Protective Effect of Black Rice Cyanidin-3-Glucoside on Testicular Damage in STZ-Induced Type 1 Diabetic Rats

Diabetic testicular damage is quite a common and significant complication in diabetic men, which could result in infertility. The natural fertility rate of type 1 diabetes men is only 50% because of testicular damage. This research first aimed to explore the intervention effect of C3G on testicular tissue damage induced by diabetes. Here, a streptozotocin-induced type 1 diabetic rat model was established, and then C3G was administered. After 8 weeks of C3G supplementation, the symptoms of diabetes (e.g., high blood glucose, lower body weight, polydipsia, polyphagia) were relieved, and at the same time that sperm motility and viability increased, sperm abnormality decreased in C3G-treated diabetic rats. Furthermore, the pathological structure of testis was restored; the fibrosis of the testicular interstitial tissue was inhibited; and the LH, FSH, and testosterone levels were all increased in the C3G-treated groups. Testicular oxidative stress was relieved; serum and testicular inflammatory cytokines levels were significantly decreased in C3G-treated groups; levels of Bax, Caspase-3, TGF-β1 and Smad2/3 protein in testis decreased; and the level of Bcl-2 was up-regulated in the C3G-treated groups. A possible mechanism might be that C3G improved antioxidant capacity, relieved oxidative stress, increased anti-inflammatory cytokine expression, and inhibited the apoptosis of spermatogenic cells and testicular fibrosis, thus promoting the production of testosterone and repair of testicular function. In conclusion, this study is the first to reveal that testicular damage could be mitigated by C3G in type 1 diabetic rats. Our results provide a theoretical basis for the application of C3G in male reproductive injury caused by diabetes.

Spectral characteristics of the flavones and anthocyanins present in passionflower (Passiflora incarnata)

Rich in antioxidants with a variety of flavones and anthocyanins, passionflower/fruit has been extensively used in food, beverage, medicinal, and natural dyes industries. The individual components present in passionflower are identified by extracting them in methanol, partitioning them between ethyl acetate and aqueous layers, and recording their ESI mass spectrometric data. The steady-state absorption and fluorescence spectra of the extract in methanol and dimethyl sulfoxide are recorded and the lifetime of the fluorescing species is reported. The pH dependence of the absorption spectrum confirms the presence of the anthocyanins.

A Review of the Role of an Anthocyanin, Cyanidin-3-O-β-glucoside in Obesity-Related Complications

Obesity has become a major health issue worldwide and obese individuals possess higher levels of adipose tissue when compared with healthy individuals. Obesity is highly associated with the development of different chronic diseases, such as diabetes, cardiovascular diseases, hypertension, cancers, etc. Previous studies established that anthocyanin compounds play an important role in attenuating obesity-related consequences. Among various anthocyanin compounds, cyanidin-3-O-β-glucoside (C3G) is the most important component and is widely distributed in various colored edible plant materials, especially berries, cherries, black rice, purple corn, etc. In recent decades, several studies have reported the therapeutical properties of C3G. C3G has various biological properties and health benefits, such as antioxidant, antimicrobial, anti-inflammatory, antidiabetic, anti-obesity, neuroprotective, anticancer, etc. In this review, we summarized the in vitro and in vivo studies in relation to the role of C3G in obesity-related complications. Several mechanistic studies demonstrated that C3G maintains the metabolism of glucose, fatty acids, and lipids by regulating different genes and signaling pathways. It could be concluded that the consumption of C3G protects healthy individuals from obesity-related issues by maintaining body weight and regulating their metabolism and energy balance. This review provides some important signaling pathways/targets of C3G to facilitate the prevention and treatment of obesity, leading to the development of important food supplements.

Characterizing the Gut Microbial Metabolic Profile of Mice with the Administration of Berry-Derived Cyanidin-3-Glucoside

Dietary modulation of the gut microbiota has recently received considerable attention. It is well established that consumption of berries confers a number of health benefits. We previously reported that a black raspberry (BRB)-rich diet effectively modulates the gut microbiota. Given the role of anthocyanins in the health benefits of berries, coupled with interactions of gut microbial metabolites with host health, the objective of this follow-up study was to further characterize the profile of functional metabolites in the gut microbiome modulated by anthocyanins. We utilized a berry-derived classic anthocyanin, cyanidin-3-glucoside (C3G), combined with a mouse model to probe C3G-associated functional metabolic products of gut bacteria through a mass spectrometry-based metabolomic profiling technique. Results showed that C3G substantially changed the gut microbiota of mice, including its composition and metabolic profile. A distinct metabolic profile in addition to a variety of key microbiota-related metabolites was observed in C3G-treated mice. Microbial metabolites involved in protein digestion and absorption were differently abundant between C3G-treated and control mice, which may be linked to the effects of berry consumption. Results of the present study suggest the involvement of the gut microbiota in the health benefits of C3G, providing evidence connecting the gut microbiota with berry consumption and its beneficial effects.

Phytochemical Analysis and Biological Activities of Ripe Fruits of Mistletoe (Psittacanthus calyculatus)

Psittacanthus calyculatus is a hemiparasitic plant of an arboreal species (e.g., forest, fruit trees). Its foliage has therapeutic potential; however, little is known about its fruits. In this study, the phytochemical profile and biological activities of P. calyculatus fruits hosted by Prosopis laevigata and Quercus deserticola were evaluated. The fruits of P. calyculatus from P. laevigata showed the highest content of total phenols (71.396 ± 0.676 mg GAE/g DW). The highest content of flavonoids and anthocyanins was presented in those from Q. deserticola (14.232 ± 0.772 mg QE/g DW; 2.431 ± 0.020 mg C3GE/g DW). The anthocyanin cyanidin-3-glucoside was detected and quantified via high-performance thin-layer chromatography (HPTLC) (306.682 ± 11.804 mg C3GE/g DW). Acidified extracts from host P. laevigata showed the highest antioxidant activity via ABTS^•+ (2,2'azinobis-(3-ethylbenzothiazdin-6-sulfonic acid) (214.810 ± 0.0802 mg TE/g DW). Fruit extracts with absolute ethanol from the P. laevigata host showed the highest antihypertensive activity (92 ± 3.054% inhibition of an angiotensin converting enzyme (ACE)). Fruit extracts from both hosts showed a minimum inhibitory concentration (MIC) of 6.25 mg/mL and a minimum bactericidal concentration (MBC) of 12.5 mg/mL against Escherichia coli, Salmonella choleraesuis and Shigella flexneri. Interestingly, a significant host effect was found. P. calyculatus fruits extract could be used therapeutically. However, further confirmation experiments should be carried out.

