cyanidin-3-O-β-glucoside Research Articles

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.

Supplementation of cyanidin-3-O-β-glucoside-rich haskap (Lonicera caerulea L.) berry extract attenuates hepatic lipid dysregulation in diet-induced obese mice

Haskap (Lonicera caerulea L.) berry is enriched in anthocyanins, primarily cyanidin-3-O-β-glucoside (C3G). It remains unknown whether C3G counteracts metabolic alterations of the pathogenesis of obesity. In this study, mice were fed high-fat high-sucrose (HFHS) diet supplemented either with C3G-rich extract (HFHS + CE) or berry powder with low C3G (HFHS + BP). Mice fed HFHS + CE displayed short-term protection against weight gain, independent of food intake. HFHS + CE mice had lower hepatic diacylglycerols and triacylglycerols content and reduced expression of key lipogenic transcription factors. These metabolic changes also translated into improved glucose tolerance and insulin sensitivity. 16S rRNA sequencing revealed altered gut microbiota composition in the HFHS + CE group. In summary, we demonstrate that C3G enrichment in the HFHS diet attenuates short-term weight gain, decreases hepatic lipid content by suppressing key lipogenic gene expression and improves glucose homeostasis during obesity development, supporting the therapeutic utility of C3G as a bioactive phytonutrient to manage obesity-related complications.

The effect of dietary supplementation with blueberry, cyanidin-3-O-β-glucoside, yoghurt and its peptides on gene expression associated with glucose metabolism in skeletal muscle obtained from a high-fat-high-carbohydrate diet induced obesity model.

Obesity is a leading global health problem contributing to various chronic diseases, including type II diabetes mellitus (T2DM). The aim of this study was to investigate whether blueberries, yoghurt, and their respective bioactive components, Cyanidin-3-O-β-glucoside (C3G) and peptides alone or in combinations, alter the expression of genes related to glucose metabolism in skeletal muscles from diet-induced obese mice. In extensor digitorum longus (EDL), yoghurt up-regulated the expression of activation of 5’adenosine monophosphate-activated protein kinase (AMPK), insulin receptor substrate-1 (IRS-1), phosphatidylinositol-3 kinase (PI3K) and glucose transporter 4 (GLUT4), and down-regulated the expression of angiotensin II receptor type 1 (AGTR-1). The combination of blueberries and yoghurt down-regulated the mRNA expression of AGTR-1 and Forkhead box protein O1 (FoxO1) in the EDL. Whereas the combination of C3G and peptides down-regulated AGTR-1 and up-regulated GLUT4 mRNA expression in the EDL. In the soleus, blueberries and yoghurt alone, and their combination down-regulated AGTR-1 and up-regulated GLUT4 mRNA expression. In summary blueberries and yoghurt, regulated multiple genes associated with glucose metabolism in skeletal muscles, and therefore may play a role in the management and prevention of T2DM.

Transcriptomic and Chemical Analyses Reveal the Hub Regulators of Flower Color Variation from Camellia japonica Bud Sport

Camellia japonica is a woody ornamental plant with multiple flower color variations caused by bud sport; however, the molecular mechanism remains unclear. Here, chemical and transcriptomic analyses of C. japonica were performed with white, pink, red, and dark red flowers caused by bud sport. Seven anthocyanins were detected in these samples, except in C. japonica ‘YuDan’ (white petals). The total anthocyanin content of C. japonica ‘JinBiHuiHuang’ was the highest, and cyanidin 3-O-β-glucoside (Cy3G) was the main anthocyanin affecting the redness of petals. Furthermore, the ratio of Cy3G and cyanidin-3-O-(6-O-(E)-p-coumaroyl)-B-glucoside) was significantly correlated with the red petal phenotype. In total, 5673 genes were identified as differentially expressed genes (DEGs). The potential co-expression modules related to anthocyanin accumulation were established, which featured transcription factors, anthocyanin biosynthesis, and plant hormone signal transduction. Thirteen structural genes in the anthocyanin biosynthetic pathway were identified as DEGs, most of them were upregulated with deepening of flower redness. An integrated promoter and cluster analysis suggested that CjMYB62, CjMYB52, and CjGATA may play important roles in anthocyanin accumulation. These results provide insight and candidate genes for the transcriptional mechanism responsible for the bud sport phenotype.

