Delphinidin and cyanidin inhibit PDGF(AB)-induced VEGF release in vascular smooth muscle cells by preventing activation of p38 MAPK and JNK

Targeted Therapy of Spinal Cord Injury: Inhibition of Apoptosis Is a Promising Therapeutic Strategy

Spinal cord injury (SCI) is a serious disabling central nervous system injury that can lead to motor, sensory, and autonomic dysfunction below the injury level. SCI can be divided into primary injury and secondary injury according to pathological process. Primary injury is mostly irreversible, while secondary injury is a dynamic regulatory process. Apoptosis is an important pathological event of secondary injury and has a significant effect on the recovery of nerve function after SCI. Nerve cell death can further aggravate the microenvironment of the injured site, leading to neurological dysfunction and thus affect the clinical outcome of patients. Therefore, apoptosis plays a crucial role in the pathological progression of secondary SCI, while inhibiting apoptosis may be a promising therapeutic strategy for SCI. This review will summarize and explore the factors that lead to cell death after SCI, the influence of cross talk between signaling pathways and pathways involved in apoptosis and discuss the influence of apoptosis on SCI, and the therapeutic significance of targeting apoptosis on SCI. This review helps us to understand the role of apoptosis in secondary SCI and provides a theoretical basis for the treatment of SCI based on apoptosis.

Novel Insight into the Cellular and Molecular Signalling Pathways on Cancer Preventing Effects of Hibiscus sabdariffa: A Review

A category of diseases known as cancer includes abnormal cell development and the ability to infiltrate or spread to other regions of the body, making them a major cause of mortality worldwide. Chemotherapy, radiation, the use of cytotoxic medicines, and surgery are the mainstays of cancer treatment today. Plants or products produced from them hold promise as a source of anti-cancer medications that have fewer adverse effects. Due to the presence of numerous phytochemicals that have been isolated from various parts of the Hibiscus sabdariffa (HS) plant, including anthocyanin, flavonoids, saponins, tannins, polyphenols, organic acids, caffeic acids, citric acids, protocatechuic acid, and others, extracts of this plant have been reported to have anti-cancer effects. These compounds have been shown to reduce cancer cell proliferation, induce apoptosis, and cause cell cycle arrest. They also increase the expression levels of the cell cycle inhibitors (p53, p21, and p27) and the pro-apoptotic proteins (BAD, Bax, caspase 3, caspase 7, caspase 8, and caspase 9). This review highlights various intracellular signalling pathways involved in cancer preventive potential of HS.

Receptor Tyrosine Kinase: Still an Interesting Target to Inhibit the Proliferation of Vascular Smooth Muscle Cells

Vascular smooth muscle cells (VSMCs) proliferation is a critical event that contributes to the pathogenesis of vascular remodeling such as hypertension, restenosis, and pulmonary hypertension. Increasing evidences have revealed that VSMCs proliferation is associated with the activation of receptor tyrosine kinases (RTKs) by their ligands, including the insulin-like growth factor receptor (IGFR), fibroblast growth factor receptor (FGFR), epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR), and platelet-derived growth factor receptor (PDGFR). Moreover, some receptor tyrosinase inhibitors (TKIs) have been found and can prevent VSMCs proliferation to attenuate vascular remodeling. Therefore, this review will describe recent research progress on the role of RTKs and their inhibitors in controlling VSMCs proliferation, which helps to better understand the function of VSMCs proliferation in cardiovascular events and is beneficial for the prevention and treatment of vascular disease.

Cyanidin inhibits adipogenesis in 3T3-L1 preadipocytes by activating the PLC-IP3 pathway

Cyanidin is the most abundant anthocyanin found in red-purple plants and possesses anti-obesity properties. However, its mechanism of action in adipocytes remains unknown. The objective of this study was to elucidate how cyanidin inhibits adipocyte formation in 3T3-L1 preadipocytes. Cells were cultured in adipogenic differentiation medium supplemented with cyanidin and examined for adipogenesis, cell viability, and adipocyte gene expression using Oil Red O staining, MTT assay, and RT-qPCR. Real-time Ca²⁺ imaging analysis was performed in living cells to elucidate cyanidin's mechanism of action. The results demonstrated that cyanidin (1-50 μM) supplementation to the adipogenic medium inhibited adipogenesis by downregulating adipogenic marker gene expression (PPARγ, C/EBPα, adiponectin, and aP2) without affecting cell viability after 4 days of treatment. Stimulation of cells with cyanidin (30-100 μM) increased intracellular Ca²⁺ in a concentration dependent manner with peak calcium increases at 50 μM. Pretreatment of cells with the phospholipase C (PLC) inhibitor U73122, inositol triphosphate (IP₃) receptor blocker 2-APB, and depletion of endoplasmic reticulum Ca²⁺ stores by thapsigargin abolished the Ca²⁺ increases by cyanidin. These findings suggested that cyanidin inhibits adipocyte formation by activating the PLC-IP₃ pathway and intracellular Ca²⁺ signaling. Our study is the first report describing the mechanism underlying the anti-obesity effect of cyanidin.

Pomegranate juice anthocyanidins induce cell death in human cancer cells by mobilizing intracellular copper ions and producing reactive oxygen species

Anthocyanidins are the most abundant polyphenols in pomegranate juice. This class of molecules includes Delphinidin (Del), Cyanidin (Cya), and Pelargonidin (Pel). Using prostate, breast and pancreatic cancer cell lines PC3, MDA-MB-231, BxPC-3 and MiaPaCa-2, we show that anthocyanidins inhibit cell proliferation (measured by MTT assay) and induce apoptosis like cell death (measured by DNA/Histone ELISA). Copper chelator neocuproine and reactive oxygen species scavengers (thiourea for hydroxyl radical and superoxide dismutase for superoxide anion) significantly inhibit this reaction thus demonstrating that intracellular copper reacts with anthocyanidins in cancer cells to cause DNA damage via ROS generation. We further show that copper-supplemented media sensitizes normal breast epithelial cells (MCF-10A) to Del-mediated growth inhibition as determined by decreased cell proliferation. Copper supplementation results in increased expression of copper transporters Ctr1 and ATP7A in MCF-10A cells, which is attenuated by the addition of Del in the medium. We propose that the copper mediated, ROS-induced mechanism of selective cell death of cancer cells may in part explain the anticancer effects of anthocyanidins.

Insights into the Mechanisms of Action of Proanthocyanidins and Anthocyanins in the Treatment of Nicotine-Induced Non-Small Cell Lung Cancer

In traditional medicine, different parts of plants, including fruits, have been used for their anti-inflammatory and anti-oxidative properties. Plant-based foods, such as fruits, seeds and vegetables, are used for therapeutic purposes due to the presence of flavonoid compounds. Proanthocyanidins (PCs) and anthocyanins (ACNs) are the major distributed flavonoid pigments in plants, which have therapeutic potential against certain chronic diseases. PCs and ACNs derived from plant-based foods and/or medicinal plants at different nontoxic concentrations have shown anti-non-small cell lung cancer (NSCLC) activity in vitro/in vivo models through inhibiting proliferation, invasion/migration, metastasis and angiogenesis and by activating apoptosis/autophagy-related mechanisms. However, the potential mechanisms by which these compounds exert efficacy against nicotine-induced NSCLC are not fully understood. Thus, this review aims to gain insights into the mechanisms of action and therapeutic potential of PCs and ACNs in nicotine-induced NSCLC.

