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Antioxidant activity of blueberry fruit is impaired by association with milk
Abstract
The antioxidant properties of dietary phenolics are believed to be reduced in vivo because of their affinity for proteins. In this study we assessed the bioavailability of phenolics and the in vivo plasma antioxidant capacity after the consumption of blueberries (Vaccinium corymbosum L.) with and without milk. In a crossover design, 11 healthy human volunteers consumed either (a) 200 g of blueberries plus 200 ml of water or (b) 200 g of blueberries plus 200 ml of whole milk. Venous samples were collected at baseline and at 1, 2, and 5 h postconsumption. Ingestion of blueberries increased plasma levels of reducing and chain-breaking potential (+6.1%, p<0.001; +11.1%, p<0.05) and enhanced plasma concentrations of caffeic and ferulic acid. When blueberries and milk were ingested there was no increase in plasma antioxidant capacity. There was a reduction in the peak plasma concentrations of caffeic and ferulic acid (-49.7%, p<0.001, and -19.8%, p<0.05, respectively) as well as the overall absorption (AUC) of caffeic acid (p<0.001). The ingestion of blueberries in association with milk, thus, impairs the in vivo antioxidant properties of blueberries and reduces the absorption of caffeic acid.
... - Serafini et al., 2009 Probiotic yoghurt Soy isoflavones Crossover study with 31 volunteers ...
... They have concluded that there was no statistically significant differences between strawberry with cream and strawberry alone digestions (Mullen et al., 2008). On the other hand, Serafini et al. (2009) investigated the bioavailability and the in vivo plasma antioxidant capacity of polyphenols following the consumption of blueberries (Vaccinium corymbosum L.) with and without milk. They have conducted a crossover design study with 11 healthy human volunteers consuming 200 g of blueberries with 200 mL of water or 200 mL of whole milk. ...
... In case milk and blueberries were digested together, the plasma antioxidant capacity did not increase. The administration of blueberries together with milk, impaired the in vivo antioxidant activity of blueberries (Serafini et al., 2009). Nizamova, Ziyatdinova, and Budnikov (2011) suggested a method for measuring the polyphenol bioavailability using a coulometric titrant electrogenerated bromine. ...
Background:Dietary flavonoids have drawn great interest owing to their potential positive effects on health, which considerably rely on their bioaccessibility, transport and further metabolism in the body. One of the key parameters that influence the flavonoid bioavailability is the interaction of these compounds with other nutrients present in the human diet.
Scope and Approach:This review highlights the current findings on the influence of co-ingestion of flavonoids with other macro- (carbohydrates, lipids and proteins) and micro-constituents (vitamins, minerals, and other micronutrients) in foods.
Key Findings and Conclusions:Majority of both in vitro and in vivo studies in the literature suggest that proteins, dietary fiber, and minerals may induce disadvantageous impact on the bioavailability of flavonoids. On the other hand, lipids, digestible carbohydrates, vitamins, alkaloids, carotenoids and other flavonoids are likely to improve flavonoid bioavailability. Nevertheless, interaction of flavonoids with food matrix components is a complicated parameter that needs to be explored further in order to ensure utmost positive health effects to humans.
... In the same line, it was reported that the addition of milk had no significant effect on black tea catechin bioaccessibility [52]. By contrast, Serafini et al. (2009) observed that the absorption of blueberry phenolic compounds (caffeic and ferulic acid) was reduced when they were ingested with milk [53]. An important limitation of these studies is that, although the observed effect could be the result of an interaction between proteins and phenolic compounds, the involvement of other milk components such as lipids or carbohydrates cannot be discarded. ...
... In the same line, it was reported that the addition of milk had no significant effect on black tea catechin bioaccessibility [52]. By contrast, Serafini et al. (2009) observed that the absorption of blueberry phenolic compounds (caffeic and ferulic acid) was reduced when they were ingested with milk [53]. An important limitation of these studies is that, although the observed effect could be the result of an interaction between proteins and phenolic compounds, the involvement of other milk components such as lipids or carbohydrates cannot be discarded. ...
When analysing the beneficial effects of phenolic compounds, several factors that exert a clear influence should be taken into account. The content of phenolic compounds in foods is highly variable, directly affecting individual dietary intake. Once ingested, these compounds have a greater or lesser bioaccessibility, defined as the amount available for absorption in the intestine after digestion, and a certain bioavailability, defined as the proportion of the molecule that is available after digestion, absorption and metabolism. Among the external factors that modify the content of phenolic compounds in food are the variety, the cultivation technique and the climate. Regarding functional foods, it is important to take into account the role of the selected food matrix, such as dairy matrices, liquid or solid matrices. It is also essential to consider the interactions between phenolic compounds as well as the interplay that occurs between these and several other components of the diet (macro- and micronutrients) at absorption, metabolism and mechanism of action levels. Furthermore, there is a great inter-individual variability in terms of phase II metabolism of these compounds, composition of the microbiota, and metabolic state or metabotype to which the subject belongs. All these factors introduce variability in the responses observed after ingestion of foods or nutraceuticals containing phenolic compounds.
... Of the 18 eligible articles, 20 studies were described: 2 studies had exclusively male participants [28,29], 1 included women only [22], 12 included both males and females [12,[16][17][18][19][20]23,26,27,31,32], and 4 did not report genders [21,24,25,32]. Most studies (n = 10) recruited middleaged adults (mean age [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] [12,[17][18][19][20]22,25,26,28,31], 8 studies involved young adults (mean age [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] [16,20,21,23,24,27,29,32]. Mean age was not reported in 1 study [30]. The health statuses of participants varied-9 studies recruited healthy participants [12,[21][22][23][24]27,29,31,32] and 3 were restricted to the overweight or obese [19,25,26]. ...
... The effects of food matrices were also observed in in-vivo studies, in which an increased plasma antioxidant capacity was observed after healthy participants ingested blueberries with water, but not with defatted milk [53]. A similar study also noted greater plasma radicalscavenging levels from blueberry intake in the absence of food, but not when blueberries were consumed with milk [54]. It was speculated that the differing antioxidant capacities in these in-vivo studies were a result of varying anthocyanin bioavailability from matrix effects. ...
Accumulating epidemiological evidence suggests that anthocyanin intake is associated with reduced risks of cardiometabolic disorders, highlighting the importance of incorporating the phytochemical in our diets. Numerous food-based intervention studies have examined, in controlled meal settings, the role of anthocyanin on cardiometabolic health; but their effects have not been systematically summarized. This study aims to systematically review and summarize the effects of anthocyanin consumption with composite meals on cardiometabolic health from randomized controlled feeding trials. A systematic literature search for relevant human nutritional intervention studies was performed using PubMed, Embase, Cochrane Library, CINAHL Plus with Full Text, and Scopus databases. The Cochrane Risk of Bias tool was used to assess the study quality. Eighteen articles involving 371 participants were included in this review. Consistent improvements from anthocyanin intake were found in glycemic, gastric inhibitory peptide (GIP), interleukin-6 (IL-6), and oxygen radical absorbance capacity (ORAC) responses. Anthocyanin intake did not significantly affect other markers of energy metabolism, vascular functions, oxidative stress and antioxidant status, as well as inflammatory responses. Inconsistencies in successful outcomes between epidemiological studies and included interventions were largely attributed to matrix effects, which may impede the bioaccessibility of anthocyanins and consequently, limiting its health benefits when co-delivered with some foods.
... Also, co-consumption of milk and coffee impaired the bioavailability of chlorogenic acid in healthy individuals, leading to a decreased recovery of chlorogenic acid and related metabolites in the urine (Duarte and Farah 2011). Additionally, the combined consumption of milk and blueberry fruit reduced the peak plasma concentrations of constitutive phenolic acids as well as the overall absorption of caffeic acid in healthy volunteers (Serafini et al. 2009). This deteriorative effect of proteins on the bioavailability of co-ingested phenolics might constitute an explanation for the inconsistent outcomes of the health benefits of phenolic-rich food materials (Perez-Gregorio and Simal-Gandara 2017; Zhang, Yu, Sun, ). ...
... In human and animal trials, milk addition to black tea reduced the area under the curve of plasma catechins but did not obviate their ability to modulate oxidative stress and antioxidant status in healthy male adults (Reddy et al. 2005). Similarly, the ingestion of milk and blueberries did not induce differences in plasma markers of lipid oxidation in healthy volunteers (Serafini et al. 2009). However, the consumption of whole milk with jujube juice significantly reduced the plasma antioxidant capacity of male Wistar rats (Zhang et al. 2012). ...
Dietary proteins and phenolic compounds are commonly co-existing components that readily interact with each other to yield complexes in a wide range of food systems. The formed complexes play a critical role in the physiochemical characteristics of both reacting molecules, thereby impacting nutritional and quality profiles of related products. In this review, we provided the most updated knowledge on dietary protein-phenolic interactions related with food science and human nutrition, including their mechanisms of complexation, analytical technologies, and alterations in the functionality and nutraceutical properties of both reacting partners. Their potential applications in the industries regarding stability during food processing and storage, impacts on product quality, and fabrication of novel delivery systems for liable bioactives were also discussed. The interactions between dietary proteins and phenolics, either via non-covalent or covalent processes, are ubiquitous in food systems and are closely associated with chemical structures of both compounds and the surrounding conditions, mainly temperature, pH, and the presence of phenolic oxidases. Albeit in different ways, such intermolecular associations induced changes in protein conformational structures, which subsequently impacted their techno-functional properties, digestibility, and allergenic potentials; in turn, the bioaccessibility/bioavailability and health-protecting features of interacted phenolics were modified to various extents, as noticed by in vitro and in vivo evidence. Largely depending on the interaction molecules and preparation steps, those influences can be either favorable or unfavorable in different systems and therefore can be tailored to develop food products and nutraceuticals with maximized functionality and quality attributes.
... The washout period used was 7 d, based on previous observations (29) , after which the participant underwent the same testing methods with the other treatment arm, and during this washout period participants were instructed again not to consume any berries as part of the exclusion criteria. ...
... Blueberries are rich in both anthocyanins (approximately 92 mg/100 g) and phenolic acids (approximately 31 mg/ 100 g) (29) . The major anthocyanin components (out of a total fourteen anthocyanin species, approximately) are malvidin-3-O-arabinoside and the 3-O-galactosides of cyanidin, dephinidin, petinidin and malvidin (42) . ...
The consumption of berries has been linked to decreased risk of degenerative disease. Berries are regularly processed into juices. It is largely unknown how the juicing process affects the bioavailability of metabolites. As metabolomics has shown to be a valuable nutritional tool to study global metabolite differences, the aim of this study was to investigate the effect of juicing on the relative appearance of blueberry metabolites in humans using metabolomics. Nine healthy subjects consumed 250 g of fresh blueberries either as the whole fruit or after juicing, and provided blood and urine samples before and 2 h after intake in a cross-over design. Samples underwent metabolite profiling using LCMS, and data were mined with multivariate analysis. Overall, <12 % of all ions detected were significantly influenced by blueberry treatment ( P <0·05). Partial least-squared discriminant analysis models of post-treatment samples revealed good discrimination. In urinary samples, whole blueberry treatment resulted in 108 ions that were significantly higher compared with juiced treatment (positive and negative mode combined), whereas only eight were significantly higher after juiced treatment. Examples of putative annotations included metabolites of ferulic and caffeic acids, several phenolic metabolites conjugated to sulphate, glycoside or glucuronide and fatty acyl derivatives, which were of higher intensity after whole blueberry treatment. In conclusion, consumption of whole blueberries resulted in a higher range of phenolic and other metabolites in plasma and urine samples 2 h after consumption. Both whole and juiced blueberries resulted in very similar metabolite profiles at 2 h, although this was the only time point measured.
... Mullen et al. (2009) reported that milk hinders the absorption and excretion of cocoa flavan-3-ols, 10 and Serafini et al. found suppressed absorption of caffeic and ferulic acid when blueberries were consumed with milk compared to blueberries consumed with water. 11 In a study with strawberries served with and without cream, which is almost exclusively fat, oral bioavailability was not significantly different, however, the peak in pelargonidin-3-O-glucuronide, a major strawberry anthocyanin metabolite, was delayed by more than 1 hour (h). 12 In contrast, a recent in vitro digestion study by Cebaci et al. reported that whole or skim milk decreased the total phenolic content of blueberries as well as an oatmeal and blueberry mix, but does not impact the potential bioavailability measured by a co-digestion assay. ...
... reported reduced C max of caffeic and ferulic acids in plasma, as well as a significant reduction of caffeic acid absorption overall, when blueberries were consumed with whole milk. 11 Additionally, peak concentrations of plasma flavan-3-ols were significantly lower after healthy male subjects consumed tea with milk than those after consuming black tea alone. 33 The inhibitory effects of milk may be due to interactions among nutrients, and in the present study, the interaction of anthocyanins and milk proteins. ...
