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At least 73 records · Page 4Linked to original sources
PubMed1998

Dietary pectin with high viscosity lowers plasma and liver cholesterol concentration and plasma cholesteryl ester transfer protein activity in hamsters.

We fed semipurified diets containing pectin with either a high or low in vitro viscosity at a level of 3 g/100 g air-dried diet to hamsters for 8 wk. A control group was fed cellulose and a positive control group was fed psyllium. The pectins used were a calcium-sensitive pectin (CS-pectin) that has a high viscosity and a noncalcium-sensitive pectin (NCS-pectin) that has a low viscosity. In the presence of calcium, CS-pectin has a more than 80-fold higher viscosity than NCS-pectin which offered the opportunity to investigate the possible role of viscosity in the hypolipidemic properties of pectin. The hamsters fed CS-pectin or psyllium had considerably lower plasma cholesterol concentrations (3.69 +/- 0.44 and 4.21 +/- 0.45 mmol/L, respectively, mean +/- SD, n = 14) than those fed NCS-pectin (5.03 +/- 1.15 mmol/L) or cellulose (5.72 +/- 1. 04 mmol/L). Differences in total plasma cholesterol were reflected in both high density lipoprotein and very low density lipoprotein cholesterol. There was no effect of fiber on low density lipoprotein cholesterol levels. Liver cholesterol concentrations paralleled the plasma cholesterol levels and were 9.91 +/- 2.48 micromol/g of liver for the CS-pectin group, 15.03 +/- 5.75 for the psyllium group, 17. 69 +/- 10.66 for the NCS-pectin group, and 25.57 +/- 9.23 for the cellulose group. Fecal bile acid and neutral steroid excretion tended to be higher in the hamsters fed CS-pectin than in their counterparts fed NCS-pectin. The hamsters fed psyllium had significantly greater fecal excretions of bile acids than the hamsters fed cellulose, CS-pectin or NCS-pectin, whereas the excretion of fecal neutral sterols tended to be lower. Plasma cholesteryl ester transfer protein activity was significantly lower in the hamsters fed CS-pectin than in those fed NCS-pectin. The results of this study suggest that the viscosity of pectins may determine their cholesterolemic effect.

Animals↗
PubMedDate not supplied

Harry M. Vars award. The effect of a pectin-supplemented elemental diet on intestinal adaptation to massive small bowel resection.

The effect of a pectin-supplemented elemental diet on intestinal adaptation to massive small bowel resection in the rat was investigated in this study. Sixty adult Sprague-Dawley rats underwent placement of a feeding gastrostomy and swivel apparatus. Control animals (N = 16) were then returned to their cages while the remaining animals underwent an 80% small bowel resection and anastomosis (resected, N = 44). Postoperatively, animals were randomly assigned to receive either a fat- and fiber-free elemental diet (no pectin) or the same diet supplemented with 2% pectin (pectin). After 8 days of full strength diet, samples of jejunum, ileum, and colon were obtained for analysis. The weights per unit length of the ileum and colon were significantly greater in the resected pectin group than either the resected no pectin or pectin control groups. Mucosal parameters (unit weight, DNA, RNA, and protein content) were significantly increased in the jejunum and ileum of both the resected pectin and resected no pectin groups relative to their respective control groups. However, jejunal and ileal mucosal parameters were significantly greater (1.3- to 2-fold) for the resected pectin group than for the resected no pectin group. All the mucosal parameters of the colons were significantly greater for the pectin resected group than for the pectin control group, while only colonic mucosal RNA was significantly greater for the no pectin resected group than for the no pectin control group. These data indicate that the addition of pectin to an elemental diet significantly enhanced intestinal adaptation to massive small bowel resection in the rat.

Adaptation, Physiological↗
PubMed1999

Immunocytochemical localization of pectins in the maturing anther of Allium cepa L.

