Bioavailability and In Vivo Antioxidant Activity of a Standardized Polyphenol Mixture Extracted from Brown Propolis.

Several lines of evidence demonstrate the antioxidant, anti-inflammatory and antimicrobial activities of propolis, mostly ascribed to its polyphenol content. However, little is known regarding the bioavailability of propolis in acute and prolonged settings of oral administration. In this study, we first determined the content of the main polyphenols in a brown propolis extract obtained using a patented extraction method (Multi Dinamic Extraction-M.E.D.) by RP-HPLC-UV-PDA-MSn analysis, followed by the bioavailability of galangin and chrysin, the most abundant polyphenols in the mixture (7.8% and 7.5% respectively), following acute (single bolus of 500 mg/kg containing about 3.65 mg of the polyphenol mixture) and prolonged (100, 250 and 500 mg/kg body for 30 days) oral administration in 30 male 8 weeks old C57BL/6 wild-type mice. In the acute setting, blood was taken at 30 s and 5, 10, 15, 20, 25, 30, 45, 60 and 120 min following the oral bolus. In the prolonged setting, blood samples were obtained after 10, 20 or 30 days of administration. At the end of treatment, expression of antioxidant enzymes (superoxyde dismutase, SOD-1; catalase, CAT; glutathione peroxidase, GSS) was evaluated in liver tissue. Following both acute and prolonged administration, neither galangin nor chrysin were detectable in the plasma of mice, whereas the glucuronide metabolite of galangine was detectable 5 min after acute administration. At the end of the prolonged treatment SOD-1 was found to have increased significantly, unlike CAT and GSS. Overall, these data suggest that oral administration of whole brown propolis extract is followed by rapid absorption and metabolization of galangin followed by adaptations of the antioxidant first line defense system.

Targeting STATs in neuroinflammation: The road less traveled!

JAK/STAT transduction pathway is a highly conserved pathway implicated in regulating cellular proliferation, differentiation, survival and apoptosis. Dysregulation of this pathway is involved in the onset of autoimmune, haematological, oncological, metabolic and neurological diseases. Over the last few years, the research of anti-neuroinflammatory agents has gained considerable attention. The ability to diminish the STAT-induced transcription of inflammatory genes is documented for both natural compounds (such as polyphenols) and chemical drugs. Among polyphenols, quercetin and curcumin directly inhibit STAT, while Berberis vulgaris L. and Sophora alopecuroides L extracts act indirectly. Also, the Food and Drug Administration has approved several JAK/STAT inhibitors (direct or indirect) for treating inflammatory diseases, indicating STAT can be considered as a therapeutic target for neuroinflammatory pathologies. Considering the encouraging data obtained so far, clinical trials are warranted to demonstrate the effectiveness and potential use in the clinical practice of STAT inhibitors to treat inflammation-associated neurodegenerative pathologies.

Exosome biogenesis, bioactivities and functions as new delivery systems of natural compounds.

A rapidly growing body of experimental evidence has begun to shed light on the wide ranging molecular mechanisms which modulate intra- and inter-cellular communications. A substantial quantity of the available knowledge has only been uncovered in recent years, and we are learning that donor cells release nanovesicles, known as exosomes, which regulate the cellular behavior of recipient cells following uptake. Based on the impressive capacity of exosomes in delivering their "payload", different therapeutic agents, are currently being tested using this delivery method for more effective therapy. This review summarizes the most recent developments in exosome bioactivities and discusses the biochemical nature of exosomes and their biogenesis. It also summarizes the use of exosomes as delivery vehicles for drugs and natural compounds to the targeted site.

Effect of Green and Brown Propolis Extracts on the Expression Levels of microRNAs, mRNAs and Proteins, Related to Oxidative Stress and Inflammation.

A large body of evidence highlights that propolis exerts many biological functions that can be ascribed to its antioxidant and anti-inflammatory components, including different polyphenol classes. Nevertheless, the molecular mechanisms are yet unknown. The aim of this study is to investigate the mechanisms at the basis of propolis anti-inflammatory and antioxidant activities. The effects of two brown and green propolis extracts-chemically characterized by RP-HPLC-PDA-ESI-MSn-on the expression levels of miRNAs associated with inflammatory responses (miR-19a-3p and miR-203a-3p) and oxidative stress (miR-27a-3p and miR-17-3p), were determined in human keratinocyte HaCat cell lines, treated with non-cytotoxic concentrations. The results showed that brown propolis, whose major polyphenolic components are flavonoids, induced changes in the expression levels of all miRNAs, and was more active than green propolis (whose main polyphenolic components are hydroxycinnamic acid derivatives) which caused changes only in the expression levels of miR-19a-3p and miR-27a-3p. In addition, only brown propolis was able to modify (1) the expression levels of mRNAs, the target of the reported miRNAs, which code for Tumor Necrosis Factor-α (TNF-α), Nuclear Factor, Erythroid 2 Like 2 (NFE2L2) and Glutathione Peroxidase 2 (GPX2), and (2) the protein levels of TNF-α and NFE2L2. In conclusion, brown and green propolis, which showed different metabolite profiles, exert their biological functions through different mechanisms of action.

