Consumption Of Anthocyanins Research Articles

The effect of bioactive compounds on in vitro and in vivo antioxidant activity of different berry juices.

BackgroundBerry fruit is known for its high contents of various bioactive compounds. The latter constitute of anthocyanins, flavonols and flavanols and posses high antioxidative activity. The highly dynamic antioxidant system can be evaluated in vitro and in vivo in several model organisms. These measurements represent a good approximation of the real potential of bioactive compounds in the cells of higher eucarions. The aim of the study was thus to determine in vitro and in vivo antioxidant activity of different berry juices, which reportedly contain high amounts of phenolics.Methodology/Principal FindingsFive different berry species were collected from several locations in central Slovenia and juice was extracted from each species separately. Juice was assessed for their in vitro and in vivo antioxidant activity. Phenolic profiles of berries were determined with the use of a HPLC/MS system, in vitro antioxidant activity with the DPPH radical scavenging method and in vivo antioxidative activity using Saccharomyces cerevisiae. The highest diversity of individual phenols was detected for bilberry juice. The highest in vitro antioxidant capacity was determined for blackcurrant juice. A decrease in intracellular oxidation compared to control was observed in the following order: blackcurrant < chokeberry = blueberry < bilberry. The results indicate important differences in antioxidant activity of berry juices between in vitro and in vivo studies.Conclusion/SignificanceIn addition to the total content of phenolic compounds entering the cells, a key factor determining antioxidative activity of berry juices is also the ratio between the compounds. Where high content levels of anthocyanins and very low content levels of flavonols and hydroxycinnamic acids were measured a lower intracellular oxidation has been detected. Specifically, intracellular oxidation increased with higher consumption of hydroxycinnamic acids and lower consumption of anthocyanins in the cells. Antioxidative activity also increased when the consumption of analyzed phenols was rather low.

Anti-inflammatory effect of purified dietary anthocyanin in adults with hypercholesterolemia: A randomized controlled trial

Background and aimAtherosclerosis is a chronic inflammatory disease and previous studies have demonstrated that anthocyanin inhibits atherosclerosis. In the present study, we explored the effects of anthocyanins on inflammatory cytokines in hypercholesterolemic adults and cell lines. Methods and resultsA total of 150 subjects with hypercholesterolemia consumed a purified anthocyanin mixture (320 mg/d) or a placebo twice a day for 24 weeks in a randomized, double-blind trial. Anthocyanin consumption significantly decreased the levels of serum high sensitivity C-reactive protein (hsCRP) (−21.6% vs. −2.5%, P = 0.001), soluble vascular cell adhesion molecule-1 (sVCAM-1) (−12.3% vs. 0.4%, P = 0.005) and plasma IL-1β (−12.8% vs. −1.3%, P = 0.019) compared to the placebo. We also found a significant difference in the LDL-cholesterol (−10.4% vs. 0.3%, P = 0.030) and HDL-cholesterol level changes (14.0% vs. −0.9%, P = 0.036) between the two groups. In cell culture assays in vitro, purified anthocyanin mixture, delphinidin-3-Ο-β-glucoside (Dp-3g) and cyanidin-3-Ο-β-glucoside (Cy-3g) inhibited IL-6 and IL-1β-induced CRP production (P < 0.05) in HepG2 cell line and LPS-induced VCAM-1 secretion (P < 0.05) in porcine iliac artery endothelial cell line respectively in a dose-dependent manner. In addition, the reduction of inflammatory cytokines associated with anthocyanin mixture was stronger when compared with the effects of Dp-3g and Cy-3g separately (P < 0.05). ConclusionsAnthocyanin mixture reduced the inflammatory response in hypercholesterolemic subjects. In addition, different anthocyanin compounds were found to have additive or synergistic effects in mediating anti-inflammatory responses in vitro cell culture assays.

