Anthocyanin

UIDB/05021/2020 UIDP/05021/2020What do jabuticaba (Myrciaria jaboticaba), Jamun berry (Syzygium cumini), Malay apple (Syzygium malaccense), crimson glory vine (Vitis coignetiae) and roselle (Hibiscus sabdariffa) have in common? They are good sources of anthocyanins, and this Special Issue collects different studies showing their characteristics. Anthocyanins are widespread water-soluble pigments that have important roles in the propagation, protection, and physiology of higher plants. Anthocyanins are mainly present in flowers, cereals, and root vegetables, being the greatest in quantity in fruits, especially, grapes and berries. They belong to the polyphenol family and are included in the large class of secondary metabolites known as flavonoids, with a core structure in the form of 2-phenylbenzopyrylium or flavylium cation. Anthocyanins mainly derive from six anthocyanidins (aglycone form): cyanidin, delphinidin, pelargonidin, peonidin, petunidin, and malvidin [1,2]. Environmental factors affect anthocyanin production in plants, and it was shown that anthocyanin amount and profiles change with stress conditions. In this Special Issue, the Hinojosa-Gómez et al. [3] study shows that total anthocyanin content in the roselle (Hibiscus sabdariffa) calyx increases when a moderate water stress irrigation regime (65% moisture) is applied. It was also observed that extreme water stress (33% moisture) during plant development led to a decrease in anthocyanin content in all the roselle cultivars [3]. This study highlights the importance of the agricultural practices in the anthocyanins content towards an increase in plant health-promoting benefits. In the last decades, anthocyanins have caught the interest of industry because they are water-soluble pigments present in high amounts in plants, which display interesting nutraceutical and technological properties. Mattioli et al. [1] summarized for this Special Issue the existing procedures to extract, isolate and characterize anthocyanins. The most frequently employed approach to extract anthocyanins from biological matrices consists in the use of a solvent, being water, ethanol, methanol, acetone, and acetonitrile the more widely used. Natural deep eutectic solvents (NADES) are promising green alternatives to conventional solvents to extract anthocyanins from natural products. NADES represent a green chemistry alternative to organic solvents, and have some advantages, including immediately available components, low cost, easy preparation, low toxicity, and high sustainability. The techniques used to extract anthocyanins are non-selective, so after this procedure, it is necessary to purify them. For aqueous extracts, an effective and cheap purification approach is the absorption of anthocyanins on solid phase extraction. In this technique, dissolved anthocyanins are retained in a resin packed column based on their physicochemical features, and then they are separated from other compounds by increasing the polarity with distinct solvents. After extraction and purification, the chromatographic isolation of anthocyanins can be carried out to characterize their structure. Nuclear magnetic resonance analysis is the gold standard for the clear elucidation of chemical structures of novel compounds [1]. This Special Issue provides an overview of the current knowledge on anthocyanins and their health benefits. Particularly, two reviews focus on summarizing results from studies carried out to explore the impact of anthocyanins on cardiovascular and neurodegenerative diseases [1] and type 2 diabetes [2]. In both papers, the authors highlight the value of anthocyanins to counteract the pro-inflammatory state, since this is a major contributing factor in the onset, development, and progression, of those chronic diseases. Regarding neurodegenerative diseases, Mattioli et al. [1] summarize the results of several studies showing that anthocyanins mitigate many of the damaging effects of processes implicated in neurodegeneration such as oxidative and nitrosative stress, glial inflammation, excitotoxicity, protein aggregation, and the induction of apoptotic signaling proteins. About cardiovascular diseases, the same authors [1] show that anthocyanins have protective effects by targeting different pathways that are involved in the pathogenesis of metabolic syndromes leading to cardiovascular disease. The studies reviewed indicate that anthocyanins positively affect the lipid profile by reducing total cholesterol, low-density lipoprotein, cholesterol, and triglycerides levels. Furthermore, anthocyanins increase the ratio of polyunsaturated fatty acids and decrease the amount of saturated fatty acids in plasma. Anthocyanins also have antioxidant proprieties; for example, they increase the activity of the high-density lipoprotein-associated paraoxonase 1, which breaks down harmful oxidized lipids in lipoproteins, in macrophages and in atherosclerotic plaques. Finally, it is also shown that anthocyanins have vasorelaxant, antihypertensive, antihemolytic activities and attenuate platelet aggregation [1]. The inverse relationship between anthocyanins intake and the total cholesterol:high density lipoprotein (HDL) cholesterol levels was also observed in the cross-sectional study carried out by Hershey et al. [4] and published in this issue. Furthermore, the joint effect of a low anthocyanin intake and low physical exercise more than doubled the relative risk of having HDL cholesterol<40 mg/dL, compared to high anthocyanins/high activity joint exposure, although the results lack statistical significance [4]. Diabetes is a prime risk factor for cardiovascular disease, and its global prevalence has increased rapidly over the last few decades. In this Special Issue, the review written by Oliveira et al. [2] explores the anthocyanins’ antidiabetic potential. The literature analysis shows that anthocyanins have therapeutic properties in diabetes through different pathways and mechanisms. Anthocyanins can reduce diabetes-related hyperglycemia and hemoglobin A1c levels. The authors also discuss the different mechanisms found, by which anthocyanins inhibit α-amylase and α-glucosidase, as well as interfere with glucose transport, glycogenolysis and lipid metabolism by different molecular pathways. Anthocyanins also control blood glucose by normalizing insulin secretion and resistance. As mentioned, anthocyanins have anti-inflammatory and antioxidant activities, which are important in the control of the apoptotic factors and consequent pancreatic β cells protection. These antioxidant properties are important to decrease not only the cardiovascular damage but also the renal one [2]. Authors from both review papers alert for the need to perform double-blind clinical trials recruiting a high number of patients to unequivocally evaluate the efficacy of anthocyanins. The importance of carrying out studies to determine and explain mechanisms attributed to each individual anthocyanin is also pointed out. Anthocyanins could have both chemopreventive and therapeutic effects against various types of cancer. In this Special Issue, four papers explored the anthocyanins’ anti-cancer effects [5,6,7,8]. Two of those papers report the results of in vitro studies carried out, by the same research group, to evaluate the anticancer effects of Vitis coignetiae Pulliat [5,6]. The authors demonstrated that anthocyanins extracted from the fruits act as inhibitors of NF-κB (factor nuclear kappa B) in MCF-7 cells. The authors suggest anthocyanins inhibit the tumor necrosis factor-α (TNF-α) effect by suppressing genes involved in cancer cell proliferation, invasion, adhesion, and angiogenesis in a NF-κB dependent manner. Moreover, it was observed that anthocyanins have anti-metastatic effects by suppressing the proliferation, adhesion of cancer cells to human umbilical vein endothelial cells, and invasion, as well as the gene expression involving cell proliferation, invasion, and angiogenesis [5]. In the other study, Paramanantham et al. [6] showed that anthocyanins extracted from Vitis coignetiae Pulliat also increase cisplatin sensitivity by inhibiting the protein kinase B (Akt) and NF-κB activity of MCF-7 cells that show relative intrinsic cisplatin resistance. Therefore, it may be speculated that adding anthocyanins to cisplatin could be an alternative therapeutic option by combining TNF-α inhibitor and cisplatin in human breast cancer [6]. Anthocyanins from the fruits of Vitis coignetiae Pulliat also have anti-cancer effects in terms of proliferation, migration, and invasion at low concentrations (10–100 µg/mL), on Hep3B human hepatocellular carcinoma cells, as shown in another paper of this issue [7]. As with breast cancer cells, the anthocyanins’ anti-cancer effects in Hep3B h cells are mediated through the inhibition of NF-κB and its target proteins, which are involved in cancer cell proliferation, invasion, and angiogenesis. However, results seem to indicate that when TNF-α is high, the anthocyanins’ anti-cancer effect decreases. This result highlights the need for further research to validate the anti-cancer effects of anthocyanins in highly metastatic cancer or far advanced cancers characterized by high TNF-α levels [7]. Simas Frauches et al. [8] carried out a study which aimed to characterize and compare the constituents of jabuticaba (Myrciaria jaboticaba), Jamun berry (Syzygium cumini), and Malay apple (Syzygium malaccense) extracts and their effect on antioxidant activity in vitro and antiproliferative effects on human colon adenocarcinoma cells. The results, published in this Special Issue, show a decrease in cell viability of HT-29 cells after treatment with Myrtaceae fruits extracts. Moreover, the studied anthocyanin-rich extracts induced G2/M cell cycle arrest and, consequently, apoptosis. Taken together, the results indicate that peel powders from Myrtaceae fruits are an important source of natural antioxidants and could be used to suppress colon cancer cell growth [8]. In conclusion, this Special Issue brings together information about the extraction of anthocyanins from natural sources and their health-promoting properties. In future, it will be important to design appropriate clinical studies to assess the potential benefits of anthocyanins on metabolic disorders, as well as interactions of these flavonoids with the gut microbiome.publishersversionpublishe

