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PubMed1974

The relationship of root-cap slimes to pectins.

1. The patterns of incorporation of radioactivity from d-[U-(14)C]glucose into the pectic components of sections of sycamore roots changed so that sections nearer the tip incorporated relatively more label into arabinose and galactose compared with uronic acid. 2. Radioactive maize root-cap slime was prepared and found to contain three water-soluble component polymers which were electrophoretically (i) neutral, (ii) weakly acidic and (iii) strongly acidic at pH6.5. The neutral component was a glucan. The other components, which could be degraded by trans-elimination, consisted of an acidic backbone chain composed of galacturonic acid and glucose, attached to which were different proportions of neutral sugars. Arabinose, galactose and fucose, the main neutral sugars of the weakly and strongly acidic materials, were absent from the neutral fraction. 3. Fucose was a major sugar in maize-root slime and in a slime of similar composition synthesized by a maize callus of shoot origin. Only trace amounts were found in sycamore, pea and wheat root tips, and in pectin prepared from maize roots and coleoptiles. A high proportion of fucose is therefore a chemical characteristic of maize slime, and slime synthesis indicated a state of differentiation of the tissue. 4. The similarity between the slime and pectin is discussed; slime is a form of pectin modified in such a way as to provide a hydrated protective coating around the root tip.

Arabinose↗
PubMed1991

Pectin methylesterase, metal ions and plant cell-wall extension. The role of metal ions in plant cell-wall extension.

The study of pectin methylesterase and wall-loosening enzyme activities in situ, as well as the estimation of the electrostatic potential of the cell wall, suggest a coherent picture of the role played by metal ions and pH in cell-wall extension. Cell-wall growth brings about a decrease of local proton concentration because the electrostatic potential difference (delta psi) of the wall decreases. This in turn activates pectin methylesterase, which restores the initial delta psi value. This process is amplified by the attraction of metal ions in the polyanionic cell-wall matrix. The amplification process is basically due to the release of enzyme molecules that were initially bound to 'blocks' of carboxy groups. This increase of metal-ion concentration also results in the activation of wall-loosening enzymes. Moreover, the apparent 'inhibition' of pectin methylesterase by high salt concentrations may be considered as a device which prevents the electrostatic potential from becoming too high.

Carboxylic Ester Hydrolases↗
PubMed2000

Interaction between human complement and a pectin type polysaccharide fraction, PMII, from the leaves of Plantago major L.

The interaction between a pectin type polysaccharide fraction, PMII, isolated from the leaves of Plantago major, and human complement was tested in two different hemolytic complement-fixation tests and in addition by two ELISA methods detecting complement-activation products. Sera were used as a complement source of 10 arbitrary human volunteers, individually and as a pool. The complement-fixation tests were designed to measure the concentration of the pectin necessary to inhibit 50% of the hemolysis (ICH(50)). The ELISA tests for complement-activation products were measured in AU/mg using a fully activated serum as a standard. We observed a more than 200-fold difference in ICH(50) activity of the PMII pectin in one of the hemolytic tests by varying the individual sera used as complement-source. On the other hand, the ELISA complement-activation tests showed no significant variation in activity of the PMII depending on the complement-serum used. The level of antibodies against PMII detected in the complement-sera did not correlate with the ICH(50) activity of PMII. The results show that PMII is a potent complement activator with an activity of the same order of magnitude on a weight basis as that of aggregated human immunoglobulin (Ig)G. This activation leads to a complement consumption probably explaining the PMII's effect in the complement-fixation tests. PMII seems to be an activator both on the classical and the alternative pathway of activation. The results might be related to the reported wound-healing effect of the leaves of Plantago major.

Adult↗
PubMedDate not supplied

Oral administration of pectin-rich plant extract enhances C3 and C4 complement concentration in woman colostrum.

C3 and C4 components of the complement are normally present in human colostrum. These compounds are natural antibacterial agents. Pectin-rich plant extracts have been shown to induce prolactin release and milk synthesis when administered by the oral route in rat. In the present work, extract from a plant rich in pectin, Gossypium herbaceum was given orally to women 2 days after parturition. The extract enhanced concentration of C3 and C4 in colostrum but did not modify the total hemolytic complement activity (TCH50). No change in the concentration of the three compounds was observed in serum of the treated women. Control experiments showed that a treatment by placebo had no effect on colostrum composition. These data suggest that pectin-rich plant extracts favour transfer of C3 and C4 from blood to colostrum by an unknown mechanism. This observation suggests that some plant extracts might be used to reinforce the antibacterial activity of human colostrum.