Metabolism of Anthocyanins by Human Gut Microflora and Their Influence on Gut Bacterial Growth

Consumption of anthocyanins has been related with beneficial health effects. However, bioavailability studies have shown low concentration of anthocyanins in plasma and urine. In this study, we have investigated the bacterial-dependent metabolism of malvidin-3-glucoside, gallic acid and a mixture of anthocyanins using a pH-controlled, stirred, batch-culture fermentation system reflective of the distal human large intestine conditions. Most anthocyanins have disappeared after 5 h incubation while gallic acid remained constant through the first 5 h and was almost completely degraded following 24 h of fermentation. Incubation of malvidin-3-glucoside with fecal bacteria mainly resulted in the formation of syringic acid, while the mixture of anthocyanins resulted in formation of gallic, syringic and p-coumaric acids. All the anthocyanins tested enhanced significantly the growth of Bifidobacterium spp. and Lactobacillus-Enterococcus spp. These results suggest that anthocyanins and their metabolites may exert a positive modulation of the intestinal bacterial population.

Dietary flavonoid intakes and risk of type 2 diabetes in US men and women

Data from mechanistic studies support a beneficial effect of specific flavonoids on insulin sensitivity. However, few studies have evaluated the relation between intakes of different flavonoid subclasses and type 2 diabetes. The objective was to evaluate whether dietary intakes of major flavonoid subclasses (ie, flavonols, flavones, flavanones, flavan-3-ols, and anthocyanins) are associated with the risk of type 2 diabetes in US adults. We followed up a total of 70,359 women in the Nurses' Health Study (NHS; 1984-2008), 89,201 women in the NHS II (1991-2007), and 41,334 men in the Health Professionals Follow-Up Study (1986-2006) who were free of diabetes, cardiovascular disease, and cancer at baseline. During 3,645,585 person-years of follow-up, we documented 12,611 incident cases of type 2 diabetes. Higher intakes of anthocyanins were significantly associated with a lower risk of type 2 diabetes (pooled HR for the 3 cohorts from a comparison of extreme quintiles: 0.85; 95% CI: 0.80, 0.91; P-trend < 0.001) after multivariate adjustment for age, BMI, and lifestyle and dietary factors. Consumption of anthocyanin-rich foods, particularly blueberries (pooled HR: 0.77 from a comparison of ≥2 servings/wk with <1 serving/mo; 95% CI: 0.68, 0.87; P-trend < 0.001) and apples/pears (pooled HR: 0.77 from a comparison of ≥5 servings/wk with <1 serving/mo; 95% CI: 0.65, 0.83; P-trend < 0.001), was also associated with a lower risk of type 2 diabetes. No significant associations were found for total flavonoid intake or other flavonoid subclasses. A higher consumption of anthocyanins and anthocyanin-rich fruit was associated with a lower risk of type 2 diabetes.

Anthocyanins and cardiovascular disease prevention

In this review, recent studies on the CVD preventive activities of anthocyanins, including results from in vitro cell culture and in vivo animal model systems as well as data from clinical trials and human epidemiological studies are presented. Anthocyanins have become increasingly important to the food and dietary supplement industries as their use as natural alternatives to artificial colors, functional ingredients, and as botanical extracts has become widespread and knowledge of their health‐promoting properties is evident. Epidemiological studies suggest that consumption of anthocyanins lowers the risk of CVD, the most common cause of mortality. Anthocyanins frequently interact with other phytochemicals, exhibiting synergistic biological effects but making contributions from individual components difficult to decipher. Over the past 2 decades, many peer‐reviewed publications have demonstrated that in addition to their noted in vitro antioxidant activity, anthocyanins may regulate different signaling pathways involved in the development of CVD.

Purified Anthocyanin Supplementation Improves Endothelial Function via NO-cGMP Activation in Hypercholesterolemic Individuals

