Anthocyanidins Cyanidin Research Articles

The Anthocyanidin Peonidin Interferes with an Early Step in the Fibrillation Pathway of α-Synuclein and Modulates It toward Amorphous Aggregates.

Parkinson's disease (PD) is characterized by progressive degeneration of the dopaminergic neurons in the brain, accompanied by the accumulation of proteinaceous inclusions, Lewy bodies (LB), mainly comprised of alpha synuclein (α-syn) aggregates. The heterogeneity and the transient nature of the intermediate species formed in the α-syn fibrillation pathway have made it difficult to develop an effective therapeutic intervention. Therefore, any therapeutic molecule that could prevent as well as treat PD would be of great interest. Anthocyanidins are natural flavonoid compounds that have been shown to have neuroprotective properties and to modulate factors that cause neuronal death. Herein, we have explored the modulation and inhibition of α-syn fibrillation by the anthocyanidins cyanidin, delphinidin, and peonidin using a number of biophysical and structural tools. α-Syn fibrillation monitored using thioflavin T (ThT) fluorescence and light scattering suggested concentration dependent inhibition of α-syn fibrillation by all the three anthocyanidins. While cyanidin and delphinidin induced the formation of oligomers and small fibrillar structures of α-syn, respectively, peonidin led to the formation of amorphous aggregates, as observed by Atomic Force Microscopy (AFM). Peonidin proved to be most effective of the three anthocyanidins toward alleviating cell toxicity of SH-SY5Y neuroblastoma cells at concentrations where α-synuclein fibrillation was completely suppressed. Hence, the inhibition mechanism of peonidin was further explored by studying its interaction with α-syn using titration calorimetry and molecular docking. The results show its weak binding (in mM range) to the NAC region of α-syn through hydrogen bonding interactions. Also, circular dichroism and Raman spectroscopy revealed the structural aspects of peonidin-induced α-syn amorphous aggregates showing alpha helical structures with exposed Phe and Tyr regions. Due to the neuroprotective nature of peonidin, the findings reported here are significant and can be further explored toward developing a modifying therapy that could address both disease onset as well as the progression of PD.

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).

In vitro and cellular antioxidant activities of 3-deoxyanthocyanidin colourants

3-Deoxyanthocyanidins are a rare type of plant colourant with potential high antioxidant activity. This study investigated the in vitro and cellular antioxidant activity of four 3-deoxyanthocyanidins: apigeninidin, 7-methoxy-apigeninidin, luteolinidin and 5,7-dimethoxy-luteolinidin, compared to a common anthocyanidin: cyanidin, and several well-known antioxidants. The aim was to understand the antioxidant potency of 3-deoxyanthocyanidins and their structure-activity relationships. The 3-deoxyanthocyanidin luteolinidin and 5,7-dimethoxy-luteolinidin and the anthocyanidin cyanidin consistently demonstrated significantly high antioxidant activity in all assays. The results showed that the antioxidant activity of 3-deoxyanthocyanidins was highly structurally dependent. The A-ring OCH3, B-ring catechol and C-ring C3–OH groups all had significant influences on the antioxidant activity, and the B-ring catechol group was essential for high antioxidant activity of 3-deoxyanthocyanidins in all the assays. This was the first study evaluating the cellular antioxidant activity of 3-deoxyanthocyanidins, and the results suggested that luteolinidin and 5,7-dimethoxy-luteolinidin might be good candidates for development as antioxidant supplements.

LC–MS/MS and UPLC–UV Evaluation of Anthocyanins and Anthocyanidins during Rabbiteye Blueberry Juice Processing

