Effect of fruit juice intake on urinary quercetin excretion and biomarkers of antioxidative status

Bioactive Flavonoids: A Comprehensive Review on Pharmacokinetics and Analytical Aspects

Flavonoids are a diversified group of natural substances which were discovered to provide a variety of health benefits in human beings. Vegetables, fruits, wine and tea are the primary flavonoid dietary sources for humans and as the flavonoids are so closely connected to human dietary items and health, it is vital to explore the structural-activity connection. The arrangement, replacement of functional groups, and total number of hydroxyl groups around flavonoid's nucleus structure affect their biological activity, metabolism, and bioavailability. Various flavonoids have been proven to have hepatoprotective properties, that help in the prevention of coronary heart disease. Similarly, these flavonoids also possess anticancer, and anti-inflammatory activities. Flavonoids have been found to have a functional and structural link with their enzyme inhibitory action, that appears to have antiviral effect through acting as antioxidants, damaging cell membranes, blocking enzymes, activating mechanisms of host self-defense, and limiting virus penetration and attaching to cells. Identification, characterization, isolation, and biological role of flavonoids, as well as their uses on health advantages, are all major topics in research and development currently. This review represents a summary of various sources of flavonoids, class, subclass, their chemical structures, biological activities, the pharmacokinetics of flavonoids and various analytical, bioanalytical and electrochemical methods for determination of flavonoids from different matrices.

New perspectives on the therapeutic potential of quercetin in non-communicable diseases: Targeting Nrf2 to counteract oxidative stress and inflammation

Non-communicable diseases (NCDs), including cardiovascular diseases, cancer, metabolic diseases, and skeletal diseases, pose significant challenges to public health worldwide. The complex pathogenesis of these diseases is closely linked to oxidative stress and inflammatory damage. Nuclear factor erythroid 2-related factor 2 (Nrf2), a critical transcription factor, plays an important role in regulating antioxidant and anti-inflammatory responses to protect the cells from oxidative damage and inflammation-mediated injury. Therefore, Nrf2-targeting therapies hold promise for preventing and treating NCDs. Quercetin (Que) is a widely available flavonoid that has significant antioxidant and anti-inflammatory properties. It modulates the Nrf2 signaling pathway to ameliorate oxidative stress and inflammation. Que modulates mitochondrial function, apoptosis, autophagy, and cell damage biomarkers to regulate oxidative stress and inflammation, highlighting its efficacy as a therapeutic agent against NCDs. Here, we discussed, for the first time, the close association between NCD pathogenesis and the Nrf2 signaling pathway, involved in neurodegenerative diseases (NDDs), cardiovascular disease, cancers, organ damage, and bone damage. Furthermore, we reviewed the availability, pharmacokinetics, pharmaceutics, and therapeutic applications of Que in treating NCDs. In addition, we focused on the challenges and prospects for its clinical use. Que represents a promising candidate for the treatment of NCDs due to its Nrf2-targeting properties.

A detailed overview of quercetin: implications for cell death and liver fibrosis mechanisms

Background

Quercetin, a widespread polyphenolic flavonoid, is known for its extensive health benefits and is commonly found in the plant kingdom. The natural occurrence and extraction methods of quercetin are crucial due to its bioactive potential.

Purpose

This review aims to comprehensively cover the natural sources of quercetin, its extraction methods, bioavailability, pharmacokinetics, and its role in various cell death pathways and liver fibrosis.

Methods

A comprehensive literature search was performed across several electronic databases, including PubMed, Embase, CNKI, Wanfang database, and ClinicalTrials.gov, up to 10 February 2024. The search terms employed were "quercetin", "natural sources of quercetin", "quercetin extraction methods", "bioavailability of quercetin", "pharmacokinetics of quercetin", "cell death pathways", "apoptosis", "autophagy", "pyroptosis", "necroptosis", "ferroptosis", "cuproptosis", "liver fibrosis", and "hepatic stellate cells". These keywords were interconnected using AND/OR as necessary. The search focused on studies that detailed the bioavailability and pharmacokinetics of quercetin, its role in different cell death pathways, and its effects on liver fibrosis.

Results

This review details quercetin's involvement in various cell death pathways, including apoptosis, autophagy, pyroptosis, necroptosis, ferroptosis, and cuproptosis, with particular attention to its regulatory influence on apoptosis and autophagy. It dissects the mechanisms through which quercetin affects these pathways across different cell types and dosages. Moreover, the paper delves into quercetin's effects on liver fibrosis, its interactions with hepatic stellate cells, and its modulation of pertinent signaling cascades. Additionally, it articulates from a physical organic chemistry standpoint the uniqueness of quercetin's structure and its potential for specific actions in the liver.

Conclusion

The paper provides a detailed analysis of quercetin, suggesting its significant role in modulating cell death mechanisms and mitigating liver fibrosis, underscoring its therapeutic potential.

A critical examination of human data for the biological activity of quercetin and its phase-2 conjugates

This critical review examines evidence for beneficial effects of quercetin phase-2 conjugates from clinical intervention studies, volunteer feeding trials, and in vitro work. Plasma concentrations of quercetin-3-O-glucuronide (Q3G) and 3'-methylquercetin-3-O-glucuronide (3'MQ3G) after supplementation may produce beneficial effects in macrophages and endothelial cells, respectively, especially if endogenous deglucuronidation occurs, and lower blood uric acid concentration via quercetin-3'-O-sulfate (Q3'S). Unsupplemented diets produce much lower concentrations (<50 nmol/l) rarely investigated in vitro. At 10 nmol/l, Q3'S and Q3G stimulate or suppress, respectively, angiogenesis in endothelial cells. Statistically significant effects have been reported at 100 nmol/l in breast cancer cells (Q3G), primary neuron cultures (Q3G), lymphocytes (Q3G and3'MQ3G) and HUVECs (QG/QS mixture), but it is unclear whether these translate to a health benefit in vivo. More sensitive and more precise methods to measure clinically significant endpoints are required before a conclusion can be drawn regarding effects at normal dietary concentrations. Future requirements include better understanding of inter-individual and temporal variation in plasma quercetin phase-2 conjugates, their mechanisms of action including deglucuronidation and desulfation both in vitro and in vivo, tissue accumulation and washout, as well as potential for synergy or antagonism with other quercetin metabolites and metabolites of other dietary phytochemicals.