Strawberries are a dietary source of anthocyanins, particularly pelargonidin glycosides. Dietary anthocyanins have received increasing attention among researchers and consumers due to their health benefits. The oral bioavailability of anthocyanins is reported to be low and various dietary factors may influence their oral bioavailability further. Milk is suggested to reduce (poly)phenols’ oral bioavailability. However, the effect of milk on anthocyanin oral bioavailability remains uncertain. Likewise, mixed nutrient meals may influence the oral bioavailability of anthocyanins. Therefore, the purpose of this study was to assess the effect of milk on the oral bioavailability and other pharmacokinetic (PK) variables of strawberry anthocyanins consumed with and without a meal. Nine healthy participants consumed a strawberry beverage prepared in milk or water with a standard meal on two occasions. On two additional occasions, the beverages were given to a subset (n = 4) of participants to determine the impact of the meal on anthocyanin PK variables, including oral bioavailability. Independent of the meal, beverages prepared in milk significantly reduced the peak plasma concentrations (Cmax) of pelargonidin-3-O-glucoside (P-3-G), pelargonidin-glucuronide (PG) and pelargonidin-3-O-rutinoside (P-3-R), as well as the PG and P-3-R area under the curve (AUC) (p < 0.05) compared to beverages prepared in water. Milk did not influence the oral relative bioavailability of pelargonidin anthocyanins under meal conditions; however, the oral relative bioavailability of pelargonidin anthocyanins was reduced by ∼50% by milk under without meal conditions (p < 0.05). Consuming strawberry beverages made with milk and consuming those made with water with and without a meal influenced different aspects of strawberry anthocyanin PKs. The significance of this effect on clinical efficacy requires additional research.
... A reduction in antioxidant activity was positively correlated with the fat contents of milk samples. [112] Niseteo et al. [113] and Sanchez-Gonzalez et al. [114] reported a decrease in the antioxidant activity of coffee phenolics when milk was added to coffee, whereas Dupas et al. [115] could not find any significant effects of interactions with milk proteins on the antioxidant activity of coffee polyphenols. ...
... The in vivo antioxidant activity of green and black tea has been reported to be affected negatively when consumed with milk. [117][118][119][120] Serafini et al. [112] discussed the ingestion of blueberries with milk and concluded that consumption with milk impaired the in vivo antioxidant properties of blueberries. Similarly, chocolate polyphenols have been reported to pose a higher total antioxidant capacity in vivo compared to milk chocolate or dark chocolate ingested with milk. ...
The biological activity and techno-functional properties of phenolic compounds has gained great importance due to the epidemiologically-proved health benefits. Use of polyphenols as fortification agents for functional food production and nanotechnological approaches using natural vehicles for polyphenol delivery have been recently discussed. In this respect, milk proteins and dairy products represent unique characteristics for polyphenol studies. The conflicting results on the functionality of polyphenols interacting with milk proteins either in model systems or in complex dairy matrices reveal the need of future studies.
... Participants were instructed to consume two packets of powder (35 g)-which for the blueberries was the equivalent of two cups of fresh blueberries-daily for 180 days. Participants were further instructed that the powders were not to be heated, cooked, or added to already hot foods; it was also recommended that they not mix the powder with dairy products [23,24]. Participants recorded powder consumption times and details in a provided food diary. ...
... Data were collected in a standardized format with the aid of food models for accurate Participants were instructed to consume two packets of powder (35 g)-which for the blueberries was the equivalent of two cups of fresh blueberries-daily for 180 days. Participants were further instructed that the powders were not to be heated, cooked, or added to already hot foods; it was also recommended that they not mix the powder with dairy products [23,24]. Participants recorded powder consumption times and details in a provided food diary. ...
Blueberries are rich in antioxidants and may protect against disease. Uric acid accounts for about 50% of the antioxidant properties in humans. Elevated levels of serum uric acid (SUA) or hyperuricemia is a risk factor for cardiovascular disease (CVD). The aim was to determine the effect of blueberries on SUA in older adults. Participants (n = 133, 65–80 years) experiencing mild cognitive impairment (MCI) were randomized in a double-blind 6-month clinical trial to either blueberry or placebo. A reference group with no MCI received no treatment. The mean (SD) SUA at baseline were 5.45 (0.9), 6.4 (1.3) and 5.8 (1.4) mg/dL in reference, placebo, and treatment groups, respectively. Baseline SUA was different in men and women (6.25 (1.1) vs. 5.35 (1.1), p = 0.001). During the first three months, SUA decreased in the blueberry group and was significantly different from the placebo group in both men and women (p < 0.0003). Sex-specific differences became apparent after 3 months, when only men showed an increase in SUA in the blueberry group and not in the placebo (p = 0.0006) between 3 and 6 months. At 6 months SUA had rebounded in both men and women and returned to baseline levels. Baseline SUA was correlated with CVD risk factors, waist circumference and triglycerides (p < 0.05), but differed by sex. Overall, 6 m SUA changes were negatively associated with triglycerides in men, but not in women. Group-wise association between 6 m SUA changes and CVD risk factors showed associations with diastolic blood pressure, triglycerides and high-density lipoprotein (HDL) cholesterol in women of the Blueberry group but not in men or any sex in the placebo group. In summary, blueberries may affect SUA and its relationship with CVD risk in a sex-specific manner.
... Polyphenol bioavailability can also be impacted by the formation of polyphenol-protein complexes with exogenous proteins (such as those found in milk), but these noncovalent protein-polyphenol interactions are generally more likely to form with larger molecular weight polyphenols such as tannins rather than the lower molecular weight flavonoids [54]. Conflicting studies also exist regarding the extent of the effect of milk protein on flavonoid bioavailability, with some reporting no effect while others have reported lower levels of polyphenolic metabolites or lower antioxidant activity, suggesting lower bioavailability [55][56][57][58][59][60]. Interestingly, in the study by Reddy et al., the addition of milk lowered the apparent bioavailability of tea catechins by~20% (determined by the area under the curve of catechin plasma metabolites), but did not limit its antioxidant activity in vivo [58]. ...
Background
Submaximal endurance exercise has been shown to cause elevated gastrointestinal permeability, injury, and inflammation, which may negatively impact athletic performance and recovery. Preclinical and some clinical studies suggest that flavonoids, a class of plant secondary metabolites, may regulate intestinal permeability and reduce chronic low-grade inflammation. Consequently, the purpose of this study was to determine the effects of supplemental flavonoid intake on intestinal health and cycling performance.
Materials and methods
A randomized, double-blind, placebo-controlled crossover trial was conducted with 12 cyclists (8 males and 4 females). Subjects consumed a dairy milk-based, high or low flavonoid (490 or 5 mg) pre-workout beverage daily for 15 days. At the end of each intervention, a submaximal cycling trial (45 min, 70% VO 2 max) was conducted in a controlled laboratory setting (23°C), followed by a 15-minute maximal effort time trial during which total work and distance were determined. Plasma samples were collected pre- and post-exercise (0h, 1h, and 4h post-exercise). The primary outcome was intestinal injury, assessed by within-subject comparison of plasma intestinal fatty acid-binding protein. Prior to study start, this trial was registered at ClinicalTrials.gov (NCT03427879).
Results
A significant time effect was observed for intestinal fatty acid binding protein and circulating cytokines (IL-6, IL-10, TNF-α). No differences were observed between the low and high flavonoid treatment for intestinal permeability or injury. The flavonoid treatment tended to increase cycling work output (p = 0.051), though no differences were observed for cadence or total distance.
Discussion
Sub-chronic supplementation with blueberry, cocoa, and green tea in a dairy-based pre-workout beverage did not alleviate exercise-induced intestinal injury during submaximal cycling, as compared to the control beverage (dairy-milk based with low flavonoid content).
... Proteins also modify essential amino acids resulting in decreased bioavailability of phenolic compounds. 29 The addition of milk with a protein content of 8% triggers a decrease in phenolic and flavonoid levels. ...
The effect of milk on physicochemical and functional properties of kencur jelly drink has been investigated. The results of the analysis showed a decrease in water, ash, total sugar, phenol and flavonoid content, antioxidant activity, and syneresis in the kencur-milk jelly drinks. However, the addition of milk was detected to increase protein, fat, pH, and antibacterial activity against Salmonella typhimurium and Escherichia coli bacteria.
... The results observed after blueberry supplementation propound its protective effect against aging via neutralization of oxygen free radicals. Several studies indeed suggest a linear correlation between antioxidant activity and the total phenolic concentrations as well as anthocyanins in blueberries [40][41][42][43]. ...
Aging and age-related disorders are prominent issues. Aging is associated with a gradual impairment of physiology at the genetic, cellular, tissue, and whole organism level that directly influences the development of chronic diseases and organ failure. Blueberries, on the other hand, are well known for their high content of bioactive compounds and have demonstrated positive impacts on metabolic factors that influence health and general well-being. This study is aimed at evaluating the ameliorating the effects of blueberry on the liver of aged rats by monitoring changes in metabolic disturbances, oxidative stress, and inflammatory disruption. The aged group of rats was orally administered with blueberry extract (200 mg/kg) for a period of 4 weeks. The results revealed that aging was associated with an increase in body weight, liver weight, and metabolic parameters like serum insulin, triglycerides, total cholesterol, and liver function markers accompanied with a decrease in vitamin D levels. Furthermore, the results showed a significant diminish in the activities of antioxidant enzymes, glutathione content with an elevation in lipid peroxidation, inflammatory mediators (tumor necrosis factor alpha, interleukin 6, and nuclear factor kappa-light-chain-enhancer of activated B cells) as well as fibrotic markers (TGF-β1) in the liver of aged rats. Compared to the young rats (control group), blueberry effectively reversed age-mediated disruption of the aforementioned parameters. Hence, blueberries can be used as a potential therapeutic strategy for the management of age-related liver dysfunction and disease.
... Two of these compounds, vanillic acid and phenylacetic acid, showed greater bioavailability if dissolved in milk, while the other 7 were negatively affected with respect to water (ferulic acids, protocatechuic acid, 3,4-dihydroxyphenylacetic acid, 4-hydroxybenzoic acid, 4-hydroxyhippuric acid, caffeic and hippuric acid) (Urpi-Sarda et al., 2010). Another clinical study evaluated the bioavailability, at the plasma level, and the antioxidant capacity of phenolic compounds deriving from blueberries (Vaccinium corymbosum L.) consumed with or without the presence of milk: a net decrease in the plasma concentration of caffeic acid and ferulic acid was noted as well as a marked decreased antioxidant capacity in vivo in subjects consuming milk (Serafini et al., 2009). ...
Polyphenols are plant secondary metabolites, whose biological activity has been widely demonstrated. However, the research in this field is a bit reductive, as very frequently the effect of individual compound is investigated in different experimental models, neglecting more complex, but common, relationships that are established in the diet. This review summarizes the data that highlighted the interaction between polyphenols and other food components, especially macro- (lipids, proteins, carbohydrates and fibers) and micronutrients (minerals, vitamins and organic pigments), paying particular attention on their bioavailability, antioxidant capacity and chemical, physical, organoleptic and nutritional characteristics. The topic of food interaction has yet to be extensively studied because a greater knowledge of the food chemistry behind these interactions and the variables that modify their effects, could offer innovations and improvements in various fields ranging from organoleptic, nutritional to health and economic field.
... ABTS is an artificial free radical that is used for direct assessment of free radical scavenging activity whereas FRAP is a measure of the Fe 3+ -reducing ability of a sample. 25,26 We next examined the effects of MV on the total antioxidant capacity of H 2 O 2 -treated cells and found that treatment with 90 and 60 µg/mL MV significantly increased total antioxidant capacity (P<0.001; Figure 4B and C); moreover, the effects were superior to those of VC although they were not observed at a low MV concentration. ...
Purpose:
Damage caused by oxidative stress leads to the premature aging of cells. Mogrosides, the main active components of Siraitia grosvenorii, have strong antioxidant activity; however, it is unclear whether mogroside V (MV) exerts these effects in skin cells. This was investigated in the present study by evaluating the protective effects of MV against oxidative damage induced by hydrogen peroxide (H2O2) in skin fibroblasts.
Methods:
Mouse skin fibroblasts (MSFs) were treated with H2O2 and cell viability, total antioxidant capacity, reactive oxygen species (ROS) production, malondialdehyde (MDA) content, and antioxidant enzyme activity were assessed.
Results:
Treatment with MV reduced the ROS level and MDA content in MSFs treated with H2O2. This was accompanied by increased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities.
Conclusion:
MV reduces H2O2-induced oxidative stress and enhances endogenous antioxidant activity in skin fibroblasts. Thus, MV can potentially be used as an ingredient in anti-aging cosmetic products.
... Likewise, in a recent study from our group, long-term supplementation of BB juice boosted serum antioxidant activity in a healthy Wistar rats [130]. Nevertheless, there has been some controversy on BB-derived polyphenols benefits on total antioxidant activity in both in vivo and human studies [131][132][133][134][135]. Distinct BB doses, food matrices and/or alternative methodologies to assess total antioxidant status may foster such ambiguity. ...