Adult↗
PubMed2006

Double-blind, randomized evaluation of clinical efficacy and tolerability of an apple pectin-chamomile extract in children with unspecific diarrhea.

BACKGROUND: Acute diarrhea is one of the most common childhood diseases. The main aim of therapy is oral rehydration, mostly using a glucose-electrolyte solution. Results from a previous study (DIALOG I) investigating adjuvant treatment with a medicinal preparation containing an apple pectin-chamomile extract (Diarrhoesan) indicated a significantly reduced duration of diarrhea in children. OBJECTIVES: The objective of the present clinical placebo-controlled, double-blind study (DIALOG II) was to assess the clinical efficacy and tolerability of the apple pectin-chamomile extract on a larger number of patients. METHODS: The investigation was designed as a multicenter, randomized, double-blind, placebo-controlled parallel study enrolling 255 patients presenting with acute diarrhea. Patients were aged between 6 months and 6 years and treated on an outpatient basis with either an apple pectin-chamomile preparation or placebo. As a basic medication, each child received a glucose-electrolyte solution on the first day of treatment. RESULTS: The primary outcome (primary efficacy parameter) included a combined analysis of stool frequency, stool The statistical analysis revealed a superior efficacy of the tested preparation over placebo with a significantly reduced stool frequency in the treatment group compared to the control group. The results were corroborated by efficacy assessment performed by investigators and patients. Treatment was well tolerated, with an incidence of adverse effects similar to placebo. CONCLUSION: These findings support the concept of a beneficial influence of the investigated vegetable extract in shortening the course of the disease and relieving associated symptoms.

Antidiarrheals↗
PubMed1994

Polyclonal antibody against a complement-activating pectin from the roots of Angelica acutiloba.

Anti-sera against a complement-activating pectin (AR-2IIb), which was purified from the roots of Angelica acutiloba Kitagawa, were obtained by immunization of rabbits, and a polyclonal anti-AR-2IIb antibody of the IgG class was purified by affinity chromatography on AR-2IIb-immobilized Sepharose and Protein G-Sepharose. Periodate oxidation of AR-2IIb significantly reduced its inhibitory activity on the reactivity of AR-2IIb to anti-AR-2IIb-IgG, but pronase digestion of AR-2IIb did not affect its inhibitory activity. Other pharmacologically active pectins from A. autiloba, Bupleurum falcatum, and Glycyrrhiza uralensis and the complement-activating pectic arabinogalactan from A. autiloba also showed significant inhibitory activities on the reactivity of AR-2IIb to anti-AR-2IIb-IgG, but these inhibitory activities were lower than that of AR-2IIb. Other pectins, polygalacturonic acid, arabinogalactan, galactan, and araban tested had negligible inhibitory activity. Endo-a-(1-->4)-polygalacturonase digestion of AR-2IIb indicated that its "ramified" region (rhamnogalacturonan core possessing neutral oligosaccharide side-chains) contained epitopes for anti-AR-2IIb-IgG, but that 2-keto-3-deoxyoctulosonic acid (KDO)-containing regions and oligogalacturonides obtained from AR-2IIb were not recognized by anti-AR-2IIb-IgG. Although carboxyl-reduction of galacturonic acid in the "ramified" region decreased the inhibitory activity of the "ramified" on its reactivity to anti-AR-2IIb, an acidic tetrasaccharide unit in the rhamnogalacturonan core had negligible inhibitory activity.

Animals↗
PubMed1994

Existence of a rhamnogalacturonan II-like region in bioactive pectins from medicinal herbs.