Anthocyanins Reduce Cell Invasion and Migration through Akt/mTOR Downregulation and Apoptosis Activation in Triple-Negative Breast Cancer Cells: A Systematic Review and Meta-Analysis

BACKGROUND

Studies have suggested the chemopreventive effects of anthocyanins on breast cancer carcinogenesis. This systematic review and meta-analysis aimed to evaluate the effect of anthocyanins on triple-negative breast cancer cells (TNBC) cultured in vitro.

METHODS

We searched for all relevant studies that evaluated the mechanisms of migration, invasion, Akt/mTOR and MAPK pathways, and apoptosis, using PubMed and Scopus. Means and standard deviation were used, and a randomized effects model was applied, with a confidence interval of 95%. Statistical heterogeneity between studies was assessed using the Chi2 test and I2 statistics. All analyses were performed using RevMan software (version 5.4).

RESULTS

Eleven studies were included in the systematic review and ten in the meta-analysis, where the roles of anthocyanin-enriched extract or cyanidin-3-O-glucoside (C-3-O-G) on MDA-MB-231 and MDA-MB-453 cells were investigated.

DISCUSSION

There was a significant reduction in invasion (mean difference: -98.64; 95% CI: -153.98, -43.3; p ˂ 0.00001) and migration (mean difference: -90.13; 95% CI: -130.57, -49.68; p ˂ 0.00001) in TNBC cells after anthocyanins treatment. Anthocyanins also downregulated Akt (mean difference: -0.63; 95% CI: -0.70, -0.57; p ˂ 0.00001) and mTOR (mean difference: -0.93; 95% CI: -1.58, -0.29; p = 0.005), while JNK (mean difference: -0.06; 95% CI: -1.21, 1.09; p = 0.92) and p38 (mean difference: 0.05; 95% CI: -1.32, 1.41; p = 0.95) were not modulated. There was also an increase in cleaved caspase-3 (mean difference: 1.13; 95% CI: 0.11, 2.16; p = 0.03), cleaved caspase-8 (mean difference: 1.64; 95% CI: 0.05, 3.22; p = 0.04), and cleaved PARP (mean difference: 0.93; 95% CI: 0.54, 1.32). Although the difference between control and anthocyanin groups was not significant regarding apoptosis rate (mean difference: 3.63; 95% CI: -2.88, 10.14; p = 0.27), the analysis between subgroups showed that anthocyanins are more favorable in inducing overall apoptosis (p ˂ 0.00001).

CONCLUSION

The results show that anthocyanins hold promise in fighting against TNBC, but their effects should not be generalized. In addition, further primary studies should be conducted so that more accurate conclusions can be drawn.

Untargeted Lipidomics Revealed the Protective Effects of Cyanidin-3-O-glucoside on Bisphenol A-Induced Liver Lipid Metabolism Disorder in Rats

Bisphenol A (BPA) is an estrogenic endocrine disruptor that induces metabolic disorders. Cyanidin-3-O-glucoside (C3G) has multiple functional activities and is the most abundant anthocyanin belonging to the flavonoid subgroup. This study aimed to investigate the protective effect of C3G on BPA-induced liver lipid metabolism disorder and explore its mechanism via lipidomics analysis. The results showed that C3G supplementation significantly ameliorated the serum levels of low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total cholesterol, triacylglycerols (TG), and alanine and aspartate aminotransferase (ALT and AST). Furthermore, liver lipidomics indicated that C3G effectively facilitated the recovery of differential lipid metabolites, including TGs, phosphatidylethanolamines, phosphatidylcholines, lysophosphatidylcholines, phosphatidylinositol, cholesteryl esters, and phosphatidylserine, and reversed the levels of hepatic lipid synthesis-related genes. Our results suggest that C3G has an effective regulatory effect on BPA-induced disorders of lipid metabolism.

Elderberries as a potential supplement to improve vascular function in a SARS-CoV-2 environment

Coronavirus disease 2019 (COVID-19) pandemic has been triggered by the severe acute respiratory syndrome coronavirus (SARS-CoV-2). Although recent studies demonstrate that SARS-CoV-2 possibly does not directly infect endothelial cells (EC), the endothelium may be affected as a secondary response due to the damage of neighboring cells, circulating pro-inflammatory cytokines, and/or other mechanisms. Long-term COVID-19 symptoms specifically nonrespiratory symptoms are due to the persistence of endothelial dysfunction (ED). Based on the literature, anthocyanins a major subgroup of flavonoid polyphenols found in berries, have been well researched for their vascular protective properties as well as the prevention of cardiovascular disease (CVD)-related deaths. Elderberries have been previously used as a natural remedy for treating influenza, cold, and consequently cardiovascular health due to a high content of cyanidin-3-glucoside (C3G) a major anthocyanin found in the human diet. The literature reported many studies demonstrating that EE has both antiviral and vascular protective properties that should be further investigated as a nutritional component used against the (in)direct effect of SARS-CoV-2 in vascular function. PRACTICAL APPLICATIONS: While previous work among the literature looks promising and builds a suggestion for investigating elderberry extract (EE) against COVID-19, further in vitro and in vivo research is required to fully evaluate EE mechanisms of action and its use as a supplement to aid current therapies.

The Effects of Berry Extracts on Oxidative Stress in Cultured Cardiomyocytes and Microglial Cells: A Potential Cardioprotective and Neuroprotective Mechanism

Oxidative stress is a key underlying factor in cognitive decline and atherosclerosis. Oxidative stress occurs at the cellular level with an imbalance between reactive oxygen species and reactive nitrogen species and a deficiency in antioxidants. Mounting evidence suggests that berry flavonoids may promote cellular health by exerting antioxidant properties. Black currant and various berry extracts were tested in microglia (BV-2) and cardiomyocyte (HL-1) cell lines to study their biological effects. The principal ingredients in black currant and cranberry extract–delphinidin 3-rutinoside (D3R) and cyanidin 3-glucoside (C3G), were also assessed. A menadione-induced oxidative stressor was used, and its output was quantified to detect oxidative stress (CellROX^TM). Black currant extract had similar antioxidant effects as N-acetylcysteine (NAC) in HL-1 cells with regard to cellular protection, whereas cranberry extract was ineffective. In contrast, cranberry extract was comparable in effectiveness to black currant extract in BV-2 cells. D3R and C3G also reduced oxidative stress similarly to whole berry extracts, which indicates that these ingredients may confer the antioxidant effects of berries. Black currant and cranberry extracts inhibit oxidative stress in microglial and cardiomyocyte cell lines. Black currant extract was more effective in reducing oxidative stress in the HL-1 cells, whereas cranberry extract was comparable in reducing oxidative stress in the BV-2 cells. The results suggest that berry flavonoids exert neuro- and cardioprotective effects.