Extra-virgin olive oil phenols block cell cycle progression and modulate chemotherapeutic toxicity in bladder cancer cells

Epidemiological data indicate that the daily consumption of extra‑virgin olive oil (EVOO), a common dietary habit of the Mediterranean area, lowers the incidence of certain types of cancer, in particular bladder neoplasm. The aim of the present study was to evaluate the antiproliferative activity of polyphenols extracted from EVOO on bladder cancer (BCa), and to clarify the biological mechanisms that trigger cell death. Furthermore, we also evaluated the ability of low doses of extra‑virgin olive oil extract (EVOOE) to modulate the in vitro activity of paclitaxel or mitomycin, two antineoplastic drugs used in the management of different types of cancer. Our results showed that EVOOE significantly inhibited the proliferation and clonogenic ability of T24 and 5637 BCa cells in a dose‑dependent manner. Furthermore, cell cycle analysis after EVOOE treatment showed a marked growth arrest prior to mitosis in the G2/M phase for both cell lines, with the subsequent induction of apoptosis only in the T24 cells. Notably, simultaneous treatment of mitomycin C and EVOOE reduced the drug cytotoxicity due to inhibition of ROS production. Conversely, the co‑treatment of T24 cells with paclitaxel and the polyphenol extract strongly increased the apoptotic cell death at each tested concentration compared to paclitaxel alone. Our results support the epidemiological evidence indicating that olive oil consumption exerts health benefits and may represent a starting point for the development of new anticancer strategies

An expedient synthesis of 2,5-dihydroxytyrosol and studies on its effects on cell growth inhibition

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Proline synthesis in developing microspores is required for pollen development and fertility

Background: In many plants, the amino acid proline is strongly accumulated in pollen and disruption of proline synthesis caused abortion of microspore development in Arabidopsis. So far, it was unclear whether local biosynthesis or transport of proline determines the success of fertile pollen development. Results: We analyzed the expression pattern of the proline biosynthetic genes PYRROLINE-5-CARBOXYLATE SYNTHETASE 1 & 2 (P5CS1 & 2) in Arabidopsis anthers and both isoforms were strongly expressed in developing microspores and pollen grains but only inconsistently in surrounding sporophytic tissues. We introduced in a p5cs1/p5cs1 p5cs2/P5CS2 mutant background an additional copy of P5CS2 under the control of the Cauliflower Mosaic Virus (CaMV) 35S promoter, the tapetum-specific LIPID TRANSFER PROTEIN 12 (Ltp12) promoter or the pollen-specific At5g17340 promoter to determine in which site proline biosynthesis can restore the fertility of proline-deficient microspores. The specificity of these promoters was confirmed by β-glucuronidase (GUS) analysis, and by direct proline measurement in pollen grains and stage-9/10 anthers. Expression of P5CS2 under control of the At5g17340 promoter fully rescued proline content and normal morphology and fertility of mutant pollen. In contrast, expression of P5CS2 driven by either the Ltp12 or CaMV35S promoter caused only partial restoration of pollen development with little effect on pollen fertility. Conclusions: Overall, our results indicate that proline transport is not able to fulfill the demand of the cells of the male germ line. Pollen development and fertility depend on local proline biosynthesis during late stages of microspore development and in mature pollen grains

Erythrocyte's aging in microgravity highlights how environmental stimuli shape metabolism and morphology