Cyanidin-3-O-β-glucoside inactivates NLRP3 inflammasome and alleviates alcoholic steatohepatitis via SirT1/NF-κB signaling pathway

Alcoholic liver disease (ALD) is a major cause of liver disease worldwide. In patients with ALD, an increased level of hepatic inflammasome components was observed, together with an increased circulating pro-inflammatory cytokines. Cyanidin-3-O-β-glucoside (Cy-3-G) is a bioactive compound belonging to the anthocyanin group, which widely exists in deep-colored fruits and vegetables. Consumption of Cy-3-G is associated with lower risks of non-alcoholic fatty liver disease (NAFLD), liver fibrosis, obesity, atherosclerosis, and inflammation. However, whether Cy-3-G has effects on inflammasome formation and activation thereby protects against alcohol-induced liver damage remain elusive. In this study, we identified that dietary provision of Cy-3-G remarkably attenuated liver damage caused by excess energy intake and alcohol consumption. Supplement with Cy-3-G mediated NAD+ homeostasis, which stimulated SirT1 activity, resulting in suppressed NF-κB acetylation. Interestingly, Cy-3-G treatment suppressed NF-κB acetylation when SirT1 action was blunted by selective antagonist, and subsequently suppressed NLRP3 inflammasome activation and proinflammatory cytokines release in hepatic cell lines. Our findings first demonstrate that Cy-3-G at a physiologically achievable dosage alleviates alcohol-induced hepatic inflammation via inactivation of NLRP3 inflammasome and deacetylation of NF-κB, suggesting a promising therapeutic approach to alleviate alcohol-induced liver damage.

Sirtuin 6 (SIRT6) Content and Hypoxia‐Inducible Factor 1‐Alpha (HIF‐1α) Expression in Human Umbilical Vein Endothelial Cells (HUVECs) in Response to Cyanidin‐3‐O‐ β‐glucoside (C3G): Pregnancy Complicated by Diabetes (PCD) vs. Normoglycemic Pregnancy (NP)

Diabetes during pregnancy induces chronic hypoxia stress and excessive inflammatory response in placental tissue, particularly evident at the endothelial level. Hypoxia‐inducible factor 1‐alpha (HIF‐1α) is the oxygen‐sensitive subunit of the transcription factor HIF‐1, and its expression is increased in placentas from PCD. SIRT6, a chromatin‐associated protein with both histone deacetylase and mono‐ADP ribosyltransferase enzymatic activities, plays an important role in placental development and homeostasis. SIRT6 is believed to protect cells against oxidative stress, however, this mechanism of action in the human placenta has not been clarified enough. According to recent studies, SIRT6 may act as as a corepressor of the transcription factor HIF1α to control the expression of multiple glycolytic genes to regulate glucose homeostasis. A typical anthocyanin, C3G, a naturally occuring pigment belonging to the group of flavonoids (a subclass of the polyphenol family) was found to be potent SIRT6 activator. The aim of this study was to examine comparatively the effect of C3G on SIRT6 level in HUVECs isolated after PCD (White’s class C) vs. NP. In addition, HIF‐1α expressions were compared. HUVECs were isolated immediately after cesarean section delivery from PCD (N = 24) and NP (N = 24) patients (group I and group II, respectively). The umbilical cord segments was subjected to collagenase digestion and the HUVECs were cultured in vitro under normoxia. Upon reaching confluence, HUVECs were exposed to C3G (0.1, 1.0 and 10 μM) administered into the culture media in the respective subgroups A, B and C during the 7 day period. SIRT6 levels were determined in HUVECs culture lysates obtained in the days 1,3 and 7, using ELISA. After termination of the cultures immunostaining for HIF1α was performer with polyclonal antibody in formalin fixed and paraffin embedded sections. To estimate the mean expression of HIF1α, quantitative immunohostochemistry was applied. The initial HIF1α expression was estimated in the respective controls. After 3 and 7 days of the culture, in both groups the mean SIRT6 levels were significantly (p < 0.05) higher in the subgroups B and C, compared to the initial levels at day 1. However, the mean SIRT6 levels in group I were 5.7‐fold and 2.9‐fold lower (the subgroups B and C, respectively) than observed in euglycemic group II. The initial expression of HIF1α was significantly higher in PCD and amounted to 265% of the average value determned in NP (group II). The mean expression of HIF1α was significantly (p < 0.05) downregulated in group I (the subgroups B and C), whereas in group II was nearly unaffected. These results may suggest potential beneficial effect of SIRT6 activation by C3G in PCD with regard to counteracting oxidative stress and modulation of placental metabolic changes at endothelial level. It is likely that by attenuating HIF1α transcriptional output, SIRT6 promotes mitochondrial oxidative metabolism.Support or Funding InformationWUM grant: 2M2‐W1‐19