Anthocyanins and Functional Compounds Change in a Third-Generation Snacks Prepared Using Extruded Blue Maize, Black Bean, and Chard: An Optimization

The effect of extrusion cooking on bioactive compounds in third-generation snacks (TGSE) and microwave-expanded snacks (MWSE) prepared using black bean, blue maize, and chard (FBCS) was evaluated. FBCS was extruded at different moisture contents (MC; 22.2–35.7%), extrusion temperatures (ET; 102–142 °C), and screw speeds (SP; 96–171 rpm). Total anthocyanin content (TAC), contents of individual anthocyanins, viz., cyanidin-3-glucoside, malvidin-3-glucoside, pelargonidin-3-glucoside, pelargonidin-3-5-diglucoside, and delphinidin-3-glucoside chloride, total phenolic content (TPC), antioxidant activity (AA), and color parameters were determined. TAC and individual anthocyanin levels increased with the reduction in ET. ET and MC affected the chemical and color properties; increase in ET caused a significant reduction in TPC and AA. Microwave expansion reduced anthocyanin content and AA, and increased TPC. Extrusion under optimal conditions (29% MC, 111 rpm, and 120 °C) generated products with a high retention of functional compounds, with high TAC (41.81%) and TPC (28.23%). Experimental validation of optimized process parameters yielded an average error of 13.73% from the predicted contents of individual anthocyanins. Results suggest that the TGSE of FBCS obtained by combining extrusion and microwave expansion achieved significant retention of bioactive compounds having potential physiological benefits for humans.

Evaluation of Anthocyanin Profiles in Various Blackcurrant Cultivars over a Three-Year Period Using a Fast HPLC-DAD Method

Anthocyanins are the most important polyphenolic substances contained in blackcurrant fruits. They are responsible for the various health benefits caused, in particular, by their high antioxidant activity. Anthocyanins derived from anthocyanidins cyanidin and delphinidin are typical for blackcurrant fruits, especially their rutinoside and glucoside forms. These four anthocyanins usually represent about 97–98% of total anthocyanins in blackcurrant fruits. In this study, we developed and validated a new HPLC-DAD method for rapid anthocyanin separation and determination in fifteen perspective blackcurrant cultivars (‘Ruben’, ‘Ben Lomond’, ‘Ben Conan’, ‘Ceres’, ‘Moravia’, ‘Ometa’, ‘Lota’, ‘Fokus’, ‘Tenah’, ‘Sejanec’, ‘Consort’, ‘Triton’, ‘Ben Hope’, ‘Ben Gairn’, and one gooseberry hybrid ‘Josta’). Eight of them were monitored throughout the three-year experiment. The most represented anthocyanins in all monitored blackcurrant cultivars were delphinidin-3-rutinoside (36.7–63.6%), cyanidin-3-rutinoside (26.4–40.6%), delphinidin-3-glucoside (6.1–17.9%), and cyanidin-3-glucoside (1.3–9.9%). The individual anthocyanin proportion (%) in each cultivar was specific, and a similar profile was verified in a three-year period for eight available cultivars. Total anthocyanin content expressed as a sum of four major anthocyanins present in blackcurrants was compared with values expressed as the equivalent of cyanidin-3-glucoside, as many authors do. We revealed an underestimation of about 20% with the latter method. Cultivars with the highest average total anthocyanin content were ‘Ben Gairn’ (294.38 mg/100 g), ‘Ceres’ (281.31 mg/100 g), and ‘Ometa’ (269.09 mg/100 g).

Computational and Transcriptomic Analysis Unraveled OsMATE34 as a Putative Anthocyanin Transporter in Black Rice (Oryza sativa L.) Caryopsis

Anthocyanin is a flavonoid compound with potential antioxidant properties beneficial to human health and sustains plant growth and development under different environmental stresses. In black rice, anthocyanin can be found in the stems, leaves, stigmas, and caryopsis. Although the anthocyanin biosynthesis in rice has been extensively studied, limited knowledge underlying the storage mechanism and transporters is available. This study undertook the complementation of computational and transcriptome analysis to decipher a potential multidrug and toxic compound extrusion (MATE) gene candidate for anthocyanin transportation in black rice caryopsis. The phylogenetic analysis showed that OsMATE34 has the same evolutionary history and high similarities with VvAM1, VvAM3, MtMATE2, SlMATE/MTP77, RsMATE8, AtFFT, and AtTT12 involved in anthocyanin transportation. RNA sequencing analysis in black caryopsis (Bc; Bc11, Bc18, Bc25) and white caryopsis (Wc; Wc11, Wc18, Wc25), respectively, at 11 days after flowering (DAF), 18 DAF, and 25 DAF revealed a total of 36,079 expressed genes, including 33,157 known genes and 2922 new genes. The differentially expressed genes (DEGs) showed 15,573 genes commonly expressed, with 1804 and 1412 genes uniquely expressed in Bc and Wc, respectively. Pairwise comparisons showed 821 uniquely expressed genes out of 15,272 DEGs for Wc11 vs. Bc11, 201 uniquely expressed genes out of 16,240 DEGs for Wc18 vs. Bc18, and 2263 uniquely expressed genes out of 16,240 DEGs for Wc25 vs. Bc25. Along with anthocyanin biosynthesis genes (OsPAL, OsCHS, OsCHI, OsF3H, OsDFR, OsANS, and OsUFGT/Os3GT), OsMATE34 expression was significantly upregulated in all Bc but not in Wc. OsMATE34 expression was similar to OsGSTU34, a transporter of anthocyanin in rice leaves. Taken together, our results highlighted OsMATE34 (Os08g0562800) as a candidate anthocyanin transporter in rice caryopsis. This study provides a new finding and a clue to enhance the accumulation of anthocyanin in rice caryopsis.

