In vitro inhibition of the activity of phosphorylase kinase, protein kinase C and protein kinase A by caffeic acid and a procyanidin-rich pine bark (Pinus marittima) extract

Putative role of natural products as Protein Kinase C modulator in different disease conditions

INTRODUCTION

Protein kinase C (PKC) is a promising drug target for various therapeutic areas. Natural products derived from plants, animals, microorganisms, and marine organisms have been used by humans as medicine from prehistoric times. Recently, several compounds derived from plants have been found to modulate PKC activities through competitive binding with ATP binding site, and other allosteric regions of PKC. As a result fresh race has been started in academia and pharmaceutical companies to develop an effective naturally derived small-molecule inhibitor to target PKC activities. Herein, in this review, we have discussed several natural products and their derivatives, which are reported to have an impact on PKC signaling cascade.

METHODS

All information presented in this review article regarding the regulation of PKC by natural products has been acquired by a systematic search of various electronic databases, including ScienceDirect, Scopus, Google Scholar, Web of science, ResearchGate, and PubMed. The keywords PKC, natural products, curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, protocatechuic acid, tannic acid, PKC modulators from marine organism, bryostatin, staurosporine, midostaurin, sangivamycin, and other relevant key words were explored.

RESULTS

The natural products and their derivatives including curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, bryostatin, staurosporine, and midostaurin play a major role in the management of PKC activity during various disease progression.

CONCLUSION

Based on the comprehensive literature survey, it could be concluded that various natural products can regulate PKC activity during disease progression. However, extensive research is needed to circumvent the challenge of isoform specific regulation of PKC by natural products.

Propolis Extract and Its Bioactive Compounds-From Traditional to Modern Extraction Technologies

Propolis is a honeybee product known for its antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. It is rich in bioactive molecules whose content varies depending on the botanical and geographical origin of propolis. These bioactive molecules have been studied individually and as a part of propolis extracts, as they can be used as representative markers for propolis standardization. Here, we compare the pharmacological effects of representative polyphenols and whole propolis extracts. Based on the literature data, polyphenols and extracts act by suppressing similar targets, from pro-inflammatory TNF/NF-κB to the pro-proliferative MAPK/ERK pathway. In addition, they activate similar antioxidant mechanisms of action, like Nrf2-ARE intracellular antioxidant pathway, and they all have antimicrobial activity. These similarities do not imply that we should attribute the action of propolis solely to the most representative compounds. Moreover, its pharmacological effects will depend on the efficacy of these compounds’ extraction. Thus, we also give an overview of different propolis extraction technologies, from traditional to modern ones, which are environmentally friendlier. These technologies belong to an open research area that needs further effective solutions in terms of well-standardized liquid and solid extracts, which would be reliable in their pharmacological effects, environmentally friendly, and sustainable for production.

Compounds from Natural Sources as Protein Kinase Inhibitors

The advantage of natural compounds is their lower number of side-effects when compared to most synthetic substances. Therefore, over the past several decades, the interest in naturally occurring compounds is increasing in the search for new potent drugs. Natural compounds are playing an important role as a starting point when developing new selective compounds against different diseases. Protein kinases play a huge role in several diseases, like cancers, neurodegenerative diseases, microbial infections, or inflammations. In this review, we give a comprehensive view of natural compounds, which are/were the parent compounds in the development of more potent substances using computational analysis and SAR studies.

Nanomaterial based electrochemical sensors for the safety and quality control of food and beverages

The issue of foodborne related illnesses due to additives and contaminants poses a significant challenge to food processing industries. The efficient, economical and rapid analysis of food additives and contaminants is therefore necessary in order to minimize the risk of public health issues. Electrochemistry offers facile and robust analytical methods, which are desirable for food safety and quality assessment over conventional analytical techniques. The development of a wide array of nanomaterials has paved the way for their applicability in the design of high-performance electrochemical sensing devices for medical diagnostics and environment and food safety. The design of nanomaterial based electrochemical sensors has garnered enormous attention due to their high sensitivity and selectivity, real-time monitoring and ease of use. This review article focuses predominantly on the synthesis and applications of different nanomaterials for the electrochemical determination of some common additives and contaminants, including hydrazine (N2H4), malachite green (MG), bisphenol A (BPA), ascorbic acid (AA), caffeine, caffeic acid (CA), sulfite (SO32-) and nitrite (NO2-), which are widely found in food and beverages. Important aspects, such as the design, fabrication and characterization of graphene-based materials, gold nanoparticles, mono- and bimetallic nanoparticles and metal nanocomposites, sensitivity and selectivity for electrochemical sensor development are addressed. High-performance nanomaterial based electrochemical sensors have and will continue to have myriad prospects in the research and development of advanced analytical devices for the safety and quality control of food and beverages.

Sensitive Electrochemical Detection of Caffeic Acid in Wine Based on Fluorine-Doped Graphene Oxide

We report here a novel electrochemical sensor developed using fluorine-doped graphene oxide (F-GO) for the detection of caffeic acid (CA). The synthesized graphene oxide (GO) and F-GO nanomaterials were systematically characterized with a scanning electron microscope (SEM), and the presence of semi-ionic bonds was confirmed in the F-GO using X-ray photoelectron spectroscopy. The electrochemical behaviours of bare glassy carbon electrode (GCE), F-GO/GCE, and GO/GCE toward the oxidation of CA were studied using cyclic voltammetry (CV), and the results obtained from the CV investigation revealed that F-GO/GCE exhibited the highest electrochemically active surface area and electrocatalytic activity in contrast to the other electrodes. Differential pulse voltammetry (DPV) was employed for the analytical quantitation of CA, and the F-GO/GCE produced a stable oxidation signal over the selected CA concentration range (0.5 to 100.0 μM) with a low limit of detection of 0.018 μM. Furthermore, the acquired results from the selectivity studies revealed a strong anti-interference capability of the F-GO/GCE in the presence of other hydroxycinnamic acids and ascorbic acid. Moreover, the F-GO/GCE offered a good sensitivity, long-term stability, and an excellent reproducibility. The practical application of the electrochemical F-GO sensor was verified using various brands of commercially available wine. The developed electrochemical sensor successfully displayed its ability to directly detect CA in wine samples without pretreatment, making it a promising candidate for food and beverage quality control.

Cancer Prevention and Therapy with Polyphenols: Sphingolipid-Mediated Mechanisms

Polyphenols, chemically characterized by a polyhydroxylated phenolic structure, are well known for their widespread pharmacological properties: anti-inflammatory, antibiotic, antiseptic, antitumor, antiallergic, cardioprotective and others. Their distribution in food products is also extensive especially in plant foods such as vegetables, cereals, legumes, fruits, nuts and certain beverages. The latest scientific literature outlines a resilient interconnection between cancer modulation and dietary polyphenols by sphingolipid-mediated mechanisms, usually correlated with a modification of their metabolism. We aim to extensively survey this relationship to show how it could be advantageous in cancer treatment or prevention by nutrients. From this analysis it emerges that a combination of classical chemotherapy with nutrients and especially with polyphenols dietary sources may improve efficacy and decreases negative side effects of the antineoplastic drug. In this multifaceted scenario, sphingolipids play a pivotal role as bioactive molecules, emerging as the mediators of cell proliferation in cancer and modulator of chemotherapeutics.