The determination of the function of cells in zero-gravity conditions is a subject of interest in many different research fields. Due to their metabolic unicity, the characterization of the behaviour of erythrocytes maintained in prolonged microgravity conditions is of particular importance. Here, we used a 3D-clinostat to assess the microgravity-induced modifications of the structure and function of these cells, by investigating how they translate these peculiar mechanical stimuli into modifications, with potential clinical interest, of the biochemical pathways and the aging processes. We compared the erythrocyte's structural parameters and selected metabolic indicators that are characteristic of the aging in microgravity and standard static incubation conditions. The results suggest that, at first, human erythrocytes react to external stimuli by adapting their metabolic patterns and the rate of consumption of the cell resources. On longer timeframes, the cells translate even small differences in the environment mechanical solicitations into structural and morphologic features, leading to distinctive morphological patterns of agin

Intranasal rapamycin ameliorates Alzheimer-like cognitive decline in a mouse model of Down syndrome

Background: Down syndrome (DS) individuals, by the age of 40s, are at increased risk to develop Alzheimer-like dementia, with deposition in brain of senile plaques and neurofibrillary tangles. Our laboratory recently demonstrated the disturbance of PI3K/AKT/mTOR axis in DS brain, prior and after the development of Alzheimer Disease (AD). The aberrant modulation of the mTOR signalling in DS and AD age-related cognitive decline affects crucial neuronal pathways, including insulin signaling and autophagy, involved in pathology onset and progression. Within this context, the therapeutic use of mTOR-inhibitors may prevent/attenuate the neurodegenerative phenomena. By our work we aimed to rescue mTOR signalling in DS mice by a novel rapamycin intranasal administration protocol (InRapa) that maximizes brain delivery and reduce systemic side effects. Methods: Ts65Dn mice were administered with InRapa for 12 weeks, starting at 6 months of age demonstrating, at the end of the treatment by radial arms maze and novel object recognition testing, rescued cognition. Results: The analysis of mTOR signalling, after InRapa, demonstrated in Ts65Dn mice hippocampus the inhibition of mTOR (reduced to physiological levels), which led, through the rescue of autophagy and insulin signalling, to reduced APP levels, APP processing and APP metabolites production, as well as, to reduced tau hyperphosphorylation. In addition, a reduction of oxidative stress markers was also observed. Discussion: These findings demonstrate that chronic InRapa administration is able to exert a neuroprotective effect on Ts65Dn hippocampus by reducing AD pathological hallmarks and by restoring protein homeostasis, thus ultimately resulting in improved cognition. Results are discussed in term of a potential novel targeted therapeutic approach to reduce cognitive decline and AD-like neuropathology in DS individuals

Anti-Inflammatory activity of a polyphenolic extract from Arabidopsis thaliana in in vitro and in vivo models of Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder and the primary form of dementia in the elderly. One of the main features of AD is the increase in amyloid-beta (Aβ) peptide production and aggregation, leading to oxidative stress, neuroinflammation and neurodegeneration. Polyphenols are well known for their antioxidant, anti-inflammatory and neuroprotective effects and have been proposed as possible therapeutic agents against AD. Here, we investigated the effects of a polyphenolic extract of Arabidopsis thaliana (a plant belonging to the Brassicaceae family) on inflammatory response induced by Aβ. BV2 murine microglia cells treated with both Aβ25⁻35 peptide and extract showed a lower pro-inflammatory (IL-6, IL-1β, TNF-α) and a higher anti-inflammatory (IL-4, IL-10, IL-13) cytokine production compared to cells treated with Aβ only. The activation of the Nrf2-antioxidant response element signaling pathway in treated cells resulted in the upregulation of heme oxygenase-1 mRNA and in an increase of NAD(P)H:quinone oxidoreductase 1 activity. To establish whether the extract is also effective against Aβ-induced neurotoxicity in vivo, we evaluated its effect on the impaired climbing ability of AD Drosophila flies expressing human Aβ1⁻42. Arabidopsis extract significantly restored the locomotor activity of these flies, thus confirming its neuroprotective effects also in vivo. These results point to a protective effect of the Arabidopsis extract in AD, and prompt its use as a model in studying the impact of complex mixtures derived from plant-based food on neurodegenerative diseases

Muscle activations during functional tasks in individuals with chronic ankle instability: a systematic review of electromyographical studies