Recent Insights into Anthocyanin Pigmentation, Synthesis, Trafficking, and Regulatory Mechanisms in Rice (Oryza sativa L.) Caryopsis

Anthocyanins are antioxidants used as natural colorants and are beneficial to human health. Anthocyanins contribute to reactive oxygen species detoxification and sustain plant growth and development under different environmental stresses. They are phenolic compounds that are broadly distributed in nature and are responsible for a wide range of attractive coloration in many plant organs. Anthocyanins are found in various parts of plants such as flowers, leaves, stems, shoots, and grains. Considering their nutritional and health attributes, anthocyanin-enriched rice or pigmented rice cultivars are a possible alternative to reduce malnutrition around the globe. Anthocyanin biosynthesis and storage in rice are complex processes in which several structural and regulatory genes are involved. In recent years, significant progress has been achieved in the molecular and genetic mechanism of anthocyanins, and their synthesis is of great interest to researchers and the scientific community. However, limited studies have reported anthocyanin synthesis, transportation, and environmental conditions that can hinder anthocyanin production in rice. Rice is a staple food around the globe, and further research on anthocyanin in rice warrants more attention. In this review, metabolic and pre-biotic activities, the underlying transportation, and storage mechanisms of anthocyanins in rice are discussed in detail. This review provides potential information for the food industry and clues for rice breeding and genetic engineering of rice.

Counter-Current Fractionation-Assisted Bioassay-Guided Separation of Active Compound from Blueberry and the Interaction between the Active Compound and α-Glucosidase

An efficient strategy for the selection of active compounds from blueberry based on counter-current fractionation and bioassay-guided separation was established in this study. Blueberry extract showed potential α-glucosidase inhibitory activity. After extraction by different solvents, the active components were enriched in water. The water extract was divided into six fractions via high-speed counter-current chromatography to further track the active components. Results indicated that the α-glucosidase inhibition rate of F4 was remarkable higher than the others. Cyanidin-3-glucoside (C3G) with a purity of 94.16% was successfully separated from F4 through column chromatography, and its structure was identified by ultraviolet spectral, Fourier-transformed infrared spectroscopy, high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, ¹H nuclear magnetic resonance (NMR), and ¹³C NMR. The interaction mechanism between C3G and α-glucosidase was clearly characterized and described by spectroscopic methods, including fluorescence and circular dichroism (CD) in combination with molecular docking techniques. C3G could spontaneously bind with α-glucosidase to form complexes by hydrogen bonds. The secondary structure of α-glucosidase changed in varying degrees after complexation with C3G. The α-helical and β-turn contents of α-glucosidase decreased, whereas the β-sheet content and the irregular coil structures increased. Molecular docking speculated that C3G could form hydrogen bonds with α-glucosidase by binding to the active sit (Leu 313, Ser 157, Tyr 158, Phe 314, Arg 315, and two Asp 307). These findings may be useful for the development of functional foods to tackle type 2 diabetes.

Morus nigra L. extract prolongs survival of rats with hepatocellular carcinoma

Morus nigra is a rich source of anthocyanins, phytochemicals that have anticancer effects. This study aimed to investigate the effects of M. nigra extract (MNE) on diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC). Male Sprague-Dawley rats were assigned into four groups (n = 10): control, DEN, and DEN +100 or 400 mg/kg of MNE. After 4 months, the DEN group showed a significant mortality rate, hepatic lipid peroxidation, dysplastic nodules in the cirrhotic liver, and an increase of blood bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). Also, the body weight gain, blood albumin and glucose, liver antioxidant capacity (thiol groups), and some hematological parameters (RBC, hematocrit, hemoglobin, and platelet) were significantly decreased in the DEN group. MNE significantly increased survival, reduced the size of HCC nodules, improved liver oxidant/antioxidant status, and prevented the above-mentioned changes in the blood (except ALP, glucose, and platelet). Quantitative real-time PCR showed that MNE decreased the expression of Wnt4 and β-catenin, while had no significant effect on PI3K, Akt, and PTEN expression. The MNE did not exhibit antiproliferative activity against HepG2 liver cancer cells. In conclusion, MNE exhibits a hepatoprotective effect through inhibiting oxidative stress and Wnt4/β-catenin pathway and therefore prolongs the survival of rats with HCC.

Anthocyanins Are Converted into Anthocyanidins and Phenolic Acids and Effectively Absorbed in the Jejunum and Ileum

Anthocyanins have been known for their health benefits. However, the in vivo digestion and absorption of anthocyanins through the gastrointestinal tract have not been fully clarified, creating challenges for understanding why anthocyanins have high biological activities and purported low bioavailability in vivo. Twenty-seven male rats were intubated with a 500 mg/kg dose of cyanidin-3-glucoside (C3G). Samples from rats' stomach, duodenum, jejunum, ileum, colon, and serum were collected at 0.5, 1, 2, 3, 4, 5, 6, 12, and 24 h after intubation. Three rats without C3G were used as the control with samples collected at 0 h. C3G and its metabolites in each sample were analyzed using high-performance liquid chromatography-PDA-electrospray ionization-MS/MS. These in vivo studies' results unequivocally demonstrated that cyanidin and phenolic acids were the primary C3G metabolites absorbed, mainly in the jejunum and ileum, between 1 and 5 h post-ingestion. We speculate that C3G uses phloroglucinaldehyde and protocatechuic acid metabolic pathways in its metabolism in vivo.

Down-Regulation of Claudin-2 Expression by Cyanidin-3-Glucoside Enhances Sensitivity to Anticancer Drugs in the Spheroid of Human Lung Adenocarcinoma A549 Cells

Claudin-2 (CLDN2), an integral membrane protein located at tight junctions, is abnormally expressed in human lung adenocarcinoma tissues, and is linked to drug resistance in human lung adenocarcinoma A549 cells. CLDN2 may be a target for the prevention of lung adenocarcinoma, but there are few compounds which can reduce CLDN2 expression. We found that cyanidin-3-glucoside (C3G), the anthocyanin with two hydroxyl groups on the B-ring, and cyanidin significantly reduce the protein level of CLDN2 in A549 cells. In contrast, pelargonidin-3-glucoside (P3G), the anthocyanin with one hydroxyl group on the B-ring, had no effect. These results suggest that cyanidin and the hydroxyl group at the 3-position on the B-ring play an important role in the reduction of CLDN2 expression. The phosphorylation of Akt, an activator of CLDN2 expression at the transcriptional level, was inhibited by C3G, but not by P3G. The endocytosis and lysosomal degradation are suggested to be involved in the C3G-induced decrease in CLDN2 protein expression. C3G increased the phosphorylation of p38 and the p38 inhibitor SB203580 rescued the C3G-induced decrease in CLDN2 expression. In addition, SB203580 rescued the protein stability of CLDN2. C3G may reduce CLDN2 expression at the transcriptional and post-translational steps mediated by inhibiting Akt and activating p38, respectively. C3G enhanced the accumulation and cytotoxicity of doxorubicin (DXR) in the spheroid models. The percentages of apoptotic and necrotic cells induced by DXR were increased by C3G. Our data suggest that C3G-rich foods can prevent the chemoresistance of lung adenocarcinoma A549 cells through the reduction of CLDN2 expression.