Ornamental Flowers Grown in Human Surroundings as a Source of Anthocyanins with High Anti-Inflammatory Properties

Flowers have always accompanied people thanks to their manifold aesthetic properties. Some species have also become a component of the human diet. Recent years have seen an increased interest in edible flowers and, consequently, research has been undertaken to determine their chemical composition. Dyes that are abundantly contained in flowers, whose role is to attract pollinating animals, are recognized substances with health-promoting properties. Anthocyanins are a group of dyes that are very common in petals and other parts of flowers. Studies carried out in the twentieth and twenty-first century on flowers growing in temperate climates have found very strong antioxidant and anti-inflammatory properties of anthocyanins. Therefore, flowers used by humans for centuries to decorate their surroundings may become an easily available source of nutrients and health-promoting substances. This paper discusses the health-promoting properties of anthocyanins and collects literature on anthocyanin content in edible flowers commonly grown on balconies, terraces, and roofs in countries of temperate climate.

Delphinidin and Its Glycosides' War on Cancer: Preclinical Perspectives

Until now, several studies have looked at the issue of anthocyanin and cancer, namely the preventive and inhibitory effects of anthocyanins, as well as the underlying molecular processes. However, no targeted review is available regarding the anticarcinogenic effects of delphinidin and its glycosides on various cancers and their plausible molecular mechanisms. Considerable evidence shows significant anticancer properties of delphinidin-rich preparations and delphinidin alone both in vitro and in vivo. This review covers the in vitro and preclinical implications of delphinidin-mediated cell protection and cancer prevention; thus, we strongly recommend that delphinidin-rich preparations be further investigated as potential functional food, dietary antioxidant supplements, and natural health products targeting specific chronic diseases, including cancer. In addition to in vitro investigations, future research should focus on more animal and human studies to determine the true potential of delphinidin.

Differences in the Effects of Anthocyanin Supplementation on Glucose and Lipid Metabolism According to the Structure of the Main Anthocyanin: A Meta-Analysis of Randomized Controlled Trials

The effectiveness of anthocyanins may differ according to their chemical structures; however, randomized clinical controlled trials (RCTs) or meta-analyses that examine the consequences of these structural differences have not been reported yet. In this meta-analysis, anthocyanins in test foods of 18 selected RCTs were categorized into three types: cyanidin-, delphinidin-, and malvidin-based. Delphinidin-based anthocyanins demonstrated significant effects on triglycerides (mean difference (MD): −0.24, p < 0.01), low-density lipoprotein cholesterol (LDL-C) (MD: −0.28, p < 0.001), and high-density lipoprotein cholesterol (HDL-C) (MD: 0.11, p < 0.01), whereas no significant effects were observed for cyanidin- and malvidin-based anthocyanins. Although non-significant, favorable effects on total cholesterol (TC) and HDL-C were observed for cyanidin- and malvidin-based anthocyanins, respectively (both p < 0.1). The ascending order of effectiveness on TC and LDL-C was delphinidin-, cyanidin-, and malvidin-based anthocyanins, and the differences among the three groups were significant (both p < 0.05). We could not confirm the significant effects of each main anthocyanin on glucose metabolism; however, insulin resistance index changed positively and negatively with cyanidin- and delphinidin-based anthocyanins, respectively. Therefore, foods containing mainly unmethylated anthocyanins, especially with large numbers of OH groups, may improve glucose and lipid metabolism more effectively than those containing methylated anthocyanins.

Cyanidin 3-glucoside modulated cell cycle progression in liver precancerous lesion, in vivo study

BACKGROUND

Cyanidin-3-O-glucoside (cyan) exhibits antioxidant and anticancer properties. The cell cycle proteins and antimitotic drugs might be promising therapeutic targets in hepatocellular carcinoma.

AIM

To investigate the effect of cyan administration on cell cycle in hepatic precancerous lesion (PCL) induced by diethylnitrosamine/2-acetylaminofluorene (DEN/2-AAF) in Wistar rats.

METHODS

In vivo, DEN/2-AAF-induced hepatic PCL, rats were treated with three doses of cyan (10, 15, and 20 mg/kg/d, for four consecutive days per week for 16 wk). Blood and liver tissue samples were collected for measurement of the followings; alpha fetoprotein (AFP) liver function and RNA panel differential expression was evaluated via real time polymerase chain reaction. Histopathological examination of liver sections stained with H&E and immunohistochemical study using glutathione S-transferase placental (GSTP) and proliferating cell nuclear antigen (PCNA) antibodies were assessed.

RESULTS

Cyan administration mitigated the effect of DEN/2-AFF induced PCL, decreased AFP levels, and improved liver function. Remarkably, treatment with cyan dose dependently decreased the long non-coding RNA MALAT1 and tubulin gamma 1 mRNA expressions and increased the levels of miR-125b, all of which are involved in cell cycle and mitotic spindle assembly. Of note, cyan decreased GSTP foci percent area and PCNA positively stained nuclei.

CONCLUSION

Our results indicated that cyan could be used as a potential therapeutic agent to inhibit liver carcinogenesis in rat model via modulation of cell cycle.

Antileishmanial Activity of Lignans, Neolignans, and Other Plant Phenols

Secondary metabolites (SM) from organisms have served medicinal chemists over the past two centuries as an almost inexhaustible pool of new drugs, drug-like skeletons, and chemical probes that have been used in the "hunt" for new biologically active molecules with a "beneficial effect on human mind and body." Several secondary metabolites, or their derivatives, have been found to be the answer in the quest to search for new approaches to treat or even eradicate many types of diseases that oppress humanity. A special place among SM is occupied by lignans and neolignans. These phenolic compounds are generated biosynthetically via radical coupling of two phenylpropanoid monomers, and are known for their multitarget activity and low toxicity. The disadvantage of the relatively low specificity of phenylpropanoid-based SM turns into an advantage when structural modifications of these skeletons are made. Indeed, phenylpropanoid-based SM previously have proven to offer great potential as a starting point in drug development. Compounds such as Warfarin^® (a coumarin-based anticoagulant) as well as etoposide and teniposide (podophyllotoxin-based anticancer drugs) are just a few examples. At the beginning of the third decade of the twenty-first century, the call for the treatment of more than a dozen rare or previously "neglected" diseases remains for various reasons unanswered. Leishmaniasis, a neglected disease that desperately needs new ways of treatment, is just one of these. This disease is caused by more than 20 leishmanial parasites that are pathogenic to humans and are spread by as many as 800 sandfly species across subtropical areas of the world. With continuing climate changes, the presence of Leishmania parasites and therefore leishmaniasis, the disease caused by these parasites, is spreading from previous locations to new areas. Thus, leishmaniasis is affecting each year a larger proportion of the world's population. The choice of appropriate leishmaniasis treatment depends on the severity of the disease and its form of manifestation. The success of current drug therapy is often limited, due in most cases to requiring long hospitalization periods (weeks to months) and the toxicity (side effects) of administered drugs, in addition to the increasing resistance of the parasites to treatment. It is thus important to develop new drugs and treatments that are less toxic, can overcome drug resistance, and require shorter periods of treatment. These aspects are especially important for the populations of developing countries. It was reported that several phenylpropanoid-based secondary metabolites manifest interesting antileishmanial activities and are used by various indigenous people to treat leishmaniasis. In this chapter, the authors shed some light on the various biological activities of phenylpropanoid natural products, with the main focus being on their possible applications in the context of antileishmanial treatment.