Association of Vegetable and Fruit Consumption with Urinary Oxidative Biomarkers in Teenaged Girls: A School-Based Pilot Study in Japan

Hexanoyl-lysine (HEL), 8-hydroxy-2'deoxyguanosine (8-OHdG), and dityrosine (DT) have served as potential biomarkers for detecting oxidative modified lipids, DNA, and proteins in biological samples, respectively. Whether regular higher levels of consumption of vegetables/fruit (V/F) would decrease oxidative modification of these biomolecules in the body remain unelucidated. To examine the association of regular V/F consumption with the generation of these reactive oxygen species-induced biomarkers, this study evaluated V/F consumption in a school-based sample of teenaged girls (mean age 15.6 ± 1.7 years, n = 103), and quantified the formation of oxidative stress biomarkers in their urine. Only 19.4% and 23.3% of participants reported that they consumed the recommended daily amount of vegetables and fruits, respectively. Individuals who consumed lower levels of fruit (<100g/day) or vegetables (<250g/day) had significantly higher HEL excretion in their urine than those who consumed higher levels of fruit (≥100g/day) (p < 0.05) or vegetables (≥250g/day) (p = 0.057). The results of a multiple regression analysis showed that vegetable consumption was an important inhibiting factor of early lipid peroxidation measured as HEL in urine, independent of various confounders (β = - 0.332, p < 0.05). The findings suggest that relatively higher consumption of vegetables would help in the prevention of early lipid peroxidation in adolescents.

The potential biological effects of quercetin based on pharmacokinetics and multi-targeted mechanism in vivo

Quercetin is a plant-derived polyphenol flavonoid that has been proven to be effective for many diseases. However, the mechanism and in vivo metabolism of quercetin remains to be clarified. It achieves a wide range of biological effects through various metabolites, gut microbiota and its metabolites, systemic mediators produced by inflammation and oxidation, as well as by multiple mechanisms. The all-round disease treatment of quercetin is achieved through the organic combination of multiple channels. Therefore, this article clarifies the metabolic process of quercetin in the body, and explores the new pattern of action of quercetin in the treatment of diseases.

Role of Phenolic Compounds in Human Disease: Current Knowledge and Future Prospects

Inflammation is a natural protective mechanism that occurs when the body's tissue homeostatic mechanisms are disrupted by biotic, physical, or chemical agents. The immune response generates pro-inflammatory mediators, but excessive output, such as chronic inflammation, contributes to many persistent diseases. Some phenolic compounds work in tandem with nonsteroidal anti-inflammatory drugs (NSAIDs) to inhibit pro-inflammatory mediators' activity or gene expression, including cyclooxygenase (COX). Various phenolic compounds can also act on transcription factors, such as nuclear factor-κB (NF-κB) or nuclear factor-erythroid factor 2-related factor 2 (Nrf-2), to up-or downregulate elements within the antioxidant response pathways. Phenolic compounds can inhibit enzymes associated with the development of human diseases and have been used to treat various common human ailments, including hypertension, metabolic problems, incendiary infections, and neurodegenerative diseases. The inhibition of the angiotensin-converting enzyme (ACE) by phenolic compounds has been used to treat hypertension. The inhibition of carbohydrate hydrolyzing enzyme represents a type 2 diabetes mellitus therapy, and cholinesterase inhibition has been applied to treat Alzheimer's disease (AD). Phenolic compounds have also demonstrated anti-inflammatory properties to treat skin diseases, rheumatoid arthritis, and inflammatory bowel disease. Plant extracts and phenolic compounds exert protective effects against oxidative stress and inflammation caused by airborne particulate matter, in addition to a range of anti-inflammatory, anticancer, anti-aging, antibacterial, and antiviral activities. Dietary polyphenols have been used to prevent and treat allergy-related diseases. The chemical and biological contributions of phenolic compounds to cardiovascular disease have also been described. This review summarizes the recent progress delineating the multifunctional roles of phenolic compounds, including their anti-inflammatory properties and the molecular pathways through which they exert anti-inflammatory effects on metabolic disorders. This study also discusses current issues and potential prospects for the therapeutic application of phenolic compounds to various human diseases.

Interaction between CETP Taq1B polymorphism and HEI, DQI and DPI on metabolic biomarkers in patients with type 2 diabetes

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a multidimensional consequence of environmental and genetic factors. Cholesteryl ester transfer protein (CETP) Taq1B polymorphism has been reported as a main predictor of dyslipidaemia, comprising an important complication in persons with T2DM. However, diet could affect T2DM patients metabolic health.

METHODS

We investigated the combination of gene-diet effects on some metabolic biomarkers. In our cross-sectional study, blood samples of 220 patients were collected. Dietary indices (healthy eating index, dietary quality index and dietary phytochemical index) were obtained from a validated semi-quantitative food frequency questionnaire. CETP Taq1B polymorphism was genotyped by a polymerase chain reaction-restriction fragment polymorphism method. Data were analysed by analysis of covariance.

RESULTS

The interaction between the CETP Taq1B polymorphism and dietary indices on low density lipoprotein/high density lipoprotein was significant (p < 0.001 both crude and adjusted models). In addition, the interaction between polymorphism and dietary quality index on total antioxidant capacity (p = 0.004 crude model, p = 0.005 after adjusting) and pentraxin 3 (p = 0.01 both crude and adjusted models) was significant. Also, the interaction between polymorphism and healthy eating index on waist circumference (p = 0.005 both crude and adjusted models) and dietary phytochemical index on interleukin-18 (p = 0.03 crude model) was significant.

CONCLUSIONS

Our results indicated the effect of CETP Taq1B polymorphism on some inflammatory and anthropometrics markers (total antioxidant capacity, pentraxin 3, interleukin-18, low density lipoprotein/high density lipoprotein and waist circumference) with high and low adherence to dietary incides.

Nanotechnology Innovations to Enhance the Therapeutic Efficacy of Quercetin

Quercetin is a flavonol present in many vegetables and fruits. Generally, quercetin can be found in aglycone and glycoside forms, mainly in leaves. The absorption of this compound occurs in the large and small intestine, where it suffers glucuronidation, sulfidation, and methylation to improve hydrophilicity. After metabolization, which occurs mainly in the gut, it is distributed throughout the whole organism and is excreted by feces, urine, and exhalation of carbon dioxide. Despite its in vitro cytotoxicity effects, in vivo studies with animal models ensure its safety. This compound can protect against cancer, cardiovascular diseases, chronic inflammation, oxidative stress, and neurodegenerative diseases due to its radical scavenging and anti-inflammatory properties. However, its poor bioavailability dampens the potential beneficial effects of this flavonoid. In that sense, many types of nanocarriers have been developed to improve quercetin solubility, as well as to design tissue-specific delivery systems. All these studies manage to improve the bioavailability of quercetin, allowing it to increase its concentration in the desired places. Collectively, quercetin can become a promising compound if nanotechnology is employed as a tool to enhance its therapeutic efficacy.

The Green Anti-Cancer Weapon. The Role of Natural Compounds in Bladder Cancer Treatment

Bladder cancer (BC) is the second most common genitourinary cancer. In 2018, 550,000 people in the world were diagnosed with BC, and the number of new cases continues to rise. BC is also characterized by high recurrence risk, despite therapies. Although in the last few years, the range of BC therapy has considerably widened, it is associated with severe side effects and the development of drug resistance, which is hampering treatment success. Thus, patients are increasingly choosing products of natural origin as an alternative or complementary therapeutic options. Therefore, in this article, we aim to elucidate, using the available literature, the role of natural substances such as curcumin, sulforaphane, resveratrol, quercetin, 6-gingerol, delphinidin, epigallocatechin-3-gallate and gossypol in the BC treatment. Numerous clinical and preclinical studies point to their role in the modulation of the signaling pathways, such as cell proliferation, cell survival, apoptosis and cell death.