Anthocyanins have been shown to improve endothelial function in animal models. However, whether these compounds have similar beneficial effects in humans is largely unknown. In a short-term crossover study, 12 hypercholesterolemic individuals were given oral anthocyanins (320 mg) isolated from berries or placebo. Brachial artery flow-mediated dilation (FMD) was assessed before and after the intervention. In a long-term intervention trial (12 weeks), 150 hypercholesterolemic individuals were given anthocyanins (320 mg/day, n = 75) or placebo (n = 75), after which we measured FMD, plasma cGMP, and other serum biomarkers. Another short-term intervention was conducted in the presence of NO-cGMP inhibitors in 6 people and in a rat aortic ring model (n = 8). Significant increases of FMD from 8.3% (0.6%) at baseline to 11.0% (0.8%) at 1 h and 10.1% (0.9%) at 2 h were observed after short-term anthocyanin consumption, concomitantly with increases of plasma anthocyanin concentrations (P < 0.05). In the study participants who received long-term anthocyanin intervention, compared with the control group, we observed significant increases in the FMD (28.4% vs 2.2%), cGMP (12.6% vs -1.2%), and HDL-cholesterol concentrations, but decreases in the serum soluble vascular adhesion molecule-1 and LDL cholesterol concentrations (P < 0.05). The changes in the cGMP and HDL cholesterol concentrations positively correlated with FMD in the anthocyanin group (P < 0.05). In the presence of NO-cGMP inhibitors, the effects of anthocyanin on endothelial function were abolished in human participants and in a rat aortic ring model. Anthocyanin supplementation improves endothelium-dependent vasodilation in hypercholesterolemic individuals. This effect involves activation of the NO-cGMP signaling pathway, improvements in the serum lipid profile, and decreased inflammation.

Why fruits go to the dark side

The colours of fleshy fruits are usually attributed to attract seed dispersers to the plant. A cursory look at the gaudy colours of fleshy fruits on offer in a local fruit stall gives the impression that plants use primarily bright colours to attract fruit consumer. This impression is misleading; many small fruits ‘go to the dark side’ and become dark purple or black when ripe. Intermingled in foliage, these colours, which are produced by anthocyanins, can be fairly inconspicuous and are thus not easily reconciled with a signalling function to attract seed dispersers. In this review I therefore discuss complementary hypotheses on the function and evolution of fruit colouration. First, I focus on the evidence that fruit colours indeed function as signals to attract seed dispersers. I then show that anthocyanins, the most prevalent fruit pigments, are important dietary antioxidants that can be selected by blackcaps ( Sylvia atricapilla) which are important avian seed dispersers of many European plants. Moreover, the consumption of anthocyanins increases the likelihood that blackcaps mount an immune response during immune challenges. As a next step, I review evidence that anthocyanins accumulate in fruit skin in response to abiotic factors, in particular high illumination coupled with low temperature favour the increase of anthocyanins. Finally, I show that anthocyanins can also be selected for by fruit antagonists, consumers that do not disperse seeds. In particular, high contents of anthocyanins strongly reduce fungal growth in fruit tissue. Taken together, there are various selective pressures which likely influence fruit colour evolution. Currently, the relative importance of each of these selective agents is unknown. There is consequently a need to develop a more encompassing framework on fruit colour evolution.

Gut Metabolites of Anthocyanins, Gallic Acid, 3-O-Methylgallic Acid, and 2,4,6-Trihydroxybenzaldehyde, Inhibit Cell Proliferation of Caco-2 Cells

Gut microflora metabolize anthocyanins to phenolic acids and aldehydes. These metabolites may explain the relationship between anthocyanin consumption and reduced incidence of colon cancer. Here, all six major metabolites, along with a Cabernet Sauvignon anthocyanin extract, were incubated with Caco-2 cells at concentrations of 0-1000 microM over 72 h to determine effects on cell proliferation and for 24 h to assess cytotoxicity effects and at 140 microM for 24 h to measure induction of apoptosis. These measurements were based on colorimetric methods. Gallic acid and 3-O-methylgallic acid inhibited cell proliferation and lacked cytotoxicity at low concentrations. The aldehyde metabolite and anthocyanin extract also inhibited cell proliferation at low concentrations and had low cytotoxicity at a wide range of concentrations. Of the four substances that effectively reduced cell proliferation, the aldehyde was the best inducer of apoptosis. In addition, these same four treatments degraded quickly in growth media, suggesting the involvement of subsequent oxidation products in the reduction of cell viability. These results indicate that the anthocyanin microfloral metabolites gallic acid, 3-O-methylgallic acid, and 2,4,6-trihydroxybenzaldehyde reduce cell proliferation in Caco-2 cells more effectively than anthocyanins and may offer protection against colon cancer after their formation in the gut.