Prediabetes, a subclinical impairment between euglycemia and hyperglycemia, is a risk factor for the development of type 2 diabetes mellitus (T2DM) and associated micro- and macrovascular complications. Lifestyle therapy, the first-line treatment of prediabetes, includes physical exercise and dietary regimens enriched in phytochemicals with health-related properties. Blueberries (Vaccinium spp.), given their pleasant taste and great abundance in beneficial phytochemicals, have gained public interest all over the world. Along with a high antioxidant activity, this functional fruit is also well-recognized due to its hypoglycemic and insulin-sensitizing effects and has been recommended for overt T2DM management. Yet blueberries target several other pathophysiological traits, namely gut microbiota dysbiosis and hepatic dysmetabolism, that ensue when prediabetes begins and for which pharmacological interventions tend to be delayed. In this work, we revisited preclinical data from in vitro assays, animal models and human studies, aiming to disclose the potential mechanisms by which blueberries may be a fruitful source of phytochemicals able to prevent (pre)diabetes progression. Collectively, future efforts should focus on longer-term studies with standardized interventions and readouts, particularly in humans, that will hopefully bring more robust evidence and concrete guidance for blueberries’ effective use in prediabetes.
... First, it included premenopausal women, but menstrual cycle hormonal fluctuation can influence cardiometabolic biomarkers especially those associated to the lipid profile [75] and endothelial function [76]. Since the only constraint regarding powder intake was not to heat it, it is possible that consuming it with food such as milk could have had an effect on its antioxidant properties due to the matrix effect [77]. Furthermore, milled freeze-dried highbush BBP was used as a surrogate of whole fresh blueberries for practical reasons. ...
Background
Blueberries contain high levels of polyphenolic compounds with high in vitro antioxidant capacities. Their consumption has been associated with improved vascular and metabolic health.
Purpose
The objective was to examine the effects of blueberry supplement consumption on metabolic syndrome (MetS) parameters and potential underlying mechanisms of action.
Methods
A randomized double-blind placebo-controlled intervention trial was conducted in adults at risk of developing MetS. Participants consumed 50 g daily of either a freeze-dried highbush blueberry powder (BBP) or a placebo powder for 8 weeks ( n = 49). MetS phenotypes were assessed at weeks 0, 4 and 8. Fasting blood gene expression profiles and plasma metabolomic profiles were examined at baseline and week 8 to assess metabolic changes occurring in response to the BBP. A per-protocol analysis was used.
Results
A significant treatment effect was observed for plasma triglyceride levels that was no longer significant after further adjustments for age, sex, BMI and baseline values. In addition, the treatment*time interactions were non-significant therefore suggesting that compared with the placebo, BBP had no statistically significant effect on body weight, blood pressure, fasting plasma lipid, insulin and glucose levels, insulin resistance (or sensitivity) or glycated hemoglobin concentrations. There were significant changes in the expression of 49 genes and in the abundance of 35 metabolites following BBP consumption. Differentially regulated genes were clustered in immune-related pathways.
Conclusion
An 8-week BBP intervention did not significantly improve traditional markers of cardiometabolic health in adults at risk of developing MetS. However, changes in gene expression and metabolite abundance suggest that clinically significant cardiometabolic changes could take longer than 8 weeks to present and/or could result from whole blueberry consumption or a higher dosage. BBP may also have an effect on factors such as immunity even within a shorter 8-week timeframe.
Clinical trial registration
clinicaltrials.gov, NCT03266055 , 2017
... Biological membranes are more permeable to less polar (poly)phenols than to more polar ones (glucuronidated and sulfated derivatives) (Scheepens, Tan, and Paxton 2010). Therefore, it is not surprising that highly polar anthocyanins are characterized by very low blood and urine concentrations (Del Rio et al. 2013) due to their poor absorption, which may also result from their high affinity for proteins present in food (Serafini et al. 2009). However, the markedly reduced absorption and bioavailability of anthocyanins do not appear to disturb their effects on the CNS. ...
Neuroinflammation is a key process in the pathogenesis of many neurological disorders, i.e. Alzheimer’s disease and Parkinson’s disease. However, there are no anti-inflammatory medical interventions recommended so far in the treatment of neuroinflammation-related brain disorders. Therefore, the burden of searching for effective and safe antineuroinflammatory agents is well founded, especially in the aging society. Compounds of plant origin, mainly (poly)phenols, have attracted considerable attention in recent years. Notably, the role of flavonoids in ameliorating neuroinflammation is in the limelight. Thus, we used comprehensive literature retrieval to summarize the effects and active components of edible fruits and their phenolic compounds. As a result, this review presents a valuable summary of results of in vitro, ex vivo, and in vivo studies on the antineuroinflammatory effects of edible fruits and their (poly)phenolic extracts as well as dietary flavonoids and other selected (poly)phenols based on the detailed description of foregoing studies. Additionally, problems resulting from the limited bioavailability of (poly)phenols were discussed.
... This interaction can produce changes in WP solubility, thermal stability, digestibility (Rawel et al., 2001;Cao and Xiong, 2017), antioxidant activity, and foaming and emulsifying properties (Ali et al., 2013;Rodríguez et al., 2015;Jia et al., 2016). Similarly, complexation with WP can result in changes in the functional characteristics of phenolic compounds, such as antioxidant activity, in vivo bioavailability, stability, and solubility (Rohn et al., 2004;Liang et al., 2008;Serafini et al., 2009;Chung et al., 2015), and the chemical structure of the phenolic compound interacting with WP (Ozdal et al., 2013). Although literature shows extensive research on the changes in functional properties of phenolic compounds in response to their complexation with WP, the information available on the influence of WP on the color expression of phenolic colorants is scarce. ...
Anthocyanins (ACN) are pigments with vivid colors, but their application as food colorants is restricted by their limited stability and color expression. Anthocyanins exhibit higher stability in dairy systems than in buffers at similar pH, suggesting that pigments may be able to interact with dairy components such as proteins, resulting in improved performance as colorants. Our objective was to determine the type of interaction between whey proteins (WP) and ACN leading to color enhancements and to determine the role of the ACN chemical structure in this interaction. Model solutions colored with semipurified pigments from sources with different ACN profiles (Berberis boliviana, grape skin, purple corn, black carrot, and red cabbage) were mixed with different concentrations of whey protein isolate (WPI) in pH 3 buffer. Absorption spectra of these solutions were acquired using an absorbance microplate reader, and color parameters were calculated from spectral data. Isolated ACN 3-glucosides were used to determine the role of the aglycone structure in the WP-ACN interaction using visible and fluorescence spectroscopy. In silico modeling was used to visualize potential differences in the interaction between β-lactoglobulin and ACN. Addition of WPI resulted in hyperchromic shifts at the wavelength of maximum absorption in the visible range (λvis-max) of up to 19%, and a significant increase in tinctorial strength for all ACN sources (ΔE > 5). Moreover, ACN acylation did not seem to play a significant role in the WP-ACN interaction. When using isolated ACN, WPI addition resulted in hyperchromic shifts at the λvis-max only for methoxylated ACN such as petunidin-3-glucoside (up to 24%), and malvidin-3-glucoside (up to 97%). The bimolecular quenching constant values (Kq > 10¹⁰ M⁻¹s⁻¹) strongly suggested that the predominant type of quenching interaction was static. Analysis of enthalpy, entropy, and Gibbs free energy showed that this binding was spontaneous; depending on the chemical structure of the ACN, the predominant binding forces could be hydrophobic interactions or hydrogen bonding. Modeling suggested that methoxylations in the B ring of the aglycon structure promoted interactions with electron acceptor amino acids. Overall, WP could be used to enhance the tinctorial strength of select ACN depending on their structural characteristics. Therefore, ACN source selection may play a key role for specific applications in dairy products.
... Polyphenols (especially polyhydroxy polyphenols) form non-covalent hydrophobic interactions with proteins, which may subsequently be stabilized by hydrogen bonding [33], and can, among other effects, change the bioavailability of polyphenols. Different authors observed negative effects of milk proteins on bioavailability of polyphenols of different origin [34][35][36][37][38]. The majority of observed negative interactions in literature were observed for casein, which is consistent with our results showing the stronger negative effects of foods with casein content in comparison to other high-protein foods (although total protein content was relatively low). ...
Background: olive pomace extract (OPE) is a rich source of health promoting polyphenols (hydroxytyrosol (HTS) and tyrosol (TS)) and can be used as a nutraceutical ingredient of dietary supplements and functional foods. Its adequate bioavailability is a prerequisite for excreting biological activity and can be significantly and specifically affected by different food matrices. Methods: in order to investigate food effects on polyphenol bioaccessibility, OPE was co-digested with different foods according to internationally harmonized in vitro digestibility method. Impact of particular nutrients on
HTS and TS permeability was assessed on Caco-2 cell monolayer. Results: HTS and TS bioaccessibility
and transepithelial permeability can be significantly affected by foods (nutrients), especially by casein and certain types of dietary fiber. Those effects are polyphenol-and nutrient-specific and are achieved either through complexation in gastrointestinal lumen and/or through direct effects of nutrients on intestinal monolayer. Conclusions: obtained results emphasize the significance and complexity of polyphenol interactions within the food matrix and the necessity of individual investigational approaches with respect to particular food/nutrient and interacting phenolic compounds.
... First, it included premenopausal women, but menstrual cycle hormonal uctuation can in uence cardiometabolic biomarkers especially those associated to the lipid pro le (72) and endothelial function (73). Since the only constraint regarding powder intake was not to heat it, it is possible that consuming it with food such as milk could have had an effect on its antioxidant properties due to the matrix effect (74). Furthermore, milled freeze-dried highbush BBP was used as a surrogate of whole fresh blueberries for practical reasons. ...
Background: Blueberries contain high level of polyphenolic compounds with high in vitro antioxidant capacities. Their consumption has been associated with improved vascular and metabolic health.
Purpose: The objective was to examine the effects of blueberry supplement consumption on metabolic syndrome (MetS) parameters and potential underlying mechanisms of action.
Methods: A randomized double-blind placebo-controlled intervention trial was conducted in adults at risk of developing MetS. Participants consumed 50g daily of either a freeze-dried highbush blueberry powder (BBP) or a placebo powder for 8 weeks (n=49). MetS phenotypes were assessed at week 0, 4 and 8. Fasting blood gene expression profiles and plasma metabolomic profiles were examined at baseline and week 8 to assess metabolic changes occurring in response to the BBP. A per-protocol analysis was used.
Results: Interaction effects were non-significant demonstrating that compared to the placebo, BBP had no statistically significant effect on body weight, blood pressure, fasting plasma lipid, insulin and glucose levels, insulin resistance (or sensitivity) and on glycated hemoglobin concentrations. However, there were significant within- and between-group differences including increased insulin resistance in the placebo group only, greater TG at week 4 in the BBP compared to placebo group and increased fasting insulin from week 4 to 8 in both groups. Moreover, there were significant changes in the expression of 49 genes and 35 metabolites following BBP consumption. Differentially regulated genes were clustered in immune-related pathways.
Conclusion: An 8-week BBP intervention did not significantly improve traditional markers of cardiometabolic health in adults at risk of developing MetS. However, metabolically relevant changes in gene expression and metabolites suggest that clinically significant cardiometabolic changes could take longer than 8 weeks to present and/or could result from whole blueberry consumption or a higher dosage. BBP may also have an effect on factors such as immunity even within a shorter 8-week timeframe.
Clinical trial registration: clinicaltrials.gov, NCT03266055, 2017, https://clinicaltrials.gov/ct2/show/NCT03266055?term=blueberry+vohl&draw=2&rank=1
... All samples were divided into 2 groups by varying the different purple corn pigment levels using a completely randomized design, with 6 duplicates per treatment. The milk samples were prepared via the addition of 0 or 0.3% purple corn pigment and mixed until well combined, according to Serafini et al. (2009). As a result, there were 2 groups: (1) control, raw milk; and (2) treatment, the addition of 0.3% (wt/ vol) purple corn pigment in raw milk, and the milk was not pasteurized. ...
Unsaturated fatty acids (UFA) in milk give rise to radicals and lead to lipid oxidation during storage, reducing the commercial value of milk. The objective of this study was to observe the effect of anthocyanins from purple corn pigment on the oxidation of UFA in milk. Milk samples were randomly divided into 2 groups: (1) the control (without purple corn pigment) and (2) treatment (0.3% purple corn pigment), using a completely randomized design. The milk samples were placed into plastic tubes and stored at 4°C for a period of 0, 1, 3, and 7 d. Individual anthocyanin composition and UFA were detected by HPLC-mass spectrometry and gas chromatography-mass spectrometry, respectively. The results indicated that pelargonidin (0.258 vs. 0.054 µg/mL), cyanidin (5.550 vs. 1.808 µg/mL), petunidin (0.464 vs. 0.107 µg/mL), delphinidin (2.061 vs. 0.123 µg/mL), and total anthocyanin (8.332 vs. 2.091 µg/mL) significantly decreased in response to increasing storage day. Of interest, purple corn pigment had a significant effect on most of the UFA (C14:1n-5, C16:1n-7, C18:1n-9, C18:2n-6, C18:3n-3, C18:3n-6, C20:2n-6, C20:3n-3, and C20:4n-6), except for C17:1n-7 and C20:3n-6. Specifically, various stronger positive correlations were noted for anthocyanin composition and UFA (pelargonidin and petunidin with C14:1n-5, C17:1n-7, C18:2n-6, C20:2n-6, C20:3n-3, and C20:4n-6; and cyanidin and total anthocyanins with C14:1n-5, C16:1n-7, C17:1n-7). Collectively, the current study suggested that the addition of anthocyanins from purple corn pigment had the potential to maintain UFA concentrations in milk during the storage period.