The Influence of Chemical Structure and the Presence of Ascorbic Acid on Anthocyanins Stability and Spectral Properties in Purified Model Systems.

The loss of color pigment is an important quality factor of food products. This work aimed to systematically study, in purified model systems, the influence of anthocyanins’ structure (by increasing the size of the conjugated sugar) and the presence of ascorbic acid on their stability and spectral properties during storage at two pH levels relevant to medium and high acid foods (6.5 and 4.5, respectively). Anthocyanins (cyanidin (Cy), cyanidin 3-O-β-glucoside (Cy3G) and cyanidin 3-O-β-rutinoside (Cy3R)) displayed first-order degradation rates, presenting higher stability in acidic medium and enhanced stability with increasing size of conjugated sugar. The addition of ascorbic acid resulted in significantly enhanced degradation. Changes in ultra violet visible (UV-VIS) spectral properties presented a decrease in typical color intensity and pointed towards formation of degradation products. Identification and kinetics of formation for cyanidin degradation products were obtained by high performance liquid chromatography system-mass spectrometry (HPLC-MS).

The effects of supplementation with blueberry, cyanidin-3-O-β-glucoside, yoghurt and its peptides on obesity and related comorbidities in a diet-induced obese mouse model

Abstract It is widely acknowledged that type 2 diabetes mellitus (T2DM) is associated with obesity, insulin resistance and hypertension. Cyanidin-3-O-β-glucoside (C3G), an anthocyanin in blueberry, and peptides with angiotensin converting enzyme (ACE) inhibitory activity derived from yoghurt are potentially beneficial for numerous health conditions including improving insulin resistance and glucose intolerance. In this study, the synergistic/additive effects of combined supplementations with blueberry and yoghurt, and C3G and peptides were determined. Blueberry and yoghurt alone, and the combination of C3G and peptides significantly reduced both systolic and diastolic blood pressure in diet-induced obese mice. Yoghurt supplementation significantly reduced body weight, percentage body fat and improved intraperitoneal glucose tolerance. Furthermore, peptides and the combination of peptides and C3G resulted in a significant reduction of percentage body fat and improved intraperitoneal glucose tolerance. As widely available, safe and nutritious foods, blueberry and yoghurt showed therapeutic potential in the treatment of obesity, diabetes and hypertension.

The effect of cyanidin-3-O-β-glucoside and peptides extracted from yoghurt on glucose uptake and gene expression in human primary skeletal muscle myotubes from obese and obese diabetic participants

Incidence of type II diabetes mellitus (T2DM) is rapidly increasing worldwide. This study aimed to investigate whether cyanidin-3-O-β-glucoside (C3G), or peptides with angiotensin converting enzyme (ACE) inhibitory activity, alone or in combination, alter glucose regulation in human primary myotubes derived from obese and obese T2DM participants. In the obese group, both low and high concentration of peptides and the combination of these peptides with high C3G concentration significantly enhanced glucose uptake in the presence or absence of insulin, and high concentration of peptide alone and its combination with low C3G down-regulated the mRNA expression of angiotensin II receptor, type 1 (AGTR-1), and up-regulated the mRNA expression of insulin receptor substrate 1 (IRS-1), and glucose transporter 4 (GLUT4). However, only high peptide concentration increased glucose uptake in the absence of insulin in the obese T2DM group, and the expression of AGTR-1 was decreased with high peptide and its combinations of C3G.