Anthocyanins: Natural Colorants with Health-Promoting Properties

Anthocyanins are flavonoids in fruits and vegetables that render them vivid red to blue. To date, there have been more than 635 anthocyanins identified in nature, featuring six common aglycones and various types of glycosylations and acylations. Dietary consumption of anthocyanins is high compared to other flavonoids, owing to their wide distribution in plant materials. Based upon many cell-line studies, animal models, and human clinical trials, it has been suggested that anthocyanins possess anti-inflammatory and anti-carcinogenic activity, cardiovascular disease prevention, obesity control, and diabetes alleviation properties, all of which are more or less associated with their potent antioxidant property. Evidence suggests that absorption of anthocyanins occurs in the stomach and small intestine. Epithelial tissue uptake seems to be highly efficient, yet transportation into circulation, tissue distribution, and urine excretion are very limited. The bioactivity of bioavailable anthocyanins should be a focus of future research regarding their putative health-promoting effects.

Cardiovascular Disease Risk Biomarkers and Liver and Kidney Function Are Not Altered in Postmenopausal Women after Ingesting an Elderberry Extract Rich in Anthocyanins for 12 Weeks ,

Growing evidence supports a cardio-protective role for anthocyanins; however, there is limited evidence on their efficacy and safety following the consumption of relatively high but dietarily achievable doses in humans. We conducted a parallel-designed, randomized, placebo-controlled study to examine the effect of chronic consumption of anthocyanins on biomarkers of cardiovascular disease (CVD) risk and liver and kidney function in 52 healthy postmenopausal women (n = 26 in treatment and placebo groups). Volunteers (BMI, 24.7 ± 3.6 kg/m2; age, 58.2 ± 5.6 y) consumed 500 mg/d anthocyanins as cyanidin glycosides (from elderberry) or placebo for 12 wk (2 capsules twice/d). At the beginning (wk 0) and end of the 12-wk intervention, levels of anthocyanins and biomarkers of CVD (inflammatory biomarkers, platelet reactivity, lipids, and glucose) and liver and kidney function (total bilirubin, albumin, urea, creatinine, alkaline phosphatase, alanine aminotransferase, and γ-glutyl transferase) were assessed in fasted blood. Anthropometric, blood pressure, and pulse measurements were also taken. In addition, postprandial plasma anthocyanins were measured (t = 1, 2, 3 h) following a 500-mg oral bolus dose. After 12 wk of chronic exposure to anthocyanins, there was no significant change in biomarkers of CVD risk and liver and kidney function remained within clinically acceptable ranges. We observed no plasma accumulation of anthocyanins; however, postprandial metabolism increased (P = 0.02). In conclusion, these data suggest that chronic consumption of 500 mg/d of elderberry extract for 12 wk is apparently safe, but ineffective in altering biomarkers of CVD risk in healthy postmenopausal women.

Short-term blackcurrant extract consumption modulates exercise-induced oxidative stress and lipopolysaccharide-stimulated inflammatory responses

Exercise-induced oxidative stress is instrumental in achieving the health benefits from regular exercise. Therefore, inappropriate use of fruit-derived products (commonly applied as prophalytic antioxidants) may counteract the positive effects of exercise. Using human exercise and cellular models we found that 1) blackcurrant supplementation suppressed exercise-induced oxidative stress, e.g., plasma carbonyls (0.9 +/- 0.1 vs. 0.6 +/- 0.1 nmol/mg protein, placebo vs. blackcurrant), and 2) preincubation of THP-1 cells with an anthocyanin-rich blackcurrant extract inhibited LPS-stimulated cytokine secretion [TNF-alpha (16,453 +/- 322 vs. 10,941 +/- 82 pg/ml, control vs. extract, P < 0.05) and IL-6 (476 +/- 14 vs. 326 +/- 32 pg/ml, control vs. extract, P < 0.05)] and NF-kappaB activation. In addition to its antioxidant and anti-inflammatory properties, we found that postexercise plasma collected after blackcurrant supplementation enhanced the differential temporal LPS-stimulated inflammatory response in THP-1 cells, resulting in an early suppression of TNF-alpha (1,741 +/- 32 vs. 1,312 +/- 42 pg/ml, placebo vs. blackcurrant, P < 0.05) and IL-6 (44 +/- 5 vs. 36 +/- 3 pg/ml, placebo vs. blackcurrant, P < 0.05) secretion after 24 h. Furthermore, by using an oxidative stress cell model, we found that preincubation of THP-1 cells with hydrogen peroxide (H(2)O(2)) prior to extract exposure caused a greater suppression of LPS-stimulated cytokine secretion after 24 h, which was not evident when cells were simultaneously incubated with H(2)O(2) and the extract. In summary, our findings support the concept that consumption of blackcurrant anthocyanins alleviate oxidative stress, and may, if given at the appropriate amount and time, complement the ability of exercise to enhance immune responsiveness to potential pathogens.