How Robust is the Evidence for a Role of Oxidative Stress in Autism Spectrum Disorders and Intellectual Disabilities?

Growing interest in the pathogenesis of autism spectrum disorders (ASDs) and other intellectual and developmental disabilities (IDD) has led to emerging evidence implicating a role for oxidative stress. However, understanding the strength of this association is made challenging by the use of a variety of purported biomarkers of oxidative stress, many of which have either uncertain specificity or flawed methods of analysis. This review aims to address this issue, which is widespread in the ASD and IDD literature, by providing readers with information concerning the strengths and limitations of the choice and analysis of biomarkers of oxidative stress. We highlight that biomarkers and assays should be specific, sensitive, reproducible, precise, robust, and chosen with careful consideration. Future studies should be sufficiently powered and address sample collection, processing, and storage which are, additionally, poorly considered, sources of bad practice, and potential errors. Only with these issues considered, will the data lead to conclusions as to the precise role of oxidative stress in ASDs and IDD.

Inclusion of Salvia hispanica L. and Chenopodium quinoa into bread formulations improves metabolic imbalances derived from a high-fat intake in hyperglycaemic mice

High-energy intake causes imbalances in nutrient homeostasis contributing to a high prevalence of metabolic chronic diseases. The extent to what metabolic imbalances can be ameliorated by the inclusion of immunonutritional ingredients obtained from flours favouring nutrient and calorie management remains poorly understood. Herein, it is demonstrated that partial replacement of wheat flour (WB) with that from Chenopodium quinoa varieties [red (RQ, 25% w/w) and white (WQ, 25% w/w)] as well as from Salvia hispanica L., [whole (Ch, 20% w/w) and semi-defatted (Ch_D, 20% w/w)] in bread formulations ameliorates the metabolic and inflammation consequences of high-fat diet consumption in hyperglycaemic animals. Feeding animals with bread formulations replacing wheat flour effectively reduced insulin resistance (by 2-fold, HOMAir). The reduction in starch content did not appear as a determinant of controlling HOMAir. Only animals fed with RQ and Ch diet displayed increased plasma levels of triglycerides, which significantly contributed to mitigate HFD-induced hepatic lipid peroxidation. The latter was increased in animals receiving Ch_D diet, where PUFAs were eliminated from chia's flour. Feeding with WQ and Ch samples caused an upward trend in hepatic TNF-α and IL-6 levels. Despite similarities between immunonutritional agonists in animals fed with RQ and WQ, IL-17 levels were quantified higher for animals fed with WQ. All bread formulations except Ch_D samples significantly increased the hepatic granulocyte-monocyte colony stimulation factor levels. These results indicated that replacement of wheat flour with that from quinoa and chia improved the metabolic imbalances in hyperglycaemic animals.

Effect of intravenous lidocaine on ischemia-reperfusion injury in DIEP microsurgical breast reconstruction. A prospective double-blind randomized controlled clinical trial

BACKGROUND

Ischemia-reperfusion injury in free flaps is associated with tissue damage and is one of the main factors causing flap failure in reconstructive microsurgery. The aim of this study is to assess whether any ischemia-reperfusion injury takes place during a microsurgical flap reconstruction as seen through the levels of malondialdehyde (MDA) and superoxide dismutase, biomarkers of oxidative stress, and to analyze the effect of lidocaine in this process.

METHODS

Twenty-four patients operated for immediate breast reconstruction using the Deep Inferior Epigastric Perforator free flap technique were divided into two groups: one group was treated with a lidocaine intravenous perfusion and the other group with a saline perfusion. MDA and superoxide dismutase (SOD) levels were measured at several points before, during, and after surgery.

RESULTS

There was an increase in MDA levels in both groups, but the lidocaine group experienced a decrease during reperfusion. On the other hand, we observed a rise in SOD levels in both groups, but a decrease during reperfusion in the placebo group. However, these differences between groups were not statistically significant.

CONCLUSIONS

The decreased SOD activity and increased MDA content in our research prove a redox imbalance and high reactive oxygen species levels in flaps, indicating that tissues experience ischemia-reperfusion injury during microsurgical reconstruction. Lidocaine may have a protective effect in free flap surgery, but our results were not statistically significant, so further studies will be required.

Twenty-five years of total antioxidant capacity measurement of foods and biological fluids: merits and limitations

This review summarises 25 years of investigations on antioxidants research in foods and biological fluids and critically analyses the merits and limitations of using the total antioxidant capacity (TAC) measurement in the metabolomic era. An enormous bulk of knowledge was produced regarding the antioxidant capacity of foods and large TAC databases were developed. A direct link between a food TAC value and any health benefit is erroneous and has led to several cases of consumer deception. However, the striking epidemiological evidence associating a high dietary TAC with some disease prevention and the availability of well-constructed TAC databases deserve attention and must be taken into account to establish the usefulness of measuring TAC in both foods and biological samples. The in vivo TAC measurement, usually performed in plasma, is influenced by many external factors, such as dietary habits, as well as environmental and behavioural factors, which are integrated towards homeostatic control by fine physiological mechanisms with high inter-individual variability. Therefore, plasma TAC cannot be considered as a unique biomarker of individual antioxidant status. However, the combined evaluation of plasma TAC with known markers of disease, individual metabolism, inflammation and genetics, as well as with markers of gut microbiota composition and activity, may lead to the identification of populations that are more responsive to food/diet TAC. In this framework, the appropriate use of TAC measurement both in food and in vivo can still provide support for the interpretation of complex phenomena and be a tool for sample screening when making a quick decision toward in-depth research investigations. © 2018 Society of Chemical Industry.

Quercetin reduces tendon adhesion in rat through suppression of oxidative stress

Background

Tendon adhesion is one of the most common clinical problems, which poses a considerable challenge to orthopedics doctors. Quercetin (QUE) as a popular drug at present, it has various biological functions, including anti-inflammatory, anti-ischemic, anti-peroxidation, and antioxidant. The purpose of this study was to investigate the effect of quercetin on tendon adhesion and whether quercetin can inhibit oxidative stress.

Method

Thirty-six rats were randomly divided into three groups, including control group, low QUE (50 mg/kg/day) group, and high QUE (100 mg/kg/day) group. After 1 week, the levels of SOD, MDA and GPx were measured. The degree of tendon adhesion was assessed by macroscopic evaluation and histological evaluation. After 4 weeks. Besides, the pharmacological toxicity of quercetin to main organs were evaluated by histological analysis.

Results

The extent of superoxide dismutase (SOD) and glutathione peroxidase (GPx) of tendon tissue in high QUE group was significantly higher than those of low QUE group and control group. And the extent of malondialdehyde (MDA) of tendon tissue in high QUE group was significantly lower than that of low QUE group and control group. By macroscopic evaluation and histological analysis, the extent of tendon adhesion in high QUE group was lower than low QUE group and control group. However, there were no significant changes of the major organs through histological analysis.