Cyanidin-3-O-β-glucoside regulates the activation and the secretion of adipokines from brown adipose tissue and alleviates diet induced fatty liver

Cyanidin-3-O-β-glucoside (Cy-3-G) the most abundant monomer of anthocyanins has multiple protective effects on many diseases. To date, whether Cy-3-G could regulate the function of brown adipose tissue (BAT) is still unclear and whether this regulation could influence the secretion of adipokines from BAT to prevent non-alcoholic fatty liver disease (NAFLD) indirectly remains to be explored. In this study we investigated the effect of Cy-3-G on BAT and the potential role of Cy-3-G to prevent fatty liver through regulating the secretion of BAT. Male C57BL/6 J mice were fed with a high fat high cholesterol (HFC) diet with or without 200 mg/kg B.W Cy-3-G for 8 weeks. In in vitro experiments, the differentiated brown adipocytes (BAC) and C3H10T1/2 clone8 cells were treated with 0.2 mM palmitate with or without Cy-3-G for 72 or 96 h. Then the culture media of C3H10T1/2 clone8 cells were collected for measuring the adipokines secretion by immunoblot assay and were applied to culture HepG2 cells or LO2 cells for 24 h. Lipid accumulation in HepG2 cells or LO2 cells were evaluated by oil red O staining. Here we found that Cy-3-G regulated the activation of BAT and the expression of adipokines in BAT which were disrupted by HFC diet and alleviated diet induced fatty liver in mice. In in vitro experiments, Cy-3-G inhibited the release of adipokines including extracellular nicotinamide phosphoribosyltransferase (eNAMPT) and fibroblast growth factor 21 (FGF21) from differentiated C3H10T1/2 clone8 cells induced by palmitate, which was accompanied by a reduction of lipid accumulation in HepG2 cells and LO2 cells cultured by the corresponding collected media of C3H10T1/2 clone8 cells. These results indicate that Cy-3-G can regulate the thermogenic and secretory functions of BAT. Furthermore, our data suggest that the protective effect of Cy-3-G on hepatic lipid accumulation is probably via regulating the secretion of adipokines from BAT.

Cyanidin-3-O-β-glucoside protects against liver fibrosis induced by alcohol via regulating energy homeostasis and AMPK/autophagy signaling pathway

Cyanidin-3-O-β-glucoside (Cy-3-G) has protective properties in many diseases. Whether Cy-3-G has protective effects on alcohol induced liver injuries remains uncertain. In our study, mice were fed with a high fat high cholesterol diet (HFC) plus ethanol for 12weeks. Cy-3-G supplementation reversed the liver damage induced by alcohol. In vitro studies, Cy-3-G restored the intracellular energy status of LX-2 cells and inhibited the activation of LX-2 cells induced by ethanol plus palmitate. The protective effect of Cy-3-G is via the increase of AMPK phosphorylation and autophagy. In conclusion, Cy-3-G ameliorated chronic alcoholic liver injuries, possibly by improving energy metabolic status. Specifically, liver fibrosis was protected by Cy-3-G via inhibiting the activation of stellate cells, which was mediated partially by AMPK/autophagy signaling pathway.

Interaction between Mimic Lipid Membranes and Acylated and Nonacylated Cyanidin and Its Bioactivity.

We investigated the effects of acylated cyanidin-3-O-β-(6″-O-E-p-coumaroyl-sambubioside)-5-O-β-glucoside (C3-cs-5G) and nonacylated cyanidin, cyanidin-3,5-di-O-β-glucoside (C3,5G) and cyanidin-3-O-β-glucoside (C3G), on cell-mimic membranes (MM) that reflected the membrane lipid composition of tumor cells. The relationship between structural derivatives of cyanidin (Cy-d), membrane interactivity, their antioxidant activity, and interaction with albumin were characterized. Studies showed that Cy-d caused an increase in packing order mainly in the hydrophilic region of the membranes. Cy-d have shown high antioxidant activity against liposome oxidation induced by AAPH and ability to bind to albumin through a static quenching mechanism. The results showed that glycosylation number and the presence of aromatic acid attached to sugars affected the membrane properties, according to the sequence C3-cs-5G > C3,5G > C3G. It can be stated that Cy-d in the process of interaction with MM caused a rigidifying effect, which is fundamental for understanding their anticancer and antioxidant activity and is one of the possible pharmaceutical mechanisms.