... The identification was based on the comparison of retention times, mass spectral data (NIST) and reports of previous studies [21,26,27]. 18 anthocyanins were identified, including 4 phenolic acids in blueberry cv. ...
The Blueberry cv. Biloxi is characterized by its high phenolic compounds content, mainly anthocyanins, which are relevant for their application in the prevention of chronic degenerative diseases. In this study, we have demonstrated that the encapsulation of blueberry extracts is feasible using as a matrix a combination of biopolymers through the electrohydrodynamic process from aqueous solutions. Corn prolamin zein, whey protein concentrate and high polymerization grade agave fructans were used as polymers. The properties of the solution and the capacity of atomization with high voltage were evaluated by adding glycerol as an adjuvant. The results of this investigation showed that most of the solutions were within the recommended ranges to be electrospun. However, not all exhibited stability when the blueberry polyphenolic extract was added. The morphology of structures was characterized and then related to the properties of the solution. The corn prolamin zein was able to obtain capsules loaded with encapsulation efficiency of 52.65% of polyphenolic extract by electrospraying process with homogeneous morphology and smooth, as well as continuous nanofibers by electrospinning process.
Graphic abstract
... Several factors affect the bioavailability of phenolic compounds, such as their chemical structure (Talavera et al., 2004), pH alterations along the gastrointestinal tract (Stalmach et al.,2012), presence of other flavonoids (Walton et al., 2006), interaction with other diet components (as proteins, Complimentary Contributor Copy fats, and fibers) (Serafini et al., 2009), and the metabolism of the large intestine in charge of the gut microbiota (Jiménez-Girón et al., 2013). ...
The bioactive compounds present in the genus Rubus have garnered special attention due to the health benefits of their consumption, mainly, phenolic compounds such as flavonoids (anthocyanins, flavanols and phenolic acids) and ellagitannins. However, their biological activity is related with their absorption and metabolism. The purpose of this chapter is to summarize the available scientific information of the bioactive compounds in Rubus blackberries and raspberries and their bioavalibility, as well as their effect on intestinal microbiota and tissue distribution. Similarly, we review the role of the phenolic compounds in Rubus berries in the prevention and treatment of neurodegenerative disorders. Experimental studies suggest that anthocyanins of these fruits improve cognition and improve human health.
... Complexes can be formed reversibly or irreversibly, depending on protein type and phenolic concentration and properties (Rodríguez-Roque et al., 2015). Meanwhile, the lipid content of milk could supply a favorable environment for protein-phenolic compound linkage (Serafini et al., 2009) and protein precipitation could mask the phenolics and therefore reduce their bioaccessibility. The bioaccessibility of phenolic compounds in KJ was negligibly Fig. 3. Individual phenolic (A, quinic acid; B, sinensetin; C, chlorogenic acid; D, caffeoyl-glucoside; E, EGC) content during in vitro gastrointestinal digestion of KJ subjected to HPHP, T80, T90 and in the presence of soy milk, skimmed and whole milk. ...
We investigated the effects of high-pressure homogenization processing (HPHP), thermal treatment (TT), and milk matrix (soy, skimmed, or whole milk) on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) scavenging activity and in vitro bioaccessibility of total and individual phenolics in pomelo juice (PJ) and kiwi juice (KJ). HPHP and TT resulted in an increase of 10.6–17.5% in the phenolic contents of KJ and PJ but diminished phenolic bioaccessibility from 1.3% to 46.8%. Addition of milk matrix effectively enhanced phenolic bioaccessibility in KJ and PJ from 21.6% to 37.8% and 60.1% to 63.3%, respectively, except that addition of soy milk reduced total phenolic (TP) bioaccessibility by 14.9% in PJ. Skimmed milk improved TP bioaccessibility in KJ to a greater extent than did soy or whole milk, and whole milk effectively enhanced bioaccessibility in PJ. Our results suggest that the bioaccessibility of phenolics in fruit can be improved by regulating processing conditions and food matrices.
... Serafini, Ghiselli, and Ferro-Luzzi 1996;Spencer et al. 1988). The study by Serafini et al. was conducted to provide some answers to this question (Serafini et al. 2009), and the researchers showed in healthy volunteers that the consumption of a fruit rich in antioxidants, such as blueberry, in combination with whole milk decreases its ability to increase plasma endogenous antioxidant defenses and to deliver bioactive molecules, such as caffeic acid, into the blood circulation. ...
Epidemiological studies suggest that the protective effects of fruits against chronic diseases may vary according to their extent of processing. We therefore reviewed what the scientific literature states about the potential mechanisms underlying this “processing” effect by focusing on the most significant nutritional properties, namely, the nutritional density of bioactive compounds, the digestive bio-accessibility of nutrients, and the antioxidant, satietogenic, alkalizing and glycemic potentials. When possible, we have ranked fruits according to the international NOVA classification as un-/minimally processed, processed (mainly with added sugars), and ultra-processed fruits. Our literature review confirms that the more fruits are processed, the lower are their alkalizing, antioxidant and satietogenic potentials. For the glycemic index, the results are more difficult to interpret because fruits are a significant source of fructose with a very low glycemic index that "distorts" the “processing” effect. However, fruits in syrup tend to have a higher glycemic index, probably because of the highly bioavailable added sugars. Overall, the destructuration of the fruit fibrous matrix by thermal and mechanical treatments, combined with the addition of simple sugars, constitute the treatments that most degrade the fruit nutritive quality by diluting the nutritional density and attenuating the "matrix" effect. The new technological processes described as "nonthermal" (e.g., pulsed electric fields, high pressures, supercritical CO2, radiation, etc.) seem promising as they limit vitamin C and antioxidant phytonutrient losses in fruit while allowing satisfactory storage time. To preserve fruit longer, drying appears to be an interesting alternative to maintain the health potential of fruit, although it causes antioxidant losses. Finally, although "5 fruits and vegetables a day" is a well-known nutritional recommendation, in view of the results reviewed here, it would be relevant to be precise and include "preferably minimally processed".
... Some early studies claimed that maximum antioxidant capacity and better health benefit could be gained by ingesting milk proteins-phenols complex, however, later studies reported reduced bioavailability of phenolics after ingestion with milk (Hoffman et al. 2001), Serafini et al. 2009). ...
... Chocolate consumption with milk has been linked to a decrease in flavonoid bioavailability due to dual bonds formed between chocolate flavonoids and milk proteins (Serafini et al. 2009). In another study, effect of milk on dietary polyphenols in tea was studied by an in vivo method and decreasing effect of semi-skimmed milk on the ...
In this study, it is aimed to understand the changes in sour cherry phytochemicals when their co-digestions are simulated in dairy model systems comprising skim milk, non-fat-yoghurt, probiotic yoghurt or cream. These co-digestions were analyzed for their total phenolic and anthocyanin contents, total antioxidant activity (TAA) in addition to phenolic and anthocyanin profiles, individually. Sour cherry phenolics were stable during gastric conditions (120%); 54% lost in pancreatic digestion and being available (59%) in serum available fraction (IN). Anthocyanins were lost both in gastric (30%) and pancreatic digestions (16%), being only little available (0.6%) in IN. Soymilk had inhibitory effects on TAA. Dairy food matrix components evaluated were found to have distinct effects on the measured bioavailability of individual sour cherry phenolics. This study might aid both consumers and industry on selecting the food matrices to aiding increase in bioavailability.
... The effect of food matrix on anthocyanin bioavailability has not yet been elucidated. Serafini et al. (2009) analyzed the antioxidant properties of blueberry consumption combined with milk and suggested that the combined ingestion caused a decrease of bioavailability and, thus, a reduction of beneficial antioxidant effects in plasma. Other authors observed a relative bioavailability of red wine anthocyanins within 57.1%-76.3% ...
The use of natural pigments as colorants is a trend in food technology because of the safety hazard and long-term repercussions on health from the chemically synthetized pigments. Anthocyanins are flavonoid pigments with a general C6C3C6 structure widely spread in fruits, flowers, leaves, and other vegetal tissue. The color of natural anthocyanins covers most of the visual spectra from yellow-orange to blue-violet so they are a very interesting tool to improve the color of many foods and beverages. Also, flavonoids, being polyphenol molecules, have an interesting repercussion on human health as antioxidants. The stability of anthocyanins depends on several parameters, such as pH, temperature, and oxidative conditions, but they are normally quite stable in acidic media. A lot of research has been done on stability of anthocyanins and derived pigments. The present chapter describes the nature and properties of anthocyanins detailing the main natural sources and how these molecules can be used as pigments in beverages.
... No significant differences in excretion patterns were found when comparing a variety of metabolites in urine after consuming cocoa powder in milk or in water [86]. It is suggested that polyphenol absorption and metabolism might be affected because of the interactions between milk polypeptides and polyphenols, which can decrease the bioaccessibility [94,95]. In addition, polyphenol absorption could also be affected by carbohydrates, as it has been reported that flavanol uptake could increase when simultaneously consuming these macronutrients [50]. ...
Cocoa is continuously drawing attention due to growing scientific evidence suggesting its effects on health. Flavanols and methylxanthines are some of the most important bioactive compounds present in cocoa. Other important bioactives, such as phenolic acids and lactones, are derived from microbial metabolism. The identification of the metabolites produced after cocoa intake is a first step to understand the overall effect on human health. In general, after cocoa intake, methylxanthines show high absorption and elimination efficiencies. Catechins are transformed mainly into sulfate and glucuronide conjugates. Metabolism of procyanidins is highly influenced by the polymerization degree, which hinders their absorption. The polymerization degree over three units leads to biotransformation by the colonic microbiota, resulting in valerolactones and phenolic acids, with higher excretion times. Long term intervention studies, as well as untargeted metabolomic approaches, are scarce. Contradictory results have been reported concerning matrix effects and health impact, and there are still scientific gaps that have to be addresed to understand the influence of cocoa intake on health. This review addresses different cocoa clinical studies, summarizes the different methodologies employed as well as the metabolites that have been identified in plasma and urine after cocoa intake.
... The latter could be carried out by other compounds formed upon processing, among which are melanoidins that can incorporate phenolic compounds (Perrone, Farah, & Donangelo, 2012). Moreover, it can be inferred that even in the presence of a higher bioaccessibility, complexation phenomena occurring between phenolic compounds and milk proteins upon high-pressure homogenization (Paquin, 1999) and digestion (Hasni et al., 2011) might result in a reduced bioactivity (Serafini et al., 2009). ...
This study aimed at investigating the effect of coffee formulation and high-pressure homogenization (HPH) on chlorogenic acid bioaccessibility and α-glucosidase inhibition. Coffee was added with milk (1:1) containing 0.1, 3.6 or 7.1% fat, homogenized at increasing pressure (0-150 MPa) and in vitro digested. Using milk with the highest fat concentration (7.1%) promoted the formation of smaller particles after HPH treatment, as well as upon digestion. Digested samples with the highest fat content also presented lower ζ-potential, suggesting higher stability. Chlorogenic acids (CGAs) bioaccessibility and α-glucosidase inhibition were evaluated upon in vitro digestion. CGAs bioaccessibility increased from nearly 25% to > 50% by adding milk and using HPH. These could promote CGAs micellarization, reducing their susceptibility to degradation during digestion. Properly combined milk and HPH also improved α-glucosidase inhibitory effect. No correlation was found between CGAs bioaccessibility and α-glucosidase inhibition, suggesting that other components may govern antidiabetic properties of coffee.
... Antioxidants are scavengers of free radicals, which can cause oxidative damage to DNA, proteins, and lipids (Seifried et al., 2003). Having a meal high in lipids and energy increases the postprandial oxidative and inflammatory stress, mediated by proinflammatory cytokines including tumor necrosis factor-α, interleukin-6 and oxidized lipids (Adibhatla et al., 2008;Serafini et al., 2009). The presence of foods rich in antioxidants along with a high-fat meal might provide a battery of exogenous antioxidants, able to quench radical species produced at the gastric level, synergizing with endogenous antioxidants and providing a more efficient protection against oxidative stress (Gorelik et al., 2008;Lamb and Goldstein, 2008). ...
