Identification of anthocyanin components of wild Chinese blueberries and amelioration of light-induced retinal damage in pigmented rabbit using whole berries

Analytical characterization of anthocyanins using trapped ion mobility spectrometry-quadrupole time-of-flight tandem mass spectrometry

Anthocyanin profiles of juices from blueberry (Vaccinium myrtillus L.) and different grape varieties (Vitis labrusca L. cv. Concord, Vitis vinifera L. cvs. Accent, Dunkelfelder, Dakapo, and GM 674-1) were characterized by ultra-high performance liquid chromatography (UHPLC) coupled to trapped ion mobility spectrometry-quadrupole time-of-flight tandem mass spectrometry (TIMS-QTOF-MS/MS). Ion mobility and collision cross section (CCS) values of over 50 structurally related anthocyanins based on delphinidin, cyanidin, petunidin, peonidin, and malvidin were determined. Relations between molecular mass, mobility values, and specific structural features were revealed. The mass-to-charge (m/z) ratio of the molecular ions (M+) was found to be the major factor influencing anthocyanin ion mobilities, but structural characteristics also contributed to their variability. We were able to differentiate positional and geometrical isomers and certain epimers by their respective mobility values. For instance, whereas 3-O-hexosides (i.e., 3-O-glucosides and 3-O-galactosides) were separated by TIMS, epimers of 3-O-pentosides assessed could not be distinguished.

Protective effect and mechanism of Lycium ruthenicum Murray anthocyanins against retinal damage induced by blue light exposure

Lycium ruthenicum Murray (LR) is a medicine and edible plant in Northwest China, and L. ruthenicum Murray anthocyanins (LRA) are green antioxidants with various pharmacological activities, such as antioxidant and anti-inflammatory activities. However, the protective effect and mechanism of LRA against retinal damage induced by blue light exposure are poorly understood. This study explored the protective effects and potential mechanisms of LRA on retinal damage induced by blue light exposure in vitro and in vivo. The results showed that LRA could ameliorate oxidative stress injury by activating the antioxidant stress nuclear factor-related factor 2 pathway, promoting the expression of phase II detoxification enzymes (HO-1, NQO1) and endogenous antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), and reducing reactive oxygen species and malondialdehyde levels. Additionally, LRA could inhibit inflammatory response by decreasing the expression of blue light exposure-induced nuclear factor-κB (NF-κB) pathway-related proteins (NF-κB and p-IκBα), as well as interleukin (IL)-6, tumor necrosis factor-α, IL-1β pro-inflammatory factors and pro-inflammatory chemokine VEGF, and increasing the expression of anti-inflammatory factor IL-10. Furthermore, LRA could ameliorate oxidative stress-induced apoptosis by upregulating Bcl-2 and downregulating Bax and Caspase-3 protein expression. All these results indicate that LRA can be used as an antioxidant dietary supplement for the treatment or prevention of retinal diseases.

Blueberry Anthocyanins from Commercial Products: Structure Identification and Potential for Diabetic Retinopathy Amelioration

The aim of the present study was to determine the major anthocyanins of blueberry extracts from northeast China and explore their vision health improvement effects. HPLC-Q-TOF-MS/MS results suggested that six different anthocyanins were accurately identified, among which the Cy-3-glu (C3G) was the most abundant, ranging from 376.91 ± 7.91 to 763.70 ± 4.99 μM. The blueberry extract contained a higher purity of anthocyanins, and the anthocyanosides reached 342.98 mg/kg. The anti-oxidative stress function of C3G on HG-treated ARPE-19 cells were evaluated, and showed that the GSSG level of HG-cells pretreated with 10 μM C3G was significantly decreased, while the Nrf2 and NQO1 gene expression levels were increased. Further molecular docking (MD) results indicated that the C3G displayed favorable binding affinity towards REDD1, and only the B-ring of the C3G molecule displayed binding interactions with the CYS-140 amino acids within the REDD1 protein. It implied that the oxidative stress amelioration effects of C3G on the ARPE-19 cells were related to the REDD1 protein, which was probably via the Nrf2 pathways, although further studies are needed to provide mechanism evidence. The present study provides novel insights into understanding the roles of blueberry anthocyanins in ameliorating oxidative stress-induced BRB damage in the retina.

Protective Effect of Bilberry Anthocyanin Extracts on Dextran Sulfate Sodium-Induced Intestinal Damage in Drosophila melanogaster

Inflammatory bowel disease (IBD) is a chronic recurrent disease that can be controlled by various natural extracts. Anthocyanins (ANCs) from bilberry have significant antioxidant capacity and are widely used as food colors and antioxidants. In this study, we investigated the protective effects of bilberry anthocyanin extracts (BANCs) against dextran sulphate sodium (DSS)-induced intestinal inflammation in a Drosophila melanogaster (D. melanogaster) model, and the effects on the lifespan, antioxidant capacity, intestinal characteristics, and microbiome and gene expression profiles were analyzed to elucidate the underlying biological mechanisms. In DSS-induced normal and axenic D. melanogaster, BANCs significantly increased the survival rate, maintained the intestinal morphology and integrity, and reduced the number of dead intestinal epithelial cells and the ROS level of these cells. BANC supplementation had no significant effect on the intestinal microflora of DSS-induced D. melanogaster, as demonstrated by a 16S rDNA analysis, but improved the antioxidant capacity by activating the relative gene expression of NRF2 signaling pathways in the intestine of D. melanogaster with DSS-induced inflammation. Therefore, the results demonstrate that BANCs effectively alleviate intestinal inflammatory injury induced by DSS and improve the antioxidant capacity of D. melanogaster by modulating NRF2 signaling pathways, and could thus promote the application of BANCs as functional foods.