Targeting apoptosis and autophagy following spinal cord injury: Therapeutic approaches to polyphenols and candidate phytochemicals

Spinal cord injury (SCI) is a neurological disorder associated with the loss of sensory and motor function. Understanding the precise dysregulated signaling pathways, especially apoptosis and autophagy following SCI, is of vital importance in developing innovative therapeutic targets and treatments. The present study lies in the fact that it reveals the precise dysregulated signaling mediators of apoptotic and autophagic pathways following SCI and also examines the effects of polyphenols and other candidate phytochemicals. It provides new insights to develop new treatments for post-SCI complications. Accordingly, a comprehensive review was conducted using electronic databases including, Scopus, Web of Science, PubMed, and Medline, along with the authors' expertise in apoptosis and autophagy as well as their knowledge about the effects of polyphenols and other phytochemicals on SCI pathogenesis. The primary mechanical injury to spinal cord is followed by a secondary cascade of apoptosis and autophagy that play critical roles during SCI. In terms of pharmacological mechanisms, caspases, Bax/Bcl-2, TNF-α, and JAK/STAT in apoptosis along with LC3 and Beclin-1 in autophagy have shown a close interconnection with the inflammatory pathways mainly glutamatergic, PI3K/Akt/mTOR, ERK/MAPK, and other cross-linked mediators. Besides, apoptotic pathways have been shown to regulate autophagy mediators and vice versa. Prevailing evidence has highlighted the importance of modulating these signaling mediators/pathways by polyphenols and other candidate phytochemicals post-SCI. The present review provides dysregulated signaling mediators and therapeutic targets of apoptotic and autophagic pathways following SCI, focusing on the modulatory effects of polyphenols and other potential phytochemical candidates.

The ameliorating effects of anthocyanins on the cross-linked signaling pathways of cancer dysregulated metabolism

Cancer cells underlie the dysregulated metabolism of carbohydrate, lipid and protein and thereby, employ interconnected cross-linked signaling pathways to supply adequate energy for growth and related biosynthetic procedures. In the present study, a comprehensive review of cancer metabolism and anthocyanin's effect was conducted using the existing electronic databases, including Medline, PubMed, Scopus, and Web of Science, as well as related articles in the field. Such keywords as "cancer", and "cancer metabolism" in the title/abstract/keyword and all the "anthocyanins" in the whole text were used. Data were collected without time restriction until February 2020. The results indicated the involvement of several signaling pathways, including inflammatory PI3K/Akt/mTOR pathway, Bax/Bcl-2/caspases as apoptosis modulators, and NF-κB/Nrf2 as oxidative stress mediators in the cancer dysregulated metabolism. Compelling studies have shown that targeting these pathways, as critical hallmarks of cancer, plays a critical role in combating cancer dysregulated metabolism. The complexity of cancer metabolism signaling pathways, along with toxicity, high costs, and resistance to conventional drugs urge the need to investigate novel multi-target agents. Increasing evidence has introduced plant-derived secondary metabolites as hopeful anticancer candidates which target multiple dysregulated cross-linked pathways of cancer metabolism. Amongst these metabolites, anthocyanins have demonstrated positive anticancer effects by targeting inflammation, oxidative stress, and apoptotic signaling pathways. The current study revealed the cross-linked signaling pathways of cancer metabolism, as well as the promising pharmacological mechanisms of anthocyanins in targeting the aforementioned signaling mediators. To overcome the pharmacokinetic limitations of anthocyanins in cancer treatment, their interactions with gut microbiota and the need to develop related nano-formulations were also considered.

Delphinidin attenuates pathological cardiac hypertrophy via the AMPK/NOX/MAPK signaling pathway

Reactive oxygen species (ROS) play a pivotal role in the development of pathological cardiac hypertrophy. Delphinidin, a natural flavonoid, was reported to exert marked antioxidative effects. Therefore, we investigated whether delphinidin ameliorates pathological cardiac hypertrophy via inhibiting oxidative stress. In this study, male C57BL/6 mice were treated with DMSO or delphinidin after surgery. Neonatal rat cardiomyocytes (NRCMs) were treated with angiotensin II (Ang II) and delphinidin in vitro. Eighteen-month-old mice were administered delphinidin to investigate the effect of delphinidin on aging-related cardiac hypertrophy. Through analyses of hypertrophic cardiomyocyte growth, fibrosis and cardiac function, delphinidin was demonstrated to confer resistance to aging- and transverse aortic constriction (TAC)-induced cardiac hypertrophy in vivo and attenuate Ang II-induced cardiomyocyte hypertrophy in vitro by significantly suppressing hypertrophic growth and the deposition of fibrosis. Mechanistically, delphinidin reduced ROS accumulation upon Ang II stimulation through the direct activation of AMP-activated protein kinase (AMPK) and subsequent inhibition of the activity of Rac1 and expression of p47^phox. In addition, excessive levels of ERK1/2, P38 and JNK1/2 phosphorylation induced by oxidative stress were abrogated by delphinidin. Delphinidin was conclusively shown to repress pathological cardiac hypertrophy by modulating oxidative stress through the AMPK/NADPH oxidase (NOX)/mitogen-activated protein kinase (MAPK) signaling pathway.

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

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

Anti-inflammatory effect of delphinidin on intramedullary spinal pressure in a spinal cord injury rat model

Delphinidin, a flavonoid polyphenolic compound, is widely found in nature and is used as a food supplement due to its pharmacological activity. The aims of the present study were to examine the anti-inflammatory effect of delphinidin in alleviating spinal cord injury (SCI)-induced inflammation in a rat model and to determine the underlying mechanisms in SCI. The Basso, Beattie, Bresnahan (BBB) scores of rats were assessed to evaluate the effect of delphinidin on the recovery of motor function. ELISA kits were also used to analyze the activities of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2) and caspase-3. In addition, the protein expression levels of nuclear factor (NF)-κB, activator protein 1 (AP-1) and p38-MAPK protein expression were measured using western blot analysis. Treatment with delphinidin significantly increased the BBB scores, as well as inhibited the intramedullary spinal pressure in SCI rats. Delphinidin treatment also significantly suppressed the levels of inflammatory factors and NF-κB protein expression in SCI rats. Finally, treatment with delphinidin significantly inhibited NF-κB stimulation, COX-2 activity, PGE2 production, and AP-1 and p38-MAPK protein expression in SCI rats. These results suggest that the anti-inflammatory effect of delphinidin alleviated inflammation in the SCI rat model via alleviation of the intramedullary spinal pressure through the NF-κB and p38-MAPK signaling pathways.