Procyanidin Promotes Translocation of Glucose Transporter 4 in Muscle of Mice through Activation of Insulin and AMPK Signaling Pathways

Procyanidins are the oligomeric or polymeric forms of epicatechin and catechin. In this study, we isolated and purified dimer to tetramer procyanidins from black soybean seed coat and investigated the anti-hyperglycemic effects by focusing on glucose transporter 4 (GLUT4) translocation and the underlying molecular mechanism in skeletal muscle of mice. The anti-hyperglycemic effects of procyanidins were also compared with those of monomer (−)-epicatechin (EC) and major anthocyanin, cyanidin-3-O-β-glucoside (C3G). To investigate GLUT4 translocation and its related signaling pathways, ICR mice were orally given procyanidins, EC and C3G in water at 10 μg/kg body weight. The mice were sacrificed 60 min after the dose of polyphenols, and soleus muscle was extracted from the hind legs. The results showed that trimeric and tetrameric procyanidins activated both insulin- and AMPK-signaling pathways to induce GLUT4 translocation in muscle of ICR mice. We confirmed that procyanidins suppressed acute hyperglycemia with an oral glucose tolerance test in a dose-dependent manner. Of these beneficial effects, cinnamtannin A2, one of the tetramers, was the most effective. In conclusion, procyanidins, especially cinnamtannin A2, significantly ameliorate postprandial hyperglycemia at least in part by promoting GLUT4 translocation to the plasma membrane by activating both insulin- and AMPK-signaling pathways.

Cyanidin 3-O-β-Glucoside Ameliorates Ethanol-Induced Acute Liver Injury by Attenuating Oxidative Stress and Apoptosis: The Role of SIRT1/FOXO1 Signaling.

The aim of this study was to examine the effects of Cyanidin 3-O-β-glucoside (C3G) on ethanol (EtOH)-induced acute liver injury in mice as well as in cultured hepatic cells exposed to EtOH, with a focus on the involvement of Silent Mating Type Information Regulation 2 Homolog 1 (SIRT1)/Forkhead fox-O-1 (FOXO1) signaling pathway, and to explore the underlying molecular mechanisms. C57BL/6 adolescent male mice were given EtOH via intraperitoneal injection for 2 consecutive days, and the changes in the livers were detected via hematoxylin-eosin staining. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured by biochemical methods. Protein expression of SIRT1, FOXO1, acetylated FOXO1 (ac-FOXO1), GRP78, p-eukaryotic initiation factor-2 (eIF2α), and apoptosis (p-JNK, p-c-Jun, and Bax) parameters was determined by Western blot. Reactive oxygen species (ROS) was detected by flow cytometry. Human hepatocytes Chang cell line was used to assay cell apoptosis by Annexin V and propidium iodide.In addition, mRNA levels of SIRT1, tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and monocyte chemoattractant protein 1 in liver tissues were detected by real-time polymerase chain reaction. This study demonstrated that C3G (10mg/kg) administration diminished EtOH-induced acute liver injury compared to control group, as evidenced by the significant decreases in ALT and AST levels. Pretreatment with C3G exerted anti-inflammatory effects as indicated by the decreased TNF-α and IL-6 levels, as well as decreased inflammatory foci and ballooning cells in liver tissue. The lessened hepatic injury was associated with enhancedSIRT1protein expression and activity by C3Gin vitro and in vivo. C3G treatment also provoked significant attenuation of endoplasmic reticulum stress parameters (GRP78, p-eIF2α), which was consistent with reduced levels of both p-c-Jun and Bax. Interestingly, EX527 inhibitor did not affect the protective function of C3G on alcohol-induced cell apoptosis. Moreover, alcohol exposure increased ROS level and decreased ac-FOXO1, while C3G intervention reversed this abnormality, and this may be related to SIRT1activity by C3G. Anthocyanin C3G has significant potency in antioxidant, anti-inflammatory, and anti-apoptotic effects on hepatocytes exposed to EtOH by modulating the SIRT1/FOXO1 signaling pathway. Our findings illustrate a novel and definitive therapeutic action of C3G and represent an economically feasible therapeutic intervention to treat alcoholic liver disease.