Combined Effect of Vaccinium nilgiriensis Bark Extract and 680nm Laser Irradiation in Inducing Breast Cancer Cell Death

BACKGROUND

Cancer refers to a collection of diseases where cells begin to multiply uncontrollably. Breast cancer is the most predominant malignancy in women. Herbal medicine is one of the important health care systems in most developing countries. Many studies have shown that naturally occurring compounds may support the prevention and treatment of various diseases, including cancer. Some of the plant extracts and isolated compounds show photosensitizing activities and reduce cell proliferation whereas some have revealed photoprotective effects.

OBJECTIVES

The biological properties and medicinal uses of extracts and bioactive compounds from V. nilgiriensis have not been investigated. This study aims to evaluate the cytotoxic effects of V. nilgiriensis in combination with 680nm laser irradiation on MCF-7 breast cancer cells.

METHODS

The inverted microscopy, ATP and LDH assay were used to analyze the cellular morphology, proliferation, cytotoxicity respectively after the treatment with V. nilgiriensis bark extract. The diode laser of wavelength 680nm and 15 J/cm2 fluency has been used for laser irradiation. The activity of apoptotic proteins was studied using ELISA and nuclear damage by Hoechst staining.

RESULTS

The exposure of V. nilgiriensis extracts with laser irradiation at 680nm increases the cytotoxicity and decreases the proliferation of MCF-7 cells. The results of the Hoechst stain indicated nuclear damage. Our study proved that V. nilgiriensis holds a strong cytotoxic effect on breast cancer cells alone and in combination with laser irradiation by upregulating the expression of apoptotic proteins such as caspase 3, p53 and Bax.

CONCLUSION

The results from this study showed that the bark ethyl acetate of V. nilgiriensis and in combination with laser is effective in preventing breast cancer cell proliferation in vitro. Further work is warranted to isolate the bioactive compounds from V. nilgiriensis bark extract and study the effect of compounds in the cell death induction. Due to the cytotoxic properties, V. nilgiriensis can be considered as a potent therapeutic agent for the treatment of cancer.

Anthocyanins from Purple Tomatoes as Novel Antioxidants to Promote Human Health

Anthocyanins are plant secondary metabolites belonging to the class of polyphenols, whose beneficial roles in the prevention and treatment of several important human diseases have been demonstrated in many epidemiological studies. Their intake through diet strictly depends on the eating habits, as anthocyanins are contained in red and purple fruit and vegetables as well as in some processed foods and beverages, such as red wine. Genetic engineering and breeding programs have been recently carried out to increase the content of anthocyanins in candidate plant species which cannot offer satisfactory levels of these precious compounds. Tomato (Solanum lycopersicum) is a vegetable commodity where these strategies have resulted in success, leading to the production of new anthocyanin-rich fruit varieties, some of which are already marketed. These varieties produce purple fruits with a high nutraceutical value, combining the health benefits of the anthocyanins to the other classical tomato phytochemicals, particularly carotenoids. The antioxidant capacity in tomato purple fruits is higher than in non-anthocyanin tomatoes and their healthy role has already been demonstrated in both in vitro and in vivo studies. Recent evidence has indicated a particular capacity of tomato fruit anthocyanins to act as scavengers of harmful reactive chemical species and inhibitors of proliferating cancer cells, as well as anti-inflammatory molecules.

Recent Research on the Health Benefits of Blueberries and Their Anthocyanins

Awareness of the human health benefits of blueberries is underpinned by a growing body of positive scientific evidence from human observational and clinical research, plus mechanistic research using animal and in vitro models. Blueberries contain a large number of phytochemicals, including abundant anthocyanin pigments. Of their various phytochemicals, anthocyanins probably make the greatest impact on blueberry health functionality. Epidemiological studies associate regular, moderate intake of blueberries and/or anthocyanins with reduced risk of cardiovascular disease, death, and type 2 diabetes, and with improved weight maintenance and neuroprotection. These findings are supported by biomarker-based evidence from human clinical studies. Among the more important healthful aspects of blueberries are their anti-inflammatory and antioxidant actions and their beneficial effects on vascular and glucoregulatory function. Blueberry phytochemicals may affect gastrointestinal microflora and contribute to host health. These aspects have implications in degenerative diseases and conditions as well as the aging process. More evidence, and particularly human clinical evidence, is needed to better understand the potential for anthocyanin-rich blueberries to benefit public health. However, it is widely agreed that the regular consumption of tasty, ripe blueberries can be unconditionally recommended.