Cyanidin Stimulates Insulin Secretion and Pancreatic β-Cell Gene Expression through Activation of l-type Voltage-Dependent Ca2+ Channels

Cyanidin is a natural anthocyanidin present in fruits and vegetables with anti-diabetic properties including stimulation of insulin secretion. However, its mechanism of action remains unknown. In this study, we elucidated the mechanisms of cyanidin for stimulatory insulin secretion from pancreatic β-cells. Rat pancreatic β-cells INS-1 were used to investigate the effects of cyanidin on insulin secretion, intracellular Ca²⁺ signaling, and gene expression. We detected the presence of cyanidin in the intracellular space of β-cells. Cyanidin stimulated insulin secretion and increased intracellular Ca²⁺ signals in a concentration-dependent manner. The Ca²⁺ signals were abolished by nimodipine, an l-type voltage-dependent Ca²⁺ channel (VDCC) blocker or under extracellular Ca²⁺ free conditions. Stimulation of cells with cyanidin activated currents typical for VDCCs and up-regulated the expression of glucose transporter 2 (GLUT2), Kir_6.2, and Cav_1.2 genes. Our findings indicate that cyanidin diffuses across the plasma membrane, leading to activation of l-type VDCCs. The increase in intracellular Ca²⁺ stimulated insulin secretion and the expression of genes involved in this process. These findings suggest that cyanidin could be used as a promising agent to stimulate insulin secretion.

Effects of anthocyanins on the prevention and treatment of cancer

Anthocyanins are a class of water-soluble flavonoids, which show a range of pharmacological effects, such as prevention of cardiovascular disease, obesity control and antitumour activity. Their potential antitumour effects are reported to be based on a wide variety of biological activities including antioxidant; anti-inflammation; anti-mutagenesis; induction of differentiation; inhibiting proliferation by modulating signal transduction pathways, inducing cell cycle arrest and stimulating apoptosis or autophagy of cancer cells; anti-invasion; anti-metastasis; reversing drug resistance of cancer cells and increasing their sensitivity to chemotherapy. In this review, the latest progress on the anticancer activities of anthocyanins and the underlying molecular mechanisms is summarized using data from basic research in vitro and in vivo, from clinical trials and taking into account theory and practice.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Antibody-based targeting of CD24 enhances antitumor effect of cetuximab via attenuating phosphorylation of Src/STAT3

Epidermal growth factor receptor (EGFR) is a cell-surface receptor for some extracellular protein ligands relating to cancers and has been recognized as a key target for tumor therapy. Cetuximab, a chimerical monoclonal EGFR IgG1 antibody, is used for the treatment of various malignancies. However, recent clinical trials reported that the anti-tumor effect of cetuximab is still controversial. Cluster of differentiation 24 (CD24) is a tumor-associated antigen correlating with poor prognosis and regulating the activity of Src/STAT3 in multiple cancers. G7mAb was an anti-CD24 antibody derived by hybridoma technology in our previous study. To further evaluate the relationship between cetuximab and G7mAb in cancer therapy, this combination treatment was performed in vitro (A549, HT-29 and Huh-7 cells) and in vivo (xenograft mouse models). We showed that G7mAb suppressed the invasion and enhanced the anti-proliferation effect of cetuximab in A549, HT-29 and Huh-7 cells. Combination of cetuximab with G7mAb had enhanced effects on blocking the activation of signal transducer and activator of transcription 3 (STAT3) signal pathway. Furthermore, combination therapy of cetuximab with G7mAb significantly suppressed tumor developments and improved the survival rates in xenografted mice. In conclusion, G7mAb enhanced the antitumor effect of cetuximab by attenuating phosphorylation of Src/STAT3 both in vitro and in vivo. Combination of antibodies targeting EGFR or CD24 provided a potential strategy for cancer therapy.

Synergistic effect of atorvastatin and cyanidin-3-glucoside against angiotensin II-mediated vascular smooth muscle cell proliferation and migration through MAPK and PI3K/Akt pathways

This study aimed to investigate the mechanism of cyanidin-3-glucoside (C3G) in synergy with atorvastatin, even when it is used in low concentrations. Human aortic smooth muscle cells (HASMCs) were used to verify the synergistic mechanism of atorvastatin and C3G against angiotensin II-induced proliferation and migration. BrdU incorporation assay was used to evaluate cell proliferation. Wound healing and Boyden chamber assays were used to investigate cell migration. The cell cycle was examined using flow cytometry. The results revealed that atorvastatin and C3G exhibit a synergistic effect in ameliorating HASMC proliferation and migration by enhancing cell cycle arrest. In addition, these effects also decreased mitogen-activated protein kinase (MAPK) activity by attenuating the expression of phospho-p38, phospho-extracellular signaling-regulated kinase 1/2, and phospho-c-Jun N-terminal kinase. Furthermore, the combination of atorvastatin and C3G modulated the PI3K/Akt pathway and upregulated p21Cip1, which was associated with decreases in cyclin D1 and phospho-retinoblastoma expressions. The synergistic effect of atorvastatin and C3G induced anti-proliferation and anti-migration through MAPK and PI3K/Akt pathways mediated by AT1R. These results suggest that the synergistic effect of atorvastatin and C3G may be an alternative therapy for atherosclerosis patients.

Cytoprotective Mechanism of Cyanidin and Delphinidin against Oxidative Stress-Induced Tenofibroblast Death

Age-related rotator cuff tendon degeneration is related to tenofibroblast apoptosis. Anthocyanins reduce oxidative stress-induced apoptotic cell death in tenofibroblasts. The current study investigated the presence of cell protective effects in cyanidin and delphinidin, the most common aglycon forms of anthocyanins. We determined whether these anthocyanidins have antiapoptotic and antinecrotic effects in tenofibroblasts exposed to H₂O₂, and evaluated their biomolecular mechanisms. Both cyanidin and delphinidin inhibited H₂O₂-induced apoptosis in a dose-dependent manner. However, at concentrations of 100 μg/ml or greater, delphinidin showed cytotoxicity against tenofibroblasts and a decreased antinecrotic effect. Cyanidin and delphinidin both showed inhibitory effects on the H₂O₂-induced increase in intracellular ROS formation and the activation of ERK1/2 and JNK. In conclusion, both cyanidin and delphinidin have cytoprotective effects on cultured tenofibroblasts exposed to H₂O₂. These results suggest that cyanidin and delphinidin are both beneficial for the treatment of oxidative stress-mediated tenofibroblast cell death, but their working concentrations are different.