Baccharis dracunculifolia DC (Asteraceae) selectively modulates the effector functions of human neutrophils

OBJECTIVES

To examine whether the hydroalcoholic extract from Baccharis dracunculifolia leaves (BdE) modulates the human neutrophil oxidative metabolism, degranulation, phagocytosis and microbial killing capacity.

METHODS

In-vitro assays based on chemiluminescence, spectrophotometry, flow cytometry and polarimetry were used, as well as docking calculations.

KEY FINDINGS

At concentrations that effectively suppressed the neutrophil oxidative metabolism elicited by soluble and particulate stimuli (<10 μg/ml), without clear signs of cytotoxicity, BdE (1) inhibited NADPH oxidase and myeloperoxidase activity; (2) scavenged H₂ O₂ and HOCl; (3) weakly inhibited phagocytosis; and (4) did not affect neutrophil degranulation and microbial killing capacity, the expression levels of TLR2, TLR4, FcγRIIa, FcγRIIIb and CR3 and the activity of elastase and lysozyme. Caffeic acid, one of the major B. dracunculifolia secondary metabolites, did not inhibit phagocytosis but interfered in the myeloperoxidase-H₂ O₂ -HOCl system by scavenging H₂ O₂ and HOCl, and interacting with the catalytic residues His-95, Arg-239 and Gln-91.

CONCLUSIONS

BdE selectively modulates the effector functions of human neutrophils, inhibits the activity of key enzymes and scavenges physiological oxidant species. Caffeic acid contributes to lower the levels of oxidant species. Our findings help to unravel the mechanisms by which these natural products exert immunomodulatory action towards neutrophils.

Mechanisms on spasmolytic and anti-inflammatory effects of a herbal medicinal product consisting of myrrh, chamomile flower, and coffee charcoal

Inflammatory bowel disease or irritable bowel syndrome are chronic gastrointestinal disorders which are associated with a lifelong therapeutic need. The disease results in physical, psychological, and social problems with an impact on partnership, sexuality, education, and career. Thus, the number of patients and health care professionals relying on traditional and complementary medicines and especially phytotherapy for the treatment of these chronic conditions is increasing over recent years. One traditional herbal medicinal product consisting of chamomile flower, myrrh, and coffee charcoal has been widely used in clinical practice within this indication area. Long-term experience and an increasing understanding of the pharmacological mechanisms substantiate its application and clinical effectiveness. Mainly the spasmolytic and anti-inflammatory effects provide a rationale for its therapeutic application. In addition, synergistic effects between the herbal components contribute to the overall effect of this medication.

Ingestion of Proanthocyanidins Derived from Cacao Inhibits Diabetes-Induced Cataract Formation in Rats

Proanthocyanidins derived from cacao (CLP) have various antipathophysiological functions. We have tested whether dietary supplementation with CLP prevents cataract formation in rats with diabetes induced by streptozotocin (STZ), using histological, histochemical, and biochemical analyses. Starting at 7 days after the streptozotocin challenge, the animals were fed either a normal diet or a diet containing 0.5% w/w CLP over 10 weeks. There were no significant differences in plasma and urine glucose concentrations, plasma fructose amines, and plasma thiobarbituric reactive substances (TBARS) between the two dietary groups. Antioxidant status as assessed by measuring lipid peroxide production in plasma in response to azocompounds was lower in the STZ-rats fed control diet than in animals fed CLP. Opacity was first detected in the lenses of the control dietary group 5 weeks after STZ injection and cataracts had developed in the majority of these animals by 10 weeks. These changes were rarely seen in the STZ/CLP diet group. Histological examinations of the eyes of the STZ-treated normal diet group revealed focal hyperplasia of the lens epithelium and liquefaction of cortical fibers. There were similar but considerably less severe changes in the animals fed CLP. Hydroxynonenal (HNE), a marker of oxidative stress, was detected immunohistochemically in the lenses of the STZ-treated normal diet group, but not of those receiving CLP. Our findings suggest that CLP inhibits diabetes-induced cataract formation possibly by virtue of its antioxidative activity.

Phenolic compounds alone or in combination may be involved in propolis effects on human monocytes

Objectives

Propolis is a natural product with a complex chemical composition. Its isolated compounds exert biological activities; however, its synergistic effects are unknown. The involvement of phenolic acids (caffeic – Caf, dihydrocinnamic – Cin and p-coumaric – Cou) alone or in combination was investigated in the action of propolis in human monocytes.

Methods

Cell viability was analysed by MTT assay; TNF-α, IL-6 and IL-10 production by enzyme-linked immunosorbent assay (ELISA); cell markers expression by flow cytometry; colony-forming units were counted to assess the microbicidal activity; and H2O2 production was analysed by colorimetric assay.

Key findings

Treatments did not affect monocytes viability. Propolis and combinations containing Caf enhanced TNF-α production by resting cells. Propolis, Cin, Cou and Caf + Cin stimulated IL-6 production. All treatments upregulated IL-10. In LPS-stimulated cells, treatments downregulated IL-6 and maintained TNF-α and IL-10 production. A lower TLR-2 expression was seen than propolis. Caf + Cin enhanced TLR-4 expression. Propolis, Caf and Caf + Cin stimulated H2O2 production, whereas propolis, Cin, Cou, and Caf + Cin + Cou induced a higher fungicidal activity. Cin and Cin + Cou increased the bactericidal activity of human monocytes.

Conclusion

Propolis activated human monocytes, and acids were involved differently in propolis activity.

Polyphenol compounds and PKC signaling

BACKGROUND

Naturally occurring polyphenols found in food sources provide huge health benefits. Several polyphenolic compounds are implicated in the prevention of disease states, such as cancer. One of the mechanisms by which polyphenols exert their biological actions is by interfering in the protein kinase C (PKC) signaling pathways. PKC belongs to a superfamily of serine-threonine kinase and are primarily involved in phosphorylation of target proteins controlling activation and inhibition of many cellular processes directly or indirectly.

SCOPE OF REVIEW

Despite the availability of substantial literature data on polyphenols' regulation of PKC, no comprehensive review article is currently available on this subject. This article reviews PKC-polyphenol interactions and its relevance to various disease states. In particular, salient features of polyphenols, PKC, interactions of naturally occurring polyphenols with PKC, and future perspective of research on this subject are discussed.

MAJOR CONCLUSIONS

Some polyphenols exert their antioxidant properties by regulating the transcription of the antioxidant enzyme genes through PKC signaling. Regulation of PKC by polyphenols is isoform dependent. The activation or inhibition of PKC by polyphenols has been found to be dependent on the presence of membrane, Ca(2+) ion, cofactors, cell and tissue types etc. Two polyphenols, curcumin and resveratrol are in clinical trials for the treatment of colon cancer.

GENERAL SIGNIFICANCE

The fact that 74% of the cancer drugs are derived from natural sources, naturally occurring polyphenols or its simple analogs with improved bioavailability may have the potential to be cancer drugs in the future.