Ultrasound Treatment on Stability of Total and Individual Anthocyanin Extraction from Blueberry Pomace: Optimization and Comparison

Blueberry pomace is abundant in anthocyanins. This work characterized the anthocyanins in blueberry pomace, discussed the stability of anthocyanins under ultrasound treatment, and compared the extraction conditions for different anthocyanin compositions. Thirteen anthocyanins were identified, and malvidin-3-galactoside (18.56%), which represented the most abundant anthocyanin, was selected as the individual analyte. The general linear model univariate analysis revealed that ultrasound-assisted extraction (UAE) resulted in higher recoveries of both total anthocyanins (TA) and individual anthocyanins (IA) when compared with conventional solvent extraction. The optimized extraction conditions for TA and IA were UAE in pure methanol (12.49 mg/g dry weight) at 25 °C for 30 min and UAE in 70% ethanol (3.57 mg/g dry weight) at 40 °C for 40 min, respectively. Moreover, IA was more vulnerable to degradation compared with TA. Therefore, a specific extraction process of IA is significant for monomer preparation, and harsh conditions should be avoided in UAE.

Investigation of the Antioxidant, α-Glucosidase Inhibitory, Anti-inflammatory, and DNA Protective Properties of Vaccinium arctostaphylos L

Objectives

The scope of this study was to investigate the total phenolic, anthocyanin, and flavonoid contents and the biological properties of ethanol extract (EE), methanol extract (ME), and aqueous extract (AE) from Vaccinium arctostaphylos L.

Materials and Methods

EE, ME, and AE of V. arctostaphylos were prepared. Various biological activities such as total phenolic, anthocyanin, and flavonoid contents, and antioxidant (2,2'-diphenyl-1-picrylhydrazyl ferrous ion-chelating, and ferric reducing antioxidant power assays), α-glucosidase inhibitory, anti-inflammatory, and DNA protective properties of these extracts were studied.

Results

EE exhibited the highest total phenolic, anthocyanin, and flavonoid contents with 44.42±1.22 mg gallic acid equivalents/g dry weight, 8.46±0.49 mg/Cyaniding-3-glucoside equivalents/g dry weight, and 9.22±0.92 mg quercetin equivalents/g dry weight, respectively. The antioxidant activities of the extracts followed the order: EE>ME>AE. EE and ME inhibited α-glucosidase enzyme and their IC₅₀ values were 0.301±0.002 mg/mL and 0.477±0.003 mg/mL, respectively. In addition, EE and ME were determined as noncompetitive inhibitors with inhibitory constant (K_i ) values of 0.48±0.02 mg/mL and 0.46±0.01 mg/mL, respectively. EE in 100 and 300 mg/kg doses caused a significant reduction in formalin-induced edema in mice, demonstrating the anti-inflammatory effect of EE. In DNA protective studies, all of the extracts protected supercoiled plasmid pBR322 DNA against damage caused by Fenton's reagents due to their radical scavenging activities.

Conclusion

Our results demonstrated that EE of V. arctostaphylos L. had strong antioxidant, anti-inflammatory, α-glucosidase inhibitory, and DNA protective effects, suggesting that it might be an effective medical plant to prevent or treat diseases associated with oxidative damage and inflammation.

Blueberry Malvidin-3-galactoside Suppresses Hepatocellular Carcinoma by Regulating Apoptosis, Proliferation, and Metastasis Pathways In Vivo and In Vitro

Anthocyanin, a natural antioxidant, is reported to have cytotoxicity against cancer cells; however, the mechanism remains unclear. The aim of the present study was to investigate the mechanism by which malvidin-3-galactoside (M3G), the prominent anthocyanin in blueberry, suppresses the development of hepatocellular carcinoma. In vitro, M3G suppressed the proliferation, polarization, migration, and invasion activities of HepG2 cells by regulating the protein expression of cyclin D1, cyclin B, cyclin E, caspase-3, cleaved caspase-3, Bax, p-JNK, and p-p38, activating phosphatase and tensin homologue deleted on chromosome 10 (PTEN), accompanied by a decrease in the p-AKT level, and lowering the protein expression levels of MMP-2 and MMP-9. In vivo, M3G promoted the apoptosis of liver tumor cells, as determined by immunohistochemistry (cleaved caspase-3, Ki-67, PTEN, and p-AKT), a terminal deoxynucleotidyl transferase dUTP nick end labeling assay, and hematoxylin-eosin staining. Overall, these results suggest that M3G, as an adjuvant ingredient or nutritional supplement, may be beneficial for liver cancer prevention and the modulatory mechanism seems to be associated with inhibition of proliferation, apoptosis, migration, and invasion-related pathways.