Recovery of anthocyanins from sour cherry (Prunus cerasus L.) peels via microwave assisted extraction: monitoring the storage stability

Utilization of economical and environmental methods as an alternative process to recover the industrial crops and food products into high-added value compounds is of great significant. In the current study, microwave assisted extraction (MAE) was optimized by response surface methodology (RSM) in order to evaluate the waste of sour cherry as a source of phenolic compounds rich in anthocyanins. The process parameters (microwave power, irradiation time and ethanol solvent concentration) of MAE method were optimized by face centered composite design of RSM. Responses such as total phenolic componds (TPC), total anthocyanin (TA) contents and antioxidant capacity (DPPH) of extracts were measured spectrophotometrically after extractions of samples. The optimized result of MAE was 500 W of microwave power, 90 s of irradation time and 80% ethanol solvent concentration. Antioxidant capacity was tested using by 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical. Chromatographic analysis (HPLC) was also used to measure the concentration of major anthocyanin (cyanidin-3-glucoside) of the samples. Maximum predicted TPC, TA and DPPH yields on optimized conditions were 44.15 mg-GAE/g-FM (mg- gallic acid equivalent per g- fresh matter), 12.47 mg-cyanidin-3-glucoside/g-FM and 69.90 (%, inhibition), respectively. A stability assay under different conditions (light, dark, ambient condition, refrigerator and deep freezer) has been also performed in order to display the stability of bioactivity profile. All of the process parameters were significant at the level of p < 0.0001.

Cyanidin-3-glucoside as a possible biomarker of anthocyanin-rich berry intake in body fluids of healthy humans: a systematic review of clinical trials

Context

Anthocyanins are phenolic compounds found in berries. They exhibit promising health benefits in humans, but no accurate biomarkers of berry intake have been identified thus far.

Objective

The aim of this systematic review is to propose a biomarker of anthocyanin-rich berry intake in human plasma and urine.

Data Sources

PubMed and Cochrane databases were searched from January 2008 to January 2019.

Study Selection

Databases were searched for human intervention studies that assessed the presence of anthocyanins in human body fluids using high-throughput techniques. Non-English articles and studies publishing targeted analyses were excluded.

Data Extraction

Ten clinical trials, in which 203 phenolic compounds were identified, were included and assessed qualitatively. The following criteria were used to identify biomarkers of berry intake: frequency, plausibility, dose-response, time response, robustness, reliability, stability, analytical performance, and reproducibility. Sensitivity and specificity of potential biomarkers were determined by the receiver operating characteristic curve.

Results

Of the 203 phenolic compounds identified in human samples, the anthocyanin cyanidin-3-glucoside was the molecule found most frequently in urine (58.06%) and plasma (69.49%). Cyanidin-3-glucoside fulfills the essential criterion of plausibility as well as the dose-response, time response, stability, and analytical performance criteria. Its positive predictive value is 74% (P = 0.210) in plasma, which is acceptable, and 61.7% (P = 0.402) in urine.

Conclusions

Current evidence suggests that cyanidin-3-glucoside is a potential biomarker of anthocyanin-rich berry intake in plasma and urine of healthy humans.

PROSPERO registration number

CRD42018096796.

Impact of Cyanidin-3-Glucoside on Gut Microbiota and Relationship with Metabolism and Inflammation in High Fat-High Sucrose Diet-Induced Insulin Resistant Mice

The present study assessed the effects of freeze-dried cyanidin-3-glucoside (C3G), an anthocyanin enriched in dark-red berries, compared to Saskatoon berry powder (SBp) on metabolism, inflammatory markers and gut microbiota in high fat-high sucrose (HFHS) diet-induced insulin-resistant mice. Male C57 BL/6J mice received control, HFHS, HFHS + SBp (8.0 g/kg/day) or HFHS + C3G (7.2 mg/kg/day, equivalent C3G in SBp) diet for 11 weeks. The HFHS diet significantly increased plasma levels of glucose, cholesterol, triglycerides, insulin resistance and inflammatory markers. The HFHS + SBp diet increased the Bacteroidetes/Firmicutes (B/F) ratio and relative abundance of Muriculaceae family bacteria in mouse feces detected using 16S rRNA gene sequencing. The HFHS + SBp or HFHS + C3G diet attenuated glucose, lipids, insulin resistance and inflammatory markers, and increased the B/F ratio and Muriculaceae relative abundance compared to the HFHS diet alone. The relative abundances of Muriculaceae negatively correlated with body weight, glucose, lipids, insulin resistance and inflammatory mediators. Functional predication analysis suggested that the HFHS diet upregulated gut bacteria genes involved in inflammation, and downregulated bacteria involved in metabolism. C3G and SBp partially neutralized HFHS diet-induced alterations of gut bacteria. The results suggest that C3G is a potential prebiotic, mitigating HFHS diet-induced disorders in metabolism, inflammation and gut dysbiosis, and that C3G contributes to the metabolic beneficial effects of SBp.

Storage stability of anthocyanins in freeze-dried elderberry pulp using low proportions of encapsulating agents

Berry fruits are well recognized for health-promoting constituents due to their properties of free radical scavengers which confer antioxidant activity against cellular oxidation reactions. Elderberry fruit contains one of the highest levels of anthocyanins. The objective of this work was to evaluate the storage stability of total monomeric anthocyanins, cyanidin-3-glucoside (one of two major anthocyanins in elderberry), and color parameters in freeze-dried elderberry encapsulated with a low proportion of different carriers (Maltodextrin, Capsul™, Promitor ™, and κ-carrageenan). Encapsulated samples were stored at two different water activities (a_w) 0.10-0.20 and 0.43 at 38 ℃ for 90 days and evaluated for the content of monomeric anthocyanins, cyanidin-3-glucoside, color parameters, and physical characteristics. Freeze-dried powders remained free-flowing during storage at 38 ℃ with a_w 0.12-0.20, but agglomeration occurred at a_w = 0.43. Total anthocyanins and color parameter a* (redness) remained unchanged during storage at the lower a_w. Glass transition temperatures (T_g) were determined and mostly correlated with observed physical phenomena. The powders had a very high total monomeric anthocyanin contents as high as 13 mg/g (cyanidin-3-glucoside). The addition of encapsulants in low proportions allowed the researchers to obtain elderberry powders with a very high concentration of total monomeric anthocyanins. a_w plays a key role in all stability parameters studied.