Unusual component sugars such as 2-methylfucose (2-Me-Fuc), 2-methylxylose (2-Me-Xyl), apiose (Api), and aceric acid (AceA) are contained in the bioactive pectins from Bupleurum falcatum, Glycyrrhiza uralensis, and Angelica acutiloba, but not in the other bioactive pectic heteroglycans and arabinogalactans from Chinese and Japanese herbs tested. Each pectin was digested with endo-alpha-(1-->4)-polygalacturonase, and gave two enzyme-resistant fractions, PG-1 (rhamnogalacturonan core with neutral sugar side-chains) and PG-2, and an oligogalacturonide fraction (PG-3) by gel filtration on Bio-gel P-30. The PG-2 fractions commonly consisted of unusual sugars such as 2-Me-Fuc, 2-Me-Xyl, Api, AceA, 3-deoxy-D-lyxo-heptulosaric acid (Dha), and 3-deoxy-D-manno-2-octulosonic acid (Kdo) in addition to Rha, Fuc, Ara, Xyl, Man, Gal, Glc, GalA, and GlcA. Lithium degradation of each PG-2 gave a pentosyl-->6-deoxyhexosyl-->6-deoxyhexosyl-->pentitol fragment as a major oligosaccharide in addition to some neutral di- to trisaccharide alditols. Methylation analysis of the lithium degradation products from each PG-2 also indicated that these oligosaccharide alditols mainly consisted of terminal Rha, Araf, Fuc, Xyl, and Gal, 4-linked Rha, 3-linked Fuc, and 3'-linked Api. HPLC analysis showed that PG-2 had molecular heterogeneity. These results indicate that the bioactive pectins from medicinal herbs commonly consist of the minor KDO-containing region which resembles the rhamnogalacturonan II in plant cell walls.

Carbohydrate Sequence↗
PubMed1976

Decreased bioavailability of digoxin due to antacids and kaolin-pectin.

Employing a Latin-square design and single-dose studies of bioavailability in 10 normal human volunteers, we tested the hypothesis that antacids and kaolin-pectin might interfere with the bioavailability of orally administered digoxin. Cumulative six-day urinary digoxin excretion (expressed as the percentage of a 0.75-mg dose recovered) was: control, 40.1+/-3.0 (S.E.); aluminum hydroxide, 30.7+/-2.9; magnesium hydroxide, 27.1+/-2.4; magnesium trisilicate, 29.1+/-1.7; and kaolin-pectin 23.4+/-2.0. The differences in means were highly significant (F = 10.47, P less than 0.005). Further analysis (multiple comparison test) revealed that control differed significantly from each of the other treatments (alpha = 0.05), but there was no such difference between any of the other treatment groups. The decreased cumulative excretion produced by antacids and kaolin-pectin reflected a striking reduction in digoxin absorption associated with these compounds that was not related to alteration of gut transit time or to adsorption of digoxin to these gastrointestinal medications.

Administration, Oral↗
PubMed2006

Functional identification of an Arabidopsis pectin biosynthetic homogalacturonan galacturonosyltransferase.

Galacturonosyltransferases (GalATs) are required for the synthesis of pectin, a family of complex polysaccharides present in the cell walls of all land plants. We report the identification of a pectin GalAT (GAUT1) using peptide sequences obtained from Arabidopsis thaliana proteins partially purified for homogalacturonan (HG) alpha-1,4-GalAT activity. Transient expression of GAUT1 cDNA in the human embryonic kidney cell line HEK293 yielded uridine diphosphogalacturonic acid:GalAT activity. Polyclonal antibodies generated against GAUT1 immunoabsorbed HG alpha-1,4-GalAT activity from Arabidopsis solubilized membrane proteins. blast analysis of the Arabidopsis genome identified a family of 25 genes with high sequence similarity to GAUT1 and homologous genes in other dicots, in rice, and in Physcomitrella. Sequence alignment and phylogenetic Bayesian analysis of the Arabidopsis GAUT1-related gene family separates them into four related clades of GAUT and GAUT-like genes that are distinct from the other Arabidopsis members of glycosyltransferase family 8. The identification of GAUT1 as a HG GalAT and of the GAUT1-related gene family provides the genetic and biochemical tools required to study the function of these genes in pectin synthesis.

Arabidopsis↗
PubMed2006

The gene responsible for borate cross-linking of pectin Rhamnogalacturonan-II is required for plant reproductive tissue development and fertilization.

