No abstract

3,4-Dihydroxyphenylethanol (hydroxytyrosol; DPE) is the major phenolic antioxidant present in extra virgin olive oil, either in a free or esterified form. Despite its relevant biological effects, no data are available on its bioavailability and metabolism. The aim of the present study is to examine the molecular mechanism of DPE intestinal transport, using differentiated Caco-2 cell monolayers as the model system. The kinetic data demonstrate that [ 14 C]DPE transport occurs via a passive diffusion mechanism and is bidirectional; the calculated apparent permeability coefficient indicates that the molecule is quantitatively absorbed at the intestinal level. The only labelled DPE metabolite detectable in the culture medium by HPLC (10% conversion) is 3-hydroxy-4-methoxyphenylethanol, the product of catechol-O-methyltransferase; when DPE is assayed in vitro with the purified enzyme a K m value of 40 W WM has been calculated.z 2000 Federation of European Biochemical Societies.

The prevalence of obesity has steadily increased worldwide over the past three decades. The conventional approaches to prevent or treat this syndrome and its associated complications include a balanced diet, an increase energy expenditure, and lifestyle modification. Multiple pharmacological and non-pharmacological interventions have been developed with the aim of improving obesity complications. Recently, the use of functional foods and their bioactive components is considered a new approach in the prevention and management of this disease. Due to their biological properties, polyphenols may be considered as nutraceuticals and food supplement recommended for different syndromes. Polyphenols are a class of naturally-occurring phytochemicals, some of which have been shown to modulate physiological and molecular pathways involved in energy metabolism. Polyphenols could act in the stimulation of β-oxidation, adipocyte differentiation inhibition, counteract oxidative stress, etc. In this narrative review, we considered the association between polyphenols (resveratrol, quercetin, curcumin, and some polyphenolic extracts) and obesity, focusing on human trials. The health effects of polyphenols depend on the amount consumed and their bioavailability. Some results are contrasting, probably due to the various study designs and lengths, variation among subjects (age, gender, ethnicity), and chemical forms of the dietary polyphenols used. But, in conclusion, the data so far obtained encourage the setting of new trials, necessary to validate benefic role of polyphenols in obese individuals.

No abstract

This paper reports the protective effect of the phenolic fraction extracted from extra virgin olive oils (OOPEs) against the cytotoxic effects of reactive oxygen species in human erythrocytes and Caco-2 cells, employed as model systems. Pretreatment of cells with various OOPEs, indeed, provides a remarkable protection against oxidative damages: this effect was strictly dependent on the o-diphenolic content of the extracts. Moreover, the protective effects observable in cellular systems were compared with in vitro antioxidant properties, measured by using the FRAP (ferric reducing/antioxidant power) assay; the reducing ability of OOPEs strictly parallels their o-phenolic content. The linear relationship demonstrated between biological effects and antioxidant capacity measured by the FRAP assay allows us to propose the use of this rapid colorimetric method in assessing and certifying the antioxidant power of extra virgin olive oil.

Using virtually range-wide sampling for three pond turtle taxa (Emys orbicularis galloitalica,\ud E. o. hellenica, E. trinacris), we analyse gene flow across their southern Italian contact zone.\ud Based on population genetic analyses of 15 highly polymorphic microsatellite loci and a\ud mitochondrial marker, we show that the general genetic pattern matches well with the current\ud taxon delimitation. Yet, single individuals with conflicting genetic identity suggest\ud translocation of turtles by humans. In addition, we identify in south-western France and the\ud vicinity of Rome populations being heavily impacted by introduced turtles. Cline analyses\ud reveal that the major genetic break between E. o. galloitalica and E. o. hellenica corresponds\ud well with the currently accepted intergradation zone in southern Italy. However, introgression\ud is largely unidirectional from E. o. galloitalica into E. o. hellenica. In the distribution\ud range of the latter subspecies, genetic footprints of E. o. galloitalica are evident along most\ud of the Italian east coast. Our results corroborate that E. o. galloitalica was introduced long\ud ago in Corsica and Sardinia and naturalized there. Gene flow between E. orbicularis and\ud E. trinacris is negligible, with the Strait of Messina matching well with the narrow cline centre\ud between the two species. This contrasts with other Mediterranean freshwater turtle species\ud with extensive transoceanic gene flow. Compared to the two subspecies of E. orbicularis,\ud the Sicilian E. trinacris shows an unexpectedly strong population structuring, a finding\ud also of some relevance for conservation. The differences between the two taxon pairs\ud E. orbicularis/E. trinacris and E. o. galloitalica/E. o. hellenica support their current taxonomic\ud classification and make them attractive objects for follow-up studies to elucidate the\ud underlying mechanisms of speciation by comparing their propertie

Protein-l-isoaspartate (d-aspartate) O-methyltransferase (PCMT; EC 2.1.1.77) catalyses the methyl esterification of the free a-carboxyl group of abnormal l-isoaspartyl residues, which occur spontaneously in protein and peptide substrates as a consequence of molecular ageing. The biological function of this transmethylation reaction is related to the repair or degradation of age-damaged proteins. Methyl ester formation in erythrocyte membrane proteins has also been used as a marker reaction to tag these abnormal residues and to monitor their increase associated with erythrocyte ageing diseases, such as hereditary spherocytosis, or cell stress (thermal or osmotic) conditions.The study shows that levels of l-isoaspartyl residues rise in membrane proteins of human erythrocytes exposed to oxidative stress, induced by t-butyl hydroperoxide or H 2 O 2 . The increase in malondialdehyde content confirmed that the cell membrane is a primary target of oxidative alterations. A parallel rise in the methaemoglobin content indicates that proteins are heavily affected by the molecular alterations induced by oxidative treatments in erythrocytes. Antioxidants largely prevented the increase in membrane protein methylation, underscoring the specificity of the effect. Conversely, we found that PCMT activity, consistent with its repair function, remained remarkably stable under oxidative conditions, while damaged membrane protein substrates increased significantly. The latter include ankyrin, band 4.1 and 4.2, and the integral membrane protein band 3 (the anion exchanger). The main target was found to be particularly protein 4.1, a crucial element in the maintenance of membrane-cytoskeleton network stability. We conclude that the increased formation/ exposure of l-isoaspartyl residues is one of the major structural alterations occurring in erythrocyte membrane proteins as a result of an oxidative stress event. In the light of these and previous findings, the occurrence of isoaspartyl sites in membrane proteins as a key event in erythrocyte spleen conditioning and hemocatheresis is proposed.

Recently, nutraceutical bioactive compounds in foods have been discovered for their potential health benefits regarding the prevention of chronic disorders, such as cancer, and inflammatory, cardiovascular, and metabolic diseases. Dietary omega-3 polyunsaturated fatty acids (ω-3PUFAs), including alpha-linolenic acid, docosapentaenoic acid, and eicosapentaenoic acid, are mostly attractive. They are available for the customers worldwide from commonly used foods and/or as components of commercial food supplements. The anti-inflammatory and hypotriglyceridemic effects of these fatty acids are well known, whereas pro-inflammatory properties have been recognized in their dietary counterparts, the ω-6PUFAs. Both ω-3 and ω-6PUFAs contribute to the production of lipid mediators such as endocannabinoids that are notably involved in control of food intake, energy sensing, and food–related disorders. In this review, we present ω-3 and ω-6PUFAs and their derivatives, endocannabinoids; discuss the anti-obesity effects of ω-3PUFAs; their roles in inflammation and colorectal cancer development; and how their action can be co-preventative and co-therapeutic.