Cyanidin-3-glucoside from Black Rice Ameliorates Diabetic Nephropathy via Reducing Blood Glucose, Suppressing Oxidative Stress and Inflammation, and Regulating Transforming Growth Factor β1/Smad Expression

Diabetic nephropathy (DN) is one of the serious complications in diabetes. Cyanidin-3-glucoside (C3G) from black rice was reported to have hypoglycemic effects and an anti-osteoporosis effect in diabetic rats. Whether it has preventive effects on DN has not been reported. In this study, we established a rat model of DN, and C3G at two doses (10 and 20 mg kg^-1 day^-1) were administered to see its anti-DN effect. A total of 8 weeks of C3G supplementation decreased blood glucose and serum insulin, improved the renal function, and relieved renal glomerular sclerosis and interstitial fibrosis of DN rats. Also, the kidneys of DN rats had improved the oxidative defense system. Pro-inflammatory mediators were markedly reduced in serum and kidneys of the C3G-treated groups. Transforming growth factor β1 (TGF-β1), phosphor-Smad2, and phosphor-Smad3 protein expression levels were significantly decreased in the kidney of the C3G-treated group, whereas the Smad7 expression level was upregulated by C3G. Our results indicate that C3G can ameliorate DN via antioxidative stress and anti-inflammation and regulate the TGF-β1/Smad2/3 pathway. Our results suggest that C3G from black rice might be used as a renal-protective nutrient in DN.

Cyanidin-3-glucoside binds to talin and modulates colon cancer cell adhesions and 3D growth

Cyanidin-3-glucoside (C3G) is a natural pigment, found in many colorful fruits and vegetables. It has many health benefits, including anti-inflammation, cancer prevention, and anti-diabetes. Although C3G is assumed to be an antioxidant, it has been reported to affect cell-matrix adhesions. However, the underlying molecular mechanism is unknown. Here, we show that the expression of talin1, a key regulator of integrins and cell adhesions, negatively correlated with the survival rate of colon cancer patients and that depletion of talin1 inhibited 3D spheroid growth in colon cancer cells. Interestingly, C3G bound to talin and promoted the interaction of talin with β1A-integrin. Molecular docking analysis shows that C3G binds to the interface of the talin-β-integrin complex, acting as an allosteric regulator and altering the interaction between talin and integrin. Moreover, C3G promoted colon cancer cell attachment to fibronectin. While C3G had no significant effect on colon cancer cell proliferation, it significantly inhibited 3D spheroid growth in fibrin gel assays. Since C3G has no or very low toxicity, it could be potentially used for colon cancer prevention or therapy.

Alleviation of Salt Stress in Upland Rice (Oryza sativa L. ssp. indica cv. Leum Pua) Using Arbuscular Mycorrhizal Fungi Inoculation

Arbuscular mycorrhizal fungi (AMF) symbionts not only promote the growth of host plant but also alleviate abiotic stresses. This study aimed to investigate the putative role of AMF in salt stress regulation of upland pigmented rice cv. Leum Pua (LP) comparing with Pokkali salt tolerant (positive check). In general, LP is a variety of glutinous rice that contains anthocyanin pigment in the black pericarp, due to which it possesses high antioxidant activities compared to non-pigmented rice. Pot experiment was conducted to evaluate the impact of inoculated AMF, Glomus etunicatum (GE), Glomus geosporum (GG), and Glomus mosseae (GM) strains, in the LP plantlets subjected to 0 (control) or 150 mM NaCl (salt stress) for 2 weeks in comparison with Pokkali (a salt tolerant rice cultivar), which was maintained as a positive check. Root colonization percentage under NaCl conditions ranged from 23 to 30%. Na⁺ content in the flag leaf tissues was increased to 18-35 mg g^-1 DW after exposure to 150 mM NaCl for 14 days in both inoculated and un-inoculated LP plants, whereas Na:K ratio was very low in cv. Pokkali. Interestingly, sucrose content in the flag leaf tissues of un-inoculated LP plants under salt stress was increased significantly by 50 folds over the control as an indicator of salt stress response, whereas it was unchanged in all AMF treatments. Fructose and free proline in GE inoculated plants under salt stress were accumulated over control by 5.75 and 13.59 folds, respectively, for osmotic adjustment of the cell, thereby maintaining the structure and functions of chlorophyll pigments, F_v/F_m, Φ_PSII, and stomatal function. Shoot height, flag leaf length, number of panicles, panicle length, panicle weight, and 100-grain weight in GE inoculated plants of cv. LP under salt stress were maintained similar to cv. Pokkali. Interestingly, cyanidin-3-glucoside (C3G) and peonidin-3-glucoside (P3G) in the pericarp of cv. LP were regulated by GE inoculation under salt stress conditions. In summary, AMF-inoculation in rice crop is a successful alternative approach to reduce salt toxicity, maintain the yield attributes, and regulate anthocyanins enrichment in the pericarp of grains.

The Effects and Mechanisms of Cyanidin-3-Glucoside and Its Phenolic Metabolites in Maintaining Intestinal Integrity

Cyanidin-3-glucoside (C3G) is a well-known natural anthocyanin and possesses antioxidant and anti-inflammatory properties. The catabolism of C3G in the gastrointestinal tract could produce bioactive phenolic metabolites, such as protocatechuic acid, phloroglucinaldehyde, vanillic acid, and ferulic acid, which enhance C3G bioavailability and contribute to both mucosal barrier and microbiota. To get an overview of the function and mechanisms of C3G and its phenolic metabolites, we review the accumulated data of the absorption and catabolism of C3G in the gastrointestine, and attempt to give crosstalk between the phenolic metabolites, gut microbiota, and mucosal innate immune signaling pathways.

Effect of intravitreal and intraperitoneal cyanidin-3-glucoside injection in oxygen-induced retinopathy mouse model

Purpose:

To evaluate the effect of cyanidin-3-glucoside (C3G) in oxygen-induced retinopathy (OIR) mouse model.

Methods:

In this experimental study, 10 C57BL / 6J type mice exposed to room air comprised two control groups (n = 5 each; a negative control and a group receiving intravitreal sterile dimethyl sulfoxide [IVS DMSO]). Thirty C57BL / 6J type mice exposed to 75% ± 2% oxygen from postnatal day 7 to postnatal day 12 comprised the OIR groups. On postnatal day 12, these mice were randomized into six groups (n = 5 each): two OIR control groups (negative control and IVS DMSO), two intravitreal C3G groups (300 and 600 ng/μL), and two intraperitoneal C3G groups (0.05 and 0.1 mg/kg). We quantified neovascularization by counting endothelial cell proliferation on the vitreal side of the inner limiting membrane of the retina and examined histological and ultrastructural changes via light and electron microscopy and apoptosis by terminal deoxynucleotidyl transferase deoxy-UTP-nick end labeling.

