Anthocyanin-rich Blackcurrant Research Articles

Anthocyanin-Rich Blackcurrant Extract Preserves Gastrointestinal Barrier Permeability and Reduces Enterocyte Damage but Has No Effect on Microbial Translocation and Inflammation After Exertional Heat Stress.

This study investigated the effects of 7days of 600mg/day anthocyanin-rich blackcurrant extract intake on small intestinal permeability, enterocyte damage, microbial translocation, and inflammation following exertional heat stress. Twelve recreationally active men (maximal aerobic capacity = 55.6 ± 6.0ml·kg-1·min-1) ran (70% VO2max) for 60min in an environmental chamber (34°C, 40% relative humidity) on two occasions (placebo/blackcurrant, randomized double-blind crossover). Permeability was assessed from a 4-hr urinary excretion of lactulose and rhamnose and expressed as a ratio of lactulose/rhamnose. Venous blood samples were taken at rest and 20, 60, and 240min after exercise to measure enterocyte damage (intestinal fatty acid-binding protein); microbial translocation (soluble CD14, lipopolysaccharide-binding protein); and interleukins 6, interleukins 10, and interleukins 1 receptor antagonist. Exercise increased rectal temperature (by ∼2.8°C) and heart rate (by ∼123 beats/min) in each condition. Blackcurrant supplementation led to a ∼12% reduction in lactulose/rhamnose ratio (p < .0034) and enterocyte damage (∼40% reduction in intestinal fatty acid-binding protein area under the curve; p < .0001) relative to placebo. No between-condition differences were observed immediately after exercise for lipopolysaccharide-binding protein (mean, 95% confidence interval [CI]; +80%, 95% CI [+61%, +99%]); soluble CD14 (+37%, 95% CI [+22%, +51%]); interleukins 6 (+494%, 95% CI [+394%, +690%]); interleukins 10 (+288%, 95% CI [+105%, +470%]); or interleukins 1 receptor antagonist (+47%, 95% CI [+13%, +80%]; all time main effects). No between-condition differences for these markers were observed after 60 or 240min of recovery. Blackcurrant extract preserves the GI barrier; however, at subclinical levels, this had no effect on microbial translocation and downstream inflammatory processes.

No Effects of Different Doses of New Zealand Blackcurrant Extract on Cardiovascular Responses During Rest and Submaximal Exercise Across a Week in Trained Male Cyclists.

Supplementation with anthocyanin-rich blackcurrant increases blood flow, cardiac output, and stroke volume at rest. It is not known whether cardiovascular responses can be replicated over longer timeframes in fed trained cyclists. In a randomized, double-blind, crossover design, 13 male trained cyclists (age 39 ± 10 years, V˙O2max 55.3 ± 6.7ml·kg-1·min-1) consumed two doses of New Zealand blackcurrant (NZBC) extract (300 and 600mg/day for 1 week). Cardiovascular parameters were measured during rest and submaximal cycling (65% V˙O2max) on day 1 (D1), D4, and D7. Data were analyzed with an RM ANOVA using dose (placebo vs. 300 vs. 600mg/day) by time point (D1, D4, and D7). Outcomes from placebo were averaged to determine the coefficient of variation within our experimental model, and 95% confidence interval (CI) was examined for differences between placebo and NZBC. There were no differences in cardiovascular responses at rest between conditions and between days. During submaximal exercise, no positive changes were observed on D1 and D4 after consuming NZBC extract. On D7, intake of 600mg increased stroke volume (3.08ml, 95% CI [-2.08, 8.26]; d = 0.16, p = .21), cardiac output (0.39L/min, 95% CI [-1.39, .60]; d = 0.14, p = .40) (both +2.5%), and lowered total peripheral resistance by 6.5% (-0.46mmHg·min/ml, 95% CI [-1.80, .89]; d = 0.18, p = .46). However, these changes were trivial and fell within the coefficient of variation of our study design. Therefore, we can conclude that NZBC extract was not effective in enhancing cardiovascular function during rest and submaximal exercise in endurance-trained fed cyclists.