In vitro polyphenol effects on apoptosis: An update of literature data.

Polyphenols are secondary plant metabolites which have been studied extensively for their health-promoting properties, and which could also exert pharmacological activities ranging from anti-inflammatory effects, to cytotoxic activity against cancer cells. The main mechanism for programmed cell death is represented by apoptosis, and its dysregulation is involved in the etiopathology of cancer. As such, substances able to induce apoptosis in cancer cells could be used as new anticancer agents. The aim of this paper is to review literature data on the apoptotic effects of polyphenols and the molecular mechanisms through which they induce these effects in cancer cells. In addition, a brief summary of the new delivery forms used to increase the bioavailability, and clinical impact of polyphenols is provided. The studies reported show that many polyphenol rich plant extracts, originating from food and herbal medicine, as well as isolated polyphenols administered individually or in combination, can regulate cell apoptosis primarily through intrinsic and extrinsic mechanisms of action in in vitro conditions. Due to these promising results, the use of polyphenols in the treatment of cancer should therefore be deeply investigated. In particular, because of the low number of clinical trials, further studies are required to evaluate the anticancer activity of polyphenols in in vivo conditions.

Enantioselective Modulatory Effects of Naringenin Enantiomers on the Expression Levels of miR-17-3p Involved in Endogenous Antioxidant Defenses.

Naringenin is a flavanone present in citrus fruit as a mixture of chiral isomers. The numerous biological properties attributed to this compound include antioxidant and anti-inflammatory activities, even though the molecular mechanisms of these remain unknown. This study aims to evaluate the effects of racemic and enantiomeric naringenin on the expression levels of miR-17-3p, miR-25-5p and relative mRNA targets, to elucidate the mechanisms underlying these antioxidant and anti-inflammatory properties. Caco-2 cells, a well characterized in vitro model which mimics the intestinal barrier, were treated with subtoxic concentrations of racemate and enantiomers. The expression levels of miR-17-3p and miR-25-5p were determined by Real-Time PCR and were found to be decreased for both miRNAs. miR-17-3p behavior was in agreement with the increased levels of target mRNAs coding for two antioxidant enzymes, manganese-dependent superoxide dismutase (MnSOD) and glutathione peroxidase 2 (GPx2), while expression levels of miR-25-5p were not in agreement with its target mRNAs, coding for two pro-inflammatory cytokines, Tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6). These results lead to the conclusion that naringenin could exert its antioxidant activity through epigenetic regulation operated by miRNAs, while anti-inflammatory activity is regulated by other miRNAs and/or mechanisms.

Effects of Tea and Coffee Consumption on Cardiovascular Diseases and Relative Risk Factors: An Update.

BACKGROUND: Tea and coffee are the second and third most consumed beverages after water, respectively. The high consumption of these beverages is due to the sensorial properties and effects on psychological and physiological functions, induced by caffeine and many other bioactive components responsible for the protective effects on human health generally ascribed to these beverages. METHODS: The goal of this review article is to collect the scientific data obtained from clinical trials published in the last five years on the role of tea and coffee consumption against cardiovascular diseases (CVDs) and CVD risk factors such as hypertension, hyperglicemia, and hyperlipidaemia. RESULTS: In normal weight subjects, clinical trials showed that the consumption of tea is inversely associated to CVD risk factors or no association was found. Differently, in overweight subjects, the clinical trials and the metaanalyses showed an inverse correlation between tea consumption and CVDs. As regards coffee, it has long been suspected to be associated to high risk of CVDs. Nevertheless, some recent investigations reported that moderate coffee consumption have no effect or even protective effects against CVDs risk factors. The results of the metaanalyses confirm this trend suggesting that moderate coffee drinkers could be associated to a lower risk of CVDs than non- or occasional coffee drinkers or no association can be demonstrated between coffee consumption and CVDs. CONCLUSION: Literature data on tea consumption and CVD risk factors support that tea consumption reduces some risk factors especially in overweight people and obese subjects. Therefore, these results seem to suggest that tea could exert a protective effects against CVD development. As regards coffee, the results are controversial and did not allow to draw conclusions. Therefore, further research is needed before definitive recommendations for coffee consumption against CVD development can be made.

Gallic acid exerts a protective or an anti-proliferative effect on glioma T98G cells via dose-dependent epigenetic regulation mediated by miRNAs.