Distribution of pectins in cell walls of maturing anther of Allium cepa L. was investigated. The monoclonal antibodies against defined epitopes of pectin were used: JIM5 recognizing unesterified pectin and JIM7 recognizing esterified pectin. It has been found that the cell walls of all anther tissues mainly contain esterified pectins. In the somatic tissues only small amounts of unesterified pectins are present in the cell wall junctions and adjacent middle lamellae and in the cell walls of the connective tissue. Thickening of the epiderm cell walls and growth of trabeculae in endothecium are completed through deposition of esterified pectins. In the cell walls of the middle layer and tapetum, unesterified pectins have been found only prior to their disintegration. The primary wall of microsporocytes is made up mainly of esterified pectins. Unesterified pectins occur outside microsporocytes only prior to the callose isolation stage. The presence of esterified pectins has also been detected on the surface of the callose wall surrounding dividing microsporocytes. Lysis of those pectins takes place after microsporogenesis, simultaneously with the lysis of the callosic walls. Before these processes pectins are unesterified. In the sporoderm of pollen grains mainly esterified pectins occur. They have been localized in the intine and aperture. The level of unesterified pectins in the intine is markedly lower.

Animals↗
PubMed1994

Comparison of utilization of pectins from various sources by pure cultures of pectinolytic rumen bacteria and mixed cultures of rumen microorganisms.

Utilization of citrus, lucerne, apple and sugar beet pulp pectins by pure strains of rumen bacteria, Prevotella ruminicola, Lachnospira multiparus and Butyrivibrio fibrisolvens was compared. Additionally, the utilization of pectins by mixed rumen microorganisms was evaluated. The comparison was based on the depletion of galacturonic acid from medium, content of cellular protein in the cultures and the amount of end products of pectin fermentation in cell-free culture fluids. It was found that citrus pectin was utilized best; utilization of lucerne, apple and sugar beet pectins was dependent on the species of bacteria. P. ruminicola and B. fibrisolvens utilized polygalacturonic acid from sugar beet pectins better than that from apple or lucerne pectin, while L. multiparus was capable of significantly better utilization of lucerne pectin than pectin from sugar beet or apple. The source of pectin was less important for mixed cultures of rumen microorganisms than for pure cultures of rumen bacteria. The amount of fermentation products in the culture fluids supported the conclusion that citrus pectin was utilized better than others. Microbial protein content in the cultures was found to be a less sensitive indicator of pectin utilization than the remaining examined parameters. P. ruminicola strains and mixed cultures of rumen microorganisms were shown to have the highest ability to utilize pectins, L. multiparus-moderate, while the B. fibrisolvens strains utilized pectin the least.

Animals↗
PubMed1995

Influence of pectin structure on the interaction with bile acids under in vitro conditions.

Structural parameters of pectin (a polysaccharide and important component of dietary fibre) influence the interaction with bile acids (BA). The effect of experimental conditions (concentration of pectin, BA and Ca2+) on such interactions was studied at pH 6.0. Series of pectins were used, prepared from virtually fully esterified pectin by gradual de-esterification with alkali or with pectinesterase from oranges. Further amidated and acetylated pectins were also tested. The greatest interaction with BA was found with a very highly esterified pectin under in vitro conditions. The interaction diminished with decreasing degrees of esterification (DE). This decrease was more intensive for pectins possessing a blockwise arrangement of free-COOH groups. Derivatives of pectin generally interacted less with BA. These results were principally confirmed with commercial pectins, with pectins prepared on a pilot-plant scale and with pectins originating from a defined botanical source. The interactions of these preparations with BA were less intensive than with those of pectins having an ideal random distribution of free -COOH groups in the polysaccharide molecules at the same DE. The interaction with pectin is also likely to be influenced by the structure of BA.

Bile Acids and Salts↗
PubMed2001

Citrus pectin: characterization and inhibitory effect on fibroblast growth factor-receptor interaction.