Anthocyanin-rich blackcurrant intake by old rats improves blood pressure, vascular oxidative stress and endothelial dysfunction associated with SGLT1- and 2-mediated vascular uptake of anthocyanin

Aging-related endothelial dysfunction and vascular oxidative stress affect early arterial sites at risk. Anthocyanins uptake via sodium-glucose co-transporter 1 (SGLT1) are potent inducers of endothelial formation of nitric oxide (NO). This study examined if anthocyanin-rich blackcurrant (ARB) improves the endothelial function in old rats. Male Wistar rats (22-month old) received ARB (60 and 120 mg/kg/d) orally for 2 weeks. Systolic blood pressure (SBP) was assessed by tail-cuff sphygmomanometry, vascular reactivity using organ chambers, protein expression by immunofluorescence, oxidative stress using dihydroethidium, and anthocyanin uptake by Neu reagent. Old rats showed increased SBP, abolished endothelium-dependent hyperpolarization-mediated relaxation and increased contractile response to phenylephrine in the mesenteric artery, which were improved by ARB. Old aorta showed increased oxidative stress and expression levels of eNOS, which were improved by ARB. SGLT1 immunofluorescence predominantly in the endothelium was more pronounced in the aortic arch than the aorta and higher in old than young rats, whereas the SGLT2 signal was low. The ARB treatment induced a dose-dependent accumulation of anthocyanins in the aorta and aortic arch. An ARB purified extract promoted ex vivo greater anthocyanins uptake mostly in the endothelium in the aortic arch than aorta, and in old compared to young rats. The anthocyanins uptake was inhibited to a greater extent by a dual SGLT1/2 inhibitor than by a selective SGLT2 inhibitor in the aorta of young and old rats. Both SGLT inhibitors reduced also ex vivo the age-related vascular oxidative stress. The upregulation of SGLT1, and the greater SGLT1 and SGLT2-mediated uptake of anthocyanins predominantly in the endothelium at arterial sites at risk in old rats suggest that anthocyanins appear as interesting natural products to protect the endothelial function with increasing age.

P6278Ageing is associated with increased endothelial sodium-glucose cotransporter 1 expression at arterial sites at risk promoting enhanced anthocyanin accumulation and improved vascular oxidative stress

Abstract Introduction Ageing is characterized by endothelial dysfunction and vascular oxidative stress affecting initially arterial sites at risk. Anthocyanin-rich products are potent stimulators of the endothelial formation of nitric oxide. Sodium-glucose co-transporter 1 (SGLT1) expression has been shown to be increased by oxidative stress and mediate anthocyanin uptake in endothelial cells. Purpose The study determined whether ageing is associated with an upregulation of SGLT1 in arterio-susceptible (aortic arch) and resistant (aorta) sites, and evaluated the vascular SGLT1-mediated anthocyanin uptake. In addition, the impact of a 2-week ingestion of an anthocyanin-rich blackcurrant concentrate (ARBC) by old rats on vascular anthocyanin uptake and oxidative stress, and systolic blood pressure (SBP) was assessed. Methods Male Wistar rats (22-month old) were either untreated or treated with ARBC (60 and 120 mg/kg/day) in the drinking water for 2 weeks. SGLT1 expression was assessed by immunofluorescence, anthocyanin accumulation by Neu A reagent using a purified extract (BCE) prepared from ARBC, oxidative stress by dihydroethidium using confocal microscopy, and SBP by tail-cuff sphingomanometry. Results SGLT1 immunofluorescence was observed predominantly in the endothelium and was higher in the aortic arch than the aorta in old rats whereas only low levels were observed in young rats (12-week old). Exposure of vascular sections to BCE resulted in anthocyanin uptake exclusively in the endothelium, which was higher in the aortic arch than the aorta, and more pronounced in old than young rats. Anthocyanin uptake induced by BCE in the aorta was markedly reduced by LX4211 (a SGLT1/2 inhibitor) both in old and young rats. A high level of oxidative stress was observed throughout the aortic wall of old compared to young rats, which was inhibited by LX4211. Ingestion of ARBC by old rats resulted in a dose-dependent accumulation of anthocyanins throughout the aorta wall and the aortic arch. The tissue accumulation of anthocyanins was associated with a reduced level of oxidative stress. Ageing was associated with increased SBP by about 8 mmHg, which was reduced by ARBC 60 and 120 mg/kg/day treatment by about 5 and 7 mmHg, respectively. Conclusion The present findings indicate that ageing is associated with an upregulation of SGLT1 predominantly in the endothelium and that this effect is more pronounced at the aortic arch than the aorta. The increased endothelial expression level of SGLT1 promoted a greater accumulation of anthocyanins sensitive to LX4211. In addition, a 2-week ingestion of ARBC by old rats resulted in the accumulation of anthocyanins throughout the arterial wall of the aortic arch and aorta, and resulted in a reduced level of oxidative stress and systolic blood pressure. Thus, SGLT1 may be an attractive target to restore vascular protection at arterial sites at risk by promoting endothelial and vascular uptake of anthocyanins.