Blueberry Polyphenols Ameliorate Visible Light and Lipid-Induced Injury of Retinal Pigment Epithelial Cells

Although dietary polyphenols are known to be beneficial to vision, the protective distinctions among different types of polyphenols are unclear. In this work, the visual benefits of various blueberry polyphenols were evaluated using an in vitro model of visible light-lipid-induced injury of retinal pigment epithelial cells. Results showed that, at 10.0 μg/mL, the phenolic acid-rich fraction was superior in inhibiting cell death (93.6% ± 2.8% of cell viability). Anthocyanin- and flavonoid-rich fractions shared similar advantages in preventing the expression of senescence-associated β-galactosidase (34.8% ± 11.1% and 32.2% ± 9.7% of aged cells, respectively) and overexpression of vascular endothelial growth factor (51.8 ± 3.5 and 54.1 ± 6.5 pg/mL, respectively). The flavonoid-rich fraction also showed high activity in ameliorating phagocytosis (70.3% ± 12.6%) and cellular oxidative stress. These results were further confirmed by using the corresponding polyphenol standards. Improved inhibitory effects of polyphenol mixture on cell death and senescence-associated β-galactosidase expression were also observed. Therefore, various polyphenols play diverse roles and exert synergistic effects in nourishing the retina.

Molecular Mechanism and Health Role of Functional Ingredients in Blueberry for Chronic Disease in Human Beings

Functional ingredients in blueberry have the best health benefits. To obtain a better understanding of the health role of blueberry in chronic disease, we conducted systematic preventive strategies for functional ingredients in blueberry, based on comprehensive databases, especially PubMed, ISI Web of Science, and CNKI for the period 2008⁻2018. Blueberry is rich in flavonoids (mainly anthocyanidins), polyphenols (procyanidin), phenolic acids, pyruvic acid, chlorogenic acid, and others, which have anticancer, anti-obesity, prevent degenerative diseases, anti-inflammation, protective properties for vision and liver, prevent heart diseases, antidiabetes, improve brain function, protective lung properties, strong bones, enhance immunity, prevent cardiovascular diseases, and improve cognitive decline. The anthocyanins and polyphenols in blueberry are major functional ingredients for preventive chronic disease. These results support findings that blueberry may be one of the best functional fruits, and further reveals the mechanisms of anthocyanins and polyphenols in the health role of blueberry for chronic disease. This paper may be used as scientific evidence for developing functional foods, nutraceuticals, and novel drugs of blueberry for preventive chronic diseases.

Antioxidant and Anti-Inflammatory Effects of Blueberry Anthocyanins on High Glucose-Induced Human Retinal Capillary Endothelial Cells

Blueberries possess abundant anthocyanins, which benefit eye health. The purpose of this study was to explore the protective functional role of blueberry anthocyanin extract (BAE) and its predominant constituents, malvidin (Mv), malvidin-3-glucoside (Mv-3-glc), and malvidin-3-galactoside (Mv-3-gal), on high glucose- (HG-) induced injury in human retinal capillary endothelial cells (HRCECs). The results showed that BAE, Mv, Mv-3-glc, and Mv-3-gal enhanced cell viability (P < 0.05 versus the HG group at 24 h); decreased the reactive oxygen species (ROS, P < 0.01 versus the HG group both at 24 and 48 h); and increased the enzyme activity of catalase (CAT) and superoxide dismutase (SOD) (P < 0.05 versus the HG group both at 24 and 48 h). Mv could greatly inhibit HG-induced Nox4 expression both at 24 and 48 h (P < 0.05), while BAE and Mv-3-gal downregulated Nox4 only at 48 h (P < 0.05). Mv, Mv-3-glc, and Mv-3-gal also changed nitric oxide (NO) levels (P < 0.05). BAE and Mv-3-glc also influenced angiogenesis by decreasing the vascular endothelial cell growth factor (VEGF) level and inhibiting Akt pathway (P < 0.05). Moreover, Mv and Mv-3-glc inhibited HG-induced intercellular adhesion molecule-1 (ICAM-1, P < 0.001) and nuclear factor-kappa B (NF-κB) (P < 0.05). It indicated that blueberry anthocyanins protected HRCECs via antioxidant and anti-inflammatory mechanisms, which could be promising molecules for the development of nutraceuticals to prevent diabetic retinopathy.

Protective Effects of Blueberry Anthocyanins against H2O2-Induced Oxidative Injuries in Human Retinal Pigment Epithelial Cells

Blueberry anthocyanins are considered protective of eye health because of their recognized antioxidant properties. In this study, blueberry anthocyanin extract (BAE), malvidin (Mv), malvidin-3-glucoside (Mv-3-glc), and malvidin-3-galactoside (Mv-3-gal) all reduced H₂O₂-induced oxidative stress by decreasing the levels of reactive oxygen species and malondialdehyde and increasing the levels of superoxide dismutase, catalase, and glutathione peroxidase in human retinal pigment epithelial cells. BAE and the anthocyanin standards enhanced cell viability from 63.69 ± 3.36 to 86.57 ± 6.92% (BAE), 115.72 ± 23.41% (Mv), 98.15 ± 9.39% (Mv-3-glc), and 127.97 ± 20.09% (Mv-3-gal) and significantly inhibited cell apoptosis (P < 0.01 for all). Mitogen-activated-protein-kinase pathways, including ERK1/2 and p38, were involved in the bioactivities. In addition, the anthocyanins decreased vascular-endothelial-cell-growth-factor levels and activated Akt-signal pathways. These combined results supported the hypothesis that blueberry anthocyanins could inhibit the induction and progression of age-related macular degeneration (AMD) through antioxidant mechanisms.