Conclusions

Quercetin may be a good and safe strategy in preventing tendon adhesion. But further clinical research is needed before its recommendation in the prevention and treatment of tendon adhesion.

Plasma Non-Enzymatic Antioxidant Capacity (NEAC) in Relation to Dietary NEAC, Nutrient Antioxidants and Inflammation-Related Biomarkers

(1) Background: Little is known about the interlinkages between dietary and plasma non-enzymatic antioxidant capacity (D-NEAC and P-NEAC, respectively) and the body’s antioxidant and inflammation response. Our aim was to explore these associations in 210 participants from two Spanish European Prospective Investigation into Cancer and Nutrition (EPIC) centers. (2) Methods: D-NEAC was estimated using published NEAC values in food. P-NEAC and total polyphenols (TP) were quantified by FRAP (ferric-reducing antioxidant power), TRAP (total radical-trapping antioxidant parameter), TEAC-ABTS (trolox equivalent antioxidant capacity-Azino Bis Thiazoline Sulfonic), ORAC (oxygen radical absorbance capacity) and Folin–Ciocalteu assays. Nutrient antioxidants (carotenes, α-tocopherol, ascorbic acid, retinol, uric acid, Q9 and Q10 coenzymes) and inflammation markers (IL-6, IL-8, CRP, TNF-α, PAI-I, resistin and adiponectin) were also analyzed. Spearman correlation and linear regression analyses were performed in association analyses. Analyses were stratified by covariates and groups were defined using cluster analysis. (3) Results: P-FRAP was correlated with D-NEAC, and significantly associated with P-NEAC in multivariate adjusted models. P-FRAP levels were also significantly associated with plasma antioxidants (log2 scale: TP β = 0.26; ascorbic acid β = 0.03; retinol β = 0.08; α-tocopherol β = 0.05; carotenes β = 0.02; Q10 β = 0.06; uric acid β = 0.25), though not with inflammation-related biomarkers. Different profiles of individuals with varying levels of P-NEAC and biomarkers were found. (4) Conclusions: P-NEAC levels were to some extent associated with D-NEAC and plasma antioxidants, yet not associated with inflammation response.

The Efficacy of Administering Fruit-Derived Polyphenols to Improve Health Biomarkers, Exercise Performance and Related Physiological Responses

Polyphenols are secondary metabolites involved in a myriad of critical processes in plants. Over recent decades, special attention has been paid to the anti-oxidative role of fruit-derived polyphenols in the human diet, with evidence supporting the contribution of polyphenols in the prevention of numerous non-communicable disease outcomes. However, due to the low concentration in biological fluids in vivo, the antioxidant properties of polyphenols seem to be related to an enhanced endogenous antioxidant capacity induced via signaling through the nuclear respiratory factor 2 pathway. Polyphenols also seem to possess anti-inflammatory and antioxidant properties and have been shown to enhance vascular function via nitric oxide mediated mechanisms. Consequently, there is rationale to support fruit-derived polyphenol supplementation to enhance exercise performance, possibly via improved muscle perfusion. Fruit-derived polyphenol supplementation in exercise studies have included a variety of fruits, e.g., New Zealand blackcurrant, pomegranate, and cherry, in the form of extracts (multicomponent or purified), juices and infusions to varying degrees of benefit. For example, research has yet to link the health-related benefits of black elderberry (Sambucus nigra L.) ingestion to exercise performance in spite of the purported health benefits associated with black elderberry provision in vitro and in vivo models, which has been attributed to their high antioxidant capacity and polyphenol content. This review summarizes the existing evidence supporting a beneficial effect of fruit-derived polyphenols on various biological processes and outlines the potential for black elderberry ingestion to improve nitric oxide production, exercise performance, and the associated physiological responses before-, during- and post-exercise.

Dietary Anthocyanins and Stroke: A Review of Pharmacokinetic and Pharmacodynamic Studies

Cerebrovascular accidents are currently the second major cause of death and the third leading cause of disability in the world, according to the World Health Organization (WHO), which has provided protocols for stroke prevention. Although there is a multitude of studies on the health benefits associated with anthocyanin (ACN) consumption, there is no a rigorous systematization of the data linking dietary ACN with stroke prevention. This review is intended to present data from epidemiological, in vitro, in vivo, and clinical studies dealing with the stroke related to ACN-rich diets or ACN supplements, along with possible mechanisms of action revealed by pharmacokinetic studies, including ACN passage through the blood-brain barrier (BBB).

The effect of Cistus incanus herbal tea supplementation on oxidative stress markers and lipid profile in healthy adults

BACKGROUND

Oxidative stress and dyslipidemia play a critical role in the development of cardiovascular disease (CVD). Regular intake of polyphenol-rich diets is associated with a reduced risk of CVDs.

METHODS

The present study was a pilot study with 24 healthy volunteers and was designed to determine if a 12-week administration of Cistus incanus herbal tea, containing phenolic acids and flavonoids, reduces cardiovascular risk factors including oxidative stress and dyslipidemia in healthy adults. Phenolic compounds profile and antibacterial activity of Cistus incanus infusion were also measured.

RESULTS

Herbal infusion led to improvement in lipid profile by increase (D4%, p = 0.033) high-density lipoprotein cholesterol concentration and decrease triglyceride (D14%, p = 0.013) concentrations. In addition, the Cistus incanus diet was associated with decreased serum concentrations of malondialdehyde (D16%, p < 0.01) and advanced oxidation protein products (D18%, p < 0.001).

CONCLUSIONS

Cistus incanus administration decreases cardiovascular risk factors including oxidative stress and dyslipidemia and this action supports the idea of using Cistus incanus tea on a daily basis as an effective dietary component for prevention of atherosclerotic CVD.

Blood-based redox-signature and their association to the cognitive scores in MCI and Alzheimer's disease patients

Oxidative stress plays a pivotal and early role in the pathophysiology of Alzheimer's disease (AD). There is convincing evidence that oxidative alterations in AD and in mild cognitive impairment (MCI) patients are not limited to the brain but are extended to the blood compartment. However, the oxidative pattern in plasma is still inconclusive. Moreover, their potential association with the clinical scores MMSE (Mini-Mental State Examination) and MoCA (Montreal Cognitive Assessment) is poorly investigated. The aim of our study was to establish a pattern of blood-based redox alterations in prodromal AD and their evolution during the progression of the disease. Our results showed a reduction in the total antioxidant capacity (TAC) and an increase of the stress-response proteins apolipoprotein J (ApoJ) and Klotho in MCI subjects. For the first time, we evidenced circulating-proteasome activity. We found that the alteration of the circulating-proteasome activity is associated with the accumulation of oxidized proteins in plasma form early AD. Interestingly, the TAC, the levels of vitamin D and the activity of proteasome were positively associated to the clinical scores MMSE and MoCA. The levels of protein carbonyls and of ApoJ were negatively associated to the MMSE and MoCA scores. The levels of apolipoprotein D (ApoD) were not different between groups. Interestingly, the receiver operating characteristic (ROC) curves analysis indicated that these redox markers provide a fair classification of different groups with high accuracy. Overall, our results strengthen the notion that some specific oxidative markers could be considered as non-invasive blood-based biomarkers for an early MCI diagnosis and AD progression.