The impact of blackcurrant juice on attention, mood and brain wave spectral activity in young healthy volunteers

There is a growing body of evidence from randomized controlled trials which indicates that consumption of berries has a positive effect upon the cognitive function of healthy adults. It has been recommended that studies combining cognitive and physiological measures be undertaken in order to strengthen the evidence base for the putative effects of flavonoid consumption on cognitive outcomes. This pilot study utilized a randomized, double-blind and placebo controlled crossover design to assess the influence of the acute administration of anthocyanin-rich blackcurrant juice, standardized at 500 mg of polyphenols, on mood and attention. Additionally, this trial used electroencephalography (EEG) to assess if any changes in cognitive performance are associated with changes in localized prefrontal cortex neuronal activity in nine healthy young adults. Outcomes from the pilot EEG data highlight an anxiolytic effect of the consumption of a single serve blackcurrant juice, as indexed by a suppression of α spectral power, and an increase in the slow wave δ and θ spectral powers. There was also an indication of greater alertness and lower fatigue, as indexed by an increase in β power and suppression of α spectral power. Outcomes from the CogTrack™ system indicated a small acute increase in reaction times during the digit vigilance task.

Anthocyanin-Rich Blackcurrant Extract Attenuates Ovariectomy-Induced Bone Loss in Mice.

Although several animal and cell studies have indicated that blackcurrant anthocyanins exert antioxidative and anti-inflammatory properties, which could potentially improve bone mass, the effect of blackcurrant on bone health has not been reported yet. Thus, this study was aimed to evaluate the effect of blackcurrant anthocyanins on bone mass in an estrogen deficiency mouse model. Fourteen-week-old C57BL/6J mice (n = 54) were ovariectomized or sham operated. The ovariectomized mice were divided into two groups, basal diet (OVX) or basal diet containing 1% anthocyanin-rich blackcurrant extract (OVX+BC), and sacrificed at 4, 8, and 12 weeks. Femoral bone mineral density (BMD) and trabecular bone volume by dual-energy X-ray absorptiometry and micro-computed tomography, respectively, and serum bone markers were measured. Ovariectomy significantly reduced BMD and trabecular bone volume at all time points (P < .05). Blackcurrant supplementation attenuated ovariectomy-induced bone loss measured by BMD and trabecular bone volume at 8 weeks (P = .055 and P = .057) and the effect was more pronounced at 12 weeks (P = .053 and P < .05). Ovariectomy and blackcurrant treatment did not alter serum biomarkers of bone formation and resorption. Bone marrow cells extracted from OVX mice significantly induced osteoclast-like (OCL) cell formation compared with cells from sham controls (P < .05). Blackcurrant treatment decreased the number of TRAP(+) OCL compared with OVX mice at 8 and 12 weeks (P < .05). Furthermore, blackcurrant supplementation reduced bone resorption activity when measured by resorption pit assay, compared with OVX group (P < .05). These results demonstrate that blackcurrant may be effective in mitigating osteoclast-induced postmenopausal bone loss.

Abstract 4607: Chemoprevention of hepatocellular carcinoma with anthocyanin-rich black currant (Ribes nigrum L.) extract: in vitro and in vivo evidence