The ATRA-induced differentiation of medulloblastoma cells is enhanced with LOX/COX inhibitors: an analysis of gene expression

Background

A detailed analysis of the expression of 440 cancer-related genes was performed after the combined treatment of medulloblastoma cells with all-trans retinoic acid (ATRA) and inhibitors of lipoxygenases (LOX) and cyclooxygenases (COX). The combinations of retinoids and celecoxib as a COX-2 inhibitor were reported to be effective in some regimens of metronomic therapy of relapsed solid tumors with poor prognosis. Our previous findings on neuroblastoma cells using expression profiling showed that LOX/COX inhibitors have the capability of enhancing the differentiating action of ATRA. Presented study focused on the continuation of our previous work to confirm the possibility of enhancing ATRA-induced cell differentiation in these cell lines via the application of LOX/COX inhibitors. This study provides more detailed information concerning the mechanisms of the enhancement of the ATRA-induced differentiation of medulloblastoma cells.

Methods

The Daoy and D283 Med medulloblastoma cell lines were chosen for this study. Caffeic acid (an inhibitor of 5-LOX) and celecoxib (an inhibitor on COX-2) were used in combined treatment with ATRA. The expression profiling was performed using Human Cancer Oligo GEArray membranes, and the most promising results were verified using RT-PCR.

Results

The expression profiling of the selected cancer-related genes clearly confirmed that the differentiating effects of ATRA should be enhanced via its combined administration with caffeic acid or celecoxib. This effect was detected in both cell lines. An increased expression of the genes that encoded the proteins participating in induced differentiation and cytoskeleton remodeling was detected in both cell lines in a concentration-dependent manner. This effect was also observed for the CDKN1A gene encoding the p21 protein, which is an important regulator of the cell cycle, and for the genes encoding proteins that are associated with proteasome activity. Furthermore, our results showed that D283 Med cells are significantly more sensitive to treatment with ATRA alone than Daoy cells.

Conclusions

The obtained results on medulloblastoma cell lines are in accordance with our previous findings on neuroblastoma cells and confirm our hypothesis concerning the common mechanism of the enhancement of ATRA-induced cell differentiation in various types of pediatric solid tumors.

Targeting the STAT3 signaling pathway in cancer: role of synthetic and natural inhibitors

Signal transducers and activators of transcription (STATs) comprise a family of cytoplasmic transcription factors that mediate intracellular signaling that is usually generated at cell surface receptors and thereby transmit it to the nucleus. Numerous studies have demonstrated constitutive activation of STAT3 in a wide variety of human tumors, including hematological malignancies (leukemias, lymphomas, and multiple myeloma) as well as diverse solid tumors (such as head and neck, breast, lung, gastric, hepatocellular, colorectal and prostate cancers). There is strong evidence to suggest that aberrant STAT3 signaling promotes initiation and progression of human cancers by either inhibiting apoptosis or inducing cell proliferation, angiogenesis, invasion, and metastasis. Suppression of STAT3 activation results in the induction of apoptosis in tumor cells, and accordingly its pharmacological modulation by tyrosine kinase inhibitors, antisense oligonucleotides, decoy nucleotides, dominant negative proteins, RNA interference and chemopreventive agents have been employed to suppress the proliferation of various human cancer cells in culture and tumorigenicity in vivo. However, the identification and development of novel drugs that can target deregulated STAT3 activation effectively remains an important scientific and clinical challenge. This review presents the evidence for critical roles of STAT3 in oncogenesis and discusses the potential for development of novel cancer therapies based on mechanistic understanding of STAT3 signaling cascade.

Modulatory effects of Pycnogenol in a rat model of insulin-dependent diabetes mellitus: biochemical, histological, and immunohistochemical evidences

A number of experimental and clinical findings have consistently demonstrated the protective effects of Pycnogenol (PYC) in the management of diabetes. However, the protective mechanism by which PYC provides protection in a model type I diabetes has not been studied. This study examines the beneficial effect of PYC on hyperglycemia, inflammatory markers, and oxidative damage in diabetic rats. We also evaluated the possible mechanism of action of PYC which might be that it stimulates beta islet expression, which has been implicated in the process of insulin secretion and diabetes management. Diabetes was induced in rats by an intraperitoneal injection of streptozotocin (STZ; 60 mg/kg body weight) followed by free access to 5 % glucose for the next 24 h. Four days after STZ injection, rats were supplemented with PYC (10 mg/kg body weight) for 4 weeks. At the end of the experiment, blood was drawn, and rats were then sacrificed, and their livers and pancreases were dissected for biochemical and histological assays. The level of fasting blood glucose and glycosylated hemoglobin significantly increased but amylase, insulin, and hepatic glycogen level decreased in the STZ group. PYC significantly augmented these effects in STZ + PYC group. The STZ group showed elevated level of nitric oxide, tumor necrosis factor-α, and interleukin-1beta in serum which were decreased by PYC treatment. Moreover, PYC significantly ameliorated increased thiobarbituric reactive substances, protein carbonyl, and decreased levels of glutathione, glutathione-s-transferase, and catalase activity in the liver and pancreas of the STZ rats. Histopathological and immunohistochemical examination also revealed a remarkable protective effect of PYC. The study suggests that PYC is effective in reducing diabetic-related complications in a type I model of diabetes and might be beneficial for the treatment of diabetic patients.

Neuroprotective effect of Pycnogenol® following traumatic brain injury

Traumatic brain injury (TBI) involves primary and secondary injury cascades that underlie delayed neuronal dysfunction and death. Oxidative stress is one of the most celebrated secondary injury mechanisms. A close relationship exists between levels of oxidative stress and the pathogenesis of TBI. However, other cascades, such as an increase in proinflammatory cytokines, also play important roles in the overall response to the trauma. Pharmacologic intervention, in order to be successful, requires a multifaceted approach. Naturally occurring flavonoids are unique in possessing not only tremendous free radical scavenging properties but also the ability to modulate cellular homeostasis leading to a reduction in inflammation and cell toxicity. This study evaluated the therapeutic role of Pycnogenol (PYC), a patented combinational bioflavonoid. Young adult Sprague-Dawley rats were subjected to a unilateral moderate cortical contusion and treated post injury with PYC or vehicle. At either 48 or 96 h post trauma, the animals were killed and the cortex and hippocampus analyzed for changes in enzymatic and non-enzymatic oxidative stress markers. In addition, possible changes in both pre- and post-synaptic proteins (synapsin-1, PSD-95, drebrin, synapse associated protein-97) were analyzed. Finally, a separate cohort of animals was used to evaluate two proinflammatory cytokines (IL-6, TNF-α). Following the trauma there was a significant increase in oxidative stress in both the injured cortex and the ipsilateral hippocampus. Animals treated with PYC significantly ameliorated levels of protein carbonyls, lipid peroxidation, and protein nitration. The PYC treatment also significantly reduced the loss of key pre- and post-synaptic proteins with some levels in the hippocampus of PYC treated animals not significantly different from sham operated controls. Although levels of the proinflammatory cytokines were significantly elevated in both injury groups, the cohort treated with PYC showed a significant reduction compared to vehicle treated controls. These results are the first to show a neuroprotective effect of PYC following TBI. They also suggest that the diverse effects of bioflavonoids may provide a unique avenue for possible therapeutic intervention following head trauma.