Delphinidin prevents high glucose-induced cell proliferation and collagen synthesis by inhibition of NOX-1 and mitochondrial superoxide in mesangial cells

This study examined the effect of delphinidin on high glucose-induced cell proliferation and collagen synthesis in mesangial cells. Glucose dose-dependently (5.6-25 mM) increased cell proliferation and collagen I and IV mRNA levels, whereas pretreatment with delphinidin (50 μM) prevented cell proliferation and the increased collagen mRNA levels induced by high glucose (25 mM). High glucose increased reactive oxygen species (ROS) generation, and this was suppressed by pretreating delphinidin or the antioxidant N-acetyl cysteine. NADPH oxidase (NOX) 1 was upregulated by high glucose, but pretreatment with delphinidin abrogated this upregulation. Increased mitochondrial superoxide by 25 mM glucose was also suppressed by delphinidin. The NOX inhibitor apocynin and mitochondria-targeted antioxidant Mito TEMPO inhibited ROS generation and cell proliferation induced by high glucose. Phosphorylation of extracellular signal regulated kinase (ERK)1/2 was increased by high glucose, which was suppressed by delphinidin, apocynin or Mito TEMPO. Furthermore, PD98059 (an ERK1/2 inhibitor) prevented the high glucose-induced cell proliferation and increased collagen mRNA levels. Transforming growth factor (TGF)-β protein levels were elevated by high glucose, and pretreatment with delphinidin or PD98059 prevented this augmentation. These results suggest that delphinidin prevents high glucose-induced cell proliferation and collagen synthesis by inhibition of NOX-1 and mitochondrial superoxide in mesangial cells.

The genetic aspects of berries: from field to health

Berries are a relevant source of micronutrients and nonessential phytochemicals, such as polyphenol compounds, that play a synergistic and cumulative role in human health promotion. Several systematic analyses showed that berry phenolics are able to detoxify reactive oxygen and nitrogen species, blocking their production, to intervene in the cell cycle, participating in the transduction and expression of genes involved in apoptosis, and to repair oxidative DNA damage. As a consequence, the improvement of the nutritional quality of berries has become a new quality target of breeding and biotechnological strategies, to control or to increase the content of specific health-related compounds in fruits. This work reviews, on the basis of the in vitro and in vivo evidence, the main berries' phytochemical compounds and their possible mechanisms of action on pathways involved in several type of diseases, with particular attention to cancer, inflammation, neurodegeneration, diabetes and cardiovascular diseases.

Phytochemical Compounds and Protection from Cardiovascular Diseases: A State of the Art

Cardiovascular diseases represent a worldwide relevant socioeconomical problem. Cardiovascular disease prevention relies also on lifestyle changes, including dietary habits. The cardioprotective effects of several foods and dietary supplements in both animal models and in humans have been explored. It was found that beneficial effects are mainly dependent on antioxidant and anti-inflammatory properties, also involving modulation of mitochondrial function. Resveratrol is one of the most studied phytochemical compounds and it is provided with several benefits in cardiovascular diseases as well as in other pathological conditions (such as cancer). Other relevant compounds are Brassica oleracea, curcumin, and berberine, and they all exert beneficial effects in several diseases. In the attempt to provide a comprehensive reference tool for both researchers and clinicians, we summarized in the present paper the existing literature on both preclinical and clinical cardioprotective effects of each mentioned phytochemical. We structured the discussion of each compound by analyzing, first, its cellular molecular targets of action, subsequently focusing on results from applications in both ex vivo and in vivo models, finally discussing the relevance of the compound in the context of human diseases.

Vaccinium myrtillus extract prevents or delays the onset of diabetes--induced blood-retinal barrier breakdown

Many dietary supplements have been sold through advertising their large number of beneficial effects. The aim of this study was to determine whether bilberries (Vaccinium myrtillus) help to prevent diabetes-induced retinal vascular dysfunction in vivo. V. myrtillus extract (VME; 100 mg/kg) was orally administered to streptozotocin-induced diabetic rats for 6 weeks. All diabetic rats exhibited hyperglycemia, and VME did not affect the blood glucose levels and body weight during the experiments. In the fluorescein-dextran angiography, the fluorescein leakage was significantly reduced in diabetic rats treated with VME. VME treatment also decreased markers of diabetic retinopathy, such as retinal vascular endothelial growth factor (VEGF) expression and degradation of zonula occludens-1, occludin and claudin-5 in diabetic rats. In conclusion, VME may prevent or delay the onset of early diabetic retinopathy. These findings have important implications for prevention of diabetic retinopathy using a dietary bilberry supplement.

Cytoprotective and antioxidant effects of Echium amoenum anthocyanin-rich extract in human endothelial cells (HUVECs)

OBJECTIVE

Echium amoenum Fisch. & C.A. Mey. is used for the treatment of various diseases in traditional medicine. This plant is a major source of anthocyanins with beneficial cardiovascular properties such as anti-atherosclerotic and antihypertensive effects. In the present study, the protective and antioxidant effects of anthocyanin-rich E. amoenum extract were evaluated on human vascular endothelial cells (HUVECs) under oxidative stress.

MATERIALS AND METHODS

Cell viability and oxidative status were assessed on H2O2-induced oxidative stress (0.5 mM H2O2 for 2 h) in HUVECs pretreated by anthocyanin-rich extract from the petals of E. amoenum (25-1000 µg/ml). Cytoprotective effect of the extract was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The hydroperoxides concentration and ferric reducing antioxidant power (FRAP) were assessed in intra- and extra-cellular fluid of pretreated cells.

RESULTS

Pretreatment of HUVECs with E. amoenum extract at the concentrations of 100-1000 µg/ml reduced the cell death resulted from the exposure to H2O2 in a concentration-dependent manner. E. amoenum extract decreased hydroperoxides concentration and increased FRAP value in both intra- and extra-cellular fluid at different concentration ranges. Moreover, it did not show cytotoxic effects at the concentration range of 25-1000 µg/ml.

CONCLUSION

These results suggest antioxidant and protective effect of anthocyanin-rich extract of the petals of E. amoenum against H2O2-induced oxidative stress in HUVECs. However, further investigations are needed for understanding the detailed mechanisms of cytoprotective effects of this traditional herbal medicine.

