical, demographic and lifestyle characteristics were collected. Results were then compared between men whose disease remained low- to intermediate-risk and men whose disease progressed.

RESULTS

Demographic, clinical and physical characteristics were similar between comparative groups and cohorts, with the exception that age at the time of diagnosis and questionnaire was increased among men whose disease progressed. Lifestyle scores among men who remained low- to intermediate-risk were higher than those whose risk progressed; however, scores were only significant in one cohort on univariable analysis. On multivariable analysis, the only predictor of progression was age at diagnosis. Physical activity was consistently higher in both low risk groups, although this difference was insignificant. Consistent differences in other lifestyle variables were not observed.

CONCLUSIONS

Age remains an important predictor of PCa progression. Improving lifestyle characteristics among men initially managed with AS might help to reduce the risk of progression. Given the limitations of this study, more rigorous investigation is required to confirm whether lifestyle characteristics influence the progression of low- to intermediate-risk PCa.

Food Antioxidants and Their Anti-Inflammatory Properties: A Potential Role in Cardiovascular Diseases and Cancer Prevention

Mediterranean-style diets caused a significant decline in cardiovascular diseases (CVDs) in early landmark studies. The effect of a traditional Mediterranean diet on lipoprotein oxidation showed that there was a significant reduction in oxidative stress in the intervention group (Mediterranean diet + Virgin Olive Oil) compared to the low-fat diet group. Conversely, the increase in oxidative stress causing inflammation is a unifying hypothesis for predisposing people to atherosclerosis, carcinogenesis, and osteoporosis. The impact of antioxidants and anti-inflammatory agents on cancer and cardiovascular disease, and the interventive mechanisms for the inhibition of proliferation, inflammation, invasion, metastasis, and activation of apoptosis were explored. Following the Great Oxygen Event some 2.3 billion years ago, organisms have needed antioxidants to survive. Natural products in food preservatives are preferable to synthetic compounds due to their lower volatility and stability and generally higher antioxidant potential. Free radicals, reactive oxygen species, antioxidants, pro-oxidants and inflammation are described with examples of free radical damage based on the hydroxyl, nitric oxide and superoxide radicals. Flavonoid antioxidants with 2- or 3-phenylchroman structures such as quercetin, kaempferol, myricetin, apigenin, and luteolin, constituents of fruits, vegetables, tea, and wine, which may reduce coronary disease and cancer, are described. The protective effect of flavonoids on the DNA damage caused by hydroxyl radicals through chelation is an important mechanism, though the converse may be possible, e.g., quercetin. The antioxidant properties of carotenoids, which are dietary natural pigments, have been studied in relation to breast cancer risk and an inverse association was found with plasma concentrations: higher levels mean lower risk. The manipulation of primary and secondary human metabolomes derived especially from existing or transformed gut microbiota was explored as a possible alternative to single-agent dietary interventions for cancer and cardiovascular disease. Sustained oxidative stress leading to inflammation and thence to possibly to cancer and cardiovascular disease is described for spices and herbs, using curcumin as an example of an intervention, based on activation of transcription factors which suggest that oxidative stress, chronic inflammation, and cancer are closely linked.

Could gestational diabetes mellitus be managed through dietary bioactive compounds? Current knowledge and future perspectives

Gestational diabetes mellitus (GDM) is a serious problem growing worldwide that needs to be addressed with urgency in consideration of the resulting severe complications for both mother and fetus. Growing evidence indicates that a healthy diet rich in fruit, vegetables, nuts, extra-virgin olive oil and fish has beneficial effects in both the prevention and management of several human diseases and metabolic disorders. In this review, we discuss the latest data concerning the effects of dietary bioactive compounds such as polyphenols and PUFA on the molecular mechanisms regulating glucose homoeostasis. Several studies, mostly based on in vitro and animal models, indicate that dietary polyphenols, mainly flavonoids, positively modulate the insulin signalling pathway by attenuating hyperglycaemia and insulin resistance, reducing inflammatory adipokines, and modifying microRNA (miRNA) profiles. Very few data about the influence of dietary exposure on GDM outcomes are available, although this approach deserves careful consideration. Further investigation, which includes exploring the ‘omics’ world, is needed to better understand the complex interaction between dietary compounds and GDM.