Green synthesis of gold-chitosan nanocomposites for caffeic acid sensing

In this work, colloidal gold nanoparticles (AuNPs) stabilized into a chitosan matrix were prepared using a green route. The synthesis was carried out by reducing Au(III) to Au(0) in an aqueous solution of chitosan and different organic acids (i.e., acetic, malonic, or oxalic acid). We have demonstrated that by varying the nature of the acid it is possible to tune the reduction rate of the gold precursor (HAuCl(4)) and to modify the morphology of the resulting metal nanoparticles. The use of chitosan, a biocompatible and biodegradable polymer with a large number of amino and hydroxyl functional groups, enables the simultaneous synthesis and surface modification of AuNPs in one pot. Because of the excellent film-forming capability of this polymer, AuNPs-chitosan solutions were used to obtain hybrid nanocomposite films that combine highly conductive AuNPs with a large number of organic functional groups. Herein, Au-chitosan nanocomposites are successfully proposed as sensitive and selective electrochemical sensors for the determination of caffeic acid, an antioxidant that has recently attracted much attention because of its benefits to human health. A linear response was obtained over a wide range of concentration from 5.00 × 10(-8) M to 2.00 × 10(-3) M, and the limit of detection (LOD) was estimated to be 2.50 × 10(-8) M. Moreover, further analyses have demonstrated that a high selectivity toward caffeic acid can be achieved without interference from catechin or ascorbic acid (flavonoid and nonphenolic antioxidants, respectively). This novel synthesis approach and the high performances of Au-chitosan hybrid materials in the determination of caffeic acid open up new routes in the design of highly efficient sensors, which are of great interest for the analysis of complex matrices such as wine, soft drinks, and fruit beverages.

Chlorogenic acid suppresses pulmonary eosinophilia, IgE production, and Th2-type cytokine production in an ovalbumin-induced allergic asthma: activation of STAT-6 and JNK is inhibited by chlorogenic acid

Asthma is a chronic inflammatory disease of the airways characterized by reversible airway obstruction, airway hyperreactivity, and remodeling of the airways. Chlorogenic acid (CGA), an ester of caffeic acid with quinic acid, is one of the most abundant polyphenol compounds in various agricultural products. CGA shows various biological properties, such as anti-oxidant, anti-viral, anti-carcinogenic and anti-inflammatory activities. We investigated suppressive effects of CGA on ovalbumin (OVA)-induced allergic asthma in mice and underlying mechanisms of them. CGA significantly reduced pulmonary eosinophilia and expression of IL-4, IL-5 and TNF-α in the lung as well as the serum levels of total and OVA-specific IgE, while CGA enhanced those of total and OVA-specific IgG3, of which isotype switching is down-regulated by IL-4. In vitro IgE production from LPS/IL-4-stimulated splenocytes was remarkably reduced by CGA, while that of IgG3 was enhanced. The Cε germ line transcription, which is necessary for IL-4 mediated IgE isotype switching, was reduced by CGA in LPS/IL-4-stimulated splenocytes. IgE isotype switching is mediated via several transduction pathways, activating several molecules including STAT-6, NF-κB, ERK1/2, and JNK. Among the molecules, which were activated by IL-4/LPS, activation of STAT-6 and JNK was inhibited by CGA.

Caffeic acid, tyrosol and p-coumaric acid are potent inhibitors of 5-S-cysteinyl-dopamine induced neurotoxicity

Parkinson's disease is characterized by a progressive and selective loss of dopaminergic neurons in the substantia nigra. Recent investigations have shown that conjugates such as the 5-S-cysteinyl-dopamine, possess strong neurotoxicity and may contribute to the underlying progression of the disease pathology. Although the neuroprotective actions of flavonoids are well reported, that of hydroxycinnamates and other phenolic acids is less established. We show that the hydroxycinnamates caffeic acid and p-coumaric acid, the hydroxyphenethyl alcohol, tyrosol, and a Champagne wine extract rich in these components protect neurons against injury induced by 5-S-cysteinyl-dopamine in vitro. The protection induced by these polyphenols was equal to or greater than that observed for the flavonoids, (+)-catechin, (-)-epicatechin and quercetin. For example, p-coumaric acid evoked significantly more protection at 1muM (64.0+/-3.1%) than both (-)-epicatechin (46.0+/-4.1%, p<0.05) and (+)-catechin (13.1+/-3.0%, p<0.001) at the same concentration. These data indicate that hydroxycinnamates, phenolic acids and phenolic alcohol are also capable of inducing neuroprotective effects to a similar extent to that seen with flavonoids.

Age-related toxicity of amyloid-beta associated with increased pERK and pCREB in primary hippocampal neurons: reversal by blueberry extract

Further clarification is needed to address the paradox that memory formation, aging and neurodegeneration all involve calcium influx, oxyradical production (ROS) and activation of certain signaling pathways. In aged rats and in APP/PS-1 mice, cognitive and hippocampal Ca(2+) dysregulation was reversed by food supplementation with a high antioxidant blueberry extract. Here, we studied whether neurons were an important target of blueberry extract and whether the mechanism involved altered ROS signaling through MAP kinase and cyclic-AMP response element binding protein (CREB), pathways known to be activated in response to amyloid-beta (Aβ). Primary hippocampal neurons were isolated and cultured from embryonic, middle-age or old-age (24 months) rats. Blueberry extract was found to be equally neuroprotective against Aβ neurotoxicity at all ages. Increases in Aβ toxicity with age were associated with age-related increases in immunoreactivity of neurons to pERK and an age-independent increase in pCREB. Treatment with blueberry extract strongly inhibited these increases in parallel with neuroprotection. Simultaneous labeling for ROS and for glutathione with dichlorofluorescein and monochlorobimane showed a mechanism of action of blueberry extract to involve transient ROS generation with an increase in the redox buffer glutathione. We conclude that the increased age-related susceptibility of old-age neurons to Aβ toxicity may be due to higher levels of activation of pERK and pCREB pathways that can be protected by blueberry extract through inhibition of both these pathways through an ROS stress response. These results suggest that the beneficial effects of blueberry extract may involve transient stress signaling and ROS protection that may translate into improved cognition in aging rats and APP/PS1 mice given blueberry extract.

Pycnogenol prevents potassium dichromate K2Cr2O7-induced oxidative damage and nephrotoxicity in rats

Environmental and occupational exposure to chromium compounds, especially hexavalent chromium [Cr(VI)], is widely recognized as a potential nephrotoxic in humans and animals. Its toxicity is associated with overproduction of free radicals, which induces oxidative damage. Recent evidence indicates that Pycnogenol (PYC), French maritime pine bark extract, exhibits antioxidant potential and protects against various oxidative stressors. The aim of the present study was to examine the modulating impacts of PYC on potassium dichromate K2Cr2O7-induced oxidative damage and nephrotoxicity in rats. Male Wistar rats were divided into four groups. The first group was control, the second group was control plus pre-treated with PYC (10 mg/kg, body weight; in saline; intraperitoneally; once daily for 3 weeks) as drug control and the third group was saline pre-treated plus treated with a single injection of K2Cr2O7 (15 mg/kg, body weight; in saline; intraperitoneally) as toxicant group. The fourth group was PYC pre-treated plus K2Cr2O7 injected. Forty-eight hours after K2Cr2O7-treatment, blood was drawn for estimation of renal injury markers in serum. Rats were then sacrificed, and their kidneys were dissected for biochemical and histopathological assays. K2Cr2O7-treated rats showed significant increases in markers of renal injury in serum, including blood urea nitrogen (BUN), serum creatinine (Scr), and alkaline phosphatase (ALP), which were significantly (P < 0.05) decreased by PYC pre-treatment. Moreover, prophylactic pre-treatment of rats with PYC significantly (P < 0.05) ameliorated increased thiobarbituric reactive substances (TBARS), malonaldehyde (MDA) and protein carbonyl (PC), and decreased levels of glutathione (GSH) and catalase activity in the kidney homogenate of K2Cr2O7-treated rats. These results were also supported and confirmed with histopathological findings. The study suggests that PYC is effective in preventing K2Cr2O7-induced oxidative mediated nephrotoxicity, but more studies are needed to confirm the effects of PYC as a nephroprotective agent.