Nutritional and Phytochemical Composition of Vaccinium padifolium Sm Wild Berries and Radical Scavenging Activity

Blueberries have a well-deserved reputation as a potential functional food, supported by studies which have identified and quantified various nutrients and bioactive phytochemicals with known benefits for human diet and health. Wild blueberries have attracted particular attention due to the levels and concentrations of those phytonutrients. This study aims to evaluate for the first time the chemical composition of Madeira Island's endemic Vaccinium padifolium Sm wild berry. Results show that this fruit contains high values of total soluble phenolic content (around 4 g GAE kg^-1 FW), as well as significant values of total monomeric anthocyanin content (around 3 g eq. cyanidin kg^-1 FW) and DPPH scavenging activity (around 86.72%). Additionally, results reveal that this fruit has water content of about 88% as well as low sugar content (17.98 and 29.73 g kg^-1 for glucose and fructose, respectively). Results also confirm that this wild blueberry is a good source of dietary fiber, fat and minerals. The high level of terpenoid compounds stands out in the aroma profile analysis.

PRACTICAL APPLICATION

This study is in line with the efforts of the scientific community to identify new sources of phytonutrients that are beneficial to human health, characterizing the wild Madeira blueberry in terms of phytonutrients that suggest there may be health benefits associated with its consumption. The findings of this research are very important for both the commercial and agricultural sectors that produce this fruit, and for consumers who seek phytonutrient-rich foods.

Oxidative Stress as a Critical Factor in Nonalcoholic Fatty Liver Disease Pathogenesis

SIGNIFICANCE

Nonalcoholic fatty liver disease (NAFLD), characterized by liver triacylglycerol build-up, has been growing in the global world in concert with the raised prevalence of cardiometabolic disorders, including obesity, diabetes, and hyperlipemia. Redox imbalance has been suggested to be highly relevant to NAFLD pathogenesis. Recent Advances: As a major health problem, NAFLD progresses to the more severe nonalcoholic steatohepatitis (NASH) condition and predisposes susceptible individuals to liver and cardiovascular disease. Although NAFLD represents the predominant cause of chronic liver disorders, the mechanisms of its development and progression remain incompletely understood, even if various scientific groups ascribed them to the occurrence of insulin resistance, dyslipidemia, inflammation, and apoptosis. Nevertheless, oxidative stress (OxS) more and more appears as the most important pathological event during NAFLD development and the hallmark between simple steatosis and NASH manifestation.

CRITICAL ISSUES

The purpose of this article is to summarize recent developments in the understanding of NAFLD, essentially focusing on OxS as a major pathogenetic mechanism. Various attempts to translate reactive oxygen species (ROS) scavenging by antioxidants into experimental and clinical studies have yielded mostly encouraging results.

FUTURE DIRECTIONS

Although augmented concentrations of ROS and faulty antioxidant defense have been associated to NAFLD and related complications, mechanisms of action and proofs of principle should be highlighted to support the causative role of OxS and to translate its concept into the clinic. Antioxid. Redox Signal. 26, 519-541.

Separation and Identification of Anthocyanins Extracted from Blueberry Wine Lees and Pigment Binding Properties toward β-Glucosidase

Anthocyanins were isolated from blueberry wine lees using Sephadex LH-20 column chromatography and semipreparative high-performance liquid chromatography (semipreparative HPLC) and then identified by HPLC-DAD-ESI-MS/MS. Our results show that malvidin-3-hexose (Mv-3-hex) and malvidin-3-(6'acetyl)-hexose (Mv-3-ace-hex) are the major components in the anthocyanin extracts of blueberry wine lees (>90%). The binding characteristics of Mv-3-hex and Mv-3-ace-hex with β-glucosidase were investigated by fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular docking. Spectroscopic analysis revealed that β-glucosidase fluorescence quenched by Mv-3-hex and Mv-3-ace-hex follows a static mode. Binding of Mv-3-hex and Mv-3-ace-hex to β-glucosidase mainly depends on electrostatic force. The result from CD spectra shows that adaptive structure rearrangement and increase of β-sheet structure occur only in the presence of Mv-3-ace-hex. A molecular docking study suggests that Mv-3-ace-hex has stronger binding with β-glucosidase than Mv-3-hex.

Polyphenol profile and antioxidant activity of the fruit and leaf of Vaccinium glaucoalbum from the Tibetan Himalayas

Vaccinium glaucoalbum, a perennial evergreen shrub, is naturally distributed in high-altitude areas. In this study, the composition and content of polyphenolic compounds in the fruit and leaf of V. glaucoalbum were characterized. In total, 24 chemical compounds were detected and identified by HPLC-DAD and HPLC-ESI-MS². Among all the compounds determined, 15 were anthocyanins and detected in fruit, 5 were flavonols and monitored in leaf, and 4 were chlorogenic acids and found in both fruit and leaf. The total anthocyanin content (TAC) of fruit (682mg/100gFW) was the highest among wild Vaccinium berries in China which have been investigated for now, and the total flavonol content of leaf was 2764mg/100gFW. The antioxidant activity of both fruit and leaf was assessed by DPPH and FRAP assays. Given its high TAC and strong antioxidant activity, the fruit of V. glaucoalbum has great potential in functional food.