Anthocyanins and polyphenol oxidase from dried arils of pomegranate (Punica granatum L.)

Anthocyanins are natural pigments responsible for red, purple, and blue colouration in plants. Human consumption of anthocyanins is increasing because of the rising awareness and interest in their potential health benefits. Pomegranate is one of the major sources of polyphenolic phytochemicals, such as anthocyanins. Dried pomegranate raisins (anardana) are consumed in large quantities in Asian countries, and contain substantial amounts of anthocyanins. Five anthocyanins were found to be present in pomegranate raisins. Drying adversely affected the amount of anthocyanins, with polyphenol oxidase (PPO) playing a possible role in oxidative degradation of anthocyanins. Anthocyanins are heat-stable compounds, and inactivation of PPO by processing at high temperature for short periods may prevent PPO-catalysed anthocyanin oxidation in pomegranate arils. Pomegranate PPO kinetics were partially characterised by investigating the effect of substrate (catechol) concentration; optimum pH for PPO activity was found to be 6.0.

Enrichment of tomato fruit with health-promoting anthocyanins by expression of select transcription factors

Dietary consumption of anthocyanins, a class of pigments produced by higher plants, has been associated with protection against a broad range of human diseases. However, anthocyanin levels in the most commonly eaten fruits and vegetables may be inadequate to confer optimal benefits. When we expressed two transcription factors from snapdragon in tomato, the fruit of the plants accumulated anthocyanins at levels substantially higher than previously reported for efforts to engineer anthocyanin accumulation in tomato and at concentrations comparable to the anthocyanin levels found in blackberries and blueberries. Expression of the two transgenes enhanced the hydrophilic antioxidant capacity of tomato fruit threefold and resulted in fruit with intense purple coloration in both peel and flesh. In a pilot test, cancer-susceptible Trp53(-/-) mice fed a diet supplemented with the high-anthocyanin tomatoes showed a significant extension of life span.

Red wine anthocyanins are rapidly absorbed in humans and affect monocyte chemoattractant protein 1 levels and antioxidant capacity of plasma

Epidemiological studies suggest that a moderate consumption of anthocyanins may be associated with protection against coronary heart disease. The main dietary sources of anthocyanins include red-coloured fruits and red wine. Although dietary anthocyanins comprise a diverse mixture of molecules, little is known how structural diversity relates to their bioavailability and biological function. The aim of the present study was to evaluate the absorption and metabolism of the 3-monoglucosides of delphinidin, cyanidin, petunidin, peonidin and malvidin in humans and to examine both the effect of consuming a red wine extract on plasma antioxidant status and on monocyte chemoattractant protein 1 production in healthy human subjects. After a 12-h overnight fast, seven healthy volunteers received 12 g of an anthocyanin extract and provided 13 blood samples in the 24 h following the test meal. Furthermore, urine was collected during this 24-h period. Anthocyanins were detected in their intact form in both plasma and urine samples. Other anthocyanin metabolites could also be detected in plasma and urine and were identified as glucuronides of peonidin and malvidin. Anthocyanins and their metabolites appeared in plasma about 30 min after ingestion of the test meal and reached their maximum value around 1.6 h later for glucosides and 2.5 h for glucuronides. Total urinary excretion of red wine anthocyanins was 0.05±0.01% of the administered dose within 24 h. About 94% of the excreted anthocyanins was found in urine within 6 h. In spite of the low concentration of anthocyanins found in plasma, an increase in the antioxidant capacity and a decrease in MCP-1 circulating levels in plasma were observed.