Glioblastoma multiforme (GBM) is the most malignant primary brain tumor in adulthood, characterized by very high recurrence. Following the limited results for conventional therapies, novel therapeutic agents are under investigation. Among the putative new molecules, gallic acid (GA) represents a promising new anticancer drug. The anticancer effect of this drug has been based on its antioxidant effects. The aim of the present study was to investigate the toxic effects of GA on the T98G human glioblastoma cell line and its capacity to modulate the expression of microRNAs targeting the genes involved in tumor growth and invasion. Cytotoxicity, clonogenic ability and cell migration after GA treatment were tested. Moreover, the expression of miRNAs that target genes for antioxidant mitochondrial enzymes (mir-17-3p), p-21 protein (mir-21-5p) and ATM (mir-421-5p) was determined by qRT-PCR. The results confirmed in the T98G cells the anti-proliferative effect of GA reported for other glioma cell lines and showed that the miRNA expression changes depending on GA concentrations. Different GA concentrations can determine a protective or a toxic effect on tumor cells. Thus, the key for GA to induce a specific anticancer action is to use an optimal concentration that avoids these twin effects.

Plants belonging to the genus Thymus as antibacterial agents: from farm to pharmacy.

In traditional medicine, plants have been used since ancient times for the prevention and/or protection against infectious diseases. In recent years, the use of herbal medicines and food supplements containing botanical ingredients, as alternative therapy for infectious diseases, has been intensified due to their high content of antimicrobial agents such as polyphenols, i.e. flavonoids, tannins, and alkaloids. Plants from the genus Thymus are important medicinal herbs, which are known to contain antimicrobial agents, and are rich in different active substances such as thymol, carvacrol, p-cymene and terpinene. In this review, we summarise the available literature data about the in vitro antibacterial effects of the main plants belonging to the genus Thymus. We also provide information about cultivation, chemical composition of the essential oils obtained from these plants, and their use for medicinal purposes.

Modulation of human miR-17-3p expression by methyl 3-O-methyl gallate as explanation of its in vivo protective activities.

SCOPE: Methyl-3-O-methyl gallate (M3OMG) possesses in vivo antioxidant activity due to the partial restoration of the antioxidant enzymes, whose expression is altered in oxidative stress. Literature data suggest that miR-17-3p is a microRNA involved in the regulation of cellular redox status, interfering with transcription of the mRNAs responsible for the synthesis of antioxidant enzymes. To obtain deeper insight into the potential mechanism of action of M3OMG, the aim of this study was to investigate its effect on the expression levels of miR-17-3p in human cells. METHODS AND RESULTS: Peripheral blood mononuclear cells and EVC-304 cells were treated with increasing subtoxic concentrations of M3OMG. The expression levels of miR-17-3p, extracted from cells and exosomes, were determined by quantitative real-time PCR. M3OMG induced a decrease in the miR-17-3p levels, and an increase in the levels of mRNA coding for the antioxidant enzymes, when compared to the control samples. Differently, in exosomes the expression levels of miR-17-3p were depended on the compound, its concentration, and the type of cell. CONCLUSION: These results suggest a potential mechanism of action of M3OMG that, inducing the reduction of the levels of miR-17-3p and the increase of mRNA coding for antioxidant enzymes, allows to these latter to perform their protective effects.

Tea consumption and risk of ischemic stroke: a brief review of the literature.

Stroke is an important cerebrovascular disease which causes chronic disability and death in patients. Despite of its high morbidity and mortality, there are limited available effective neuroprotective agents for stroke. In recent years, the research aimed at finding novel neuroprotective agents from natural origins has been intensified. Camellia sinensis L. (tea) is the second most consumed beverage worldwide, after water. It is classified into green and white, oolong, black and red, and Pu-erh tea based on the manufacturing process. Catechins are the main phytochemical constituents of Camellia sinensis which are known for their high antioxidant capacity. On other hand, it is well known that oxidative stress plays an important role in the initiation and progression of different cardiovascular diseases such as stroke. Therefore, the present article is aimed to review scientific studies that show the protective effects of tea consumption against ischemic stroke.

Influence of in vitro simulated gastroduodenal digestion on methylglyoxal concentration of Manuka ( Lectospermum scoparium ) honey.

Manuka honey (MH) is a functional food that shows in vitro antimicrobial activity and to which wound healing properties, positive effects on oral health, and beneficial properties during the treatment of gastrointestinal infection diseases and upper gastrointestinal dyspepsia are assigned. The antibacterial activity of MH is mainly due to its high concentration of methylglyoxal (MGO), a highly bifunctional alkylating agent that can induce rapid nonenzymatic modifications of proteins. The aim of the present study was to investigate the influence of in vitro simulated gastric and gastroduodenal digestion on MGO content of MH. To this aim commercial MH samples, with different MGO concentrations, were submitted to digestion, and MGO was determined before and after digestion by a validated RP-HPLC-DAD method. Moreover, the role of MGO in causing carbonylation of the digestive proteins and influencing their enzymatic activities was investigated. The results showed that after digestion MGO concentration decreases because it reacts with digestive enzymes by carbonylating their free amino groups. Nevertheless, carbonylation of pepsin and pancreatin does not influence their physiological activity and therefore does not seem to interfere with the digestion process.