Background: Recent studies have shown that dietary total antioxidant capacity (D-TAC) may affect risk of cancer; however, findings are conflicting. Hence, we aimed to summarize the current evidence on the association between D-TAC and risk of cancer. Methods: We searched the online databases of PubMed, ISI Web of Science, Scopus, ProQuest, Science Direct and Embase until October 2018 using relevant keywords. To pool data, fixed- or random-effects models were used where appropriate. Results: In total, 19 studies including 8 prospective and 11 case-control studies with 721429 individuals and 16159 cases of cancer were included in the current systematic review and meta-analysis. Combining 15 effect sizes from 6 prospective and 8 case-control studies revealed a significant inverse association between D-TAC (obtained from ferric reducing antioxidant power (FRAP)) and risk of cancer (combined effect size: 0.86, 95% CI: 0.81-0.92, P < 0.001). Such inverse association was also seen for D-TAC obtained from other methods including trolox equivalence antioxidant capacity (TEAC) (combined effect size: 0.80, 95% CI: 0.70–0.90, P < 0.001), total radical trapping antioxidant parameter (TRAP) (combined effect size: 0.69, 95% CI: 0.62–0.78, P < 0.001) and oxygen radical absorbance capacity (ORAC) (combined effect size: 0.72, 95% CI: 0.52–1.00, P = 0.04). In addition, a significant non-linear association was found between D-TAC (based on FRAP and TRAP) and cancer risk (P-nonlinearity<0.001). Based on linear dose-response meta-analysis, a-10 mmol/day increase in FRAP and a-5 mmol/day increase in TRAP and TEAC were associated with 9%, 17% and 14% reduction in risk of cancer, respectively. Furthermore, D-TAC was inversely associated with risk of colorectal (combined effect size: 0.82, 95% CI: 0.75-0.89, P < 0.001), gastric (combined effect size: 0.63, 95% CI: 0.53-0.73, P < 0.001), and endometrial cancer (combined effect size: 0.78, 95% CI: 0.69-0.89, P < 0.001). Conclusions: Diet with high antioxidant capacity might have protective effects against cancer.
... Some carotenoids have provitamin A action as well as antioxidant functions. The bioavailability of polyphenols in milk is somewhat controversial (Leenen et al. 2000;Hoffman et al. 2001;Lorenz et al. 2007;Serafini et al. 2009; Gad and Abd El-salam 2010). ...
... An example is the case of fruits with milk, which is contraindicated. This concept is recently validated by a study conducted on milk and blue berries where it is demonstrated that, when used together, it leads 23 to reduction in the antioxidant properties of blueberries. Like this, eighteen types of virudha have been mentioned, when consumed for a prolonged time leads to various metabolic as well as other systemic diseases. ...
... Similarly, no significant effects of milk proteins on in vivo bioavailability of tea and coffee phenolics were reported (Hollman et al., 2001;Leenen et al., 2000;Reddy et al., 2005;Renouf et al., 2010). In terms of blueberry polyphenols, their interactions with milk proteins led to a lower in vivo antioxidant potential and decreased caffeic acid absorption (Serafini et al., 2009). Contradictory results were obtained regarding the effects of milk proteins on the bioavailability of cocoa polyphenols e.g. ...
... Berries are rich in phenolic compounds, and several researchers have reported the content and antimicrobial activity of phenolic compounds in berries (Vallejo, Aredes-Fernández, Farías, & Rodríguez-Vaquero, 2013). Blueberry (Vaccinium spp.) contains relatively high amounts of acids and phenolic compounds (Kalt et al., 2008) that display potential health benefits such as protection against cancer and cardiovascular diseases (Almeida, Farah, Silva, Nunam, & Glória, 2006;Santos, Almeida, Lopes, & Souza, 2006;Serafini et al., 2009). However, at present there is no evidence of antifungal activity of phenolic blueberry extracts against yeasts isolated from commercial deteriorated natural juice in Argentina. ...
The aims of the present work were to isolate and identify the principal yeasts present in spoiled Argentine strawberry juice, identify polyphenols present in four blueberry cultivars and use these blueberry extracts in the control of yeasts using strawberry juice as food system model. Hanseniaspora osmophila and Starmerella bacillaris were identified for the first time in Argentine strawberry juice. The blueberry extracts assayed showed antifungal activity against H. osmophila and S. bacillaris through individual phenolic compounds such as quercetin, kaempferol and chlorogenic, ρ-coumaric and ellagic acid. The cytotoxicity assay demonstrated that the blueberries were not toxic to humans and that they did not modify the sensorial qualities of strawberry juice. No viable S. bacillaris and H. osmophila cells were detected after 7 days in strawberry juice supplemented with 150 μg/ml Blue Crisp or Millennium extract, inoculated with the isolated spoilage yeasts and conserved at 4 °C. This is the first evidence of S. bacillaris and H. osmophila in spoiled Argentine strawberry juice and blueberry extracts could be a good natural and non-toxic alternative to prevent growth of these yeasts. Blueberry extracts could be feasible alternatives to improve the microbiological quality without impact on the organoleptic properties of polyphenol-enriched strawberry juice.
... However, consumers are increasingly concerned about the potential harmful effects of chemical preservatives and prefer foods containing no chemical preservatives (Wu et al., 2008;Marta et al., 2012). Berries are rich in phenolics and have been reported to protect against cancer and cardiovascular diseases Serafini et al., 2009). ...
The aim of this study was to evaluate the content of phenolic compounds, flavonoids and total anthocyanins, as well as the antioxidant and antimicrobial activity of blueberry extracts (Vaccinium ashei Reade) of the Climax variety. The extracts were obtained by focused microwave extraction at different temperatures (30, 40, 50 and 60°C) and solvent concentrations (60% and 80% hydroethanolic). The antioxidant activity of the extracts was quantified by the DPPH radical sequestration method, inhibition of auto-oxidation of the β-carotene system, ABTS+, FRAP and IC50. The antimicrobial activity was evaluated by the disk diffusion method. The antioxidant activity (FRAP, ABTS+ and DPPH), total phenolics and total anthocyanins showed a positive linear trend in relation to the extraction temperature, with no significant difference between the solvent concentrations (60 and 80%). The IC50 and β-carotene showed the greatest inhibition at 60°C at solvent concentrations of 60% and 80%, respectively. The flavonoids showed no significant difference in terms of the extraction temperature or the concentration of solvent that was used. No antimicrobial activity was detected in the extracts in relation to the tested microorganisms. The results showed a positive correlation between the total phenolic content and the determined antioxidant activities. This study confirms the potential of this fruit as a source of phenolic compounds with high antioxidant activity and it also provides a new and efficient technique to extract bioactive compounds using microwaves.
... In a sporting context, several strategies are often implemented without knowing if there is a potential conflicting effect between them. For example, a recent study showed that the antioxidant power of red fruit is reduced when it is consumed with milk, a high protein content drink (Serafini et al., 2009). Therefore, it would be interesting to evaluate the effect of the implementation of several recovery strategies together on muscle function and recovery kinetics followed exercise-induced muscle damage. ...
The aim of this study was to analyze the effects of oral consumption of curcumin and piperine in combination on the recovery kinetics after exercise-induced muscle damage. Fortyeight hours before and following exercise-induced muscle damage, ten elite rugby players consumed curcumin and piperine (experimental condition) or placebo. A randomized cross-over design was performed. Concentric and isometric peak torque for the knee extensors, one leg 6 seconds sprint performance on a non-motorized treadmill, counter movement jump performance, blood creatine kinase concentration and muscle soreness were assessed immediately after exercise, then at 24h, 48h and 72h post-exercise. There were moderate to large effects of the exercise on the concentric peak torque for the knee extensors (Effect size (ES) = -1.12; Confidence interval at 90% (CI90%): -2.17 to -0.06), the one leg 6 seconds sprint performance (ES=-1.65; CI90% = -2.51to -0.80) and the counter movement jump performance (ES = -0.56; CI90% = -0.81 to -0.32) in the 48h following the exercise. There was also a large effect of the exercise on the creatine kinase level 72h after the exercise in the control group (ES = 3.61; CI90%: 0.24 to 6.98). This decrease in muscle function and this elevation in creatine kinase indicate that the exercise implemented was efficient to induce muscle damage. Twenty four hours post-exercise, the reduction (from baseline) in sprint mean power output was moderately lower in the experimental condition (-1.77 ± 7.25%; 1277 ± 153W) in comparison with the placebo condition (-13.6 ± 13.0%; 1130 ± 241W) (Effect Size = -1.12; Confidence Interval 90%=-1.86 to -0.86). However, no other effect was found between the two conditions. Curcumin and piperine supplementation before and after exercise can attenuate some, but not all, aspects of muscle damage.
... The positive effects depend on the phenolic and flavonoid compounds such as chlorogenic acids (quinyl esters of hydroxycinnamic acid) 12 , caffeic, ferulic, p-coumaric acids 13 and proanthocyanidins 13,14 . These biological compounds are secondary metabolites from plants 6 and have potent strong antioxidant and radical scavenging activities 15,16 , which help the body to reduce the oxidative stress 17 . ...
Polyphenols have been widely studied and considered as a health promotingand disease preventive agents in humans. Several studies investigated the antioxidantproperties of polyphenols and their abilities to eliminate free radicals. In this study, theantioxidant activity of coffee in the presence of different types of cows’ milk at differentconcentrations, 10% or 20%, was investigated. Our results showed that milk could eitherenhance the scavenging of DPPH or decrease the metal chelating and metal reducingactivity of polyphenol. However, more investigations are required to evaluate themechanisms by which fats in milk can alter the antioxidant activity of coffee.
... milk, yoghurt, and cheese, and the effect on antioxidant activity (Hala et al. 2010;Najgebauer-Lejko et al. 2011;Sharma et al. 2011;Sun-Waterhouse et al. 2012;Giroux et al. 2013), although none was found to study the effect of catechins on antioxidant properties in a whole milk system. The in vivo plasma antioxidant capacity after consumption of blueberry fruit, with and without milk, was assessed and it was found that the simultaneous consumption of blueberry with milk could impair the antioxidant properties of blueberry while reducing the absorption of caffeic acid (Serafini et al. 2009). Similarly, Langley-Evans (2000 reported that addition of whole, semi-skimmed and skimmed milk to black tea results in 28%, 22% and 12% of plasma antioxidant activity (measured by FRAP assay) of the consumed tea in nine healthy subjects, in agreement with other researchers (Serafini et al. 1996;Pfeuffer & Schrezenmeir 2007;Ryan & Petit 2010). ...
Due to their well-known health benefits, green tea catechins have received recent attention as natural additives in foods such as dairy products. However, they may present some irreversible associations with milk components (e.g. protein and milk fat globules). To investigate the behaviour of two important green tea catechins, (+)-catechin (C) and (-)-epigallocatechin gallate (EGCG), in a standard whole milk system under the conditions of cheesemaking, 250 and 500 ppm of each catechin were added to whole milk (3.3% fat). Although both C and EGCG at either concentration increased both total phenolic content and total antioxidant capacity of the subnatants obtained from the milk system, there was a less linear increase when the concentration of the catechins was doubled, whereas C or EGCG were recovered (measured by HPLC) differently. Overall, these results suggest a degree of associations between green tea catechins with milk proteins and milk fat.
Increasing epidemiological evidence suggests inverse association between consumption of diets rich in fruits and vegetables and the incidence of cardiovascular diseases (CVD), metabolic syndrome disorders, certain types of cancer, neurodegenerative disorders, and other forms of human chronic diseases. This may be due to the contents of some bioactive phytochemicals, especially polyphenols, which are abundant in fruits and vegetables and have antioxidant effects. Berry fruits are reported to have the highest total antioxidant capacity (TAC) among fruits. They may protect against CVD and hypertension either directly or in tandem with other cellular mechanisms. Blueberry anthocyanins have been reported to exhibit cardiovascular protective health effects by preventing cholesterol-induced atherosclerosis, and reduction of oxidative and inflammatory damages to the endothelium through several mechanisms. Such mechanisms may involve suppressing the release of inflammatory mediators, protection against ischemic damage of the heart as well as cardiomyocyte survival, lower systolic and mean arterial pressures and renal nitrite content in addition to multiple other beneficial effects. However, several limitations in existing studies make it difficult to draw conclusions regarding the preventive effects of blueberries and other polyphenols-rich foods, especially as data supporting a causal relationship between direct antioxidant capacity and CVD are insufficient or limited. It is also unclear, which molecules exert this effect since few studies with isolated polyphenols have been conducted in addition to a lack of proper understanding of other mechanisms that may be involved. This review is, therefore aimed at discussing some of the current literature information on the cardiovascular protective effects of blueberries with suggestions for future research directions.
Graphical Abstract
Graphical abstract demonstrating the overall mechanisms of CVD protection by blueberry and blueberry polyphenols and anthocyanins. Blueberry consumption leads to reduced CVD complications due to the modulation of several mechanisms associated with CVD.
Polyphenol has been used in treatment for some health disorders due to their diverse health promoting properties. These compounds can reduce the impacts of oxidation on the human body, prevent the organs and cell structure against deterioration and protect their functional integrity. The health promoting abilities are attributed to their high bioactivity imparting them high antioxidative, antihypertensive, immunomodulatory, antimicrobial, and antiviral activity, as well as anticancer properties. The application of polyphenols such as flavonoids, catechin, tannins, and phenolic acids in the food industry as bio-preservative substances for foods and beverages can exert a superb activity on the inhibition of oxidative stress via different types of mechanisms. In this review, the detailed classification of polyphenolic compunds and their important bioactivity with special focus on human health are addressed. Additionally, their ability to inhibit SARS-CoV-2 could be used as alternative therapy to treat COVID patients. Inclusions of polyphenolic compounds in various foods have demonstrated their ability to extend shelf life and they positive impacts on human health (antioxidative, antihypertensive, immunomodulatory, antimicrobial, anticancer). Additionally, their ability to inhibit the SARS-CoV-2 virus has been reported. Considering their natural occurrence and GRAS status they are highly recommended in food.