Deficiencies in boron, a microelement that is essential for the growth and development of higher plants, often cause problems in reproductive growth. Rhamnogalacturonan-II (RG-II) in cell wall pectin acts as the sole receptor for boron in plant cells, forming a borate cross-linked RG-II dimer (dRG-II-B), but the physiological functions of dRG-II-B remain unknown. We have previously shown that the pectin glucuronyltransferase 1 gene NpGUT1, which is involved in the biosynthesis of RG-II sugar chains, is essential for the formation of the RG-II-B complex, resulting in tight intercellular attachment in meristematic tissues. Because NpGUT1 expression was found to be abundant in reproductive organs in addition to meristematic tissues, we analyzed the expression and functions of NpGUT1 in more detail in tobacco reproductive tissues. Specific NpGUT1 expression was detected in the tapetum of flower buds and in the pollen, pollen tube tips, and transmitting tissue of the pistils of flowers. Dexamethasone-induced expression of the NpGUT1 antisense gene in flower buds resulted in the formation of sterile flowers with aberrant development of pollen and transmitting tissue. Pollen tubes could not pass through pistils with aborted transmitting tissue, and expression of an NpGUT1 antisense gene in germinating pollen inhibited pollen tube elongation, accompanied by the absence of pectin RG-II and boron in the pollen tube tip. These results indicate that expression of NpGUT1 is required for the development and functions of male and female tissues.

Borates↗
PubMed2001

Modulation of the degree and pattern of methyl-esterification of pectic homogalacturonan in plant cell walls. Implications for pectin methyl esterase action, matrix properties, and cell adhesion.

Homogalacturonan (HG) is a multifunctional pectic polysaccharide of the primary cell wall matrix of all land plants. HG is thought to be deposited in cell walls in a highly methyl-esterified form but can be subsequently de-esterified by wall-based pectin methyl esterases (PMEs) that have the capacity to remove methyl ester groups from HG. Plant PMEs typically occur in multigene families/isoforms, but the precise details of the functions of PMEs are far from clear. Most are thought to act in a processive or blockwise fashion resulting in domains of contiguous de-esterified galacturonic acid residues. Such de-esterified blocks of HG can be cross-linked by calcium resulting in gel formation and can contribute to intercellular adhesion. We demonstrate that, in addition to blockwise de-esterification, HG with a non-blockwise distribution of methyl esters is also an abundant feature of HG in primary plant cell walls. A partially methyl-esterified epitope of HG that is generated in greatest abundance by non-blockwise de-esterification is spatially regulated within the cell wall matrix and occurs at points of cell separation at intercellular spaces in parenchymatous tissues of pea and other angiosperms. Analysis of the properties of calcium-mediated gels formed from pectins containing HG domains with differing degrees and patterns of methyl-esterification indicated that HG with a non-blockwise pattern of methyl ester group distribution is likely to contribute distinct mechanical and porosity properties to the cell wall matrix. These findings have important implications for our understanding of both the action of pectin methyl esterases on matrix properties and mechanisms of intercellular adhesion and its loss in plants.

Antibodies, Monoclonal↗
PubMed2004

Changes in pectins and MAPKs related to cell development during early microspore embryogenesis in Quercus suber L.

The occurrence and significance of changes in cell wall components and signalling molecules has been investigated during early microspore embryogenesis in cork oak (Quercus suber L.) in relation to cell proliferation and cell differentiation. Microspore embryogenesis has been induced in in vitro anther cultures of Q. suber by the application of a stress treatment of 33 degrees C. After the treatment, microspores at the responsive developmental stage of vacuolate microspore switched towards proliferation and the embryogenesis pathway to further produce haploid plantlets. Ultrastructural and immunocytochemical analysis revealed changes in cell organisation after induction at different developmental stages, the cellular features displayed being in relation to the activation of proliferative activity and the beginning of differentiation in young and late proembryos. Immunogold labelling with JIM5 and JIM7 antibodies showed a different presence of pectin and level of its esterification in cell walls at different developmental stages. Non-esterified pectins were found in higher proportions in cells of late proembryos, suggesting that pectin de-esterification could be related to the beginning of differentiation. The presence and subcellular distribution of Erk 1/2 MAPK homologues have been investigated by immunoblotting, immunofluorescence and immunogold labelling. The results showed an increase in the expression of these proteins with a high presence in the nucleus, during early microspore proembryos development. The reported changes during early microspore embryogenesis are modulated in relation to proliferation and differentiation events. These findings provided new evidences for a role of MAPK signalling pathways in early microspore embryogenesis, specifically in proliferation, and would confer information for the cell fate and the direction of the cell development.