Caffeic Acid Derivatives: In Vitro and In Vivo Anti-inflammatory Properties

Caffeic acid and some of its derivatives such as caffeic acid phenetyl ester (CAPE) and octyl caffeate are potent antioxidants which present important anti-inflammatory actions. The present study assessed the in vitro and in vivo effects of five caffeic acid derivatives (caffeic acid methyl, ethyl, butyl, octyl and benzyl esters) and compared their actions to those of CAPE. In the model of LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages, the pre-incubation of all derivatives inhibited nitrite accumulation on the supernatant of stimulated cells, with mean IC50 (microM) values of 21.0, 12.0, 8.4, 2.4, 10.7 and 4.80 for methyl, ethyl, butyl, octyl, benzyl and CAPE, respectively. The effects of caffeic acid derivatives seem to be related to the scavenging of NO, as the compounds prevented SNAP-derived nitrite accumulation and decreased iNOS expression. In addition, butyl, octyl and CAPE derivatives significantly inhibited LPS-induced iNOS expression in RAW 264.7 macrophages. Extending the in vitro results, we showed that the pre-treatment of mice with butyl, octyl and CAPE derivatives inhibited carrageenan-induced paw edema and prevented the increase in IL-1beta levels in the mouse paw by 30, 24 and 36%, respectively. Butyl, octyl and CAPE derivatives also prevented carrageenan-induced neutrophil influx in the mouse paw by 28, 49 and 31%, respectively. Present results confirm and extend literature data, showing that caffeic acid derivatives exert in vitro and in vivo anti-inflammatory actions, being their actions mediated, at least in part by the scavenging of NO and their ability to modulate iNOS expression and probably that of other inflammatory mediators.

Effects of red grape juice polyphenols in NADPH oxidase subunit expression in human neutrophils and mononuclear blood cells

The NADPH oxidase enzyme system is the main source of superoxide anions in phagocytic and vascular cells. NADPH oxidase-dependent superoxide generation has been found to be abnormally enhanced in several chronic diseases. Evidence is accumulating that polyphenols may have the potential to improve cardiovascular health, although the mechanism is not fully established. Consumption of concentrated red grape juice, rich in polyphenols, has been recently shown to reduce NADPH oxidase activity in circulating neutrophils from human subjects. In the present work we studied whether red grape juice polyphenols affected NADPH oxidase subunit expression at the transcription level. For this, we used human neutrophils and mononuclear cells from peripheral blood, HL-60-derived neutrophils and the endothelial cell line EA.hy926.Superoxide production was measured with 2'7'-dichlorofluorescein diacetate or lucigenin, mRNA expression by real-time RT-PCR and protein expression by Western blot. Each experiment was performed at least three times. In all cell types tested, red grape juice, dealcoholised red wine and pure polyphenols decreased superoxide anion production. Red grape juice and dealcoholised red wine selectively reduced p47phox, p22phox and gp91phox expression at both mRNA and protein levels, without affecting the expression of p67phox. Pure polyphenols, particularly quercetin, also reduced NADPH oxidase subunit expression, especially p47phox, in all cell types tested. The present results showing that red grape juice polyphenols reduce superoxide anion production provide an alternative mechanism by which consumption of grape derivatives may account for a reduction of oxidative stress associated with cardiovascular and/or inflammatory diseases related to NADPH oxidase superoxide overproduction.

Protective effect of Pycnogenol in human neuroblastoma SH-SY5Y cells following acrolein-induced cytotoxicity

Oxidative stress is one of the hypotheses involved in the etiology of Alzheimer's disease (AD). Considerable attention has been focused on increasing the intracellular glutathione (GSH) levels in many neurodegenerative diseases, including AD. Pycnogenol (PYC) has antioxidant properties and stabilizes intracellular antioxidant defense systems including glutathione levels. The present study investigated the protective effects of PYC on acrolein-induced oxidative cell toxicity in cultured SH-SY5Y neuroblastoma cells. Decreased cell survival in SH-SY5Y cultures treated with acrolein correlated with oxidative stress, increased NADPH oxidase activity, free radical production, protein oxidation/nitration (protein carbonyl, 3-nitrotyrosine), and lipid peroxidation (4-hydroxy-2-nonenal). Pretreatment with PYC significantly attenuated acrolein-induced cytotoxicity, protein damage, lipid peroxidation, and cell death. A dose-response study suggested that PYC showed protective effects against acrolein toxicity by modulating oxidative stress and increasing GSH. These findings provide support that PYC may provide a promising approach for the treatment of oxidative stress-related neurodegenerative diseases such as AD.

Effect of coffee drinking on platelets: inhibition of aggregation and phenols incorporation

Epidemiological studies indicate a J-shaped relationship linking coffee consumption and cardiovascular risk, suggesting that moderate coffee consumption can be beneficial. Platelet aggregation is of critical importance in thrombotic events, and platelets play a major role in the aetiology of several CVD. The aim of this study was to evaluate the effect of coffee drinking on platelet aggregationex vivo, using caffeine as control. A crossover study was performed on ten healthy subjects. In two different sessions, subjects drank 200 ml coffee, containing 180 mg caffeine, or a capsule of caffeine (180 mg) with 200 ml water. Platelets were separated from plasma at baseline and 30 and 60 min after coffee drinking. Platelet aggregation was induced with three different agonists: collagen, arachidonic acid and ADP. Coffee drinking inhibited collagen (P < 0·05 from baseline at time 30 min) and arachidonic acid (P < 0·05 from baseline at time 60 min) induced platelet aggregation. Caffeine intake did not affect platelet aggregation induced by the three agonists. Coffee consumption induced a significant increase of platelet phenolic acids (likely present as glucuronate and sulphate derivatives), caffeic acid, the principal phenolic acid in coffee, raising from 0·3 (sem0·1) to 2·4 (sem0·6) ng/mg (P < 0·01). Caffeine was not detectable in platelets. Coffee drinking decreases platelet aggregation, and induces a significant increase in phenolic acid platelet concentration. The antiplatelet effect of coffee is independent from caffeine and could be a result of the interaction of coffee phenolic acids with the intracellular signalling network leading to platelet aggregation.

Rapid preparation of procyanidins B2 and C1 from Granny Smith apples by using low pressure column chromatography and identification of their oligomeric procyanidins

Research in the field of procyanidins is always hindered by the lack of procyanidin standards, and the preparation of procyanidins, especially in large scale, remains difficult and time-consuming. Commercial sources of procyanidin standards are scarce. In this study, a rapid preparation method of procyanidins by using low-pressure column chromatography was developed. Procyanidins in Granny Smith apples were extracted with boiled water and purified on an ADS-17 macroporous resin column to obtain a Granny Smith apple procyanidin extract (GSE). GSE was fractionated according to its degree of polymerization on a Toyopearl TSK HW-40s column. Procyanidins B2 (epicatechin-(4beta-8)-epicatechin) and C1 (epicatechin-(4beta-8)-epicatechin-(4beta-8)-epicatechin) were prepared without HPLC separation. Oligomeric procyanidins from Granny Smith apples were also identified by liquid chromatography-electrospray ionization-mass spectrometry.