Cyanidin-3-glucoside isolated from mulberry fruits protects pancreatic β-cells against glucotoxicity-induced apoptosis

The present study investigated the cytoprotective effects of cyanidin‑3‑glucoside (C3G), isolated from mulberry fruits, on the glucotoxicity‑induced apoptosis of pancreatic β‑cells to evaluate the antidiabetic effects of this compound. MIN6N pancreatic β‑cells were used to investigate the cytoprotective effects of C3G. In addition, the effects of C3G on the glucotoxicity‑induced apoptosis of pancreatic β‑cells was evaluated using MTT assay, immunofluorescent staining, flow cytometric and western blot analyses. The pancreatic β‑cells cultured under high glucose conditions exhibited distinct apoptotic features. C3G decreased the generation of intracellular reactive oxygen species, DNA fragmentation and the rate of apoptosis. C3G also prevented pancreatic β‑cell apoptosis induced by high glucose conditions by interfering with the intrinsic apoptotic pathways. In addition, C3G treatment resulted in increased insulin secretion compared with treatment with high glucose only. In conclusion, the results of the present study suggested that C3G obtained from mulberry fruits may be a potential phytotherapeutic agent for the prevention of diabetes.

Effects of polyphenolic grape extract on the oxidative status of muscle and endothelial cells

A grape pomace extract enhanced antioxidant mechanisms in muscle and endothelial cells both in the absence and in the presence of oxidative stress-induced agent tert-butyl hydroperoxide (tBHP). In particular, muscle (C2C12) and endothelial (EA.hy926) cells were treated with the extract at noncytotoxic concentrations for 24 h, and the oxidative stress markers, total reactive oxygen species (ROS), glutathione (GSH), thiobarbituric reactive substances (TBARS), and protein carbonyl levels were assessed. The results showed that the grape extract treatment reduced significantly ROS, TBARS, and protein carbonyl levels and increased GSH in C2C12 cells, while it increased GSH and decreased protein carbonyl levels in EA.hy926 cells. In the presence of tBHP, the grape extract treatment in C2C12 cells reduced significantly ROS, TBARS, and protein carbonyls and increased GSH compared with tBHP alone treatment, while, in EA.hy926 cells, the extract decreased significantly TBARS and protein carbonyls but increased GSH. The antioxidant potency of the extract was different between muscle and endothelial cells suggesting that the antioxidant activity depends on cell type. Moreover, the antioxidant activity of the grape extract, in both cell lines, exerted, at least in part, through increase in GSH levels. The present work is the first to report the effects of grape extract shown for skeletal muscle cells.

Valsartan ameliorates ageing-induced aorta degeneration via angiotensin II type 1 receptor-mediated ERK activity

Angiotensin II (Ang II) plays important roles in ageing-related disorders through its type 1 receptor (AT1 R). However, the role and underlying mechanisms of AT1R in ageing-related vascular degeneration are not well understood. In this study, 40 ageing rats were randomly divided into two groups: ageing group which received no treatment (ageing control), and valsartan group which took valsartan (selective AT1R blocker) daily for 6 months. 20 young rats were used as adult control. The aorta structure were analysed by histological staining and electron microscopy. Bcl-2/Bax expression in aorta was analysed by immunohistochemical staining, RT-PCR and Western blotting. The expressions of AT1 R, AT2 R and mitogen-activated protein kinases (MAPKs) were detected. Significant structural degeneration of aorta in the ageing rats was observed, and the degeneration was remarkably ameliorated by long-term administration of valsartan. With ageing, the expression of AT1R was elevated, the ratio of Bcl-2/Bax was decreased and meanwhile, an important subgroup of MAPKs, extracellular signal-regulated kinase (ERK) activity was elevated. However, these changes in ageing rats could be reversed to some extent by valsartan. In vitro experiments observed consistent results as in vivo study. Furthermore, ERK inhibitor could also acquire partial effects as valsartan without affecting AT1R expression. The results indicated that AT1R involved in the ageing-related degeneration of aorta and AT1R-mediated ERK activity was an important mechanism underlying the process.

High anthocyanin intake is associated with a reduced risk of myocardial infarction in young and middle-aged women

BACKGROUND

Our current knowledge of modifiable risk factors to prevent myocardial infarction (MI) in young and middle-aged women is limited, and the impact of diet is largely unknown. Dietary flavonoids exert potential beneficial effects on endothelial function in short-term trials; however, the relationship between habitual intake and risk of MI in women is unknown.

METHODS AND RESULTS

We followed up 93 600 women 25 to 42 years of age from the Nurses' Health Study (NHS) II who were healthy at baseline (1989) to examine the relationship between anthocyanins and other flavonoids and the risk of MI. Intake of flavonoid subclasses was calculated from validated food-frequency questionnaires collected every 4 years using an updated and extended US Department of Agriculture database. During 18 years of follow-up, 405 cases of MI were reported. An inverse association between higher intake of anthocyanins and risk of MI was observed (hazard ratio, 0.68; 95% confidence interval, 0.49-0.96; P=0.03, highest versus lowest quintiles) after multivariate adjustment. The addition of intermediate conditions, including history of hypertension, did not significantly attenuate the relationship (hazard ratio, 0.70; 95% confidence interval, 0.50-0.97; P=0.03). Combined intake of 2 anthocyanin-rich foods, blueberries and strawberries, tended to be associated with a decreased risk of MI (hazard ratio, 0.66; 95% confidence interval, 0.40-1.08) in a comparison of those consuming >3 servings a week and those with lower intake. Intakes of other flavonoid subclasses were not significantly associated with MI risk.

CONCLUSIONS

A high intake of anthocyanins may reduce MI risk in predominantly young women. Intervention trials are needed to further examine the health impact of increasing intakes of commonly consumed anthocyanin-rich foods.

1H NMR-based metabolic fingerprinting of urine metabolites after consumption of lingonberries (Vaccinium vitis-idaea) with a high-fat meal

The use of NMR metabolomics in clinical trials is growing; however, reports of postprandial experiments in humans are scarce. The present study investigated whether consumption of lingonberries as a supplement to an oil-rich meal modifies the postprandial fingerprints of human urine. Urine samples were analysed by (1)H NMR, and untargeted multivariate analysis was applied to the data for comprehensive fingerprinting. A clear separation of postprandial lingonberry meal samples was revealed. To evaluate statistical differences, a targeted approach was applied for the informative spectral areas. Significantly (p<0.05) increased levels of polyphenol metabolites, hippuric acid and 4-hydroxyhippuric acid, and decreased creatinine and dimethylamine levels were the major explanations for the grouping of the postprandial samples after the different meals. Thus, inclusion of polyphenol-rich lingonberry powder in a rapeseed oil-rich meal modifies the metabolic profile of urine which may be used to reveal both consumption of berries and health-promoting changes in the common metabolism.