Blueberry juice processing includes multiple steps and each one affects the chemical composition of the berries, including thermal degradation of anthocyanins. Not-from-concentrate juice was made by heating and enzyme processing blueberries before pressing, followed by ultrafiltration and pasteurization. Using LC–MS/MS, major and minor anthocyanins were identified and semi-quantified at various steps through the process. Ten anthocyanins were identified, including 5 arabinoside and 5 pyrannoside anthocyanins. Three minor anthocyanins were also identified, which apparently have not been previously reported in rabbiteye blueberries. These were delphinidin-3-(p-coumaroyl-glucoside), cyanidin-3-(p-coumaroyl-glucoside), and petunidin-3-(p-coumaroyl-glucoside). Delphinidin-3-(p-coumaroyl-glucoside) significantly increased 50% after pressing. The five known anthocyanidins—cyanidin, delphinidin, malvidin, peonidin, and petunidin—were also quantitated using UPLC–UV. Raw berries and press cake contained the highest anthocyanidin contents and contribute to the value and interest of press cake for use in other food and non-food products. Losses of 75.7% after pressing and 12% after pasteurization were determined for anthocyanidins during not-from-concentrate juice processing.

Correlation between the potency of flavonoids for cytochrome c reduction and inhibition of cardiolipin-induced peroxidase activity.

There are large differences between flavonoids to protect against apoptosis, a process in which cytochrome c (Cyt c) plays a key role. In this work, we show that 7 of 13 flavonoids studied have a capacity to reduce Cyt c similar or higher than ascorbate, the flavonols quercetin, kaempferol and myricetin, flavanol epigallocatechin-gallate, anthocyanidins cyanidin and malvidin, and the flavone luteolin. In contrast, the kaempferol 3(O)- and 3,4'(O)-methylated forms, the flavanone naringenin, and also apigenin and chrysin, had a negligible reducing capacity. Equilibrium dialysis and quenching of 1,6-diphenyl-1,3,5-hexatriene fluorescence experiments showed that flavonoids did not interfere with Cyt c binding to cardiolipin (CL)/phosphatidylcholine (PC) vesicles. However, the CL-induced loss of Cyt c Soret band intensity was largely attenuated by flavonoids, pointing out a stabilizing action against Cyt c unfolding in the complex. Moreover, flavonoids that behave as Cyt c reductants also inhibited the pro-apoptotic CL-induced peroxidase activity of Cyt c, indicating that modulation of Cyt c signaling are probable mechanisms behind the protective biological activities of flavonoids. © 2016 BioFactors, 43(3):451-468, 2017.

In vitro effects of anthocyanidins on sinonasal epithelial nitric oxide production and bacterial physiology.

T2R bitter taste receptors play a crucial role in sinonasal innate immunity by upregulating mucociliary clearance and nitric oxide (NO) production in response to bitter gram-negative quorum-sensing molecules in the airway surface liquid. Previous studies showed that phytochemical flavonoid metabolites, known as anthocyanidins, taste bitter and have antibacterial effects. Our objectives were to examine the effects of anthocyanidins on NO production by human sinonasal epithelial cells and ciliary beat frequency, and their impact on common sinonasal pathogens Pseudomonas aeruginosa and Staphylococcus aureus. Ciliary beat frequency and NO production were measured by using digital imaging of differentiated air-liquid interface cultures prepared from primary human cells isolated from residual surgical material. Plate-based assays were used to determine the effects of anthocyanidins on bacterial swimming and swarming motility. Biofilm formation and planktonic growth were also assessed. Anthocyanidin compounds triggered epithelial cells to produce NO but not through T2R receptors. However, anthocyanidins did not impact ciliary beat frequency. Furthermore, they did not reduce biofilm formation or planktonic growth of P. aeruginosa. In S. aureus, they did not reduce planktonic growth, and only one compound had minimal antibiofilm effects. The anthocyanidin delphinidin and anthocyanin keracyanin were found to promote bacterial swimming, whereas anthocyanidin cyanidin and flavonoid myricetin did not. No compounds that were tested inhibited bacterial swarming. Results of this study indicated that, although anthocyanidins may elicited an innate immune NO response from human cells, they do not cause an increase in ciliary beating and they may also cause a pathogenicity-enhancing effect in P. aeruginosa. Additional studies are necessary to understand how this would affect the use of anthocyanidins as therapeutics. This study emphasized the usefulness of in vitro screening of candidate compounds against multiple parameters of both epithelial and bacterial physiologies to prioritize candidates for in vivo therapeutic testing.