This study was undertaken to characterize the pectin from four citrus species and to determine their in vitro inhibitory activities on the binding of fibroblast growth factor (FGF) to the FGF receptor (FGFR). Pectin from various parts of lemon, grapefruit, tangerine, and orange were isolated and characterized. Tangerine had the highest pectin content among the four citrus species. Segment membrane contained as much as or more pectin than flavedo/albedo. Anhydrogalacturonic content was highest in pectin from segment membrane of tangerine and flavedo/albedo of grapefruit. Lemon pectin contained the highest methoxyl content (MC), and grapefruit contained the largest proportion of lower molecular weight (<10000 Da) pectin. Tangerine contained the highest neutral sugar in both flavedo/albedo and segment membrane. The interdependency of heparin on factor-receptor interaction provides a means for identifying new antagonists of growth factor activity and thus for treatment of various diseases. These results showed that pectin significantly inhibited the binding of FGF-1 to FGFR1 in the presence of 0.1 microg/mL heparin. The pectin from the segment membrane of lemon was the most potent inhibitor. The inhibition activity was significantly correlated with sugar content, MC, and size of pectin. Kinetic studies revealed a competitive nature of pectin inhibition with the heparin, a crucial component of the FGF signal transduction process. The observation that the heparin-dependent biological activity of FGF signal transduction is antagonized by citrus pectin should be further investigated for the use of these pectins as anti-growth factor agents for potential health benefits.

Citrus↗
PubMed1985

The hypocholesterolaemic effects of pectins in rats.

The hypocholesterolaemic effects of pectins were studied in a series of five experiments in weanling Sprague-Dawley rats. Expt A examined the effects of differing levels of dietary fat on plasma and liver lipids. Rats were given diets containing 100 g pectin, National Formulary (NF)/kg, and either 50,100, 150 or 200 g oil/kg. All diets contained 10 g cholesterol/kg. Plasma cholesterol levels were lower in all pectin-fed groups compared with rats given the control diet containing 100 g Solkafloc and 100 g oil/kg. Liver lipid and cholesterol levels increased with increasing fat content of the diet, reaching a plateau at 150 g fat/kg diet, but were still significantly lower in all pectin-fed groups compared with the control group. Expt B. The effects of molecular weight and degree of methoxylation of pectins were studied in five groups of rats given either a control diet containing 100 g Solkafloc/kg or high molecular weight, high methoxyl pectin (HMW HMP); high molecular weight, low methoxyl pectin (HMW LMP); low molecular weight, high methoxyl pectin (LMW HMP); low molecular weight, low methoxyl pectin (LMW LMP). All diets in this and subsequent experiments contained 100 g fat and 10 g cholesterol/kg. Plasma cholesterol levels were significantly lower than control values only in the HMW HMP group. Compared with controls, animals given HMW pectins had lower levels of liver lipid and liver cholesterol; on the LMW HMP diet the liver cholesterol, but not the liver lipid, was lower. Expt C. An attempt was made to clarify the possible effect of degree of methoxylation by feeding diets containing either 100 g Solkafloc/kg, 100 g pectin NF/kg or 100 g very high methoxyl pectin/kg. Plasma cholesterol levels were significantly reduced by both pectins but there was no difference in effect between the two. Both had similar viscosities suggesting that this is a more important factor than methoxyl content. Expts D and E. Effects of dose on hypocholesterolaemic effects of HMP and LMP were studied. Diets containing 50 or 100 g Solkafloc, HMP or LMP/kg were given in Expt D, and 25 g Solkafloc or HMP/kg, 50 g Solkafloc, HMP or LMP/kg and 100 g Solkafloc or LMP/kg in Expt E. Plasma cholesterol levels were significantly reduced in groups given 50 or 100 g HMP/kg and in groups given 100 g LMP/kg. HMP were found to be more effective at lowering plasma cholesterol levels than LMP. LMW pectins were not effective. This suggests that the hypocholesterolaemic effects are at least partly due to viscosity.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2005

Effect of abomasal pectin infusion on digestion and nitrogen balance in lactating dairy cows.