The aim of this study was to observe the effect of purple corn anthocyanin on the light-induced antioxidant activity, free radicals, volatile compounds, color parameters, and sensory properties of milk during storage. There were four groups: (1) negative control, no addition of anthocyanins + exposure to fluorescent light (NC); (2) positive control 1, no addition of anthocyanins + protected from fluorescent light (PC1); (3) positive control 2, the addition of 0.3% (w/v) anthocyanins + exposure to fluorescent light (PC2); and (4) the addition of 0.3% anthocyanins + protected from fluorescent light (AC). The results indicated that the concentration of antioxidant activity parameters in the NC group decreased during the entire storage period, whereas antioxidant activity parameters were unchanged except for the glutathione peroxidase (GSH-Px) in the AC group. Moreover, the NC group showed lower levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and higher levels of superoxide anion and hydrogen peroxide than the other groups after 1 d of storage period. The extent of malondialdehyde accumulation and lipid peroxidation in the control groups were greater than that of the AC group. Twenty-two volatile compounds were determined in milk, which consisted of eight alcohols, three ketones, five aldehydes, two esters, and four hydrocarbons by headspace gas chromatography mass spectrometer analysis. Specifically, individual aldehydes, esters and hydrocarbons in the AC group remained at relatively stable values during storage relative to the other three groups. Stronger positive correlations were detected between several antioxidant activities (superoxide dismutase, GSH-Px) and DPPH scavenging activity as well as total ketones in milk. Adding of anthocyanin did not impact on the color values of L*, a* and b* in light-protected milk during the entire storage period. Some sensory evaluation parameters (flat, garlic/onion/weedy, oxidized-light, oxidized-metal, rancid) in AC group were significantly higher than that of the control group at the end of the period. In conclusion, the current study revealed that the addition of purple corn anthocyanin pigment to light-protected milk had the potential to prevent lipid oxidation, enhance antioxidant activity, maintain volatile compounds and increase the sensory scores.
Accumulating evidence indicate that blueberries have anti-hypertensive properties, which may be mainly due to its rich polyphenol content and their high antioxidant capacity. Thus, we aimed to investigate the mechanisms by which blueberry polyphenols exert these effects. Human aortic endothelial cells (HAECs) were incubated with 200 µg/mL blueberry polyphenol extract (BPE) for 1 h prior to a 12 h treatment with angiotensin (Ang) II, a potent vasoconstrictor. Our results indicate that Ang II increased levels of superoxide anions and decreased NO levels in HAECs. These effects were attenuated by pre-treatment with BPE. Ang II increased the expression of the pro-oxidant enzyme NOX1, which was not attenuated by BPE. Pre-treatment with BPE attenuated the Ang II-induced increase in the phosphorylation of the redox-sensitive MAPK kinases, SAPK/JNK and p38. BPE increased the expression of the redox-transcription factor NRF2 as well as detoxifying and antioxidant enzymes it transcribes including HO-1, NQO1, and SOD1. We also show that BPE attenuates the Ang II-induced phosphorylation of the NF-κB p65 subunit. Further, we show that inhibition of NRF2 leads to a decrease in the expression of HO-1 and increased phosphorylation of the NF-κB p65 subunit in HAECs treated with BPE and Ang II. These findings indicate that BPE acts through a NRF2-dependent mechanism to reduce oxidative stress and increase NO levels in Ang II-treated HAECs.
Resveratrol has a variety of physiological activities, but its bioavailability in the body is low. In this study, the interaction between the peptide SH, prepared from Scomberomorus niphonius, and resveratrol was judged by fluorescence spectroscopy. Then, SHa1 was obtained by the purification of SH, and its effect on the characteristics of resveratrol was studied. SHa1 interacted with resveratrol at 37 °C for 30 min to obtain the complex SHa1-R, which then showed an obviously stronger inhibition on B16 cells than resveratrol using the MTT assay after in vitro gastrointestinal digestion. The solubility and digestive stability of SHa1-R were higher than that of free resveratrol. The intestinal absorption rate of SHa1-R was also increased compared with resveratrol according to the non-inverted rat intestinal sac model. The structure of SHa1 was analyzed by UPLC, auto amino acid analysis, and UPLC-MS/MS. The molecular weight of SHa1 was mainly concentrated under 1000 Da, and it was rich in glutamic acid, aspartic acid, lysine, and leucine. Eighteen possible peptides were identified from SHa1. The results suggested that the peptide SHa-1 may help to increase the bioavailability of resveratrol by increasing the solubility, digestive stability and intestinal absorption of resveratrol, thereby promoting its inhibitory effect on B16 cells.
The objectives of this research were to determine the sugar compositions, polyphenol contents and antioxidant effects of non-centrifugal sugars (NCS) of different sugarcane varieties. The polyphenols contents and compounds of nine NCSs obtained from the juices of different sugarcane varieties clarified with a 50 nm ceramic membrane (M-NCSs) were measured via ultraperformance liquid chromatography–mass spectrometry (UPLC–MS). Their antioxidant activities were investigated via 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, 2, 2′-azino-bis-(3-ethylb-enzothia-zoline-6-sulfonic acid (ABTS) assay, β-carotene–linoleate assays, and ferrous and cupric ion chelating assays. Results showed that the phenolic compound with the highest content was gallic acid, and all samples were abundant in phenolics, including flavonoids, with high antioxidative activities. The content of phenolics and flavonoids, ranged from 17.24 to 21.14 mg/mL and from 203.55 to 350.37 µg/mL, respectively. Among these M-NCSs, Funong 41 (G) genotype had the best DPPH free radical scavenging activity. The GUC 23-2 (A1) genotype showed the best ABTS free radical scavenging activity. β-carotene–linoleate assays revealed that the 15-6013 (B2) genotype exhibited the best antioxidant activity. The Guitang 42 (E) genotype displayed the best ferrous ion chelating activity. The Zhongzhe 9 (F) genotype presented the best cupric ion chelating activity. In summary, sugarcane variety influenced the polyphenols contents and antioxidant effects of M-NCSs. This study lays a foundation for the further study of M-NCSs.
The aim of the study was to analyze the antioxidant character of conched chocolate milk masses, taking into account different protein content in milk. For the study, cocoa liquor obtained from roasted and unroasted cocoa beans from different regions, as well as milk powder obtained by spray and cylindrical drying were used. The analysis that was carried out showed that the protein content of powdered milk products ranged from about 11.6% (w/w) to over 31% (w/w). Lower content of polyphenols and lower antioxidant activity were shown in the masses to which the addition of milk with higher protein content was applied. The analysis of antioxidant character of chocolate milk masses showed higher total polyphenols content in masses prepared from unroasted cocoa beans liquor.
Melatonin is a neurohormone that regulates circadian rhythms in the human body. It can also be taken to alleviate insomnia and sleep disorders. Pasteurized milk is a good source of nutrients and some bioactive compounds. Recently, the growing trend of healthy foods has resulted in higher competition with regard to milk products. Functional milk has been developed with higher bioactive compounds to respond to consumer demand. High melatonin pasteurized milk was developed using selected edible grains and mulberry leaves to fortify melatonin in pasteurized milk. Melatonin and free tryptophan of fourteen edible grains and mulberry leaves were determined using HPLC-FD. Highest melatonin concentrations were observed in white sesame, sunflower and soybean (75.24, 67.45 and 56.49 ng/g dry weight (dw), with highest concentrations of free tryptophan in soybean, red bean and mung bean (2617.83, 1527.23 and 845.27 ng/g dw, respectively), while melatonin and free tryptophan contents in fresh mulberry leaves were 51.57 ng/g and 210.53 ng/g dw, respectively. Soymilk powder and mulberry leaf tea were supplemented to prepare high melatonin pasteurized milk. Results showed that chemical compositions, melatonin and free tryptophan contents significantly increased (P < 0.05) with increasing amounts of soymilk powder and mulberry leaf tea. Sensory evaluation gave highest overall liking score for the treatment consisting of mulberry leaf tea (4.00%), soymilk powder (4.00%) and milk (89.80%). Findings indicated that mulberry leaves and soybean are both good sources of melatonin and free tryptophan and can be applied to prepare high melatonin pasteurized milk.
Fruits contain a large family of polyphenolic compounds that have antioxidant
properties. These compounds are known to associate with lower risk of major chronic
diseases. Fruits are consumed as raw and in processed forms such as shakes and
beverages. The perishable nature of fruits/fruit-based products demands processing
strategies to enhance shelf-life and assure food safety, while maintaining nutritional
quality. Dairy has been suggested to interfere with the antioxidant activity of
polyphenolic compounds when included in the formulation of fruit-based beverages.
Therefore, we propose to develop a model system for testing food matrix effects with
standard and novel processing strategies on the antioxidant capacity (AC) of fruit-based
beverages containing appreciable amounts of polyphenolic compounds. In the present
study, we used strawberry (Str) beverages as the model to investigate the effect of dairy
and high temperature-short time processing (HT–72°C-20 sec) and high pressure
processing (HPP – 200 to 600 MPa; holding time 1 to 15 minutes) on beverage AC as
measured by Oxygen Radical Scavenging Capacity (ORAC) and Ferric Reducing
Antioxidant Power (FRAP). Three beverages were prepared and subjected to HT or HPP
processing: 1) Str + Dairy beverage (D-Str), 2) Str + Distilled Water beverage (ND-Str),
3) Dairy (no Str) beverage (D-NStr). All beverages were matched for energy, macro- and
micro- nutrients. HPP and HT application resulted in significantly reduced ORAC &
FRAP values compared to their respective unprocessed beverages (P<0.001). There were significant reductions in ORAC & FRAP values in response to HT processed beverages when compared to HPP processed (up to 600 MPa). The shelf-life study (5 weeks at 4°C) of beverage samples also resulted in significant reductions in AC values when compared to initial unprocessed and processed beverage samples (P<0.05). HPP at ambient temperatures (18-22°C) and HT were observed to be effective at inhibiting the growth of microorganisms for initial week of the storage period. These findings indicate matrix and processing effects on the AC of fruit-based beverages and support further work to determine the impact of these findings on the bioavailability and bioactivity of polyphenolic compounds in in-vivo systems.
Los polifenoles son compuestos bioactivos presentes en los alimentos de origen vegetal. El estudio de los compuestos fenólicos en alimentos constituye una de las ramas de mayor desarrollo en los últimos años, por su importancia en la protección de la salud, mejora de la alimentación, y alta capacidad antioxidante frente a la acción de radicales libres, así, contribuyen en la prevención de enfermedades. Anteriores investigaciones mencionan que los arándanos son frutos con alto contenido de polifenoles, lo cual ha incrementado su comercialización como antioxidantes, y esta creciente demanda da paso a la formulación de nuevos productos derivados, de los cuales se espera, conserven sus propiedades protectoras. Por todo lo mencionado se desea determinar el contenido de compuestos fenólicos totales en arándanos frescos y productos derivados, siendo este el objetivo principal del presente trabajo. Se analizaron arándanos frescos y productos derivados tales como zumos, pulpa y arándanos deshidratados. Los resultados muestran que el contenido de polifenoles es mayor en arándanos deshidratados (en promedio 1011.5 mg GAE/100g) en comparación con otros productos analizados (379, 358.7 y 234 mg GAE/100g en pulpa de arándanos, arándanos frescos y zumos respectivamente). Por lo encontrado se menciona que las diferentes variedades de arándanos determinan el contenido de compuestos fenólicos. Los arándanos negros (Vaccinium Myrtillus L.) presentan mayor contenido de polifenoles que los arándanos rojos. Se concluye que los arándanos y sus productos derivados son una importante fuente de polifenoles, por ello se recomienda su consumo como parte de una dieta saludable.
Palabras clave: polifenoles, arándanos, antioxidantes, productos derivados.
Flavonoids are components of fruits, vegetables and wines. An abundance of flavonoids in the diet is correlated with reduced heart disease mortality, suggesting that they act as protective nutrients. However, little is known about the absorption and metabolism of flavonoids after normal foods are consumed. This study measured the levels of one abundant flavonoid, (+)-catechin, and its metabolites in plasma after five male and four female volunteers consumed 120 mL of red wine (RW) one day and de-alcoholized red wine (DRW) on a separate day. Each wine sample contained 35 +/- 1 mg catechin (mean +/- SEM). Plasma levels of catechin and its metabolite 3'-O-methylcatechin (3'MC) were determined by gas chromatography-mass spectrometry (GC-MS) of the trimethylsilylated (TMS) derivatives. Glucuronide and sulfate conjugates were determined after enzymatic hydrolysis. Before RW or DRW consumption, plasma levels of catechin, 3'MC and all conjugates were <2 nmol/L. After 1 h, average levels of catechin, 3'MC and all conjugates increased to 91 +/- 14 nmol/L (RW) and 81 +/- 11 nmol/L (DRW). At 1 h, 21 +/- 1% of the metabolites were methylated and <2% of catechin and 3'MC were unconjugated. Catechin was present as both a sulfate conjugate and a conjugate containing both glucuronide and sulfate residues. 3'MC was present primarily as a glucuronide conjugate. At every time point, catechin was present almost exclusively as metabolites, and these levels were independent of ethanol. Therefore, if flavonoids are protective nutrients, the active forms are likely to be metabolites, which are far more abundant in plasma than the forms that exist in foods.