Protective Effect of Anthocyanidins on Astrocytes and Apoptosis Induced by Oxidative Damage

As a result of the longer life expectancy in the human population, neurodegenerative diseases are increasing, so finding effective treatments together with prevention strategies are urgently needed. Anthocyanins are polyphenolic compounds from vegetal species that have shown strong antioxidant and anti-inflammatory activities in various experimental models. The effect of the anthocyanidins cyanidin, malvidin, and pelargonidin at different concentrations (5 to 100 µM) on experimental models of cell oxidation and apoptosis was studied and compared with the positive control Trolox. The human astrocyte glioblastoma, cellular line U373, was used for a cellular injury model using Fentonʼs reagent (0.5 mM FeSO 4 /1 mM H 2 O 2 ) and to measure the lactate dehydrogenase enzyme activities and lipid peroxidation level (thiobarbituric acid reactive substances) by fluorimetric analysis and malondialdehyde release by HPLC. Also, caspase 3, 8, and 9 activities were measured by fluorimetric analysis. The results show that the studied anthocyanidins are able to revert the induced apoptosis related to caspase activation and lipid peroxidation. All the assayed anthocyanidins significantly decreased the activation of caspases 8 and 3, although malvidin and cyanidin increased the activity of caspase 9 when compared to non-treated cells.

Neuroprotective effects of anthocyanidins on astrocytes and apoptosis induced by oxidative damage

As a result of the longer life expectancy in human population, neurodegenerative diseases such as Alzheimer's or Parkinson's diseases are increasing so the finding of effective treatments together with prevention strategies are urgently needed. Anthocyanins are polyphenolic compounds that can be found in several vegetal species and have shown strong antioxidant and anti-inflammatory activities in various experimental models. The effect of the anthocyanidins cyanidin, malvidin and pelargonidin at different concentrations (5 to 100µM) on experimental models of cell oxidation and apoptosis is studied. The human astrocyte glioblastoma, cellular line U373, was used for a cellular injury model using Fenton's reagent (FeSO4 0,5 mM/H2O2 1 mM) and to measure the lactate dehydrogenase (LDH) enzyme activities and lipid peroxidation level (thiobarbituric acid reactive substances -TBARS) by fluorimetric analysis and malondialdehyde (MDA) release by HPLC)[1]. Also, caspase-3, -8 and -9 activities were measured by flurometric analysis. Results show that the studied anthocyanidins are able to revert the induced apoptosis related to caspase activation (Figure 1) and lipid peroxidation [3] (Figure 2). Cyanidin and pelargonidin at the highest doses induce a direct damage on astrocytes culture, as deduced from the LDH values when compared with non-treated cells; this effect seems to be independent of the protective activity against lipid peroxidation. All the assayed anthocyanidins significantly decrease the activation of caspases 8 and -3 previously induced by H2O2 (500µM), however malvidin and cyanidin increased the activation of caspase-9 when compared to non-treated cells; nonetheless, this increased activity was not related to an increase in performer caspase-3 which could be related to other cell homeostatic functions different from apoptosis induction in cells studied [2].

Protective effects of common anthocyanidins against genotoxic damage induced by chemotherapeutic drugs in mice.

Experiments were performed to assess in mice the inhibitory effects of the anthocyanidins cyanidin, delphinidin, malvidin, and pelargonidin on genotoxic damage induced by the anticancer drugs cyclophosphamide, procarbazine, and cisplatin. Each anthocyanidin was administered 30 min before injecting the drug, and genotoxicity was assessed by measuring micronucleated polychromatic erythrocytes in bone marrow cells. In addition, we monitored the effect of anthocyanidins on apoptosis induced by cyclophosphamide and procarbazine. The results showed significant protective effects of cyanidin, delphinidin, malvidin, and pelargonidin against DNA damage induced by cyclophosphamide. With delphinidin and malvidin, a biphasic dose-response was observed for protection against cyclophosphamide. Dose-related reduction of genotoxicity was observed with pelargonidin against procarbazine. However with cyanidin, the medium dose of 2 mg/kg showed maximum protection against procarbazine. Cyanidin and pelargonidin significantly reduced the chromosomal damage induced by cisplatin. Furthermore, pre-treatment with these anthocyanidins reduced the level of apoptosis induced by cyclophosphamide and procarbazine. In conclusion, this study shows that anthocyanidins can reduce the efficacy of anticancer drugs for inducing DNA damage and apoptosis.