Cell Differentiation↗
PubMed1979

The digestion of pectin in the human gut and its effect on calcium absorption and large bowel function.

1. The effect of dietary fibre digestion in the human gut on its ability to alter bowel habit and impair mineral absorption has been investigated using the technique of metablic balance. 2. Five healthy male students were studied for 9 weeks under controlled dietary conditions and during the last 6 weeks they took 36 g pectin/d. Bowel habit, transit through the gut, faecal fibre excretion, calcium balance and faecal composition were measured. 3. During the control period only 15% of the dietary fibre ingested was excreted in the stools and when pectin was added to the diet there was no increase in fibre excretion. Stool frequency and mean transit time were unchanged by pectin but stool wet weight increased by 33% and faecal excretion increased (%) for fatty acids 80, nitrogen 47, total dry matter 28 and bile acids 35. Ca balance remained unchanged. 4. It may be concluded from these results that dietary fibre is largely metabolized in the human gut and dietary pectin completely so. This could explain its lack of effect on bowel habit and Ca balance. Other changes in the faeces may be related to an increase in bacterial mass.

Adult↗
PubMed1984

Alteration of regression of cholesterol accumulation in rats by dietary pectin.

Male, Wistar rats (50-74 g) were given a semi-purified diet containing cholesterol (10 g/kg diet) for 4 weeks, groups of control and experimental animals killed, and the remainder of the cholesterol-fed animals given either a semi-purified cholesterol-free diet without a fibre source or a similar diet with pectin (50 g/kg diet) for 8 weeks. Animals were killed at 2-week intervals and serum and liver cholesterol and triglycerides, faecal neutral steroids and acidic steroids measured. Animals given pectin had significantly lower serum cholesterol levels than animals given the basal diet after 4 and 6 weeks. Both experimental groups efficiently decreased their liver cholesterol levels during regression. Bile acid excretion was elevated in both groups, especially in rats receiving pectin, but neutral steroid excretion was unchanged. The increase in bile acid excretion was primarily in the form of chenodeoxycholic acid and its metabolites. This increased bile acid excretion is postulated to result from stimulation of the normal mechanism for increased steroid excretion in the rat, i.e. a change in the value of cholic: chenodeoxycholic acid or from a mechanism not yet elucidated.

Animals↗
PubMed1990

The effect of lactulose, pectin, arabinogalactan and cellulose on the production of organic acids and metabolism of ammonia by intestinal bacteria in a faecal incubation system.

An in vitro faecal incubation system was used to study the metabolism of complex carbohydrates by intestinal bacteria. Homogenates of human faeces were incubated anaerobically with added lactulose, pectin, the hemicellulose arabinogalactan, and cellulose, both before and after subjects had been pre-fed each carbohydrate. Fermentation of added substrate was assessed by the production of short-chain fatty acids (SCFA) and suppression of net ammonia generation over 48 h of incubation. Control faecal homogenates to which carbohydrate was not added yielded an average increment of SCFA of 43 mmol/l, equivalent to 172 mmol/kg in the original stool. The addition of lactulose, pectin and arabinogalactan each increased the yield of SCFA by a similar amount, averaging 6.5 mmol/g carbohydrate or 1.05 mol/mol hexose equivalent; organic acid yield was not increased by pre-feeding these substances for up to 2 weeks. Acetate was the major SCFA in all samples at all times and, after pre-feeding with extra carbohydrate, butyrate concentrations exceeded propionate in all samples. Faecal homogenates incubated with cellulose showed no greater SCFA production than controls over the first 48 h, but there was a slight increase when samples from two subjects pre-fed cellulose were incubated for 14 d. Net ammonia generation was markedly suppressed by addition of lactulose to faecal incubates with an initial period of net bacterial uptake of ammonia. Pectin and arabinogalactan also decreased ammonia generation, but the reductions were not significant unless subjects were pre-fed these materials; cellulose had no effect on ammonia generation.