Cyanidin-3-O-β-glucoside and protocatechuic acid activate AMPK/mTOR/S6K pathway and improve glucose homeostasis in mice

AMP-activated protein kinase (AMPK) activation is an established treatment for diabetes. Here the effects of anthocyanin extract from blood orange juice, i.e. cyanidin-3-O-β-glucoside (C3G) and its secondary metabolite protocatechuic acid (PCA), on AMPK signalling in murine hepatic cell line and in the liver of C57BL/6 mice were investigated. Results showed for the first time that C3G and PCA activate AMPK and suppress its downstream kinase mTOR/S6K both in vitro and in vivo systems. Then, C3G and particularly PCA increased expression of glut 1 and glut 4 in the liver and improved glucose tolerance in normal and obese mice. Finally, the consumption of blood orange juice was observed to increase insulin sensitivity in mice. These findings indicate that C3G and PCA are natural AMPK activators and dietary consumption of food sources of C3G and PCA improves glucose homeostasis. Mainly, blood orange juice has beneficial effect for type 2 diabetes.

Cyanidin-3-O-β-glucoside Purified from Black Rice Protects Mice against Hepatic Fibrosis Induced by Carbon Tetrachloride via Inhibiting Hepatic Stellate Cell Activation

This study investigated whether cyanidin-3-O-β-glucoside (Cy-3-G), a predominant anthocyanin, could exert a protective role on liver injury and its further mechanisms of the anti-fibrosis actions in mice. The results demonstrated that the treatment of Cy-3-G (800 mg/kg diet) for 8 weeks significantly attenuated hepatotoxicity and fibrosis in carbon tetrachloride (CCl4) administered mice. Cy-3-G strongly down-regulated the expression of α-smooth muscle actin (α-SMA), desmin, and matrix metalloproteinase (MMPs), which showed its suppression effect on the activation of hepatic stellate cells (HSCs). In addition, Cy-3-G favorably regulated oxidative stress and apoptosis in liver. Furthermore, Cy-3-G ameliorated the infiltration of inflammatory cells such as neutrophils and leukocytes and meanwhile suppressed the production of pro-inflammatory cytokines and growth factors. In conclusion, daily intake of Cy-3-G could prevent liver fibrosis progression in mice induced by CCl4 through inhibiting HSC activation, which provides a basis for clinical practice of liver fibrosis prevention.

The Role of Sodium-Dependent Glucose Transporter 1 and Glucose Transporter 2 in the Absorption of Cyanidin-3-O-β-Glucoside in Caco-2 Cells

Anthocyanins have multiple biological activities of benefit to human health. While a few studies have been conducted to evaluate the bioavailability of anthocyanins, the mechanisms of their absorption mechanism remain ill-defined. In the present study, we investigated the absorption mechanism of cyanidin-3-O-β-glucoside (Cy-3-G) in human intestinal epithelial (Caco-2) cells. Cy-3-G transport was assessed by measuring the absorptive and efflux direction. Inhibition studies were conducted using the pharmacological agents, phloridzin, an inhibitor of sodium-dependent glucose transporter 1 (SGLT1), or phloretin, an inhibitor of glucose transporter 2 (GLUT2). The results showed that phloridzin and phloretin significantly inhibited the absorption of Cy-3-G. In addition, Caco-2 cells transfected with small interfering RNA (siRNA) specific for SGLT1 or GLUT2 showed significantly decreased Cy-3-G absorption. These siRNA transfected cells also showed a significantly decreased rate of transport of Cy-3-G compared with the control group. These findings suggest that Cy-3-G absorption is dependent on the activities of SGLT1 and GLUT2 in the small intestine and that SGLT1 and GLUT2 could be a limiting step for the bioavailability of Cy-3-G.

Cyanidin-3-O-β-glucoside inhibits lipopolysaccharide-induced inflammatory response in mouse mastitis model