Two experiments were conducted to test the hypothesis that increasing carbohydrate fermentation in the large intestine would increase intestinal conversion of blood urea N to microbial protein, thereby reducing urinary N output. In experiment 1, 3 multiparous Holstein cows were used in an incomplete 4 x 4 Latin square with 14-d periods. Cows were fed the same basal diet and treatments were the abomasal infusion of 0, 0.5, or 1 kg/d of citrus pectin, or the addition of 1 kg/d of molasses to the basal diet. Experiment 2 used 6 cows in a double reversal design with four 21-d periods. Cows were fed one basal diet and treatments were the abomasal infusion of either 0 or 1 kg/d of pectin. In experiment 1, pectin infusion linearly decreased basal ration intake from 25.0 to 23.2 kg/d. This was prevented in experiment 2 by restricted feeding, and basal ration intake was 22.2 kg/d. Abomasal pectin caused numeric decreases in total tract apparent digestibility of neutral detergent fiber and neutral detergent solubles in experiment 1 and significantly decreased starch digestibility in experiment 2, suggesting that pectin may have reduced postruminal nutrient digestibility. Pectin infusion did not affect milk yield but decreased milk fat percentage from 3.69 to 3.53% in experiment 2. Increasing abomasal pectin tended to decrease urinary N and increase fecal N in experiment 1 and these effects were significant in experiment 2. For both experiments, urinary N decreased 26 g/d, approximately 10% of daily urine N output. Abomasal pectin did not affect fecal pH or DM content; however, in experiment 2, pectin decreased fecal ammonia from 19.8 to 13.4 mmol/kg of DM and increased fecal purines from 13.8 to 15.8 mmol/kg of DM. In both experiments, excretion of fecal purines was increased from 15 g/d for 0 kg/d pectin to 18 g/d for 1 kg/d pectin, although this increase was only significant in experiment 2. These results suggest that manipulating dairy diets to increase postruminal fermentation may reduce urinary N and consequently manure ammonia losses. However, abomasal pectin tended to decrease both ruminal ammonia concentration and urinary purine derivative output in experiment 2, suggesting that postruminal pectin fermentation may have compromised rumen microbial protein production.

Abomasum↗
PubMed2001

Immunocytochemical localization of esterified and unesterified pectins in unpollinated and pollinated styles of Petunia hybrida Hort.

Localization of pectins in the style of Petunia hybrida before and after pollination was investigated by immunocytochemistry using two primary monoclonal antibodies specific to highly (JIM7) and weakly (JIM5) methylesterified pectins. In the unpollinated style, esterified pectins occurred mainly in the cell walls of cortex tissue, while unesterified pectins were present mainly in the extracellular matrix (ECM) of the transmitting tract. After pollination no remarkable differences were found in pectin distribution in the ground tissue of the style. On the other hand, in the transmitting tract a reduction in the quantity of unesterified pectins was observed. Unesterified pectins in the extracellular regions of the transmitting tissue decreased before the penetration of the pollen tubes, indicating that pollination induces a reduction in the amount of unesterified pectins in the transmitting-tract ECM. The correlation between the degradation of strongly Ca2+-binding pectins and the growing level of those ions in the extracellular regions of the transmitting tract in the pollinated pistil of P. hybrida (M. Lenartowska et al. 1997) suggests that this process may constitute a mechanism for creating an optimum calcium medium for in vivo-growing pollen tubes. Both pectin categories were localized in pollen tubes. Esterified pectin epitopes were localized mainly in the vesicles of the tip cytoplasm. Unesterified pectin epitopes were found in the external fibrillar wall of pollen tubes.

Antibodies, Monoclonal↗
PubMed2006

Suppression of endotoxin-induced proinflammatory responses by citrus pectin through blocking LPS signaling pathways.