Not all anthocyanins are born equal: distinct patterns induced by stress in Arabidopsis.

Main Conclusion Different abiotic stress conditions induce distinct sets of anthocyanins, indicating that anthocyanins have different biological functions, or that decoration patterns of each anthocyanin are used for unique purposes during stress. The induction of anthocyanin accumulation in vegetative tissues is often considered to be a response of plants to biotic or abiotic stress conditions. Arabidopsis thaliana (Arabidopsis) accumulates over 20 anthocyanins derived from the anthocyanidin cyanidin in an organ-specific manner during development, but the anthocyanin chemical diversity for their alleged stress protective functions remains unclear. We show here that, when grown in various abiotic stress conditions, Arabidopsis not only often accumulates significantly higher levels of total anthocyanins, but different stress conditions also favor the accumulation of different sets of anthocyanins. For example, the anthocyanin patterns of seedlings grown at pH 3.3 or in media lacking phosphate are very similar and characterized by relatively high levels of the anthocyanins A8 and A11. In contrast, anthocyanin inductive conditions (AIC) provided by high sucrose media are characterized by high accumulation of A9* and A5 relative to other stress conditions. The modifications present in each condition correlate reasonably well with the induction of the respective anthocyanin modification enzymes. Taken together, our results suggest that Arabidopsis anthocyanin profiles provide ‘fingerprints’ that reflect the stress status of the plants.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-014-2079-1) contains supplementary material, which is available to authorized users.

Anthocyanin profiles in south Patagonian wild berries by HPLC-DAD-ESI-MS/MS

Chilean Patagonia is one of the most beautiful natural scenarios, with a great diversity of habitats and vascular plants, including different berry fruits. There is no scientific information about the polyphenol profiles of most of these fruits, as well as about their potential use as functional food.Samples of 10 different berry species were collected in the Magallanes region in the extreme South of Chile. Their anthocyanin profiles were studied using liquid chromatography with photodiode array and mass spectrometry detection on the basis of retention times, UV and MS/MS spectra. In addition, total anthocyanin concentrations obtained by HPLC-DAD, antioxidant capacity estimated by TEAC (as trolox equivalent), and ascorbic acid contents were determined in these fruits. The studied species differed in their berry anthocyanin profiles and concentrations. In the berries of Berberis genus (Berberis microphylla, Berberis empetrifolia and Berberis ilicifolia), a predominance of delphinidin, petunidin and malvidin 3-glucoside was observed; they are the fruits with the highest total anthocyanin concentration (22.91–35.99, 16.11–21.40 and 13.70μmol/g, respectively). In Ribes magellanicum and Ribes cucullatum, the 3-glucoside and 3-rutinoside derivates of cyanidins predominated, especially for R. cucullatum, showing intermediate total anthocyanin concentrations. The other studied berries (Gaultheria mucronata, Gaultheria antarctica, Rubus geoides, Myrteola nummularia and Fuchsia magellanica) presented as main anthocyanidin cyanidin and/or delphinidin derivates, with lower total concentrations in comparison with the other studied species. Antioxidant activity and especially the ascorbic acid concentration observed in these fruits were higher than those described for other widely consumed berries, reaching levels up to 75.1μmol/g and 198.8mg/100g, respectively. These findings suggest that some of the berry species from Patagonia have an interesting potential to be used as functional food.