Cyanidin-3-glucoside suppresses TNF-α-induced cell proliferation through the repression of Nox activator 1 in mouse vascular smooth muscle cells: involvement of the STAT3 signaling

Cyanidin-3-glucoside (C3G) is a member of the anthocyanin family which belongs to the flavonoid class and possesses antiatherogenic properties. Many studies have demonstrated the protective effects of C3G on vascular endothelial cells and monocytes, however, the precise effects on vascular smooth muscle cells (VSMCs) have been less thoroughly studied. Hence, we investigated the role of C3G in TNF-α-induced VSMCs proliferation and explored the possible mechanisms. TNF-α stimulated VSMCs proliferation, and pretreatment with C3G inhibited the proliferation in dose- and time-dependent manners. Then, we found that C3G attenuated TNF-α-induced ROS over generation by Dihydroethidium staining. The combination of 50 μM C3G and 100 μM apocynin significantly reduced ROS generation. Moreover, C3G pretreatment significantly suppressed the expression of Nox activator 1, a subunit of NADPH oxidase in mouse VSMCs. C3G also inhibited TNF-α-induced signal transducer and activator of transcription (STAT3) phosphorylation, and the inhibitory effect was more prominent in C3G and apocynin co-pretreated cells than that pretreated with C3G or apocynin alone. Administration of the ROS scavenger catalase (2,000 U/ml) remarkably inhibited TNF-α-induced cell proliferation and STAT3 activation. These data suggest that C3G exerts its antiproliferative effect on TNF-α-induced VSMCs proliferation through inhibiting STAT3 activation by attenuating NoxA1-derived ROS over production.

PDGF: the nuts and bolts of signalling toolbox

PDGF is a growth factor and is extensively involved in multi-dimensional cellular dynamics. It switches on a plethora of molecules other than its classical pathway. It is engaged in various transitions of development; however, if the unleashed potentials lead astray, it brings forth tumourigenesis. Conventionally, it has been assumed that the components of this signalling pathway show fidelity and act with a high degree of autonomy. However, as illustrated by the PDGF signal transduction, reinterpretation of recent data suggests that machinery is often shared between multiple pathways, and other components crosstalk to each other through multiple mechanisms. It is important to note that metastatic cascade is an intricate process that we have only begun to understand in recent years. Many of the early steps of this PDGF cascade are not readily targetable in the clinic. In this review, we will unravel the paradoxes with reference to mitrons and cellular plasticity and discuss how disruption of signalling cascade triggers cellular proliferation phase transition and metastasis. We will also focus on the therapeutic interventions to counteract resultant molecular disorders.

Dietary chalcones with chemopreventive and chemotherapeutic potential

Chalcones are absorbed in the daily diet and appear to be promising cancer chemopreventive agents. Chalcones represent an important group of the polyphenolic family, which includes a large number of naturally occurring molecules. This family possesses an interesting spectrum of biological activities, including antioxidative, antibacterial, anti-inflammatory, anticancer, cytotoxic, and immunosuppressive potential. Compounds of this family have been shown to interfere with each step of carcinogenesis, including initiation, promotion and progression. Moreover, numerous compounds from the family of dietary chalcones appear to show activity against cancer cells, suggesting that these molecules or their derivatives may be considered as potential anticancer drugs. This review will focus primarily on prominent members of the chalcone family with an 1,3-diphenyl-2-propenon core structure. Specifically, the inhibitory effects of these compounds on the different steps of carcinogenesis that reveal interesting chemopreventive and chemotherapeutic potential will be discussed.

Anthocyanins in cardiovascular disease

Anthocyanins are a group of abundant and widely consumed flavonoid constituents that occur ubiquitously in the plant kingdom, providing the bright red-orange to blue-violet colors present in many fruit- and vegetable-based food products. Their intake has been estimated to be up to 9-fold higher than that of other dietary flavonoids. Anthocyanins have become increasingly important to the food industry as their use as natural alternatives to artificial colors has become widespread and knowledge of their health-promoting properties has become more evident. Epidemiological studies suggest that increased consumption of anthocyanins lowers the risk of cardiovascular disease (CVD), the most common cause of mortality among men and women. Anthocyanins frequently interact with other phytochemicals, exhibiting synergistic biological effects but making contributions from individual components difficult to decipher. Over the past 2 decades, many peer-reviewed publications have demonstrated that in addition to their noted in vitro antioxidant activity, anthocyanins may regulate different signaling pathways involved in the development of CVD. This review summarizes the latest developments on the bioavailability/bioactivity and CVD preventative activities of anthocyanins, including results from in vitro cell culture and in vivo animal model systems as related to their multiple proposed mechanisms of action. Limited yet promising data from epidemiological studies and human clinical trials are also presented. Future studies aimed at enhancing the absorption of anthocyanins and characterizing their metabolic and/or breakdown products are necessary to ultimately evaluate their use for protection/prevention against the development of CVD.

The bioactive compounds alpha-chaconine and gallic acid in potato extracts decrease survival and induce apoptosis in LNCaP and PC3 prostate cancer cells

We recently reported that colored potato extracts and an anthocyanin rich fraction suppressed lymph-node carcinoma of the prostate (LNCaP) and prostate cancer-3 (PC-3) prostate cancer cell proliferation and induced apoptosis via caspase-dependent and caspase-independent pathways. Chlorogenic acid, caffeic acid, gallic acid, catechin, malvidin, and glycoalkaloids (alpha-chaconine and solanine) have now been identified as the major bioactive components of potato, and their effects on LNCaP and PC-3 cell proliferation and apoptosis have been investigated. alpha-chaconine (5 microg/ml) and gallic acid (15 microg/ml) exhibited potent antiproliferative properties and increased cyclin-dependent kinase inhibitor p27 levels in both cell lines. Both alpha-chaconine and gallic acid induced poly [adenosine diphosphate (ADP)] ribose polymerase cleavage and caspase-dependent apoptosis in LNCaP cells; however, caspase-independent apoptosis through nuclear translocation of endonuclease G was observed in both LNCaP and PC-3 cells. alpha-chaconine and gallic acid activated c-Jun N-terminal protein kinase (JNK), and this response played a major role in induction of caspase-dependent apoptosis in LNCaP cells; whereas modulation of JNK and mitogen-activated protein kinase did not affect alpha-chaconine- and gallic acid-induced caspase-independent apoptosis. These results suggest that apoptosis induced by whole potato extracts in prostate cancer cell lines may be in part due to alpha-chaconine and gallic acid.

Ellagitannins, ellagic acid and vascular health

Hydrolysable tannins are phenolic phytochemicals that show high antioxidant and free-radical scavenging activities. For this reason their potential effects preventing oxidative related diseases, such as cardiovascular diseases, have been largely studied. In vitro studies show that ellagitannins, at concentrations in the range 10-100 μM, show some relevant anti-atherogenic, anti-thrombotic, anti-inflammatory and anti-angiogenic effects, supporting the molecular mechanisms for the vascular health benefits. While there is good evidence supporting the vascular effects in vitro, the evidence on animal models or humans is much scarcer. The in vitro results often do not match the findings in the in vivo studies. This could be explained by the low bioavailability of the antioxidant ellagitannins and ellagic acid. The main ellagitannin metabolites circulating in plasma are ellagic acid microbiota metabolites known as urolithins, and they have lost their free-radical scavenging activity. They are present in plasma as glucuronide or sulphate conjugates, at concentrations in the nM range. Future studies should focus in the bioavailable metabolites, urolithins, and in the form (conjugated with glucuronic acid or sulphate) and concentrations (nM range) in which they are found in plasma. In this review we critically discuss the role of ellagitannins and ellagic acid on vascular health.