Beyond the Antioxidant Activity of Dietary Polyphenols in Cancer: the Modulation of Estrogen Receptors (ERs) Signaling

The potential "health benefits" of dietary polyphenols have been ascribed to their direct antioxidant activity and their impact on the regulation of cell and tissue redox balance. However, because of the relative poor bioavailability of many of these compounds, their effects could not be easily explained by the antioxidant action, which may occur only at high circulating and tissue concentrations. Therefore, many efforts have been put forward to clarify the molecular mechanisms underlining the biological effect of polyphenols in physiological and pathological conditions. Polyphenols' bioavailability, metabolism, and their effects on enzyme, membrane, and/or nuclear receptors and intracellular transduction mechanisms may define the overall impact of these compounds on cancer risk and progression, which is still debated and not yet clarified. Polyphenols are able to bind to estrogen receptor α (ERα) and β (ERβ), and therefore induce biological effects in human cells through mimicking or inhibiting the action of endogenous estrogens, even at low concentrations. In this work, the role and effects of food-contained polyphenols in hormone-related cancers will be reviewed, mainly focusing on the different polyphenols' mechanisms of action with particular attention on their estrogen receptor-based effects, and on the consequences of such processes on tumor progression and development.

Human anthocyanin bioavailability: effect of intake duration and dosing

While in vitro and animal evidence supports a role for anthocyanins in human health, future opportunities in berry health benefits will rest upon evidence from clinical intervention trials. Because little is known about the behaviour of anthocyanins during long term intake in humans, several clinical design factors were examined. Urine from volunteers (n = 17) who consumed blueberry juice daily was analysed using LC-MS/MS for predicted flavonoid-based products of anthocyanins in relation to a 5-day anthocyanin-free run-in, 28 days of blueberry juice intake, a 7-day washout and two dosing regimens. Total and parent anthocyanin content in urine varied 10-fold among the 17 participants. A high 24-0 h total anthocyanin excretion was associated with high anthocyanin retention (i.e. 0 h, before blueberry juice intake). Total anthocyanin excretion was not different before and after up to 7 days of washout indicative of a slow release of anthocyanins. Urinary excretion of anthocyanins declined during the 36-day study. The 24-0 h excretion was greater for total anthocyanins but not for parent anthocyanins when daily blueberry juice was taken all at once rather than as ⅓ doses taken thrice daily. However parent anthocyanins were retained better (higher 0 h) with 1× dosing. These findings could aid in the design of clinical research on anthocyanins and health.

Dietary Flavonoids in the Prevention of T2D: An Overview

Type 2 diabetes (T2D) is a progressive metabolic disease that is increasing in prevalence globally. It is well established that insulin resistance (IR) and a progressive decline in functional β-cell mass are hallmarks of developing T2D. Obesity is a leading pathogenic factor for developing IR. Constant IR will progress to T2D when β-cells are unable to secret adequate amounts of insulin to compensate for decreased insulin sensitivity. Recently, a considerable amount of research has been devoted to identifying naturally occurring anti-diabetic compounds that are abundant in certain types of foods. Flavonoids are a group of polyphenols that have drawn great interest for their various health benefits. Results from many clinical and animal studies demonstrate that dietary intake of flavonoids might be helpful in preventing T2D, although cellular and molecular mechanisms underlying these effects are still not completely understood. This review discusses our current understanding of the pathophysiology of T2D and highlights the potential anti-diabetic effects of flavonoids and mechanisms of their actions.

Comparison of the effects of two antioxidant diets on oxidative stress markers in triathletes

Intense exercise generates an imbalance in the redox system. However, chronic exercise can yield antioxidant adaptations. A few studies with humans have investigated the effects of antioxidant diets on athletes. Therefore we compared the effects of two dietary interventions on oxidative stress in competitive triathletes. Thirteen male triathletes were selected and divided into 2 groups: one that had a regular antioxidant diet (RE-diet) and the other that had a high antioxidant diet (AO-diet). The diet period was 14 days and blood samples were collected before and after this period. The AO-diet provided twice the dietary reference intake (DRI) of α-tocopherol (30 mg), five times the DRI of ascorbic acid (450 mg), and twice the DRI of vitamin A (1800 g), while the RE-diet provided the DRI of α-tocopherol (15 mg), twice the DRI of ascorbic acid (180 mg) and the DRI of vitamin A (900 μg). The oxidative stress parameters evaluated were: thiobarbituric acid reactive substances (TBARS), total reactive antioxidant potential (TRAP), total sulfhydryl, carbonyl, superoxide dismutase (SOD) activity, hydrogen peroxide consumption and glutathione peroxidase (GPx) activity. We observed, after the diet period, an increase in sulfhydryl, TRAP, TBARS and SOD activity, and a decrease in carbonyl levels. However, no changes were found in hydrogen peroxide consumption or GPx activity. We concluded that antioxidant-enriched diets can improve the redox status of triathletes.

Bioavailability of Quercetin in Humans with a Focus on Interindividual Variation

After consumption of plant-derived foods or beverages, dietary polyphenols such as quercetin are absorbed in the small intestine and metabolized by the body, or they are subject to catabolism by the gut microbiota followed by absorption of the resulting products by the colon. The resulting compounds are bioavailable, circulate in the blood as conjugates with glucuronide, methyl, or sulfate groups attached, and they are eventually excreted in the urine. In this review, the various conjugates from different intervention studies are summarized and discussed. In addition, the substantial variation between different individuals in the measured quercetin bioavailability parameters is assessed in detail by examining published human intervention studies where sources of quercetin have been consumed in the form of food, beverages, or supplements. It is apparent that most reported studies have examined quercetin and/or metabolites in urine and plasma from a relatively small number of volunteers. Despite this limitation, it is evident that there is less interindividual variation in metabolites which are derived from absorption in the small intestine compared to catabolites derived from the action of microbiota in the colon. There is also some evidence that a high absorber of intact quercetin conjugates could be a low absorber of microbiota-catalyzed phenolics, and vice versa. From the studies reported so far, the reasons or causes of the interindividual differences are not clear, but, based on the known metabolic pathways, it is predicted that dietary history, genetic polymorphisms, and variations in gut microbiota metabolism would play significant roles. In conclusion, quercetin bioavailability is subject to substantial variation between individuals, and further work is required to establish if this contributes to interindividual differences in biological responses.