To investigate the effect of black and green tea consumption, with and without milk, on the plasma antioxidant activity in humans.
In a complete cross-over design, 21 healthy volunteers (10 male, 11 female) received a single dose of black tea, green tea (2 g tea solids in 300 ml water) or water with or without milk. Blood samples were obtained at baseline and at several time points up to 2 h post-tea drinking. Plasma was analysed for total catechins and antioxidant activity, using the ferric reducing ability of plasma (FRAP) assay.
Consumption of black tea resulted in a significant increase in plasma antioxidant activity reaching maximal levels at about 60 min. A larger increase was observed after consumption of green tea. As anticipated from the higher catechin concentration in green tea, the rise in plasma total catechins was significantly higher after consumption of green tea when compared to black tea. Addition of milk to black or green tea did not affect the observed increases in plasma antioxidant activity.
Consumption of a single dose of black or green tea induces a significant rise in plasma antioxidant activity in vivo. Addition of milk to tea does not abolish this increase. Whether the observed increases in plasma antioxidant activity after a single dose of tea prevent in vivo oxidative damage remains to be established. European Journal of Clinical Nutrition (2000) 54, 87-92
Diets that are rich in plant foods have been associated with a decreased risk for specific disease processes and certain chronic diseases. In addition to essential macronutrients and micronutrients, the flavonoids in a variety of plant foods may have health-enhancing properties. Chocolate is a food that is known to be rich in the flavan-3-ol epicatechin and procyanidin oligomers. However, the bioavailability and the biological effects of the chocolate flavonoids are poorly understood. To begin to address these issues, we developed a method based on HPLC coupled with electrochemical (coulometric) detection to determine the physiological levels of epicatechin, catechin and epicatechin dimers. This method allows for the determination of 20 pg (69 fmol) of epicatechin, which translates to plasma concentrations as low as 1 nmol/L. We next evaluated the absorption of epicatechin, from an 80-g semisweet chocolate (procyanidin-rich chocolate) bolus. By 2 h after ingestion, there was a 12-fold increase in plasma epicatechin, from 22 to 257 nmol/L (P < 0.01). Consistent with the antioxidant properties of epicatechin, within the same 2-h period, there was a significant increase of 31% in plasma total antioxidant capacity (P < 0.04) and a decrease of 40% in plasma 2-thiobarbituric acid reactive substances (P < 0.01). Plasma epicatechin and plasma antioxidant capacity approached baseline values by 6 h after ingestion. These results show that it is possible to determine basal levels of epicatechin in plasma. The data support the concept that the consumption of chocolate can result in significant increases in plasma epicatechin concentrations and decreases in plasma baseline oxidation products.
Tea is a major source of flavonols, a subclass of antioxidant flavonoids present in plant foods which potentially are beneficial to human health. Milk added to tea, a frequent habit in the United Kingdom, could inhibit absorption of tea flavonoids, because proteins can bind flavonoids effectively. Eighteen healthy volunteers each consumed two out of four supplements during three days: black tea, black tea with milk, green tea and water. A cup of the supplement was consumed every 2 hours each day for a total of 8 cups a day. The supplements provided about 100 micromol quercetin glycosides and about 60 - 70 micromol kaempferol glycosides. Addition of milk to black tea (15 ml milk to 135 ml tea) did not change the area under the curve of the plasma concentration-time curve of quercetin or kaempferol. Plasma concentrations reached were about 50 nM quercetin and 30 - 45 nM kaempferol. We conclude that flavonols are absorbed from tea and that their bioavailability is not affected by addition of milk.
The aim of the present study was to determine whether the consumption of wild blueberries (Vaccinium angustifolium), a concentrated source of non-nutritive antioxidant phytochemicals, would enhance postprandial serum antioxidant status in healthy human subjects. A single-blinded crossover study was performed in a group of eight middle-aged male subjects (38-54 years). Subjects consumed a high-fat meal and a control supplement followed 1 week later by the same high-fat meal supplemented with 100.0 g freeze-dried wild blueberry powder. Upon brachial vein catheterization, fasting and postprandial serum samples were taken sequentially and analysed for lipids and glucose and for serum antioxidant status. Serum antioxidant status was determined using the oxygen radical absorbance capacity (ORAC) assay and the total antioxidant status (TAS) assay. The wild-blueberry treatment was associated with a significant treatment effect as determined by the ORAC assay (water-soluble fraction ORAC(perchloric acid (PCA)), P=0.04). Significant increases in serum antioxidant status above the controls were observed at 1 h (ORAC(PCA) (8.5 % greater), P=0.02; TAS (4.5 % greater), P=0.05), and 4 h (ORAC(total) (15.0 % greater), P=0.009; ORAC(acetone) (16.0 % greater), P=0.007) post-consumption of the high-fat meal. In conclusion, the consumption of wild blueberries, a food source with high in vitro antioxidant properties, is associated with a diet-induced increase in ex vivo serum antioxidant status. It has been suggested that increasing the antioxidant status of serum may result in the reduced risk of many chronic degenerative diseases.
The present study investigated whether storage under modified-atmosphere packaging (MAP) affected the antioxidant properties of fresh lettuce (Lactuca sativa). Eleven healthy volunteers (six men, five women) consumed 250 g fresh lettuce, and blood was sampled before (0 h) and 2, 3 and 6 h after consumption. The protocol was repeated 3 d later with the same lettuce stored at 5 degrees C under MAP conditions (O2-N2 (5:95, v/v)). Results showed that after ingestion of fresh lettuce, plasma total radical-trapping antioxidant potential (TRAP), measured as area under the curve, was significantly higher (1.3 (sem 0.3) mmol/l per 6 h; P<0.05) than the value obtained with MAP-stored lettuce (0.1 (sem 0.2) mmol/l per 6 h). Plasma TRAP, quercetin and p-coumaric acid were significantly different from baseline values (P<or=0.05) 2 and 3 h after fresh lettuce ingestion. Caffeic acid increased significantly at 3 h (P<0.05). Plasma beta-carotene levels increased significantly at 6 h (P<0.05). Vitamin C concentrations (mg/l) rose from 10.9 (sem 2.0) to 12.7 (sem 3.0) (P<0.001), 12.7 (sem 2.0) (P<0.01) and 12.9 (sem 3.0) (P<0.05) at 0, 2, 3 and 6 h respectively. No changes were observed after ingestion of MAP-stored lettuce for all the measured markers. Our present results showed that ingestion of MAP-stored lettuce does not modify plasma redox status in healthy subjects. Further research is needed to develop post-harvesting techniques able to preserve the bioactive molecule content of plant food.
There is some speculation that dietary flavonoids from chocolate, in particular (-)epicatechin, may promote cardiovascular health as a result of direct antioxidant effects or through antithrombotic mechanisms. Here we show that consumption of plain, dark chocolate (Fig. 1) results in an increase in both the total antioxidant capacity and the (-)epicatechin content of blood plasma, but that these effects are markedly reduced when the chocolate is consumed with milk or if milk is incorporated as milk chocolate. Our findings indicate that milk may interfere with the absorption of antioxidants from chocolate in vivo and may therefore negate the potential health benefits that can be derived from eating moderate amounts of dark chocolate.
Only a small part of the dietary anthocyanins are absorbed. Thus large amounts of the ingested compounds are likely to enter the colon. In vitro and in vivo studies have shown that colonic bacteria transform various flavonoids to smaller phenolic acids. However, there is very little information on bacterial transformations of anthocyanins.
was to explore if anthocyanin glycosides were deglycosylated,whether the resulting aglycones were degraded further to smaller phenolic compounds by colonic bacteria, and to characterise metabolites.
Isolated cyanidin-3-glucoside and -rutinoside were fermented in vitro using human faecal microbiota as an inoculum. Metabolites were analysed and characterised by HPLC-DAS and LC-MS. They were identified by comparing their characteristics with those of available standards, and semi-quantified using the amount of substrate analysed from samples at initial timepoint.
Cyanidin-3-glucoside and cyanidin aglycone could be identified as intermediary metabolites of cyanidin-3-rutinoside. At early timepoints (before 2 h), the formation of protocatechuic acid as a major metabolite for both cyanidin glycosides and detection of lower molecular weight metabolites show that anthocyanins were converted by gut microflora. Furthermore, reconjugation of the aglycone with other groups, non-typical for dietary anthocyanins, was evident at the later (after 2h) timepoints.
Bacterial metabolism of anthocyanins involves the cleavage of glycosidic linkages and breakdown of the anthocyanidin heterocycle.
Flavonoids are components of fruit and vegetables that may be beneficial in the prevention of disease such as cancer and cardiovascular diseases. Their beneficial effects will be dependent upon their uptake and disposition in tissues and cells. The metabolism and pharmacokinetics of flavonoids has been an area of active research in the last decade. To date, approximately 100 studies have reported the pharmacokinetics of individual flavonoids in healthy volunteers. The data indicate considerable differences among the different types of dietary flavonoids so that the most abundant flavonoids in the diet do not necessarily produce the highest concentration of flavonoids or their metabolites in vivo. Small intestinal absorption ranges from 0 to 60% of the dose and elimination half-lives (T1/2) range from 2 to 28h. Absorbed flavonoids undergo extensive first-pass Phase II metabolism in the small intestine epithelial cells and in the liver. Metabolites conjugated with methyl, glucuronate and sulfate groups are the predominant forms present in plasma. This review summarizes the key differences in absorption, metabolism and pharmacokinetics between the major flavonoids present in the diet. For each flavonoid, the specific metabolites that have been identified so far in vivo are indicated. These data should be considered in the design and interpretation of studies investigating the mechanisms and potential health effects of flavonoids.
Proanthocyanidins, the most abundant polyphenols in chocolate, are not depolymerized in the stomach and reach the small intestine intact, where they are hardly absorbed because of their high molecular weight. In vitro and in vivo studies using pure compounds as substrates suggest that proanthocyanidins and the related catechin monomers may be degraded into more bioavailable low-molecular-weight phenolic acids by the microflora in the colon.
The aim of the study was to estimate the amounts of phenolic acids formed by the microflora and excreted in the urine of human subjects after consumption of polyphenol-rich chocolate.
After consumption of a polyphenol-free diet for 2 d and a subsequent overnight fast, 11 healthy subjects (7 men and 4 women) consumed 80 g chocolate containing 439 mg proanthocyanidins and 147 mg catechin monomers. All urine was collected during the 24 h before chocolate consumption and at 3, 6, 9, 24, and 48 h after chocolate consumption. Aromatic acids were identified in urine by gas chromatography-mass spectrometry and were quantified by HPLC-electrospray ionization tandem mass spectrometry.
Chocolate intake increased the urinary excretion of the 6 following phenolic acids: m-hydroxyphenylpropionic acid, ferulic acid, 3,4-dihydroxyphenylacetic acid, m-hydroxyphenylacetic acid, vanillic acid, and m-hydroxybenzoic acid.
The antioxidant and biological effects of chocolate may be explained not solely by the established absorption of catechin monomers but also by the absorption of microbial phenolic acid metabolites.
The current growing interest for natural antioxidants has led to a renewed scientific attention for artichoke, due not only to its nutritional value, but, overall, to its polyphenolic content, showing strong antioxidant properties. The major constituents of artichoke extracts are hydroxycinnamic acids such as chlorogenic acid, dicaffeoylquinic acids caffeic acid and ferulic acid, and flavonoids such as luteolin and apigenin glycosides. In vitro studies, using cultured rat hepatocytes, have shown its hepatoprotective functions and in vivo studies have shown the inhibition of cholesterol biosynthesis in human subjects. Several studies have shown the effect on animal models of artichoke extracts, while information on human bioavailability and metabolism of hydroxycinnamates derivatives is still lacking. Results showed a plasma maximum concentration of 6.4 (SD 1.8) ng/ml for chlorogenic acid after 1 h and its disappearance within 2 h (P< 0.05). Peak plasma concentrations of 19.5 (SD 6.9) ng/ml for total caffeic acid were reached within 1 h, while ferulic acid plasma concentrations showed a biphasic profile with 6.4 (SD1.5) ng/ml and 8.4 (SD4.6) ng/ml within 1 h and after 8 h respectively. We observed a significant increase of dihydrocaffeic acid and dihydroferulic acid total levels after 8 h (P<0.05). No circulating plasma levels of luteolin and apigenin were present. Our study confirms the bioavailability of metabolites of hydroxycinnamic acids after ingestion of cooked edible Cynara scolymus L. (cultivar Violetto di Provenza).