Anti-inflammatory activity of natural dietary flavonoids

Over the past few decades, inflammation has been recognized as a major risk factor for various human diseases. Acute inflammation is short-term, self-limiting and it's easy for host defenses to return the body to homeostasis. Chronic inflammatory responses are predispose to a pathological progression of chronic illnesses characterized by infiltration of inflammatory cells, excessive production of cytokines, dysregulation of cellular signaling and loss of barrier function. Targeting reduction of chronic inflammation is a beneficial strategy to combat several human diseases. Flavonoids are widely present in the average diet in such foods as fruits and vegetables, and have been demonstrated to exhibit a broad spectrum of biological activities for human health including an anti-inflammatory property. Numerous studies have proposed that flavonoids act through a variety mechanisms to prevent and attenuate inflammatory responses and serve as possible cardioprotective, neuroprotective and chemopreventive agents. In this review, we summarize current knowledge and underlying mechanisms on anti-inflammatory activities of flavonoids and their implicated effects in the development of various chronic inflammatory diseases.

Blueberry fruit polyphenolics suppress oxidative stress-induced skeletal muscle cell damage in vitro

Skeletal muscle damage can result from disease and unaccustomed or excessive exercise. Muscle dysfunction occurs via an increased level of reactive oxygen species and hence there is potential in antioxidants as amelioration strategies. We explored the putative benefit of fruit polyphenolic extracts in reducing the susceptibility of skeletal muscle cells to oxidative stress. Muscle myotubes were simultaneously challenged with fruit extracts (1-50 microg/mL) and calcium ionophore (A23187), hydrogen peroxide, or 2,4-dinitrophenol and damage monitored by release of cytosolic enzymes. A blueberry fruit extract displayed a potent and significant dose-dependent protective capacity. Evaluation of the protective capacity of anthocyanin sub-extracts of blueberry fruit and pure individual glycosides, with identification of extract polyphenolic components using MS, suggested that malvidin galactoside and/or glucoside were the active compounds. These in vitro data support the concept that blueberry fruits or derived foods rich in malvidin glycosides may be beneficial in alleviating muscle damage caused by oxidative stress. More research on the benefits of blueberry fruit consumption in human intervention studies is warranted.

Differential chemosensitization of P-glycoprotein overexpressing K562/Adr cells by withaferin A and Siamois polyphenols

Background

Multidrug resistance (MDR) is a major obstacle in cancer treatment and is often the result of overexpression of the drug efflux protein, P-glycoprotein (P-gp), as a consequence of hyperactivation of NFκB, AP1 and Nrf2 transcription factors. In addition to effluxing chemotherapeutic drugs, P-gp also plays a specific role in blocking caspase-dependent apoptotic pathways. One feature that cytotoxic treatments of cancer have in common is activation of the transcription factor NFκB, which regulates inflammation, cell survival and P-gp expression and suppresses the apoptotic potential of chemotherapeutic agents. As such, NFκB inhibitors may promote apoptosis in cancer cells and could be used to overcome resistance to chemotherapeutic agents.

Results

Although the natural withanolide withaferin A and polyphenol quercetin, show comparable inhibition of NFκB target genes (involved in inflammation, angiogenesis, cell cycle, metastasis, anti-apoptosis and multidrug resistance) in doxorubicin-sensitive K562 and -resistant K562/Adr cells, only withaferin A can overcome attenuated caspase activation and apoptosis in K562/Adr cells, whereas quercetin-dependent caspase activation and apoptosis is delayed only. Interestingly, although withaferin A and quercetin treatments both decrease intracellular protein levels of Bcl2, Bim and P-Bad, only withaferin A decreases protein levels of cytoskeletal tubulin, concomitantly with potent PARP cleavage, caspase 3 activation and apoptosis, at least in part via a direct thiol oxidation mechanism.

Conclusions

This demonstrates that different classes of natural NFκB inhibitors can show different chemosensitizing effects in P-gp overexpressing cancer cells with impaired caspase activation and attenuated apoptosis.

Flavanols and anthocyanins in cardiovascular health: a review of current evidence

Nowadays it is accepted that natural flavonoids present in fruits and plant-derived-foods are relevant, not only for technological reasons and organoleptic properties, but also because of their potential health-promoting effects, as suggested by the available experimental and epidemiological evidence. The beneficial biological effects of these food bioactives may be driven by two of their characteristic properties: their affinity for proteins and their antioxidant activity. Over the last 15 years, numerous publications have demonstrated that besides their in vitro antioxidant capacity, certain phenolic compounds, such as anthocyanins, catechins, proanthocyanidins, and other non coloured flavonoids, may regulate different signaling pathways involved in cell survival, growth and differentiation. In this review we will update the knowledge on the cardiovascular effects of anthocyanins, catechins and proanthocyanidins, as implied by the in vitro and clinical studies on these compounds. We also review the available information on the structure, distribution and bioavailability of flavanols (monomeric catechins and proanthocyanidins) and anthocyanins, data necessary in order to understand their role in reducing risk factors and preventing cardiovascular health problems through different aspects of their bioefficacy on vascular parameters (platelet agregation, atherosclerosis, blood pressure, antioxidant status, inflammation-related markers, etc.), myocardial conditions, and whole-body metabolism (serum biochemistry, lipid profile), highlighting the need for better-designed clinical studies to improve the current knowledge on the potential health benefits of these flavonoids to cardiovascular and metabolic health.

Phosphoinositide 3-kinase is a novel target of piceatannol for inhibiting PDGF-BB-induced proliferation and migration in human aortic smooth muscle cells

AIMS

Abnormal migration and proliferation of human aortic smooth muscle cells (HASMCs) to the intima causes intimal thickening of the aorta, which is strongly related to the development of atherosclerosis. Previous studies have suggested that red wine polyphenols, particularly resveratrol, have great protective effects against cardiovascular diseases. Here, we compared the anti-atherosclerotic effect of piceatannol, a metabolite of resveratrol, and its underlying mechanisms.

METHODS AND RESULTS

We demonstrated that piceatannol inhibited platelet-derived growth factor (PDGF)-BB-induced cell migration using a modified Boyden chamber assay and wound healing assay. Western blot analysis showed that PDGF-BB-induced phosphorylation of Akt, p70S6K, and p38 was inhibited by piceatannol, but not resveratrol. In vitro and ex vivo phosphoinositide 3-kinase (PI3K) assays demonstrated that piceatannol suppressed PI3K activity more effectively than resveratrol. PDGF-BB-induced migration and proliferation of HASMCs were inhibited by treatment with a commercial PI3K inhibitor, LY294002. Both in vitro and ex vivo pull-down assays revealed that piceatannol directly binds with sepharose 4B-PI3K beads in an ATP-competitive manner.

CONCLUSION

The results of the present study demonstrate that piceatannol directly binds with PI3K in an ATP-competitive manner and suppresses PI3K activity with anti-atherosclerotic effects.