Pectin is composed of complex polysaccharides rich in galactoside residues, and it is most abundant in citrus fruits. Pectin and modified pectin have been found to exhibit anti-mutagenic activity and inhibit cancer metastasis and proliferation, with no evidence of toxicity or other serious side effects. In this study, we investigated the inhibitory effect of pectin at different degrees of esterification (DEs) on the expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-activated macrophages. Western blot and RT-PCR analyses demonstrated that 30% esterified pectin (DE30), DE60 pectin, and DE90 pectin significantly inhibited the protein and mRNA expressions of iNOS and COX-2 in LPS-activated macrophages, and DE90 pectin was the most-potent inhibitor. To clarify the mechanisms involved, DE90 pectin was found to inhibit the phosphorylation of MAPKs and IKK kinase activity. In addition, DE90 pectin inhibited the activation of NF-kappaB and AP-1 by electrophoretic mobility shift assay and transient transfection experiments. Finally, we found that DE90 pectin could bind with LPS, and might result in decreased binding of LPS to its receptor. These results suggest that modulation of iNOS and COX-2 expressions by dietary pectin may be important in cancer chemoprevention and anti-inflammation.

Animals↗
PubMed2003

Monovalent salt-induced gelation of enzymatically deesterified pectin.

Pectin gels were induced by monovalent salts (0.2 M) concurrently with deesterification of high methoxy pectin using a salt-independent orange pectin methylesterase (PME). Constant pH was maintained during deesterification and gelation. If salt or PME was absent, the pectin did not form a gel. The gel strength was influenced by both pH and species of monovalent cation. At pH 5.0, the pectin gel induced by KCl was significantly stronger than the NaCl-induced gel. In contrast, a much stronger gel was produced in the presence of NaCl as compared to KCl at pH 7.0. LiCl did not induce pectin gelation at either pH. Molecular weights of pectins increased from 1.38 x 10(5) to 2.26 x 10(5) during NaCl-induced gelation at pH 7. One proposal to explain these pectin molecular weight changes is a hypothetical PME transacylation mechanism. However, these pectin molecular weight changes can also be explained by metastable aggregation of the enzymatically deesterified low methoxy pectin. We postulate that gelation was induced by a slow deesterification of pectin under conditions that would normally salt out (precipitate) low methoxy pectin in the absence of PME.

Gels↗
PubMed2006

Addition of pectin and soy soluble polysaccharide affects the particle size distribution of casein suspensions prepared from acidified skim milk.

Pectins are negatively charged polysaccharides employed as stabilizers in acidified milk dispersions, where caseins aggregate because of the low pH and serum separation needs to be prevented. The objective of this research was to study the effect of charge on the stabilizing functionality of the polysaccharide in acid milk drinks. Unstandardized pectins with various charges (as degree of esterification, DE) as well as soybean soluble polysaccharide (SSPS) were tested for their stabilizing behavior as a function of pH and concentration. Skim milk was acidified by glucono-delta-lactone and then homogenized in the presence of polysaccharide at different pH values (in the range from 4.2 to 3.0). Measurements of particle size distribution demonstrated that pectins with a DE of 71.4, 68.6, and 67.4 stabilized milk at pH > 4.0. Pectins with a lower DE (63.9%) needed a higher concentration (0.4%) at the same pH to show a monomodal distribution of particle sizes. Pectins with lower DE (<50%) did not stabilize the dispersions. Although this difference in behavior was attributed mainly to the pectin charge, the efficiency in stabilizing the casein dispersion decreased with decreasing pectin size. For example, the high methoxyl pectin (HMP) with 63.9 DE was smaller in size than the HMPs with a higher charge. Pectins showed a pH-dependent stabilization effect, as at pH < 4.0 the dispersions contained aggregates. When SSPS was used to stabilize acid milk, at pH < 4.0, it showed a better stabilization behavior than HMP. When SSPS and pectin were used in combination, the particle size distribution of the acid milk dispersion was pH-dependent, and results were similar to those for samples containing pectin alone. This suggested that in the mixture, pectin dominated the behavior over SSPS, even when an excess of SSPS was added to the dispersions before homogenization.

Animals↗