Adult↗
PubMed1994

The effects of pectin and wheat bran on the distribution of a meal in the gastrointestinal tract of the rat.

The effects of wheat bran and pectin on the gastrointestinal distribution of a radiolabelled, homogenized baked-bean meal were investigated in the rat. These fibres were chosen because of their very different physical characteristics; wheat bran is a coarse, particulate, mainly insoluble fibre whilst pectin is a soluble viscous polysaccharide. Sixty male rats were administered orally with control or test meals and five from each group were killed after 50, 100, 200 and 300 min. The gut was removed and the distribution of the meal established scintigraphically. Addition of the fibres altered the distribution of the meal with faster accumulation at the distal and caecal areas. Wheat bran delayed gastric emptying whilst pectin promoted gastric emptying and had a pronounced effect on increasing the distal accumulation of the meal. These alterations in the distribution of a homogenized baked bean meal show that dietary fibres with different physical characteristics may alter gastrointestinal motility in different ways and these differences may have implications for meal absorption and clinical treatments of gastrointestinal disorders.

Animals↗
PubMedDate not supplied

A crosslinked calcium-alginate-pectinate-cellulose acetophthalate gelisphere system for linear drug release.

This study proposes a novel binary crosslinked ternary multiple-unit system, collectively referred to as calcium-alginate-pectinate-cellulose acetophthalate gelispheres (CAPCA), for the purpose of obtaining linear, controlled drug release. This polymeric system, composed of sodium alginate, pectin, and cellulose acetophthalate, was developed through a binary crosslinking reaction in a composite aqueous system consisting of calcium and acetate ions. The crosslinking reaction was optimized in terms of maximizing drug release suppression and could be obtained by exposing the gelispheres for 24 hours to a combined aqueous solution of 15% w/v acetic acid and 2% w/v calcium chloride. The highly acidic nature of this solution (pH 1.9) was desirable for enhancing the drug entrapment efficiency of the gelispheres. Synchronization of matrix swelling and erosion appeared to be responsible for the attainment of zero-order drug release. However, such perfect synchronization was only achievable through application of the ternary polymeric combination presented in this work. The main advantages of the ternary system shown in this study over the previously presented binary calcium-alginate-pectinate system (CAP) proposed by Pillay and Fassihi (1999a, 1999b), was provision of extended drug release over 18 hours, minimization of late-phase drug release tapering, and provision of superior linearity in drug release profiles. Kinetic modeling of dissolution data using various power law equations highlighted the significance of matrix relaxation and erosion in modulation of drug release rate. In all cases of model fitting excellent correlation (r(2) > 0.98) was obtained between observed and predicted data. Textural profiling of crosslinked gelispheres reflected a significantly lower reduction in matrix resilience as the concentration of cellulose acetophthalate was increased in the gelisphere formulation. This may be attributed to the concentration-dependent matrix plastic-transforming property of cellulose acetophthalate.

Alginates↗
PubMed2005

In vitro and in vivo evaluation of pectin beads for the colon delivery of beta-lactamases.

The aim of the present study was to provide a "proof of concept" of colon delivery of beta-lactamases by pectin beads aiming to degrade residual beta-lactam antibiotics, in order to prevent the emergence of resistant bacterial strains. Pectin beads were prepared according to ionotropic gelation method using CaCl2 as a gelling agent. Particles were then washed and soaked in polyethylenimine (PEI). Coating beads with PEI considerably improved their stability in simulated intestinal medium. In vitro studies showed that beta-lactamases were released from pectin beads in colonic medium due to the action of pectinolytic enzymes. When ampicillin was added to this medium, the release of beta-lactamases induced, as expected, the antibiotic inactivation. Finally, after oral administration of loaded-beads to CD1 mice, beta-lactamases were retrieved in high concentrations in faeces. Observation by SEM of beads extracted from mice intestinal tracts concluded the core degradation of beads without any modification of the PEI coating layer. This study demonstrates that a multiparticulate system with suitable characteristics for site-specific colonic delivery can be prepared. This system could be used to target beta-lactamases to the colon in order to hydrolyse antibiotic residues during treatment and prevent their impact on colonic microflora.

Animals↗