Results:

The intravitreal C3G groups yielded lower endothelial cell counts compared with the intravitreal DMSO group. The intraperitoneal high-dose group had lower cell counts compared with the OIR control groups. Electron microscopy revealed significantly less mitochondrial dysmorphology in intravitreal groups and the high-dose intraperitoneal mice. We noted no difference in apoptotic cell count between the controls, low-dose intravitreal, and both intraperitoneal groups. However, apoptotic cell count was significantly higher in the high-dose intravitreal group.

Conclusion:

C3G suppresses endothelial cell proliferation in an OIR mouse model, leads to a reduced hyperoxia-induced mitochondrial dysmorphology, but increases apoptotic cell death in high concentrations.

Protective Effect of Mulberry (Morus alba L.) Extract against Benzo[a]pyrene Induced Skin Damage through Inhibition of Aryl Hydrocarbon Receptor Signaling

Benzo[a]pyrene (B[a]P), a type of polycyclic aromatic hydrocarbon, is present in the atmosphere surrounding our environment. Although B[a]P is a procarcinogen, enzymatically metabolized benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) could intercalate into DNA to form bulky BPDE-DNA adducts as an ultimate carcinogenic product in human keratinocytes. The aim of this study was to evaluate the protective effect of mulberry extract, purified from the fruit of Morus Alba L., on B[a]P-induced cytotoxicity in human keratinocytes and its mechanisms of action. In this study, we confirmed that B[a]P induced nuclear translocation and the activation of aryl hydrocarbon receptor (AhR) were decreased by pretreatment of mulberry extract. Mulberry extract could decrease DNA damage through the suppression of B[a]P derived DNA adduct formation and restoration of cell cycle retardation at S phase in a dose-dependent manner. Additionally, cyanidin-3-glucoside (C3G), a major active compound of mulberry extract, showed biological activities to protect the cells from B[a]P exposure, similar to the effectivity of the mulberry extract. These results indicated that the inhibitory effect of C3G against B[a]P inducing skin cancer is attributable to repress the AhR signaling pathway.

Effects of Power Ultrasound on Stability of Cyanidin-3-glucoside Obtained from Blueberry

Power ultrasound (US) could potentially be used in the food industry in the future. However, the extent of anthocyanin degradation by US requires investigation. Cyanidin-3-glucoside (Cy-3-glu) obtained from blueberry extracts was used as research material to investigate the effect of power ultrasound on food processing of anthocyanin-rich raw materials. The effects of ultrasonic waves on the stability of Cy-3-glu and on the corresponding changes in UV-Vis spectrum and antioxidant activity were investigated, and the mechanisms of anthocyanin degradation induced by ultrasonic waves were discussed. To explore Cy-3-glu degradation in different environments, we kept the Cy-3-glu solution treated with ultrasonic waves in four concentrations (0%, 10%, 20%, and 50%) of ethanol aqueous solutions to simulate water, beer, wine, and liquor storage environment according to the chemical kinetics method. Results show that the basic spectral characteristics of Cy-3-glu did not significantly change after power ultrasound cell crusher application at 30 °C. However, with anthocyanin degradation, the intensity of the peak for Cy-3-glu at 504 nm significantly decreased (p < 0.05). The degradation kinetics of Cy-3-glu by ultrasonic waves (200–500 W frequency) fitted well to first-order reaction kinetics, and the degradation rate constant of Cy-3-glu under power ultrasound was considerably larger than that under thermal degradation (p < 0.05). The sensitivity of the anthocyanins of blueberry to temperature increased with increasing ethanol concentration, and the longest half-life was observed in 20% ethanol aqueous solution.

Thermal cooking changes the profile of phenolic compounds, but does not attenuate the anti-inflammatory activities of black rice

Background

Evidence on biological activities of cooked black rice is limited. This study examined the effects of washing and cooking on the bioactive ingredients and biological activities of black rice.

Methods

Cooked rice was prepared by washing 0–3 times followed by cooking in a rice cooker. The acidic methanol extracts of raw and cooked rice were used for the analyses.

Results

Raw black rice, both washed and unwashed, had higher contents of polyphenols, anthocyanins, and cyanidin-3-glucoside (C3G), but lower protocatechuic acid (PA), than did cooked samples. Similarly, raw rice extracts were higher in ferric-reducing antioxidant power (FRAP) activities than extracts of cooked samples. Nonetheless, extracts of raw and cooked rice showed similar inhibitory potencies on nitric oxide, tumor necrosis factor-α, and interleukin-6 productions in lipopolysaccharide-activated macrophages, whereas equivalent amounts of C3G and PA did not possess such inhibitory effects.

Conclusions

Thermal cooking decreased total anthocyanin and C3G contents and the FRAP antioxidative capacity, but did not affect anti-inflammatory activities of black rice. Neither C3G nor PA contributed to the anti-inflammatory activity of black rice.

Anthocyanin-rich extracts from blackberry, wild blueberry, strawberry, and chokeberry: antioxidant activity and inhibitory effect on oleic acid-induced hepatic steatosis in vitro

BACKGROUND

Limited information is available regarding the relationship between the chemical structures and inhibitory effects of anthocyanin (ACN) on triglyceride (TG) overaccumulation. Thus this study investigated the antioxidant activity and inhibitory effect of blackberry, wild blueberry, strawberry, and chokeberry ACN-rich extracts, with different structural characteristics, on oleic acid-induced hepatic steatosis in vitro. Four major ACNs from these berries, with different aglycones, namely cyanidin-3-glucoside (Cy-3-glu), delphinidin-3-glucoside, pelargonidin-3-glucoside, and malvidin-3-glucoside, were also investigated.

RESULTS

Blackberry ACN-rich extract exhibited the most significant inhibitory effect on TG clearance (30.5% ± 3.4%) and reactive oxygen species generation. TG clearance was significantly correlated with total phenolic content (r = 0.991, P < 0.05) and oxygen radical absorbance capacity value (r = 0.961, P < 0.05). Furthermore, Cy-3-glu showed the highest inhibitory effect on intracellular TG overaccumulation, with a maximum TG clearance of 61.3% at 40 µg mL(-1) .

CONCLUSION

Our findings suggest that the inhibitory effects of different ACNs on oleic acid-induced hepatic steatosis significantly vary. Cy-3-glu, which contains the ortho hydroxyl group in its B ring, possibly confers the protective effects of antioxidants and inhibits TG accumulation in HepG2 cells. © 2015 Society of Chemical Industry.