Caffeic acid and its synthetic derivative CADPE suppress tumor angiogenesis by blocking STAT3-mediated VEGF expression in human renal carcinoma cells

Tumor angiogenesis is required for tumor development and is stimulated by angiogenic inducers like VEGF (vascular endothelial growth factor). Our previous study demonstrated that STAT3 (signal transducer and activator of transcription 3) up-regulates HIF-1alpha (hypoxia inducible factor-1alpha) protein stability and enhances HIF-1-mediated VEGF expression in hypoxic solid tumor cells, thus suggesting that the inhibition of STAT3 signaling may have clinical applications. In this study, we examined in vitro and in vivo, whether caffeic acid (CA) or its derivative CADPE [3-(3,4-dihydroxy-phenyl)-acrylic acid 2-(3,4-dihydroxy-phenyl)-ethyl ester] exert anticancer activity by targeting STAT3. It was found that CA or CADPE significantly inhibit STAT3 activity, and that this in turn down-regulates HIF-1alpha activity. Consequently, sequential blockade of STAT3 and HIF-1alpha resulted in the down-regulation of VEGF by inhibiting their recruitment to the VEGF promoter. In mice bearing a Caki-I carcinoma, both CA and CADPE retarded tumor growth and suppressed STAT3 phosphorylation, HIF-1alpha expression, vascularization and STAT3-inducible VEGF gene expression in tumors. Taken together, our results demonstrate that CA and CADPE are potential inhibitors of STAT3 and that they suppress tumor angiogenesis by inhibiting the activity of STAT3, the expression of HIF-1alpha and VEGF.

Caffeic acid attenuates neuronal damage, astrogliosis and glial scar formation in mouse brain with cryoinjury

Traumatic brain injury induces neuron damage in early phase, and astrogliosis and the formation of the glial scar in late phase. Caffeic acid (3, 4-dihydroxycinnamic acid), one of the natural phenolic compounds, exerts neuroprotective effects against ischemic brain injuries with anti-oxidant and anti-inflammatory properties, and by scavenging reactive species. However, whether caffeic acid has protective effects against traumatic brain injury is unknown. Therefore, we determined the effect of caffeic acid on the lesion in the early (1 day) and late phases (7 to 28 days) of cryoinjury in mice. We found that caffeic acid (10 and 50 mg/kg, i.p., for 7 days after cryoinjury) reduced the lesion area and attenuated the neuron loss around the lesion core 1 to 28 days, but attenuated the neuron loss in the lesion core only 1 day after cryoinjury. Moreover, caffeic acid attenuated astrocyte proliferation, glial scar wall formation and glial fibrillary acidic protein (GFAP) protein expression in the late phase of cryoinjury (7 to 28 days). Caffeic acid also inhibited the reduction of superoxide dismutase activity and the increase in malondialdehyde content in the brain 1 day after cryoinjury. These results indicate that caffeic acid exerts a protective effect in traumatic brain injury, especially on glial scar formation in the late phase, which at least is associated with its anti-oxidant ability.

Influence of treatment of diabetic rats with combinations of pycnogenol, ?-carotene, and ?-lipoic acid on parameters of oxidative stress

Treatment with antioxidants may act more effectively to alter markers of free radical damage in combinations than singly. This study has determined whether treatment with combinations of pycnogenol, beta-carotene, and alpha-lipoic acid was more effective at reducing oxidative stress in diabetic rats than treatment with these antioxidants alone. It is not feasible, based on this study, to assume that there are interactive effects that make combinations of these antioxidants more effective than any one alone to combat oxidative stress. Female Sprague-Dawley rats, normal and streptozotocin-induced diabetic, were treated (10 mg/kg/day ip for 14 days) with pycnogenol, beta-carotene, pycnogenol + beta-carotene, or pycnogenol + beta-carotene + alpha-lipoic acid; controls were untreated. Concentrations of thiobarbituric acid reactive substances, glutathione and glutathione disulfide, and activities of glutathione reductase, glutathione peroxidase, superoxide dismutase, and catalase were measured in liver, kidney, and heart. Four types of effects were observed: (1) treatment with beta-carotene alone either reversed (cardiac glutathione disulfide) or elevated (cardiac glutathione, hepatic glutathione peroxidase activity) levels seen in diabetic animals; (2) beta-carotene alone produced no effect, but pycnogenol both alone and in combinations elevated (renal glutathione peroxidase and glutathione reductase activities, hepatic glutathione reductase activity and glutathione disulfide) or depressed (cardiac glutathione disulfide) levels seen in untreated diabetic animals; (3) all treatments with antioxidants, either alone or in combination, either normalized (lipid peroxidation in all tissues), elevated (hepatic GSH, cardiac glutathione peroxidase activity), or had no effect on (activities of hepatic catalase and superoxide dismutase in all tissues) levels seen in diabetic animals; (4) in only one case (cardiac glutathione reductase activity) levels in diabetic animals treated with combinations of antioxidants were normal, but elevated in animals treated with either antioxidant alone. Antioxidant effects seem to be dependent on the nature of the antioxidant used and not on combination effects.

Protective effect of chelerythrine on gentamicin-induced nephrotoxicity

Despite their beneficial effects, aminoglycosides including gentamicin (GEN) have considerable nephrotoxic side-effects. The toxicity of GEN at the level of the kidney seems to relate to the generation of reactive oxygen species (ROS). ROS have been reported to be involved in the activation of protein kinase C (PKC). The unique structural aspects of PKC cause it to function as a sensor for oxidative stress. It seems likely that the increased NAD(P)H oxidase-derived superoxide (O2) production is at least in part mediated by PKC. We investigated the effects of chelerythrine, a commonly used PKC inhibitor, on GEN-induced changes of renal malondialdehyde (MDA), nitric oxide (NO) generation, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities, glutathione (GSH) content, and serum creatinine (Cr), blood urea nitrogen (BUN) levels. Morphological changes in the kidney were also examined. GEN administration to control rats increased MDA and NO generation but decreased CAT, SOD and GSH-Px activities, and GSH content. Chelerythrine administration with GEN caused significantly decreased MDA, NO generation and increased CAT, SOD and GSH-Px activities, and GSH content when compared with GEN alone. Chelerythrine also significantly decreased serum Cr and BUN levels. Morphological changes in the kidney including tubular necrosis were evaluated qualitatively. Both biochemical findings and histopathological evidence showed that administration of chelerythrine reduced the GEN-induced kidney damage. We propose that chelerythrine acts in the kidney as a potent scavenger of free radicals to prevent the toxic effects of GEN via the inhibition of a PKC pathway.