Association between single nucleotide polymorphisms in the antioxidant genes CAT, GR and SOD1, erythrocyte enzyme activities, dietary and life style factors and breast cancer risk in a Danish, prospective cohort study

Exposure to estrogens and alcohol consumption - the two only well-established risk factors for breast cancer - are capable of causing oxidative stress, which has been linked to progression of breast cancer. Here, five functional polymorphisms in the antioxidant genes SOD1, CAT and GSR were investigated in 703 breast cancer case-control pairs in the Danish, prospective “Diet, Cancer and Health” cohort together with gene-environment interactions between the polymorphisms, enzyme activities and intake of fruits and vegetables, alcohol and smoking in relation to breast cancer risk. Our results showed that genetically determined variations in the antioxidant enzyme activities of SOD1, CAT and GSR were not associated with risk of breast cancer per se. However, intake of alcohol, fruit and vegetables, and smoking status interacted with some of the polymorphisms in relation to breast cancer risk. Four polymorphisms were strongly associated with enzyme activity, but there was no interaction between any of the studied environmental factors and the polymorphisms in relation to enzyme activity. Additionally, single measurement of enzyme activity at entry to the cohort was not associated with risk of breast cancer. Our results therefore suggest that the antioxidant enzyme activities studied here are not major determinants of breast cancer risk.

Annurca (Malus pumila Miller cv. Annurca) apple as a functional food for the contribution to a healthy balance of plasma cholesterol levels: results of a randomized clinical trial

BACKGROUND

Recent human studies have evaluated the effect of daily apple consumption on plasma cholesterol level, which is recognized as an important risk factor for cardiovascular disease (CVD). Nevertheless, slightly significant effects have been generally registered although consuming more than two apples a day for several weeks.

RESULTS

This study describes the influence of daily consumption of Annurca apples on the cholesterol levels of mildly hypercholesterolaemic healthy subjects. A monocentric, randomized, parallel-group, placebo-controlled, 4-month study was conducted. The subjects (n = 250) were randomly assigned to five treatment groups (each one of 50 subjects: 28 men and 22 women). Four groups were administered one apple per day among the following: Red Delicious, Granny Smith, Fuji, Golden Delicious. The fifth group was asked to consume two Annurca apples per day, since the weight of this cultivar is on average half that of the commercial ones considered in this study. Comparing results, Annurca led to the most significant outcome, allowing a reduction in total and low-density lipoprotein cholesterol levels by 8.3% and 14.5%, respectively, and an increase in high-density lipoprotein cholesterol levels by 15.2% (all P < 0.001).

CONCLUSION

Our data would reasonably indicate Annurca apple as a useful tool to contribute to the prevention of CVD risk through normal diet. © 2016 Society of Chemical Industry.

Short-term biomarkers of apple consumption

SCOPE

Urinary biomarkers are used to estimate the nutritional intake of humans. The aim of this study was to distinguish between low, medium, and high apple consumption by quantifying possible intake biomarkers in urine samples after apple consumption by HPLC-MS/MS. Apples were chosen as they are the most consumed fruits in Germany.

METHODS AND RESULTS

Thirty subjects took part in 7-day study. They abstained from apples and apple products except for one weighed apple portion resembling one, two, or four apples. Before apple consumption and during the following days spot urine samples were collected. These urine samples were incubated with β-glucuronidase, diluted, and directly measured by HPLC-MS/MS. Phloretin, epicatechin, procyanidin B2, and quercetin were detected in urine using Scheduled MRM^TM mode. Phloretin was confirmed as a urinary biomarker of apple intake and had the ability to discriminate between low or medium (one or two apples) and high apple consumption (four apples). The groups also differ in the excretion of epicatechin and procyanidin B2.

CONCLUSION

Apple consumption can be monitored by urinary biomarkers for a period of at least 12 h after consumption. Furthermore the amount of apples consumed can be estimated by the concentration of certain biomarkers.

Modulation of hepatocarcinogenesis in N-methyl-N-nitrosourea treated Balb/c mice by mushroom extracts

The hepatoprotective potential of edible mushrooms from Mauritius, namely Pleurotus sajor-caju and Agaricus bisporus was evaluated using an N-methyl-N-nitrosourea (MNU)-induced hepatocarcinogenesis Balb/c mice model. Mushroom extracts restored normal weight in MNU treated mice over a 3 month supplementation period. Blood parameter analyses indicated a clear modulation of hemoglobin concentration, leukocyte, platelet, lymphocyte, neutrophil, monocyte and eosinophil counts in MNU-induced mice (p < 0.05). Mushroom extract supplementation effectively reduced oxidative damage in MNU-primed mice, which was marked by a significant decrease in the extent of lipid peroxidation (p < 0.05) and a concomitant increase in the enzymatic antioxidant levels, primarily catalase, superoxide dismutase, glutathione reductase and peroxidase, and FRAP values (p < 0.05). DNA protective effects of the extracts were confirmed by Raman spectroscopy, where, the MNU-DNA interaction, as evidenced by an intense peak at 1254 cm(-1), was normalized. The findings demonstrate hepatoprotective, immunomodulatory and anti-carcinogenic effects and suggest the use of mushrooms as potential dietary prophylactics in cancer chemoprevention.

Total antioxidant status in lung cancer is associated with levels of endogenous antioxidants and disease stage rather than lifestyle factors - preliminary study

Aim of the study

Decreased total antioxidant capacity (TAC) has been reported in different neoplasms, including lung cancer. However, no study concerning the relationship between endogenous antioxidants, lifestyle factors, and TAC has been conducted among lung cancer patients. The purpose of the study was to investigate the associations between endogenous antioxidants, severity of disease, lifestyle factors, and TAC in lung cancer patients.

Material and methods

The study was conducted among 59 lung cancer patients. The levels of total antioxidant status (ATBS method), endogenous antioxidants, and C-reactive protein were measured in patients’ sera automatically. Dietary habits of the subjects were evaluated based on the Food Frequency Questionnaire (FFQ) on the day of admission to hospital.

Results

We found a positive correlation between serum albumin, uric acid (UA), and TAC and a negative correlation between CRP and TAC. Moreover, TAC was significantly positively associated with disease stage. We did not find any significant relationship between the frequency of selected food consumption and TAC in lung cancer patients, except for a positive correlation between the frequency of refined cereal products consumption and TAC level. Smoking status did not correlate with TAC.

Conclusions

Total antioxidant status of lung cancer patients results from their disease stage and levels of endogenous antioxidants rather than from lifestyle factors. The lack of influence of diet and smoking on the TAC presumably result from disturbed homeostasis in which cancer, while developing, could determine the redox state to a greater extent than lifestyle factors.

Quercetin, Inflammation and Immunity

In vitro and some animal models have shown that quercetin, a polyphenol derived from plants, has a wide range of biological actions including anti-carcinogenic, anti-inflammatory and antiviral activities; as well as attenuating lipid peroxidation, platelet aggregation and capillary permeability. This review focuses on the physicochemical properties, dietary sources, absorption, bioavailability and metabolism of quercetin, especially main effects of quercetin on inflammation and immune function. According to the results obtained both in vitro and in vivo, good perspectives have been opened for quercetin. Nevertheless, further studies are needed to better characterize the mechanisms of action underlying the beneficial effects of quercetin on inflammation and immunity.