Anthocyanidin-containing compounds occur in the periderm cell walls of the storage roots of sweet potato ( Ipomoea batatas)

Anthocyanins, which are O-glycosylated derivatives of anthocyanidins, are responsible for the red, blue and purple coloration of many organs of angiosperms where they have previously been reported to occur in vacuoles and cytoplasm. However, bright-field microscopy of sections of the storage roots of the sweet potato (Ipomoea batatas) clone 99N1/222, which contains high concentrations of anthocyanins, showed that the walls of the periderm cork cells (skin), but not those of the adjacent parenchyma cells, were coloured bright red/purple. In situ absorption spectra of the periderm cell walls were similar to those of methanolic solutions of anthocyanins. Dry cell-wall preparations obtained from the periderm and parenchyma tissues were coloured deep reddish-brown and white, respectively. Pigment was extracted from the periderm cell-wall preparation by treating with 1 M NaOH. Acid hydrolysis of this extract followed by HPLC indicated the presence of the anthocyanidins cyanidin and peonidin. It is concluded that the periderm cell walls contain covalently bound anthocyanidin-containing compounds, possibly anthocyanins.

The citrus flavanone naringenin inhibits inflammatory signalling in glial cells and protects against neuroinflammatory injury

Neuroinflammation plays an integral role in the progression of neurodegeneration. In this study we investigated the anti-inflammatory effects of different classes of flavonoids (flavanones, flavanols and anthocyanidins) in primary mixed glial cells. We found that the flavanones naringenin and hesperetin and the flavanols (+)-catechin and (−)-epicatechin, but not the anthocyanidins cyanidin and pelargonidin, attenuated LPS/IFN-γ-induced TNF-α production in glial cells. Naringenin also inhibited LPS/IFN-γ-induced iNOS expression and nitric oxide production in glial cells, thus showing the strongest anti-inflammatory activity among all flavonoids tested. Moreover, naringenin protected against inflammatory-induced neuronal death in a primary neuronal–glial co-culture system. Naringenin also inhibited LPS/IFN-γ-induced p38 mitogen-activated protein kinase (MAPK) phosphorylation and downstream signal transducer and activator of transcription-1 (STAT-1) in LPS/IFN-γ stimulated primary mixed glial cells. Taken together, our results suggest that naringenin may produce an anti-inflammatory effect in LPS/IFN-γ stimulated glial cells that may be due to its interaction with p38 signalling cascades and the STAT-1 transcription factor.

Natural flavonoids are potent inhibitors of glycogen phosphorylase

There is little known about effects to be expected from high intake of flavonoids with respect to regulation of glucose/glycogen homeostasis. Glucose/glycogen homeostasis is mainly regulated by glycogen synthase (GS) and glycogen phosphorylase (GP). We investigated effects of naturally occurring flavonoids with varying substitution pattern on the activity of isolated muscle GP. Almost all flavonoids tested inhibited phosphorylated, active GPa, as well as unphosphorylated, adenosine monophosphate-activated GPb. However, inhibition of GPa was two-to-fourfold stronger than that of GPb. The flavonol quercetin and the anthocyanidins cyanidin and delphinidin turned out to be the most potent inhibitors of GPa, with concentration values where enzymatic activity is 50% of the respective control in the low micromolar range (<5 microM). Furthermore, by comparing GPa inhibitory activity of typical representatives from all known flavonoid classes, structural elements of flavonoids required for effective GP inhibition could be identified.

Cyanidin and Malvidin from Oryza sativa cv. Heugjinjubyeo Mediate Cytotoxicity against Human Monocytic Leukemia Cells by Arrest of G2/M Phase and Induction of Apoptosis

Oryza sativa cv. Heugjinjubyeo (Gramineae), anthocyanin-pigmented rice, having dark purple grains, is known broadly as enriched rice with an improved taste. Two bioactive compounds were isolated from the 0.5% HCl-ethyl alcohol soluble fraction of the aleurone layer of O. sativa cv. Heugjinjubyeo through an activity-monitored fractionation and isolation method. From spectral analysis, the cytotoxic components were the anthocyanidins cyanidin (1) and malvidin (2) The 50% growth inhibitory concentrations (IC(50)) of cyanidin and malvidin on U937, human monocytic leukemia cells, were 60 and 40 microg/mL, respectively. These compounds showed cytotoxicity through the arrest of the G(2)/M phase of cell cycle and induction of apoptosis.