Search

Increasing evidence indicates that fruits contain functional bio-active compounds that have several preventive and therapeutic health benefits. Our group has recently conducted studies to assess the potential effects of cranberry polyphenolic fractions on intestinal Caco-2/15 epithelial cells and a substantial reduction in oxidative stress and inflammation was observed. The aim of the present work was to determine the polyphenolic species most likely responsible for the observed biological activity. Low, medium, and high molecular weight cranberry fractions were generated witha Sephadex LH-20 column by elution with 60% MeOH, 100% MeOH, and 70% acetone, respectively. The total phenolic content in these fractions was determined by the Folin-Ciocalteu method.Acombinationof LC-MS and MALDI-TOF methods were used tocharacterize the natureofpolyphenolic compounds in the cranberry extracts. High resolution mass spectrometry was used to generate empirical formulae for the detected species. The low molecular weight fraction was essentially constituted of small phenolic acids (hydroxycinnamic and hydroxybenzoic acids). The medium fraction was mostly composed of anthocyanin, flavonols (quercetin, myricetin, isorhamnetin, kaempferol), procyanidins monomers (epicatechin, catechin), dimers, and few small oligomers. The heavy fraction was devoid of phenolic acids and anthocyanins, and it contained for the most part oligomers and polymers of procyanidins. Proanthocyanidins oligomers up to n = 22 were detected, which is, to our knowledge, the largest individual polymers reported to date. With this approach, it was also possible to distinguish between the A-type and B-type linkages. Key words: polyphenols, mass spectrometry, cranberry. De plus en plus de donnees probantes indiquent que les fruits contiennent des composes bioactifs fonctionnels qui presentent plusieurs bienfaits therapeutiques et preventifs. Notre groupe a recemment mene des etudes afin d'evaluer les effets possibles des fractions phenoliques de la canneberge sur les cellules epitheliales Caco-2/15 de l'intestin, dans lesquelles une reduction substantielle du stress oxydatif et de l'inflammation a ete observee. L'objectif des presents travaux etait de determiner les especes polyphenoliques les plus susceptibles d'etre a l'origine de l'activite biologique observee. Nous avons genere a partir d'un extrait de canneberge des fractions de poids moleculaire faible, moyen et eleve a l'aide d'une colonne Sephadex LH-20 par elution avec une solution a 60 % de MeOH, du MeOH a 100 % et une solution a 70 % d'acetone, respectivement. Nous en avons determine la teneur en composes phenoliques totaux par la methode de Folin-Ciocalteu. Nous avons employe conjointement les methodes LC-MS et MALDI-TOF pour caracteriser la nature des composes polyphenoliques presents dans les extraits de canneberge. Nous avons fait appel a la spectrometrie de masse a haute resolution pour generer les formules empiriques des especes que nous avons detectees. La fraction de faible poids moleculaire etait essentiellement constituee d'acides phenoliques de petite taille (acides hydoxycinnamiques et hydroxybenzoiques). La fraction de poids moleculaire moyen etait principalement composee d'anthocyanes, de flavonols (quercetine, myricetine, isorhamnetine, kaempferol) et de monomeres (epicatechine, catechine) et dimeres procyanidiques, ainsi que de quelques petits oligomeres. La fraction de poids moleculaire eleve etait depourvue d'acides phenoliques et d'anthocyanes. Elle contenait en majeure partie des oligomeres et des polymeres procyanidiques. Nous avons detecte des oligomeres de proanthocyanidines de taille allant jusqu'a n = 22, ce qui represente, a notre connaissance, les plus grandes chaines de ces polymeres detectees individuellement a ce jour. Grace a cette approche, il etait egalement possible de distinguer les liaisons de type A de celles de type B. [Traduit par la Redaction] Mots-cles : polyphenols, spectrometrie de masse, canneberge., Introduction An increasing body of evidence classifies numerous fruits as bio-active nutrients with several preventive and therapeutic health benefits (.1-3) Among them, cranberries have recently received particular attention as a [...]

The rapidly increasing prevalence of childhood obesity and its associated co-morbidities such as hypertriglyceridemia, hyper-insulinemia, hypertension, early atherosclerosis, metabolic syndrome, and non-alcoholic fatty liver disease are major public health concerns in many countries. Therefore the trends in child and adolescent obesity should be closely monitored over time, as in the near future, we may anticipate a major increase of young adults with the stigmata of the metabolic syndrome, and of the related non-alcoholic fatty liver disease (NAFLD), that may lead to non-alcoholic steatohepatitis.