Protective mechanisms of Pycnogenol® in ethanol-insulted cerebellar granule cells

Pycnogenol (PYC), a patented combination of bioflavonoids extracted from the bark of French maritime pine (Pinus maritima), inhibits apoptosis and necrosis of developing neurons exposed acutely to ethanol (EtOH). The present study shows that the protective mechanisms of PYC in EtOH-exposed postnatal day 9 cerebellar granule cells (P9 CGCs) include (1) reduction of reactive oxygen species (ROS) production; (2) counteraction of suppressed copper/zinc superoxide dismutase (Cu/Zn SOD) and glutathione peroxidase/reductase (GSH-Px/GSSG-R) system activities; (3) upregulation of Cu/Zn SOD protein expression; (4) mitigation of the EtOH-mediated exacerbation of catalase (CAT) activity; and, (5) specific binding and inhibition of active caspase-3. These results indicate that the mechanisms by which PYC antagonizes EtOH-induced oxidative stress include oxidant scavenging and modulation of endogenous, cellular proteins. Using findings from the present and previous studies, a model delineating the mechanisms of EtOH effects on the system of antioxidant enzymes in developing CGCs is presented.

Pycnogenol® and vitamin E inhibit ethanol-induced apoptosis in rat cerebellar granule cells

Pycnogenol (PYC), a patented combination of bioflavonoids extracted from the bark of French maritime pine (Pinus maritima), scavenges free radicals and promotes cellular health. The protective capacity of PYC against ethanol toxicity of neurons has not previously been explored. The present study demonstrates that in postnatal day 9 (P9) rat cerebellar granule cells the antioxidants vitamin E (VE) and PYC (1) dose dependently block cell death following 400, 800, and 1600 mg/dL ethanol exposure (2) inhibit the ethanol-induced activation of caspase-3 in the same model system; and (3) reduce neuronal membrane disruption as assayed by phosphatidylserine translocation to the cell surface. These results suggest that both PYC and VE have the potential to act as therapeutic agents, antagonizing the induction of neuronal cell death by ethanol exposure.

Synergistic suppression of superoxide and nitric oxide generation from inflammatory cells by combined food factors

In contrast to chemopreventive strategies using individual agents, a combination of specified compounds may be effectual to achieve desirable results with higher efficacy and lower toxicity. In the present in vitro study, we examined combinations of agents and assessed which concentrations were appropriate to yield notable synergism. L-N(G)-Monomethyl-L-arginine (L-NMMA), a synthetic inducible nitric oxide synthase (iNOS) inhibitor, and zerumbone, a natural sesquiterpene that suppresses iNOS de novo synthesis, were combined at various concentrations, with the aim to diminish combined lipopolysaccharide- and interferon-gamma-induced nitric oxide generation in a murine macrophage line, RAW264.7. Although the combinatorial effects (CEs) were antagonistic or additive at higher concentrations, significant synergism was obtained at lower concentrations where each agent alone did not cause significant inhibition. Similarly, the CEs were synergistic when (-)-epigallocatechin gallate (EGCG) and genistein were combined at lower concentrations, whereas those of two iNOS inhibitors, L-NMMA and L-N(G)-aminoethyl-L-ornithine, were either additive or antagonistic at all concentrations tested, suggesting that a combination of given agents with different action mechanisms is a prerequisite for synergistic effects. For suppression of phorbol ester-induced superoxide anion radical (O(2)*(-)) generation in differentiated HL-60 cells, the CEs of 1'-acetoxycahvicol acetate (ACA), a phenyl propanoid that suppresses O(2)*(-) generation, and O(2)*(-) dismutase were also synergistic, though only at lower concentrations. The CEs of ACA/EGCG were antagonistic or additive, even at low concentrations, suggesting that the signal transduction pathways triggered by these agents are antagonistic. The present findings suggest that individual food phytochemicals have complex interactions that can be antagonistic, additive, and/or synergistic in biological systems, depending upon certain environmental factors including concentrations. Further, these results support and emphasize the concept that combinations of different types of chemicals at low concentrations are one of the essential areas of study for chemopreventive strategies.

Rosmarinic acid and caffeic acid produce antidepressive-like effect in the forced swimming test in mice

We previously showed that rosmarinic acid from the leaves of Perilla frutescens Britton var. acuta Kudo (Perillae Herba) has antidepressive-like activity. The aim of the present study was to examine (i) whether caffeic acid, a major metabolite of rosmarinic acid, also has antidepressive-like activity, and (ii) whether these substances inhibit either the uptake of monoamines to synaptosomes or mitochondrial monoamine oxidase activity. Rosmarinic acid (2 mg/kg, i.p.) and caffeic acid (4 mg/kg, i.p.) each significantly reduced the duration of immobility in the forced swimming test in mice. In contrast, neither substance, at doses that produced a significant reduction in the immobile response in the forced swimming test, affected spontaneous motor activity. These results indicate that, like rosmarinic acid, caffeic acid also possesses antidepressive-like activity. In neuropharmacological studies, neither rosmarinic acid (10 x (-9)-10 x (-3) M) nor caffeic acid (10 x (-9)-10 x (-3) M) affected either the uptake of monoamines to synaptosomes or mitochondrial monoamine oxidase activity in the mouse brain. These results suggest that both caffeic acid and rosmarinic acid may produce antidepressive-like activity via some mechanism(s) other than the inhibition of monoamine transporters and monoamine oxidase.

Effects of pine bark extract administered to immunosuppressed adult mice infected with Cryptosporidium parvum

The treatment of cryptosporidiosis using pine bark extract (Pycnogenol) in immunosuppressed adult C57BL/6N mice infected with Cryptosporidium parvum was investigated. Five groups of 10 mice/group were used. Groups 1, 2, 3, and 5 served as normal, toxicity, placebo, and positive controls, respectively. Mice in groups 2-5 were immunosuppressed with dexamethasone phosphate administered ad libitum in drinking water at a dosage level of 12 microg/ml. Mice in groups 3-5 were inoculated per os with 10(6) C. parvum oocysts on the day immunosuppression was started. Mice in groups 2 and 4 were treated by administering Pycnogenol orally at 30 mg/kg/day. In group 4, Pycnogenol was first administered on day 3 postinoculation. Of the four groups of mice immunosuppressed with DEXp (groups 2-5), the two groups treated with Pycnogenol (groups 2 and 4) had no premature deaths. The other two groups (groups 3 and 5) had 3 and 4 mice die, respectively, before the experiment ended. Consequently, Pycnogenol was judged to be non-toxic at the dosage level used and even afforded mice some positive health benefits. Fecal oocyst shedding in groups 3-5 was initially detected on day 3 postinoculation. These mice continued to shed oocysts throughout the duration of the 28-day experiment. Oocyst shedding intensities were greater in group 3 and 5 than in group 4. However, histological examination of infected intestinal tissues in groups 3-5 revealed no significant difference with regard to parasite colonization and villus/crypt (V/C) length ratios. As a result, Pycnogenol was determined to be therapeutically effective against C. parvum at 30 mg/kg/day only when measured by fecal oocyst shedding intensity. There was no effect on parasite tissue colonization and V/C ratios in infected mice. We conclude that Pycnogenol is a useful dietary supplement for C. parvum-infected patients by affording some positive health benefits, significantly reduces fecal oocyst shedding, but does not decrease parasite colonization of intestinal tissue.

Flavanols and procyanidins of cocoa and chocolate inhibit growth and polyamine biosynthesis of human colonic cancer cells

The effects of cocoa powder and extracts with different amounts of flavanols and related procyanidin oligomers were investigated on the growth of Caco-2 cells. Treatment of the cells with 50 microg/ml of procyanidin-enriched (PE) extracts caused a 70% growth inhibition with a blockade of the cell cycle at the G2/M phase. PE extracts caused a significant decrease of ornithine decarboxylase and S-adenosylmethionine decarboxylase activities, two key enzymes of polyamine biosynthesis. This led to a decrease in the intracellular pool of the polyamines. These observations indicate that polyamine metabolism might be an important target in the anti-proliferative effects of cocoa polyphenols.