Abstract Primary liver cancer, mostly hepatocellular carcinoma (HCC), represents the fifth most common malignancy and the third most common cause of cancer-related death worldwide. Although majority of newly diagnosed cases occur in Eastern Asia as well as sub-Saharan Africa, the incidence of HCC has been increasing steadily in Western countries, including the United States. In view of the severity of the disease and the limited treatment options available, a critical need exists for novel chemopreventive strategies which reduce the current morbidity and mortality associated with HCC. Natural dietary components, including fruits and vegetables, have drawn considerable attention due to their proven ability to affect carcinogenesis. Anthocyanins, a group of phytochemicals, are known to possess anticarcinogenic properties against several cancers, demonstrating potential for cancer prevention. Black currant (Ribes nigrum L.) fruits, recently termed “superfruits”, have high anthocyanin content. This fruit is known to possess potent antioxidant and anti-inflammatory properties. Although health benefits of black currant are known, limited evidence on antitumor effects of black currant exists with virtually no information on prevention of experimental carcinogenesis. The objective of the present study was to evaluate the potential antihepatocarcinogenic effects of anthocyanin-rich black currant skin extract (BCSE) against HepG2 human liver cancer cells as well as chemically-induced rat liver tumorigenesis. BCSE exhibited a potent cytotoxic effect on HepG2 cells with half maximal inhibitory concentration of 1.35 mg/mL. Treatment of rats with BCSE (100 or 500 mg/kg), started 4 weeks prior to and continued for 18 weeks following diethylnitrosamine (DENA)-initiated hepatocarcinogenesis, dose-dependently decreased the incidence, total number, multiplicity, size, and volume of preneoplastic hepatic nodules. The antihepatocarcinogenic effect of BCSE was supported by histopathological examination of hepatic sections. Immunohistochemical analysis of proliferating cell nuclear antigen and DNA fragmentation revealed BCSE-mediated inhibition of abnormal cell proliferation and induction of apoptosis in DENA-induced rat liver tumorigenesis respectively. BCSE also exerted an up-regulation of Bax and down-regulation of Bcl-2 expression at the translational level compared to DENA control. The results of the present investigation reveal, for the first time, that an anthocyanin-rich extract from black currant exerts a striking chemopreventive effect against hepatocellular carcinoma by inhibiting abnormal cell proliferation and inducing apoptosis through modulation of Bax/Bcl-2 ratio. These results along with a safety profile of BCSE encourage the development of black currant bioactive constituents as chemopreventive agents for human liver cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4607. doi:10.1158/1538-7445.AM2011-4607

Anthocyanin-rich black currant ( Ribes nigrum L.) extract affords chemoprevention against diethylnitrosamine-induced hepatocellular carcinogenesis in rats

Anthocyanins are known to possess potent anticarcinogenic properties against several cancers thus demonstrating potential for cancer prevention. Black currant ( Ribes nigrum L., Grossulariaceae) fruits have a high anthocyanin content. This “superfruit” is known to possess various pharmacological effects including alleviation of chronic oxidative stress and inflammation. In contrast to a large volume of literature on the health benefits of black currant, limited evidence on antitumor effects of black currant exists with virtually no data on the prevention of experimental carcinogenesis. In the current study, we have investigated the chemopreventive effects of an anthocyanin-rich black currant skin extract (BCSE) utilizing our well-characterized model of rat liver carcinogenesis. Initiation of hepatocarcinogenesis was done by intraperitoneal injection of diethylnitrosamine (DENA) followed by promotion with phenobarbital. The rats were exposed to dietary BCSE for 4 weeks prior to initiation, and the treatment was continued for 22 consecutive weeks. BCSE dose-dependently decreased the incidence, total number, multiplicity, size and volume of preneoplastic hepatic nodules. The antihepatocarcinogenic effect of BCSE was confirmed by histopathological examination of liver sections. Immunohistochemical analysis of proliferating cell nuclear antigen and DNA fragmentation revealed BCSE-mediated inhibition of abnormal cell proliferation and induction of apoptosis in DENA-induced rat liver tumorigenesis respectively. Mechanistic studies revealed that BCSE-mediated proapototic signal during experimental hepatocarcinogenesis may be propagated via the up-regulation of Bax and down-regulation of Bcl-2 expression at the translational level. These results along with a safety profile of BCSE encourage the development of black currant bioactive constituents as chemopreventive agents for human liver cancer.

Influence of acids, salt, sugars and hydrocolloids on the colour stability of anthocyanin rich black currant and elderberry concentrates

Anthocyanin-rich concentrates from different fruits can be used as natural food colourants. The pigments' stability is comparatively low and dependent on the composition of food matrices. Food ingredients relevant for soft drinks, jelly fruits and salad dressings were tested in model systems regarding their influence on the colour stability of elderberry and black currant concentrate determined by colour measurement (CIE L*a*b*). In aqueous solutions food-grade organic acids and salt were found to influence anthocyanin stability: colour stability increased with increasing pKa of acids and decreased with increasing salt concentrations. This may be attributed to altered solvation characteristics of aqueous solutions. A stabilizing influence was found for sugars presumably by reducing water activity. However, when heat treatment was applied, e.g. in the production of hydrocolloid gels, fructose was shown to accelerate anthocyanin decay due to the formation of sugar degradation products. Comparing hydrocolloids, alginate was shown to increase colour stability in aqueous solution and pectin displayed overall highest colour stability in a gel model system, suggesting that polyuronic acids may improve anthocyanin stability by intermolecular association.