Identification of Cabernet Sauvignon Anthocyanin Gut Microflora Metabolites

Anthocyanins are polyphenol antioxidants that have been shown to prevent many chronic diseases, including colon cancer. The compounds are largely metabolized by various enzymes and bacteria in the large intestine, and the health benefits of consuming foods rich in anthocyanins could be due mostly to the effects of these metabolites. In this study, the contents of the large intestine of pigs were used to model anthocyanin metabolism because pig and human intestinal microflora are similar. An anthocyanin extract from Cabernet Sauvignon grapes that contained delphinidin-3-glucoside, petunidin-3-glucoside, peonidin-3-glucoside, and malvidin-3-glucoside was employed. The extract was incubated anaerobically in the contents of the large intestine of freshly slaughtered pigs for 0, 0.5, and 6 h (final concentrations of 20.9, 28.2, 61.4, and 298.0 microM of the above anthocyanin compounds, respectively, at t = 0 h). Anthocyanins and their metabolites were measured by LC-ESI-MS. After 6 h, anthocyanins were no longer detected, and three metabolites were identified as 3-O-methylgallic acid, syringic acid, and 2,4,6-trihydroxybenzaldehyde. Results from this study suggest that consumption of Cabernet Sauvignon grape anthocyanins could lead to the formation of specific metabolites in the human gut, and it is possible that these metabolites offer the protective effect against colon cancer attributed to anthocyanin consumption.

Recent Advances in Anthocyanin Analysis and Characterization.

Anthocyanins are a class of polyphenols responsible for the orange, red, purple and blue colors of many fruits, vegetables, grains, flowers and other plants. Consumption of anthocyanins has been linked as protective agents against many chronic diseases and possesses strong antioxidant properties leading to a variety of health benefits. In this review, we examine the advances in the chemical profiling of natural anthocyanins in plant and biological matrices using various chromatographic separations (HPLC and CE) coupled with different detection systems (UV, MS and NMR). An overview of anthocyanin chemistry, prevalence in plants, biosynthesis and metabolism, bioactivities and health properties, sample preparation and phytochemical investigations are discussed while the major focus examines the comparative advantages and disadvantages of each analytical technique.

Protocatechuic Acid Is the Major Human Metabolite of Cyanidin-Glucosides 3

The metabolic fate of dietary anthocyanins (ACN) has not been fully clarified in humans. In all previous studies, the proportion of total ACN absorbed and excreted in urine was <1% intake. This study aimed to elucidate the human metabolism of cyanidin-glucosides (CyG) contained in blood orange juice (BOJ). One liter of BOJ, containing 71 mg CyG, was consumed by 6 healthy, fasting volunteers. Blood, urine, and fecal samples were collected at baseline and at different times up to 24 h after juice consumption. The content of native CyG, glucuronidated/methylated derivatives, and various phenolic acids was determined by HPLC/MS/MS. The serum maximal concentration of cyanidin-3-glucoside (Cy-3-glc) was 1.9 ± 0.6 nmol/L and that of protocatechuic acid (PCA) was 492 ± 62 nmol/L at 0.5 h and 2 h after juice consumption, respectively. The calculated total amounts in plasma corresponded for Cy-3-glc to 0.02% and for PCA to 44% of CyG ingested. CyG and glucuronidated/methylated metabolites, but not PCA, were detected in urine. ACN recovered in 24-h urine collections represented ∼1.2% of the ingested dose. Both CyG (1.90 ± 0.04 nmol/g) and PCA (277 ± 0.2 nmol/g) were recovered in 24-h fecal samples. Data explained the metabolic fate of 74% of BOJ ACN. PCA was for the first time, to our knowledge, identified in humans as a CyG metabolite, accounting for almost 73% of ingested CyG. A high concentration of PCA may explain the short-term increased plasma antioxidant activity observed after intake of cyanidin-rich food and it can also contribute to the numerous health benefits attributed to dietary ACN consumption.