In addition to its recognized role in bone health, recent studies point to vitamin D functions in other tissues, including the pancreas. We tested the association between the vitamin D status and glucose and lipid homeostasis in a school-based, cross-sectional survey of a representative sample of youth. We measured fasting plasma insulin, glucose, total cholesterol (TC), triglycerides (TG), HDL cholesterol (HDL-C) apolipoproteins (apo) A1 and B, and 25-hydroxyvitamin D [25(OH)D] concentrations in 878 boys and 867girls. The 25(OH)D concentrations (mean [+ or -] SD) were 45.9 [+ or -] 12.2 nmol/L in boys and 45.9 [+ or -] 13.0 nmol/L in girls. More than 93% of youth had suboptimal ( doi: 10.3945/jn.109.112250.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) posttranslationally promotes the degradation of the low-density lipoprotein receptor (LDLr) in hepatocytes and increases plasma LDL cholesterol. It is not clear, however, whether PCSK9 plays a role in the small intestine. Here, we characterized the patterns of variations of PCSK9 and LDLr in fully differentiated Caco-2/15 cells as a function of various potential effectors. Cholesterol (100 [micro]M) solubilized in albumin or micelles significantly downregulated PCSK9 gene (30%, P < 0.05) and protein expression (50%, P < 0.05), surprisingly in concert with a decrease in LDLr protein levels (45%, P < 0.05). Cells treated with 25-hydroxycholesterol (50 [micro]M) also displayed significant reduction in PCSK9 gene (37%, P < 0.01) and protein (75% P < 0.001) expression, whereas LDLr showed a decrease at the gene (30%, P < 0.05) and protein (57%, P < 0.01) levels, respectively. The amounts of PCSK9 mRNA and protein in Caco-2/15 cells were associated to the regulation of 3-hydroxy-3-methylglutaryl-CoA reductase and sterol regulatory element binding protein-2 (SREBP-2) that can transcriptionally activate PCSK9 via sterol-regulatory elements located in its proximal promoter region. On the other hand, depletion of cholesterol content by hydroxypropyl-[beta]-cyclodextrin upregulated PCSK9 transcripts (20%, P < 0.05) and protein mass (540%, P < 0.001), in parallel with SREBP-2 protein levels. The addition of bile acids (BA) taurocholate and deoxycholate to the apical culture medium lowered PCSK9 gene expression (25%, P < 0.01) and raised PCSK9 protein expression (30%, P < 0.01), respectively, probably via the modulation of farnesoid X receptor. Furthermore, unconjugated and conjugated BA exhibited different effects on PCSK9 and LDLr. Altogether, these data indicate that intestinal PCSK9 is highly modulated by sterols and emphasize the distinct effects of BA species. enterocyte; PCSK9; cholesterol; bile acids; farnesoid X receptor; SREBP-2

Oxidative stress is a cardinal manifestation of various intestinal disorders. However, very little knowledge is available on the intestine's inherent defense mechanisms against free radicals. This study was designed to determine the protein expression, subcellular localization and oxidative stress response of paraoxonase 2 (PON2), a member of a powerful antioxidant family in human and rat intestine. Biochemical and ultrastructural experiments all showed a substantial expression of PON2 in human and rat intestine. Western blot analysis disclosed higher levels of PON2 in the jejunum than in the duodenum, ileum, and colon. Cell fractionation revealed a predominant PON2 association with microsomes and lysosomes in the human jejunum, which differed from that in rats. PON2 was detected in the intestine as early as week 15 of gestation and was significantly increased by week 20. Iron ascorbate-mediated lipid peroxidation induced a marked decrease in PON2 expression in intestinal specimens coincidental to an abundant rise in malondialdehyde (MDA). On the other hand, preincubation with potent antioxidants, such as butylated hydroxytoluene, Trolox, and N-acetylcysteine, prevented irou-ascorbate-generating PON2 reduction in parallel with MDA suppression. Finally, the preincubation of permeabilized Caco-2 cells with purified PON2 led to a protection against iron-ascorbate-induced lipid peroxidation. These observations demonstrate that the human intestine is preferentially endowed with a marked PON2 expression compared with the rat intestine and this expression shows a developmental and intracellular pattern of distribution. Furthermore, our observations suggest PON2 protective effects against prooxidant stimuli in the small intestine. subcellular organelles; antioxidants; enterocytes; Caco-2 cells

Dietary vitamin A and its active metabolites are essential nutrients for many functions as well as potent regulators of gene transcription and growth. Although the epithelium of the small intestine is characterized by rapid and constant renewal and enterocytes play a central role in the absorption and metabolism of alimentary retinol, very little is known about the function of retinoids in the human gastrointestinal epithelium and mechanisms by which programs engage the cell cycle are poorly understood. We have assessed the effects of 10 [micro]M 9- and 13-cisretinoic acid (RA) on proliferation and differentiation processes, lipid esterification, apolipoprotein (apo) biogenesis and lipoprotein secretion along with nuclear factor gene transcription. Treatment of Caco-2 cells with RA at different concentrations and incubation periods revealed the reduction of thymidine incorporation in 60% preconfluent or 100% confluent cells. Concomitantly, RA 1) modulated D-type cyclins by reducing the mitogen-sensitive cyclin D 1 and upregulating cyclin D3 expressions and 2) caused a trend of increase in p38 MAPK, which triggers CDX2, a central protein in cell differentiation. RA remained without effect on lipoprotein output and apo synthesis, even for apo A-I that possesses RARE in its promoter. RA, in combination with 22-hydroxycholesterol, could induce apo A-I gene expression without any impact on apo A-I mass. Only the gene expression of peroxisome proliferator-activated receptor (PPAR)[beta], retinoic receptor (RAR)[beta], and RAR[gamma] was augmented and no alteration was noted in PPAR[alpha], PPAR[gamma], liver X receptor (LXR)[alpha], LXR[beta], and retinoid X receptors. Taken together, these data highlight RA-induced cell differentiation via specific signaling without a significant impact on apo A-I synthesis. retinoids; apolipoproteins; lipoproteins; nuclear factors; lipids