Cyanidin-3-O-β-glucoside (C3G) (CAS number 7084-24-4), a typical anthocyanin pigment that exists in the human diet, has been reported to have anti-inflammatory properties. However, the effect of C3G on lipopolysaccharide (LPS)-induced mastitis and the molecular mechanisms have not been investigated. In this study, we detected the protective effects of C3G on a LPS-induced mouse mastitis model and investigated the molecular mechanisms in LPS-stimulated mouse mammary epithelial cells (MMECs). Our results showed that C3G could attenuate mammary histopathologic changes and myeloperoxidase activity, and inhibit TNF-α, interleukin (IL)-1β, and IL-6 production caused by LPS. Meanwhile, C3G dose-dependently inhibited TNF-α and IL-6 in LPS-stimulated MMECs. C3G suppressed LPS-induced nuclear factor-κB (NF-κB) and interferon regulatory factor 3 (IRF3) activation. Furthermore, C3G disrupted the formation of lipid rafts by depleting cholesterol. Moreover, C3G activated liver X receptor (LXR)-ABCG1-dependent cholesterol efflux. Knockdown of LXRα abrogated the anti-inflammatory effects of C3G. In conclusion, C3G has a protective effect on LPS-induced mastitis. The promising anti-inflammatory mechanisms of C3G are associated with upregulation of the LXRα-ABCG1 pathway which result in disrupting lipid rafts by depleting cholesterol, thereby suppressing toll-like receptor 4-mediated NF-κB and IRF3 signaling pathways induced by LPS.

Cyanidin-3-O-β-glucoside ameliorates lipopolysaccharide-induced acute lung injury by reducing TLR4 recruitment into lipid rafts

Cyanidin-3-O-β-glucoside (C3G), a typical anthocyanin pigment that exists in the human diet, has been reported to have anti-inflammatory properties. The aim of this study was to detect the effect of C3G on LPS-induced acute lung injury and to investigate the molecular mechanisms. Acute lung injury was induced by intratracheal administration of LPS in mice. Alveolar macrophages from mice were stimulated with LPS and were treated with C3G. Our results showed that C3G attenuated lung histopathologic changes, myeloperoxidase (MPO) activity, TNF-α, IL-1β and IL-6 production in LPS-induced acute lung injury model. In vitro, C3G dose-dependently inhibited TNF-α, IL-1β, IL-6, IL-10 and IFN-β production, as well as NF-κB and IRF3 activation in LPS-stimulated alveolar macrophages. Furthermore, C3G disrupted the formation of lipid rafts by depleting cholesterol and inhibited TLR4 translocation into lipid rafts. Moreover, C3G activated LXRα-ABCG1-dependent cholesterol efflux. Knockout of LXRα abrogated the anti-inflammatory effects of C3G. In conclusion, C3G has a protective effect on LPS-induced acute lung injury. The promising anti-inflammatory mechanisms of C3G is associated with up-regulation of the LXRα-ABCG1 pathway which result in disrupting lipid rafts by depleting cholesterol and reducing translocation of TLR4 to lipid rafts, thereby suppressing TLR4 mediated inflammatory response.

Cyanidin-3-O-β-glucoside protects primary mouse hepatocytes against high glucose-induced apoptosis by modulating mitochondrial dysfunction and the PI3K/Akt pathway

Apoptosis is an early event of steatohepatitis in non-alcoholic fatty liver disease (NAFLD), and an increase in oxidative stress induced by hyperglycemia has been linked to an acceleration of apoptosis in hepatocytes. Cyanidin-3-O-β-glucoside (C3G), a classic anthocyanin, has been reported to reduce oxidative stress and attenuate non-alcoholic steatohepatitis in mice. In this study, we evaluated the toxicity of high glucose in primary hepatocytes of mice fed with a high fat diet and amelioration of this toxicity by C3G. Incubation of hepatocytes with 35mM glucose for 12h resulted in a significant decrease in cell viability and increase in apoptotic cell death. Furthermore, hyperglycemia-induced mitochondrial depolarization was accompanied by the release of cytochrome c and altered expression of Bax and Bcl-2, suggesting a mitochondria-mediated apoptotic mode of cell death. Pre-incubation with 50μM C3G induced changes associated with better cell survival and function, including a reduction in reactive species generation, improvement of mitochondrial membrane potential, inactivation of caspase-3 and -9, and down-regulation of the pro-apoptotic Bax protein. We further investigated the role of the phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinases (MAPKs) pathways with respect to the anti-apoptotic action of C3G, and our results showed that C3G could activate Akt. Additionally, C3G inactivated c-Jun N-terminal protein kinase (JNK), but not extracellular signal-regulated kinase or p38 MAPK, in glucose-stressed cells. Interestingly, JNK inhibitor enhanced the protective effect of C3G on cell survival. Our results suggest that anthocyanin C3G may exhibit hepatoprotective potential against NAFLD by promoting functional integrity and survival of hepatocytes.