Polyphenols are abundant micronutrients in our diet, and evidence for their role in the prevention of degenerative diseases is emerging. Bioavailability differs greatly from one polyphenol to another, so that the most abundant polyphenols in our diet are not necessarily those leading to the highest concentrations of active metabolites in target tissues. Mean values for the maximal plasma concentration, the time to reach the maximal plasma concentration, the area under the plasma concentration-time curve, the elimination half-life, and the relative urinary excretion were calculated for 18 major polyphenols. We used data from 97 studies that investigated the kinetics and extent of polyphenol absorption among adults, after ingestion of a single dose of polyphenol provided as pure compound, plant extract, or whole food/beverage. The metabolites present in blood, resulting from digestive and hepatic activity, usually differ from the native compounds. The nature of the known metabolites is described when data are available. The plasma concentrations of total metabolites ranged from 0 to 4 mumol/L with an intake of 50 mg aglycone equivalents, and the relative urinary excretion ranged from 0.3% to 43% of the ingested dose, depending on the polyphenol. Gallic acid and isoflavones are the most well-absorbed polyphenols, followed by catechins, flavanones, and quercetin glucosides, but with different kinetics. The least well-absorbed polyphenols are the proanthocyanidins, the galloylated tea catechins, and the anthocyanins. Data are still too limited for assessment of hydroxycinnamic acids and other polyphenols. These data may be useful for the design and interpretation of intervention studies investigating the health effects of polyphenols.
Flavanol compounds in wine, cocoa products and tea can exert a cardioprotective effect, for example by influencing endothelial-cell function1, antithrombic mechanisms2 and blood pressure3, 4. Serafini et al.5 claim that consuming dark chocolate, but not milk chocolate or dark chocolate together with milk, increases the antioxidant capacity of human plasma, and suggest that interaction between milk proteins and chocolate flavonoids inhibits the in vivo antioxidant activity of chocolate and the absorption of epicatechin into the bloodstream. This inference could have implications beyond chocolate consumption if dairy products do indeed counteract the putative health benefits of dietary flavanols.
The antioxidant activity of phenolic compounds present in berries was investigated by two copper-catalyzed in vitro oxidation assays: human low-density lipoproteins (LDL) and lecithin liposomes. The amount of total phenolics varied between 617 and 4350 mg/kg in fresh berries, as gallic acid equivalents (GAE). In LDL at 10 μM GAE, berry extracts inhibited hexanal formation in the order: blackberries > red raspberries > sweet cherries > blueberries > strawberries. In lecithin liposomes, the extracts inhibited hexanal formation in the order: sweet cherries > blueberries > red raspberries > blackberries > strawberries. Red raspberries were more efficient than blueberries in inhibiting hydroperoxide formation in lecithin liposomes. HPLC analyses showed high anthocyanin content in blackberries, hydroxycinnamic acid in blueberries and sweet cherries, flavonol in blueberries, and flavan-3-ol in red raspberries. The antioxidant activity for LDL was associated directly with anthocyanins and indirectly with flavonols, and for liposome it correlated with the hydroxycinnamate content. Berries thus contribute a significant source of phenolic antioxidants that may have potential health effects. Keywords: Berries; antioxidants; LDL oxidation; liposomes; flavonoids; hydroxycinnamates; anthocyanins; flavan-3-ols; flavonols
The tannin content of crude plant exts. or of purified prepns. was detd. by adding the sample to a std. soln. of protein, isolating the insol. tannin-protein complex, dissolving it in alk. soln., and measuring the absorbance at 510 nm after adding FeCl3. Plots of absorbance as a function of the amt. of tannin are linear for 0.20-1.0 mg tannic acid and partially purified sorghum tannins. Nontannin components of crude MeOH exts. of sorghum and cowpeas do not interfere with the assay. The results of the pptn. method are qual. similar to those obtained by vanillin assay. The pptn. assay can be used to study the effects of pH and other parameters on tannin-protein interactions
Frozen highbush blueberries (Vaccinium corymbosum L.) were processed into juice, and the influence was studied of a steam blanching step, applied to fruit before milling, on the recovery of anthocyanin pigments and total cinnamates, in relation to the radical-scavenging properties of blueberry juices. Inactivation of PPO induced a significant recovery increase of anthocyanin and cinnamate contents. Furthermore juice from blanched fruits was more blue and less red than that obtained in the traditional way, due to the positive effect of the thermal treatment on the extraction of the most soluble anthocyanin pigments, which are also the most intense blue. Blanching of fruit greatly increased the radical-scavenging activity of the juice, in relation to the higher recovery of anthocyanin pigments and total cinnamates.
Current views and opinions on polyphenol (tannin)-protein complexation are outlined. ‘Structure-activity’ relationships are delineated as are experimental approaches which seek to define the modes and sites of binding of ligand (polyphenol) to the receptor (protein). A model for polyphenol-protein complexation is proposed.
The milk fat globule is essentially an oil droplet enclosed in plasma membrane from the lactating cell. Envelopment in this membrane is the mechanism by which milk fat globules are expelled from the cell. This remarkable secretory process provides the membranologist with a unique source of plasma membrane; one that is oriented on an inert (glyceride) core with the same exterior exposure it had on the cell; also one that can be obtained in substantial quantity and purity by relatively mild manipulations.The literature on the milk fat globule membrane is reviewed in the following areas: membrane isolation, preparation, composition (lipid, protein, enzymes), stability including the presence and nature of membrane material in the skim milk phase, and “sidedness” from the standpoint of lipid and protein distributions in the exterior and inner surfaces. The emerging evidence in this latter area agrees closely with findings on limiting membranes from other types of cells; i.e. glycoproteins, 5′ nucleotidase, sphingolipids, and phosphatidylcholine are concentrated in the outer (exposed) surface, while the amino lipids (phosphatidylethanolamine and phosphatidylserine) are on the interior side of the membrane. How unstable the milk fat globule membrane is and the origin and identity of an interesting array of membrane material in skim milk are matters requiring further research. The latter material includes a variety of membranous vesicles, sloughed microvilli and on occasions membrane enclosed viruses.While there are yet many gaps in the knowledge of the globule membrane, research interest in it has been strong because of its importance in properties of milk and milk products. The value of this research interest is now further fortified by basic considerations in cytology, biochemistry and the relevance of mammary cell membranes to the breast cancer problem.
There is considerable interest in coloured fruits and berries as sources of biologically active anthocyanins. To examine the relationship between the oral dose and the amount excreted for anthocyanins from a food source across a physiological range of doses, volunteers were fed, in random order, four portions (100-400 g) of fresh strawberries as part of a standard breakfast. Urine was collected at 2 h intervals up to 8 h, and for the period 8-24 h. Fresh strawberries contained pelargonidin-3-glucoside as the major anthocyanin with smaller amounts of cyanidin-3-glucoside and pelargonidin-3-rutinoside. Anthocyanins were detected in the urine of all volunteers for all doses, predominantly as pelargonidin glucuronide and sulphate metabolites. There was a strong, linear relationship between oral dose and anthocyanin excretion (Pearson's product moment correlation coefficient = 0.692, p < 0.001, n = 40) which indicated that on an average, every additional unit of dose caused 0.0166 units of excretion. Within individuals, dose -- excretion data fitted a linear regression model (median R(2) = 0.93). We conclude that strawberry anthocyanins are partially bioavailable in humans with a linear relationship between oral dose and urinary excretion for doses up to 400 g fresh fruit.
Different cultivars of four Vaccinium species [Vaccinium corymbosum L (Highbush), Vaccinium ashei Reade (Rabbiteye), Vaccinium angustifolium (Lowbush), and Vaccinium myrtillus L (Bilberry)] were analyzed for total phenolics, total anthocyanins, and antioxidant capacity (oxygen radical absorbance capacity, ORAC). The total antioxidant capacity of different berries studied ranged from a low of 13.9 to 45.9 micromole Trolox equivalents (TE)/g of fresh berry (63.2-282.3 micromole TE/g of dry matter) in different species and cultivars of Vaccinium. Brightwell and Tifblue cultivars of rabbiteye blueberries were harvested at 2 times, 49 days apart. Increased maturity at harvest increased the ORAC, the anthocyanin, and the total phenolic content. The growing location (Oregon vs Michigan vs New Jersey) did not affect ORAC, anthocyanin or total phenolic content of the cv. Jersey of highbush blueberries. A linear relationship existed between ORAC and anthocyanin (r(xy) = 0.77) or total phenolic (r(xy) = 0.92) content. In general, blueberries are one of the richest sources of antioxidant phytonutrients of the fresh fruits and vegetables we have studied.
Our results indicate that there is an increase in total antioxidant
capacity (TAC) and (-)epicatechin content of plasma in people who have
consumed dark chocolate, and that these effects are reduced by the
presence of milk. Halliwell and Schroeter et al. raise issues that are
central to the debate over the fate and potential protective effects of
dietary antioxidants.
Flavonoids are polyphenolic antioxidants naturally present in vegetables, fruits, and beverages such as tea and wine. In vitro, flavonoids inhibit oxidation of low-density lipoprotein and reduce thrombotic tendency, but their effects on atherosclerotic complications in human beings are unknown. We measured the content in various foods of the flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin. We then assessed the flavonoid intake of 805 men aged 65-84 years in 1985 by a cross-check dietary history; the men were then followed up for 5 years. Mean baseline flavonoid intake was 25.9 mg daily. The major sources of intake were tea (61%), onions (13%), and apples (10%). Between 1985 and 1990, 43 men died of coronary heart disease. Fatal or non-fatal myocardial infarction occurred in 38 of 693 men with no history of myocardial infarction at baseline. Flavonoid intake (analysed in tertiles) was significantly inversely associated with mortality from coronary heart disease (p for trend = 0.015) and showed an inverse relation with incidence of myocardial infarction, which was of borderline significance (p for trend = 0.08). The relative risk of coronary heart disease mortality in the highest versus the lowest tertile of flavonoid intake was 0.42 (95% CI 0.20-0.88). After adjustment for age, body-mass index, smoking, serum total and high-density-lipoprotein cholesterol, blood pressure, physical activity, coffee consumption, and intake of energy, vitamin C, vitamin E, beta-carotene, and dietary fibre, the risk was still significant (0.32 [0.15-0.71]). Intakes of tea, onions, and apples were also inversely related to coronary heart disease mortality, but these associations were weaker. Flavonoids in regularly consumed foods may reduce the risk of death from coronary heart disease in elderly men.
Evaluation of the vitro antioxidant activity of green and black tea, their in vivo effect on plasma antioxidant potential in man and the effect of milk addition.
The antioxidant activity of the tea, with and without milk, was tested in vitro by measuring the length of the peroxyl radical induced lag-phase. The in vivo activity was tested on two groups of five healthy adults. Each group ingested 300 ml of either black or green tea, after overnight fast. The experiment was repeated on a separate day, adding 100 ml whole milk to the tea (ratio 1:4 ). Five subjects acted as controls. The human plasma antioxidant capacity (TRAP) was measured before and 30, 50 and 80 min from the ingestion of tea.
Both teas inhibited the in vitro peroxidation in a dose-dependent manner. Green tea was sixfold more potent than black tea. The addition of milk to either tea did not appreciably modify their in vitro antioxidant potential. In vivo, the ingestion of tea produced a significant increase of TRAP (P <0.05), similar in both teas, which peaked at 30-50 min. When tea was consumed with milk, their in vivo activity was totally inhibited.
The paper shows that tea possesses a strong antioxidant activity in vitro which is believed to be exerted by its polyphenols moiety. It also provides compelling evidence that tea has also a potent in vivo activity in man. The promptness of the in vivo response suggests that the absorption of the bioactive components of tea takes place in the upper part of the gastrointestinal system. The inhibition of this effect by milk is thought to be due to the complexation of tea polyphenols by milk proteins. These findings might help to clarify the putative role of dietary poly- phenols in modulating oxidative stress in vivo.
A simple, automated test measuring the ferric reducing ability of plasma, the FRAP assay, is presented as a novel method for assessing "antioxidant power." Ferric to ferrous ion reduction at low pH causes a colored ferrous-tripyridyltriazine complex to form. FRAP values are obtained by comparing the absorbance change at 593 nm in test reaction mixtures with those containing ferrous ions in known concentration. Absorbance changes are linear over a wide concentration range with antioxidant mixtures, including plasma, and with solutions containing one antioxidant in purified form. There is no apparent interaction between antioxidants. Measured stoichiometric factors of Trolox, alpha-tocopherol, ascorbic acid, and uric acid are all 2.0; that of bilirubin is 4.0. Activity of albumin is very low. Within- and between-run CVs are <1.0 and <3.0%, respectively, at 100-1000 micromol/liter. FRAP values of fresh plasma of healthy Chinese adults: 612-1634 micromol/liter (mean, 1017; SD, 206; n = 141). The FRAP assay is inexpensive, reagents are simple to prepare, results are highly reproducible, and the procedure is straightforward and speedy. The FRAP assay offers a putative index of antioxidant, or reducing, potential of biological fluids within the technological reach of every laboratory and researcher interested in oxidative stress and its effects.
D- and L-Ascorbic acids have been separated using liquid chromatography (LC) on a polymer-coated silica-based NH2 column and the L-isomer has been quantified in human serum, rat serum, rat lung, rat lung perfusate, infant formula (SRM 1846) and mixed food sample (SRM 2383). The D-isomer was observed only in trace amounts in the mixed food sample. The results demonstrate that ascorbic acid was stable on the column and completely recovered from supplemented samples of human serum and that this method of analysis is accurate, precise and