Bioactive compounds in pindo palm (Butia capitata) juice and in pomace resulting of the extraction process

BACKGROUND

Pindo palm (Butia capitata, Becc. 1916) is a tropical fruit native to South America and is relatively rich in bioactive compounds. It is often consumed as juice. The aim of this study was, first, to identify the degradation of these compounds by pasteurization and by cold storage (4 °C) of pindo palm juice. Physicochemical properties and concentrations of phenolic compounds, carotenoids and vitamin C have been evaluated on fresh and pasteurized juices. Moreover, another objective was to characterize the nutritional composition and the bioactive compounds of pindo palm pomace, the by-product of juice processing.

RESULTS

The results demonstrated a degradation of carotenoids with pasteurization and a degradation of vitamin C with both pasteurization and cold storage of juices. Furthermore, the evaluation of pindo palm pomace showed that it is relatively rich in total phenols (20.06 g gallic acid equivalents kg(-1) dry matter) and in β-carotene (0.22 g kg(-1) dry matter).

CONCLUSION

Thus, from the nutrition viewpoint, it does not seem interesting to pasteurize juice. On the other hand, extraction of carotenoids and phenolic compounds from the pomace appears to be a relevant process.

Antioxidative Activity of Onion Peel Extract in Obese Women: A Randomized, Double-blind, Placebo Controlled Study

BACKGROUND

Quercetin, found abundantly in onion peel, has been known to have anticholesterol, antithrombotic and insulin-sensitizing properties. Here, we investigated the effect of quercetin-rich onion peel extract (OPE) on reactive oxygen species (ROS) production and antioxidative defense in obese woman.

METHODS

This study was randomized, double-blind, placebo controlled study. Thirty-seven healthy obese participants were randomly assigned that eighteen subjects received red soft capsuled OPE (100 mg/d, 50 mg bis in die), while the other nineteen subjects received same capsuled placebo for 12 weeks. ROS production and superoxide dismutase (SOD) activity in plasma were determined by using ROS and SOD assay kits, respectively.

RESULTS

Baseline characteristics of anthropometric indicators and blood metabolic profiles were not significantly different between the two groups. Compared with baseline values, OPE consumption significantly reduced waist and hip circumference. Plasma ROS level and SOD activity were decreased in both placebo and OPE groups compared with baseline values. However, plasma ROS level in OPE group was significantly lower than in placebo group while plasma SOD activity in OPE group was significantly higher than in placebo group after 12 weeks of consumption.

CONCLUSIONS

These findings indicate that OPE consumption may exert antioxidative effect by preventing the decrease of SOD activity as well as the production of ROS in obese women.

Quercetin and Tryptanthrin: Two Broad Spectrum Anticancer Agents for Future Chemotherapeutic Interventions

The idea and practice of developing or identifying compounds capable of eliminating the transformed cells or cancer cells without being nontoxic to their normal counterparts deserves much importance. Since ages, plants have been considered and proven to be repertoires of chemicals possessing immense therapeutic potential. A proportion of these plant-derived compounds or phytochemicals were shown to be highly competent anticancer agents besides being effective against many other diseases. Representative compounds of different classes of phytochemicals are in clinical use against cancer. In this chapter, we discuss the anticancer potential of two compounds: quercetin, a flavonoid and tryptanthrin, an indoloquinazoline alkaloid, and the mechanisms behind their cytotoxic effects on cancers of different origin. The chapter also gives a brief mention of their properties that make them effective against cancer.

The potential for nutritional components of food items used for enrichment of research animals to act as confounding variables in toxicology studies

Produce and other non-certified foods may be provided to laboratory animals for enrichment, but this practice can generate scientific concerns, particularly if these food items contain nutrients that are pharmacologically active or affect animals' consumption of the basal diet. The author reviews information on potential for a number of nutritional components of food items to affect study data. On the basis of published effect levels, he proposes an upper limit for the consumption of each component in enrichment items relative to the amount present in a standard basal diet. He then assesses the amounts of these nutritional components in a broad range of food enrichment items and proposes a maximum serving size for each item for several common laboratory animals. Total caloric content and sugar content are the limiting components for many enrichment food items, but most items may be used as enrichment for laboratory animals without affecting study results, as long as the amounts of the items provided are managed.

Regular consumption of an antioxidant-rich juice improves oxidative status and causes metabolome changes in healthy adults

An improvement in oxidative status is associated with a reduction in the incidence of several chronic diseases. However, daily intake of antioxidants in Western diets is decreasing. This study evaluates the effect of daily consumption of an antioxidant-rich juice (ARJ) on oxidative status, cardiovascular disease risk parameters, and untargeted plasma and urine metabolomes. Twenty-eight healthy young adults participated in an 8-week clinical trial by drinking 200 mL of ARJ (pomegranate and grape) daily. At the end of the study, the subjects showed a significant decrease (-29%) in plasma lipid oxidation (malondialdehyde concentration), and a significant increase (+115%) in plasma antioxidant capacity. Plasma and urine metabolomes were also significantly modified and some ions modified in urine were identified, including metabolites of polyphenols, ascorbic acid and biliary acids. No significant changes were observed in lipid profile, inflammation, blood pressure or glycaemia. These results show that incorporating antioxidant-rich beverages into common diets may improve oxidative status in healthy subjects.

Anti-HIV-1 activity of flavonoid myricetin on HIV-1 infection in a dual-chamber in vitro model

HIV infection by sexual transmission remains an enormous global health concern. More than 1 million new infections among women occur annually. Microbicides represent a promising prevention strategy that women can easily control. Among emerging therapies, natural small molecules such as flavonoids are an important source of new active substances. In this study we report the in vitro cytotoxicity and anti-HIV-1 and microbicide activity of the following flavonoids: Myricetin, Quercetin and Pinocembrin. Cytotoxicity tests were conducted on TZM-bl, HeLa, PBMC, and H9 cell cultures using 0.01-100 µM concentrations. Myricetin presented the lowest toxic effect, with Quercetin and Pinocembrin relatively more toxic. The anti-HIV-1 activity was tested with TZM-bl cell plus HIV-1 BaL (R5 tropic), H9 and PBMC cells plus HIV-1 MN (X4 tropic), and the dual tropic (X4R5) HIV-1 89.6. All flavonoids showed anti-HIV activity, although Myricetin was more effective than Quercetin or Pinocembrin. In TZM-bl cells, Myricetin inhibited ≥90% of HIV-1 BaL infection. The results were confirmed by quantification of HIV-1 p24 antigen in supernatant from H9 and PBMC cells following flavonoid treatment. In H9 and PBMC cells infected by HIV-1 MN and HIV-1 89.6, Myricetin showed more than 80% anti-HIV activity. Quercetin and Pinocembrin presented modest anti-HIV activity in all experiments. Myricetin activity was tested against HIV-RT and inhibited the enzyme by 49%. Microbicide activities were evaluated using a dual-chamber female genital tract model. In the in vitro microbicide activity model, Myricetin showed promising results against different strains of HIV-1 while also showing insignificant cytotoxic effects. Further studies of Myricetin should be performed to identify its molecular targets in order to provide a solid biological foundation for translational research.