Anthocyanin Absorption and Antioxidant Status in Pigs

The effect of a simultaneous intake of food or flavonoids on anthocyanins absorption and antioxidant status in pigs was investigated. Twelve male pigs at 27.1 +/- 0.7 kg BW fitted with jugular venous cannulae were maintained in individual metabolic crates. The animals were each given one of three dietary treatments in random order: blackcurrant powder (BC) to give a dose of 100 mg total ACNs/kg BW mixed either with water and sugar (Diet A), cereal (Weet-Bix), milk, and sugar (Diet B), or cereal, milk, sugar, and an additional flavonol (rutin, approximately 100 mg/kg BW) (Diet C). The four major anthocyanins of BC, delphinidin-3-glucoside, delphinidin-3-rutinoside, cyanidin-3-glucoside, and cyanidin-3-rutinoside, were identified and quantified by HPLC-PDA in all three diets. In the pig plasma, four peaks with a reversed pattern to those of anthocyanins in the BC extract were detected. The total amount of anthocyanins absorbed was not significantly different between the three diets, but the rate of absorption and subsequent decline was slower following administration of diet B and C than diet A. All three diets increased antioxidant capacity when measured by the FRAP assay but not when measured by the ORAC and non-protein ORAC assay. However, the increase was delayed and did not appear until 4 h after ingestion, at a time when plasma anthocyanin levels had returned to baseline. The present study demonstrates that the simultaneous intake of food or other flavonoids delays the absorption profile for anthocyanins. Our results also suggest that the increase in antioxidant capacity is not due to dietary anthocyanins but may be due to metabolites that result from anthocyanin consumption.

Can an anthocyanin‐rich diet reduce risks for developing Type 2 diabetes?

The incidence of Type 2 diabetes is increasing in the United States and other nations. Low intake of fruits and vegetables is a risk factor for development of this disease. Anthocyanins are the flavonoids pigments in red and blue fruits that contribute to antioxidant activity. These pigments modulate alpha-glucosidase and aldose reductase activity and insulin production in vitro, suggesting that foods containing anthocyanins may ameliorate risks for development of Type 2 diabetes. The objective of this study was to demonstrate potential benefits of anthocyanin consumption for persons at risk for developing diabetes. Subjects in the Bangor, ME area between the ages of 21 and 65 years, with BMI of 25–30, and fasting serum glucose levels (FG) between 5.6 to 6.9 millimoles per liter were recruited for the study. Subjects were paired by gender, age and FG, and then each member of the pair was randomly assigned to the control or to the treatment group. The control group was instructed to make no changes in their dietary or exercise habits and to limit consumption of anthocyanin-containing foods to no more than 3 servings per week. The treatment group was provided with a list of serving sizes for common fruits and juices that provided ~150 mg anthocyanins; two servings were to be consumed daily for three months. Fasting serum glucose, insulin, glycosylated hemoglobin, cholesterol, triglycerides, antioxidant capacity and urinary microalbumin were measured at baseline and at 6 and 12 weeks of the study. Weight, BMI and waist circumference were also recorded. The University of Maine Institutional Review Board for the Protection of Human Subjects approved the study design and protocols. Financial support was provided by the Gustavus and Louise Pfeiffer Research Foundation.

Protective effect of anthocyanins in middle cerebral artery occlusion and reperfusion model of cerebral ischemia in rats

Ischemic stroke results from a transient or permanent reduction in cerebral blood flow that is restricted to the territory of a major brain artery. The major pathobiological mechanisms of ischemia/reperfusion injury include excitotoxicity, oxidative stress, inflammation, and apoptosis. In the present report, we first investigated the protective effects of anthocyanins against focal cerebral ischemic injury in rats. The pretreatment of anthocyanins (300 mg/kg, p.o.) significantly reduced the brain infarct volume and a number of TUNEL positive cells caused by middle cerebral artery occlusion and reperfusion. In the immunohistochemical observation, anthocyanins remarkably reduced a number of phospho-c-Jun N-terminal kinase (p-JNK) and p53 immunopositive cells in the infarct area. Moreover, Western blotting analysis indicated that anthocyanins suppressed the activation of JNK and up-regulation of p53. Thus, our data suggested that anthocyanins reduced neuronal damage induced by focal cerebral ischemia through blocking the JNK and p53 signaling pathway. These findings suggest that the consumption of anthocyanins may have the possibility of protective effect against neurological disorders such as brain ischemia.