Protective Effect of Fucoxanthin Isolated from Laminaria japonica against Visible Light-Induced Retinal Damage Both in Vitro and in Vivo

With increasingly serious eye exposure to light stresses, such as light-emitting diodes, computers, and widescreen mobile phones, efficient natural compounds for preventing visible light-induced retinal damages are becoming compelling needs in the modern society. Fucoxanthin, as the main light absorption system in marine algae, may possess an outstanding bioactivity in vision protection because of its filtration of blue light and excellent antioxidative activity. In this work, both in vitro and in vivo simulated visible light-induced retinal damage models were employed. The in vitro results revealed that fucoxanthin exhibited better bioactivities than lutein, zeaxanthin, and blueberry anthocyanins in inhibiting overexpression of vascular endothelial growth factor, resisting senescence, improving phagocytic function, and clearing intracellular reactive oxygen species in retinal pigment epithelium cells. The in vivo experiment also confirmed the superiority of fucoxanthin than lutein in protecting retina against photoinduced damage. This excellent bioactivity may be attributed to its unique structural features, including allenic, epoxide, and acetyl groups. Fucoxanthin is expected to be an important ocular nutrient in the future.

Anthocyanin can arrest the cone photoreceptor degeneration and act as a novel treatment for retinitis pigmentosa

Retinitis pigmentosa (RP) is a group of heterogeneous inherited retinal diseases that is characterized by primary death rod photoreceptors and the secondary loss of cones. The degeneration of cones causes gradual constriction of visual fields, leaving the central islands that are eventually snuffed out. Studies indicate that the hyperoxia causes oxidative damage in the retina and contributes to the cone death of RP. Moreover, abundant reactive oxidative species (ROS) which are generated in cones may result in mitochondria membrane depolarization, which has been ascribed a central role in the apoptotic process and has been proposed to act as a forward feeding loop for the activation of downstream cascades. Anthocyanin is a potent antioxidant which has been evidenced to be able to counteract oxidative damages, scavenge surplus ROS, and rectify abnormities in the apoptotic cascade. Taken together with its ability to attenuate inflammation which also contributes to the etiology of RP, it is reasonable to hypothesize that the anthocyanin could act as a novel therapeutic strategy to retard or prevent cone degeneration in RP retinas, particularly if the treatment is timed appropriately and delivered efficiently. Future pharmacological investigations will identify the anthocyanin as an effective candidate for PR therapy and refinements of that knowledge would ignite the hope of restoring the visual function in RP patients.

Visible Light-Induced Lipid Peroxidation of Unsaturated Fatty Acids in the Retina and the Inhibitory Effects of Blueberry Polyphenols

The lipid peroxidation of unsaturated fatty acids (UFAs) in the retina not only threatens visual cells but also affects the physiological health of the retina. In this work, the potential damages caused by daily visible light exposure on retinal UFAs were evaluated via a simulated in vitro model. At the same time, the benefits of dietary supplementation of blueberries to the eyes were also assessed. After prolonged light exposure, lipid peroxidation occurred for both docosahexaenoic and arachidonic acids (DHA and AA, respectively). The oxidized UFAs presented obvious cytotoxicity and significantly inhibited cell growth in retinal pigment epithelium cells. Among the different blueberry polyphenol fractions, the flavonoid-rich fraction, in which quercetin was discovered as the main component, was considerably better in preventing visible light-induced DHA lipid peroxidation than the anthocyanin- and phenolic acid-rich fractions. Then the retinal protective activity of blueberry polyphenols against light-induced retinal injury was confirmed in vivo. On the basis of the above results, inhibiting lipid peroxidation of UFAs in the retina is proposed to be another important function mechanism for antioxidants to nourish eyes.

The protective effects of berry-derived anthocyanins against visible light-induced damage in human retinal pigment epithelial cells

BACKGROUND

Studies have shown that anthocyanins (ACNs) in berries contribute to eye health. However, information on the relationship between the chemical structures and visual functions of ACNs is scarce. This study investigated the protection effects of ACNs with different structures against visible light-induced damage in human retinal pigment epithelial (RPE) cells.

RESULTS

Four ACNs with different aglycones, namely, pelargonidin-3-glucoside (Pg-3-glu), cyanidin-3-glucoside (Cy-3-glu), delphinidin-3-glucoside, and malvidin-3-glucoside (Mv-3-glu), were isolated from three berries (blueberry, blackberry and strawberry). Of these ACNs, Cy-3-glu exhibited the highest reactive oxygen species inhibitory capacity in RPE cells, with 40 µg mL(-1) Cy-3-glu showing a ROS clearance of 57.5% ± 4.2%. The expression of vascular endothelial growth factor levels were significantly (P < 0.05) down-regulated by Cy-3-glu and Mv-3-glu in a visible light-induced damage RPE cell model. Cy-3-glu and Pg-3-glu treatments significantly (P < 0.05) inhibited the increase in β-galactosidase during the RPE cell ageing caused by visible light exposure.