Production of Hydrogen Peroxide by Polyphenols and Polyphenol-rich Beverages underQuasi-physiological Conditions

To investigate the ability of the production of H(2)O(2) by polyphenols, we incubated various phenolic compounds and natural polyphenols under a quasi-physiological pH and temperature (pH 7.4, 37 degrees C), and then measured the formation of H(2)O(2) by the ferrous ion oxidation-xylenol orange assay. Pyrocatechol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, and polyphenols such as catechins yielded a significant amount of H(2)O(2). We also examined the effects of a metal chelator, pH, and O(2) on the H(2)O(2)-generating property, and the generation of H(2)O(2) by the polyphenol-rich beverages, green tea, black tea, and coffee, was determined. The features of the H(2)O(2)-generating property of green tea, black tea, and coffee were in good agreement with that of phenolic compounds, suggesting that polyphenols are responsible for the generation of H(2)O(2) in beverages. From the results, the possible significances of the H(2)O(2)-generating property of polyphenols for biological systems are discussed.

Anthocyanin metabolites are abundant and persistent in human urine

LC-MS/MS revealed that metabolites of anthocyanins (Acn) were abundant in human urine (n = 17) even after 5 days with no dietary Acn. After intake of 250 mL of blueberry juice, parent Acn were 4% and Acn metabolites were 96% of the total urinary Acn for the following 24 h. Multiple reaction monitoring revealed 226 combinations of mass transition × retention times for known Acn and predicted Acn metabolites. These were dominated by aglycones, especially aglycone glucuronides. The diversity of Acn metabolites could include positional isomers of Acn conjugates and chalcones. The persistence of Acn metabolites suggested enterohepatic recycling leading to prolonged residence time. The prevalence of Acn metabolites based on pelargonidin, which is not present in blueberry juice, may reflect ongoing dehydroxylation and demethylation of other Acn via xenobiotic and colonic bacterial action. The results suggest that exposure to Acn-based flavonoid moieties is substantially greater than suggested by earlier research.

Quercetin: a pleiotropic kinase inhibitor against cancer

Increased consumption of fruits and vegetables can represent an easy strategy to significantly reduce the incidence of cancer. From this observation, derived mostly from epidemiological data, the new field of chemoprevention has emerged in the primary and secondary prevention of cancer. Chemoprevention is defined as the use of natural or synthetic compounds able to stop, reverse, or delay the process of tumorigenesis in its early stages. A large number of phytochemicals are potentially capable of simultaneously inhibiting and modulating several key factors regulating cell proliferation in cancer cells. Quercetin is a flavonoid possessing potential chemopreventive properties. It is a functionally pleiotropic molecule, possessing multiple intracellular targets, affecting different cell signaling processes usually altered in cancer cells, with limited toxicity on normal cells. Simultaneously targeting multiple pathways may help to kill malignant cells and slow down the onset of drug resistance. Among the different substrates triggered by quercetin, we have reviewed the ability of the molecule to inhibit protein kinases involved in deregulated cell growth in cancer cells.

Anti-cancer potential of flavonoids: recent trends and future perspectives

Cancer is a major public health concern in both developed and developing countries. Several plant-derived anti-cancer agents including taxol, vinblastine, vincristine, the campothecin derivatives, topotecan, irinotecan and etoposide are in clinical use all over the world. Other promising anti-cancer agents include flavopiridol, roscovitine, combretastatin A-4, betulinic acid and silvestrol. From this list one can well imagine the predominance of polyphenols, flavonoids and their synthetic analogs in the treatment of ovarian, breast, cervical, pancreatic and prostate cancer. Flavonoids present in human diet comprise many polyphenolic secondary metabolites with broad-spectrum pharmacological activities including their potential role as anti-cancer agents. A positive correlation between flavonoids-rich diet (from vegetables and fruits) and lower risk of colon, prostate and breast cancers lead to a question that whether flavonoids mediate the protective effects as chemopreventive agents or can interact with different genes and proteins to play role in chemotherapy. The current review emphasizes onto the therapeutic potential of flavonoids and their synthetic analogs as anti-cancer agents by providing new insights into the factors, regulation and molecular mechanisms along with their significant protein interactions.

Interaction of plant phenols with food macronutrients: characterisation and nutritional-physiological consequences

Polyphenols are dietary constituents of plants associated with health-promoting effects. In the human diet, polyphenols are generally consumed in foods along with macronutrients. Because the health benefits of polyphenols are critically determined by their bioavailability, the effect of interactions between plant phenols and food macronutrients is a very important topic. In the present review, we summarise current knowledge, with a special focus on the in vitro and in vivo effects of food macronutrients on the bioavailability and bioactivity of polyphenols. The mechanisms of interactions between polyphenols and food macronutrients are also discussed. The evidence collected in the present review suggests that when plant phenols are consumed along with food macronutrients, the bioavailability and bioactivity of polyphenols can be significantly affected. The protein-polyphenol complexes can significantly change the plasma kinetics profile but do not affect the absorption of polyphenols. Carbohydrates can enhance the absorption and extend the time needed to reach a maximal plasma concentration of polyphenols, and fats can enhance the absorption and change the absorption kinetics of polyphenols. Moreover, as highlighted in the present review, not only a nutrient alone but also certain synergisms between food macronutrients have a significant effect on the bioavailability and biological activity of polyphenols. The review emphasises the need for formulations that optimise the bioavailability and in vivo activities of polyphenols.

Exposure of breastfed infants to quercetin after consumption of a single meal rich in quercetin by their mothers

SCOPE

The exposure to quercetin (Q) has not been studied in breastfed infants whose mothers were consuming a Q-rich diet. The objective of the study was to determine whether plant-origin antioxidant-Q passes from the mother's diet to her milk and to calculate the pharmacokinetic parameters of this phenomenon.

METHODS AND RESULTS

Eleven breastfeeding women were included in this controlled case study. Volunteers followed a Q-restricted diet for 5 consecutive days with the exception of the 3rd day when they received a single meal providing 1 mg of Q per kg of body weight. Urine analysis showed the presence of Q already in the first collected samples after the test (1.5-4 h), which indicated its rapid absorption from the meal. The Cmax = 68 ± 8.44 nmol/L concentration of Q in the milk was calculated for Tmax = 11.89 ± 3.37 h. It was significantly different (p = 0.007) from 40 nmol/L and (p = 0.016) from 42 nmol/L of Q concentration before and 48 h after the test, respectively.

CONCLUSIONS

Q was shown to be a component of human milk at the nmol/L level. Infants breastfed by mothers consuming a diet rich in Q are exposed to a dose of approximately 0.01 mg of Q daily.