Background: It has been reported that individuals with chronic ankle instability (CAI) show motor control ab-normalities. The study of muscle activations by means of surface electromyography (sEMG) plays a key role in understanding some of the features of movement abnormalities. Research question: Do common sEMG activation abnormalities and strategies exists across different functional movements? Methods: Literature review was conducted on PubMed, Web-of-Science and Cochrane databases. Studies pub-lished between 2000 and 2020 that assessed muscle activations by means of sEMG during any type of functional task in individuals with CAI, and used healthy individuals as controls, were included. Methodological quality was assessed using the modified Downs&Black checklist. Since the methodologies of different studies were hetero-geneous, no meta-analysis was conducted. Results: A total of 63 articles investigating muscle activations during gait, running, responses to perturbations, landing and hopping, cutting and turning; single-limb stance, star excursion balance task, forward lunges, ball- kicking, y-balance test and single-limb squatting were considered. Individuals with CAI showed a delayed activation of the peroneus longus in response to sudden inversion perturbations, in transitions between double- and single-limb stance, and in landing on unstable surfaces. Apparently, while walking on ground there are no differences between CAI and controls, walking on a treadmill increases the variability of muscles activations, probably as a “safety strategy” to avoid ankle inversion. An abnormal activation of the tibialis anterior was observed during a number of tasks. Finally, hip/spine muscles were activated before ankle muscles in CAI compared to controls. Conclusion: Though the methodology of the studies herein considered is heterogeneous, this review shows that the peroneal and tibialis anterior muscles have an abnormal activation in CAI individuals. These individuals also show a proximal muscle activation strategy during the performance of balance challenging tasks. Future studies should investigate whole-body muscle activation abnormalities in CAI individuals

Inhibition of Poly(ADP-ribose)polymerase impairs Epstein Barr Virus lytic cycle progression

<p>Abstract</p> <p>Background</p> <p>Poly(ADP-ribosylation) is a post-translational modification of nuclear proteins involved in several cellular events as well as in processes that characterize the infective cycle of some viruses. In the present study, we investigated the role of poly(ADP-ribosylation) on Epstein-Barr Virus (EBV) lytic cycle activation.</p> <p>Results</p> <p>Inhibition of PARP-1 by 3-aminobenzamide (3-ABA) during EBV induction, diminished cell damage and apoptosis in the non-productive Raji cell line while markedly reducing the release of viral particles in the productive Jijoye cells. Furthermore, incubation with 3-ABA up-regulated the levels of LMP1 and EBNA2 latent viral proteins. At the same time, it slightly affected the expression of the immediate early BZLF1 gene, but largely down-regulated the levels of the early BFRF1 protein. The modulation of the expression of both latent and lytic EBV genes appeared to be post-transcriptionally regulated.</p> <p>Conclusion</p> <p>Taken together the data indicate that PARP-1 plays a role in the progression of EBV lytic cycle and therefore, PARP inhibitors might represent suitable pharmacological adjuncts to control viral spread in EBV productive infection.</p

One- and Two-Electron Oxidations of β-Amyloid_25-35 by Carbonate Radical Anion (CO₃•-) and Peroxymonocarbonate (HCO₄-):Role of Sulfur in Radical Reactions and Peptide Aggregation

The &beta;-amyloid (A&beta;) peptide plays a key role in the pathogenesis of Alzheimer&rsquo;s disease. The methionine (Met) residue at position 35 in A&beta; C-terminal domain is critical for neurotoxicity, aggregation, and free radical formation initiated by the peptide. The role of Met in modulating toxicological properties of A&beta; most likely involves an oxidative event at the sulfur atom. We therefore investigated the one- or two-electron oxidation of the Met residue of A&beta;25-35 fragment and the effect of such oxidation on the behavior of the peptide. Bicarbonate promotes two-electron oxidations mediated by hydrogen peroxide after generation of peroxymonocarbonate (HCO4&minus;, PMC). The bicarbonate/carbon dioxide pair stimulates one-electron oxidations mediated by carbonate radical anion (CO3&bull;&minus;). PMC efficiently oxidizes thioether sulfur of the Met residue to sulfoxide. Interestingly, such oxidation hampers the tendency of A&beta; to aggregate. Conversely, CO3&bull;&minus; causes the one-electron oxidation of methionine residue to sulfur radical cation (MetS&bull;+). The formation of this transient reactive intermediate during A&beta; oxidation may play an important role in the process underlying amyloid neurotoxicity and free radical generation