CONCLUSION

Our findings suggest that the biological properties of different ACNs significantly vary. Cy-3-glu, which contains an ortho hydroxyl group in its B ring, possibly exerts multiple protective effects (antioxidant, anti-angiogenic and anti-ageing) in RPE cells. Therefore, Cy-3-glu may prove useful as a prophylactic health food for the prevention of retinal diseases.

Blueberry effects on dark vision and recovery after photobleaching: placebo-controlled crossover studies

Clinical evidence for anthocyanin benefits in night vision is controversial. This paper presents two human trials investigating blueberry anthocyanin effects on dark adaptation, functional night vision, and vision recovery after retinal photobleaching. One trial, S2 (n = 72), employed a 3 week intervention and a 3 week washout, two anthocyanin doses (271 and 7.11 mg cyanidin 3-glucoside equivalents (C3g eq)), and placebo. The other trial, L1 (n = 59), employed a 12 week intervention and an 8 week washout and tested one dose (346 mg C3g eq) and placebo. In both S2 and L1 neither dark adaptation nor night vision was improved by anthocyanin intake. However, in both trials anthocyanin consumption hastened the recovery of visual acuity after photobleaching. In S2 both anthocyanin doses were effective (P = 0.014), and in L1 recovery was improved at 8 weeks (P = 0.027) and 12 weeks (P = 0.030). Although photobleaching recovery was hastened by anthocyanins, it is not known whether this improvement would have an impact on everyday vision.

Docosahexaenoic acid aggravates photooxidative damage in retinal pigment epithelial cells via lipid peroxidation

Docosahexaenoic acid (DHA, 22:6n-3), a long-chain polyunsaturated fatty acid (PUFA) with important functions in normal human retinal activity and vision development, is recommended to promote brain and eye development. However, recent research has revealed that increased DHA level in the retina due to linoleic acid-rich diet heightens the vulnerability of the retina to photooxidative stress. Thus, many scholars have analyzed the potential risks of DHA intake on retinal damage. This study evaluated the potential adverse effects of DHA intake on individuals usually exposed to high-light intensity conditions using a visible light-induced retinal pigment epithelium (RPE) cell damage model in vitro. Results showed that DHA promoted the proliferation of RPE cells without any cytotoxicity under dark conditions. However, DHA supplement elicited deleterious effects on RPE cells under high-intensity light conditions. That is, DHA supplement inhibited cellular proliferation, destroyed cell membrane integrity, enhanced cellular senescence, increased vascular endothelial growth factor (VEGF) release, and decreased phagocytic function. Moreover, DHA supplement increased the intracellular and extracellular levels of reactive oxygen species and the extracellular level of lipid peroxidation products under high-intensity light conditions. These results demonstrate that DHA increases the vulnerability of the retina to light damage through lipid peroxidation.

Anthocyanins-rich extract of wild Chinese blueberry protects glucolipotoxicity-induced INS832/13 β-cell against dysfunction and death

As commonly observed events in diabetic patients, glucolipotoxicity induces oxidative stress, apoptosis and functional defects in β-cells. Anthocyanins are well investigated as strong antioxidants and modulators for metabolic syndromes. Therefore, this study examined the protective effects of anthocyanins-rich extracts (BAE) from wild Chinese blueberry (Vaccinium spp.) against glucolipotoxicity in β-cells. Results showed that INS832/13 β-cells subjected to glucolipotoxicity were significantly decreased (p < 0.05) in cell survival rate, which were alleviated by BAE and metformin treatments. Both BAE and metformin reduced reactive oxidative species and improved the antioxidant defense system. Moreover, BAE were effective in reducing intracellular triglycerides (TG) level, restoring intracellular insulin content, lowering basal insulin secretion (BIS) and increasing glucose-stimulated insulin secretion which in turn resulted in an elevated insulin secretion index. However, metformin only demonstrated marginal effect on secretion dysfunction and had no effect (p > 0.05) on BIS or TG. Additionally, TG levels reduced by BAE treatment were correlated with BIS (p < 0.01, r = 0.9755). This study has for the first time demonstrated that anthocyanin enriched extract of wild Chinese blueberry could effectively protect β-cells against glucolipotoxicity in vitro. These results implied the potential efficacy of BAE as a complementary measure for diabetes intervention.