Antiviral effects of black raspberry (Rubus coreanus) seed extract and its polyphenolic compounds on norovirus surrogates

Black raspberry seeds, a byproduct of wine and juice production, contain large quantities of polyphenolic compounds. The antiviral effects of black raspberry seed extract (RCS) and its fraction with molecular weight less than 1 kDa (RCS-F1) were examined against food-borne viral surrogates, murine norovirus-1 (MNV-1) and feline calicivirus-F9 (FCV-F9). The maximal antiviral effect was achieved when RCS or RCS-F1 was added simultaneously to cells with MNV-1 or FCV-F9, reaching complete inhibition at 0.1-1 mg/mL. Transmission electron microscopy (TEM) images showed enlarged viral capsids or disruption (from 35 nm to up to 100 nm) by RCS-F1. Our results thus suggest that RCS-F1 can interfere with the attachment of viral surface protein to host cells. Further, two polyphenolic compounds derived from RCS-F1, cyanidin-3-glucoside (C3G) and gallic acid, identified by liquid chromatography-tandem mass spectrometry, showed inhibitory effects against the viruses. C3G was suggested to bind to MNV-1 RNA polymerase and to enlarge viral capsids using differential scanning fluorimetry and TEM, respectively.

Enzymatic Acylation of Anthocyanin Isolated from Black Rice with Methyl Aromatic Acid Ester as Donor: Stability of the Acylated Derivatives

The enzymatic acylation of anthocyanin from black rice with aromatic acid methyl esters as acyl donors and Candida antarctica lipase B was carried out under reduced pressure. The highest conversion of 91% was obtained with benzoic acid methyl ester as acyl donor; cyanidin 3-(6″-benzoyl)-glucoside, cyanidin 3-(6″-salicyloyl)-glucoside, and cyanidin 3-(6″-cinnamoyl)-glucoside were successfully synthesized. This is the first report on the enzymatic acylation of anthocyanin from black rice with methyl aromatic esters as acyl donors and lipase as biocatalyst. Furthermore, the acylation with aromatic carboxylic acids enhanced both the thermostability and light resistivity of anthocyanin. In particular, cyanidin 3-(6″-cinnamoyl)-glucoside was the most stable among the three acylated anthocyanins synthesized.

Metabolomic Analysis Reveals Cyanidins in Black Raspberry as Candidates for Suppression of Lipopolysaccharide-Induced Inflammation in Murine Macrophages

The extracts produced by multisolvent extraction and subfractionation with preparative liquid chromatography of black raspberry (Rubus coreanus Miquel) cultivated in Gochang, South Korea, were tested for their anti-inflammatory effects. The metabolomic profiling and analysis by orthogonal partial least-squares discriminant analysis (OLPS-DA) suggested that cyanidin, cyanidin-3-glucoside (C3G), and cyanidin-3-rutinoside (C3R) were key components for the anti-inflammatory responses in the most active fraction BF3-1, where they were present at 0.44, 1.26, and 0.56 μg/mg of BF3-1, respectively. Both BF3-1 and mixture of these cyanidins at the same ratio reduced lipopolysaccharide (LPS)-induced protein level of iNOS expression and suppressed mRNA and protein expressions of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β through inhibiting the phosphorylation of mitogen-activated protein kinases (MAPKs) and STAT3 in murine macrophage RAW264.7 cells. Overall, the results suggested that co-administration of cyanidin, C3G, and C3R is more effective than that of cyanidin alone and that the coexistence of these anthocyanin components in black raspberry plays a vital role in regulating LPS-induced inflammation even at submicromolar concentrations, making it possible to explain the health beneficial activity of its extracts.

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.

Binding characteristics and protective capacity of cyanidin-3-glucoside and its aglycon to calf thymus DNA

The binding characteristics and protective capacity of cyanidin (Cy) and cyanidin-3-glucoside (C3G) to calf thymus DNA were explored for the first time. The Cy and C3G gave a bathochromic shift to the ultraviolet-visible spectra of the DNA, indicating the formation of the DNA-Cy and DNA-C3G complexes. The complexes were formed by an intercalative binding mode based on the results of the fluorescence spectra and competitive binding analysis. Meanwhile, the Cy and C3G protected the DNA from the damage induced by the hydroxyl radical. The binding capacity and protective capacity of the C3G were stronger than that of the Cy. Furthermore, the formation of the DNA-anthocyanin complexes was spontaneous when the hydrogen bond and hydrophobic force played a key role. Hence, the Cy and C3G could protect the DNA automatically from the damage induced by the hydroxyl radical.

Hypolipidaemic effects of cyanidin 3-glucoside rich extract from black rice through regulating hepatic lipogenic enzyme activities

BACKGROUND

Black rice is rich in anthocyanins, especially cyanidin-3-glucoside (C3G). This study examined the effects of a C3G-rich extract from black rice on hyperlipidaemia induced by a high fat/cholesterol diet (HFCD) in rats.

RESULTS

Male Sprague-Dawley rats were fed either HFCD or HFCD containing 150 mg kg⁻¹ body weight C3G (HFCD+C3G) for 4 weeks. We found that C3G significantly decreased serum levels of total cholesterol, free cholesterol, triglycerides, and free fatty acids in rats fed a HFCD. Similarly, hepatic cholesterol and triglyceride levels and the activities of hepatic lipogenic enzymes (malic enzyme and glucose-6-phosphate dehydrogenase) were significantly reduced by C3G supplementation.

CONCLUSION

These results suggest that C3G can ameliorate HFCD-induced hyperlipidaemia in part by modulating the activities of hepatic lipogenic enzymes.

Protection of cyanidin-3-glucoside against oxidative stress induced by acrylamide in human MDA-MB-231 cells

Acrylamide (AA) occurs in many cooked starchy foods and has caused widespread concern as a possible carcinogen. In the present study, we investigate the intervention of AA toxicity in MDA-MB-231 cells pretreated with cyanidin-3-glucoside (Cy-3-glu). Compared to the cells treated with AA, Cy-3-glu significantly inhibited AA-induced cytotoxicity, reduced reactive oxygen species (ROS) generation, recovered glutathione (GSH) depletion and decreased the activities of glutathione peroxidase (GPx) and glutathione S-transferase (GST). Moreover, the expression of GPx1, GSTP1 and gamma-glutamyl cysteine synthase (γ-GCS) were enhanced, and cytochrome P450 2E1 (CYP2E1) expression was inhibited by the pretreatment of Cy-3-glu. Cy-3-glu presents the protective role against oxidative stress induced by AA in MDA-MB-231 cells.