Inhibition mechanisms of bioflavonoids extracted from the bark of Pinus maritima on the expression of proinflammatory cytokines

The effect of bioflavonoids extracted from the bark of Pinus maritima, Pycnogenol (PYC), on gene expression of the proinflammatory cytokines interleukin-1beta (IL-1beta) and interleukin-2 (IL-2) were investigated in RAW 264.7 cells and Jurkat E6.1 cells, respectively. PYC exerted strong scavenging activities against reactive oxygen species (ROS) generated by H2O2 in RAW 264.7. In situ ELISA, immunoblot analysis, and competitive RT-PCR demonstrated that pretreatment of LPS-stimulated RAW 264.7 cells with PYC dose-dependently reduced both the production of IL-1beta and its mRNA levels. Furthermore, in the same cells, PYC blocked the activation of nuclear factor kappaB (NF-kappaB) and activator protein-1 (AP-1), two major transcription factors centrally involved in IL-1beta gene expression. Concordantly, pretreatment of the cells with PYC abolished the LPS-induced IkappaB degradation. We also investigated the effect of PYC on IL-2 gene expression in phorbol 12-myristate 13acetate plus ionomycin (PMA/Io)-stimulated human T-cell line Jurkat E6.1. PYC inhibited the PMA/Io-induced IL-2 mRNA expression. However, as demonstrated in a reporter gene assay system, the mechanism of IL-2 gene transcriptional regulation by PYC was different from the regulation of IL-1beta. PYC inhibited both NF-AT and AP-1 chloramphenicol acetyltransferase (CAT) activities in transiently transfected Jurkat E6.1, but not NF-kappaB CAT activity. We also found that PYC can destabilize PMA/Io-induced IL-2 mRNA by posttranscriptional regulation. All these results suggest that bioflavonids can be useful therapeutic agents in treating many inflammatory, autoimmune, and cardiovascular diseases based on its diverse action mechanisms.

Modulation of ceramide-induced NF-kappaB binding activity and apoptotic response by caffeic acid in U937 cells: comparison with other antioxidants

Ceramide acts as second messenger in the signal transduction triggered by a variety of stress stimuli and extracellular agents. Stress response through ceramide is involved in the development of many human diseases, such as atherosclerosis, inflammation, neurodegenerative disorders, and acquired immunodeficiency syndrome. Dietary polyphenols have been reported to exert a beneficial effect on the onset and development of most of these human chronic-degenerative pathologies. However, the mechanisms underlying this beneficial effect are mostly not understood at the present. To investigate the ability of polyphenols in modulating fundamental cellular functions, we studied the effect of caffeic acid, a widespread phenolic acid largely present in human diet, in the modulation of ceramide-induced signal transduction pathway leading to apoptosis in U937 cells, in comparison with other established antioxidants of nutritional interest (N-acetylcysteine, d-alpha-tocopherol acetate and ascorbic acid). Our results indicate that caffeic acid efficiently inhibits both ceramide-induced NF-kappaB binding activity and apoptosis at micromolar concentration. Other antioxidants tested are totally ineffective in inhibiting apoptosis, although affecting NF-kappaB activation. Caffeic acid was found to inhibit protein tyrosine kinase activity, suggesting that this mechanism can be on the basis of the inhibition of apoptosis. Our results suggest that dietary caffeic acid might modulate ceramide-induced signal transduction pathway and NF-kappaB activation through either antioxidant and nonantioxidant mechanisms.

Molecular aspects of procyanidin biological activity: disease preventative and therapeutic potentials

There is a growing interest in the utilization of procyanidins for their dietary and pharmacological properties. A wide spectrum of beneficial activity for human health has been advocated for procyanidins due, in part, to their strong antioxidant activity. More recently the ability of procyanidins to affect gene expression and cell response in vitro has been reported, providing a novel mechanistic perspective on the biological activity of these phytochemicals. This article reviews recent cellular and molecular aspects of the biological activity of procyandins and discusses their disease preventative and therapeutic potentials.

Solar ultraviolet-induced erythema in human skin and nuclear factor-kappa-B-dependent gene expression in keratinocytes are modulated by a French maritime pine bark extract

The procyanidin-rich French maritime pine bark extract Pycnogenol (PBE) has been investigated for its effect in protecting human skin against solar UV-simulated light-induced erythema. Twenty-one volunteers were given an oral supplementation of Pycnogenol: 1.10 mg/kg body weight (b. wt.)/d for the first 4 weeks and 1.66 mg/kg b. wt./d for the next 4 weeks. The minimal erythema dose (MED) was measured twice before supplementation (baseline MED), once after the first 4 weeks of supplementation, and a last time at the end of the study. The UVR dose necessary to achieve 1 MED was significantly increased during PBE supplementation. Since the activation of the pro-inflammatory and redox-regulated transcription factor NF-kappaB is thought to play a major role in UVR-induced erythema, the effect of PBE was also investigated in the human keratinocyte cell line HaCaT. PBE, added to the cell culture medium, inhibited UVR-induced NF-kappaB-dependent gene expression in a concentration-dependent manner. However, NF-kappaB-DNA-binding activity was not prevented, suggesting that PBE affects the transactivation capacity of NF-kappaB. These data indicate that oral supplementation of PBE reduces erythema in the skin. Inhibition of NF-kappaB-dependent gene expression by PBE possibly contributes to the observed increase in MED.

Effect of bioflavonoids extracted from the bark of Pinus maritima on proinflammatory cytokine interleukin-1 production in lipopolysaccharide-stimulated RAW 264.7

Currently, bioflavonoids have been known to have strong antioxidant capacities, and a variety of efforts have been made to identify the utilities of bioflavonoids in treating various diseases based on their antioxidant capacities. The effects of bioflavonoids extracted from the bark of Pinus maritima Pycnogenol (PYC) on free radical formation, activation of redox sensitive transcription factors, as well as interleukin-1 beta (IL-1 beta) production were investigated in murine macrophage cell lines. PYC exerted strong scavenging activities against reactive oxygen species generated either by H(2)O(2) or PMA in RAW 264.7 and IC-21 cells, respectively. In situ ELISA, immunoblot analysis, and competitive RT-PCR demonstrated that PYC pretreatment of LPS-stimulated RAW 264.7 cells dose-dependently reduced both the production of IL-1 beta and its mRNA levels. Furthermore, in the same cells, PYC blocked the activation of nuclear factor kappa B (NF-kappa B) and activator protein-1 (AP-1), two major transcription factors centrally involved in IL-1 beta gene expression. When RAW 264.7 cells were stimulated with LPS, the inhibitor protein I kappa B largely disappeared from cytosolic fractions. However, pretreatment of the cells with PYC abolished the LPS-induced I kappa B degradation. These results suggest that PYC can inhibit the expression of the proinflammatory cytokine IL-1 by regulating redox-sensitive transcription factors. This study may support the possibility that bioflavonoids including PYC can be used as antiinflammatory and immunosuppressive drugs based on their radical scavenging activities.