Black rice anthocyanidins prevent retinal photochemical damage via involvement of the AP-1/NF-κB/Caspase-1 pathway in Sprague-Dawley rats

The effects of black rice anthocyanidins (BRACs) on retinal damage induced by photochemical stress are not well known. In the present study, Sprague-Dawley rats were fed AIN-93M for 1 week, after which 80 rats were randomly divided into two groups and treated with (n = 40) or without BRACs (n = 40) for 15 days, respectively. After treatment, both groups were exposed to fluorescent light (3,000 ± 200 lux; 25℃), and the protective effect of dietary BRACs were evaluated afterwards. Our results showed that dietary BRACs effectively prevented retinal photochemical damage and inhibited the retinal cells apoptosis induced by fluorescent light (p < 0.05). Moreover, dietary BRACs inhibited expression of AP-1 (c-fos/c-jun subunits), up-regulated NF-κB (p65) expression and phosphorylation of IκB-α, and decreased Caspase-1 expression (p < 0.05). These results suggest that BRACs improve retinal damage produced by photochemical stress in rats via AP-1/NF-κB/Caspase-1 apoptotic mechanisms.

Flavonoid intake and eye health

In the modern era of evidence-based scientific medicine, there is little recognition of centuries of shaman observational evidence. Yet it is extremely difficult to conduct long duration controlled studies of large populations. The controversy surrounding the issue of flavonoid bioactivity and alleged benefits for eye health is also plagued by natural product industry marketing efforts that rely on small, often poorly designed studies. Ample laboratory evidence exists from in vitro and in vivo studies that provide plausible mechanistic evidence for flavonoid interactions relevant to visual function. Lacking are large randomized double-blind placebo-controlled studies in older subjects who have early signs of vision impairment. These studies could link flavonoid intake and bioavailability to efficacy in prevention of age related vision disorders that develop over decades. Support for clinical trials remains to be found before a full "recommendation" can be made regarding the value of diets high in flavonoids for eye health.

Inhibitory effect of blueberry polyphenolic compounds on oleic acid-induced hepatic steatosis in vitro

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide and is closely associated with metabolic syndromes, such as obesity, diabetes, and insulin resistance. Nonalcoholic fatty liver (NAFL), also called simple steatosis, is the initial phase of NAFLD, which is accompanied the characteristic pathological overaccumulation of lipids without inflammation. To prevent NAFLD from reaching the NAFL stage through dietary therapy, in the present work, wild Chinese blueberries (Vacciniun spp.) were selected for their well-known benefits in inhibiting metabolic syndrome. After being purified from wild Chinese blueberries, polyphenol-rich extracts were subsequently separated into three fractions, namely, anthocyanin-rich fraction, phenolic acid-rich fraction, and ethyl acetate extract. The inhibition of oleic acid (OA)-induced triglyceride (TG) deposition in HepG 2 cells was referred to as the potential activity of preventing NAFL. Biochemical indicators, such as cytotoxicity, TG level, levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and intracellular reactive oxygen species, were used to evaluate the analogous pathological stage of NAFLD. The results show that OA ≤ 1.0 mM exhibits a dose-dependent induction of TG accumulation, and no inflammation was observed based on the changes in ALT and AST levels. Therefore, 1.0 mM OA was used to simulate an in vitro fatty liver. Blueberry polyphenol-rich extract efficiently inhibited OA-induced TG accumulation in HepG2 cells, and the phenolic acid-rich fraction performed efficiently. Seven phenolic acids were subsequently identified using a high-performance liquid chromatography assay, and the main types were caffeic, chlorogenic, ferulic, p-coumaric, and cinnamic acids. These phenolic acid standards also displayed good efficiency in inhibiting TG accumulation in HepG2 cells. These results imply that wild Chinese blueberries have a potential preventive effect on NAFLD in its early stage, and phenolic acids are the most efficient component.

Blueberry anthocyanins: protection against ageing and light-induced damage in retinal pigment epithelial cells

Retinal pigment epithelium (RPE) cells are vital for retinal health. However, they are susceptible to injury with ageing and exposure to excessive light, including UV (100-380 nm) and visible (380-760 nm) radiation. To evaluate the protective effect of blueberry anthocyanins on RPE cells, in vitro cell models of replicative senescent and light-induced damage were established in the present study. After purification and fractionation, blueberry anthocyanin extracts (BAE) were yielded with total anthocyanin contents of 31·0 (SD 0·5) % and were used in this study. Replicative senescence of RPE cells was induced by repeatedly passaging cells from the fourth passage to the tenth. From the fifth passage, cultured RPE cells began to enter a replicative senescence, exhibiting reduced cell proliferation along with an increase in the number of β-galactosidase-positive cells. RPE cells maintained high cell viability (P < 0·01) and a low (P < 0·01) percentage of β-galactosidase-positive cells when treated with 0·1 μg/ml BAE. In contrast, after exposure to 2500 (SD 500) lx light (420-800 nm) for 12 h, RPE cells in the positive control (light exposure, no BAE treatment) exhibited premature senescence, low (P < 0·01) cell viability and increased (P < 0·01) vascular endothelial growth factor (VEGF) release compared with negative control cells, which were not subjected to light irradiation and BAE exposure. Correspondingly, BAE is beneficial to RPE cells by protecting these cells against light-induced damage through the suppression of ageing and apoptosis as well as the down-regulation of the over-expressed VEGF to normal level. These results demonstrate that BAE is efficacious against senescence and light-induced damage of RPE cells.