Pectin Type Research Articles

Characterization of a biologically active pectin from Plantago major L.

PMII isolated from the leaves of Plantago major L. is a pectin type polysaccharide with anti-complementary activity. It is highly esterified and partly O-acetylated with regions of 1,4 linked polygalacturonic acid and at least two different hairy regions. The galactose side chains are linked to position 4 of rhamnose in the main chain. The structure of the galactan side chains is complex, but 1,3,6 linkages are dominating in one of the isolated hairy regions. Arabinose is attached to position 3 and 6 of galactose. In the other hairy region arabinose is attached to position 3 of galacturonic acid. De-esterification and de-acetylation do not alter the anti-complementary activity of PMII. Different parts of PMII were shown to have different activities. The smooth regions are only slightly active in contrast to the hairy regions which had significantly higher activity. The hairy regions of highest molecular weight (PVa) with 1,3,6 linked galactose side chains were found to be the most active fraction. The importance of arabinose for the activity seems to depend on the site of substitution. Removal of arabinose terminally linked to galactose increases the activity slightly while removal of arabinose linked to the galacturonic acid backbone decreases the activity.

Immunogold localization of pectins and glycoproteins in tissues of peach with reference to deep supercooling

Living xylem tissues and floral buds of several species of woody plants survive exposure to freezing temperatures by deep supercooling. A barrier to water loss and the growth of ice crystals into cells is considered necessary for deep supercooling to occur. Pectins, as a constituent of the cell wall, have been implicated in the formation of this barrier. The present study examined the distribution of pectin in xylem and floral bud tissues of peach (Prunus persica). Two monoclonal antibodies (JIM5 and JIM7) that recognize homogalacturonic sequences with varying degrees of esterification were utilized in conjunction with immunogold electron microscopy. Results indicate that highly esterified epitopes of pectin, recognized by JIM7, were the predominant types of pectin in peach and were uniformly distributed throughout the pit membrane and primary cell walls of xylem and floral bud tissues. In contrast, un-esterified epitopes of pectin, recognized by JIM5, were confined to the outer surface of the pit membrane in xylem tissues. In floral buds, these epitopes were localized in middle lamellae, along the outer margin of the cell wall lining empty intercellular spaces, and within filled intercellular spaces. JIM5 labeling was more pronounced in December samples than in July/August samples. Additionally, epitopes of an arabinogalactan protein, recognized by JIM14, were confined to the amorphous layer of the pit membrane. The role of pectins in freezing response is discussed in the context of present theory and it is suggested that pectins may influence both water movement and intrusive growth of ice crystals at freezing temperatures.

Effects of Apple Pectin on Fecal Bacterial Enzymes in Azoxymethane‐induced Rat Colon Carcinogenesis

Because of the potential significance of colonic bacteria in colon carcinogenesis, we investigated the effect of pectin of different types on fecal bacterial enzymes (β‐glucuronidase, β‐glucosidase and tryptophanase) at various periods of time after feeding rats with pectin‐containing diets during azoxymethane‐induced colon carcinogenesis. The diet supplemented with 20% apple pectin or 20% citrus pectin decreased the multiplicity of colon tumors, and the number of tumors was significantly decreased in the group fed apple pectin. The incidence of colon tumors in the apple pectin group was lower than that in the control group. The mean tumor size was similar among the three groups. Apple pectin feeding decreased fecal β‐glucosidase and tryptophanase levels. Furthermore, a significant decrease in the activity of β‐glucuronidase was observed in the apple pectin group during the initiation phase. These findings suggest that the protective effect of pectin on colon carcinogenesis may be dependent on the type of pectin and be related to the decrease of β‐glucuronidase activity in the initiation stage of carcinogenesis.

Isolation and partial characterization of biologically active polysaccharides from Plantago major L.

AbstractPolysaccharide fractions were isolated from Plantago Major L. leaves by extraction with cold water, hot water and with dimethylsulphoxide (DMSO). Each of the three crude extracts obtained was further separated by ionexchange chromatography. Only the two acidic fractions from the 50°C crude extract were biologically active, demonstrated by in vitro testing of activation of the complement system and induction of tumour necrosis factor alpha (TNF‐α) production from human monocytes. One of the fractions, PM I50, contains polysaccharide material comprising arabinose, galactose and xylose with smaller proportions of galacturonic acid, glucose, mannose and rhamnose. This fraction was further fractionated by size exclusion chromatography to give three fractions PM Ia, PM Ib and PM Ic. PM Ia is probably an arabinogalactan and PM Ib is mainly a 1,4‐linked xylan. The other biologically active fraction, PM II50 is composed of 75% galacturonic acid, 3% rhamnose, 6% arabinose and 8% galactose. Structure analysis indicates that PM II50 is a pectin type polysaccharide.

Studies on pectin formulations for colonic drug delivery

An investigation has been undertaken to assess, in vitro, the potential of several pectin formulations as colonie drug delivery systems. Experiments were conducted on the release of model compounds from matrix tablets under conditions pertaining to those in vivo. The monitoring of release gives a sensitive indication of the behaviour of the pectin under the different conditions. The type of pectin, the presence of calcium and the solubility of the calcium salt all influence release. Additionally, pectins with a low degree of methoxylation were more susceptible to enzymic breakdown. Calcium enhanced the enzymic activity. Rheological studies indicated that gel strength was a factor in determining release. These findings suggest that either a high methoxy pectin formulation or a low methoxy pectin with a carefully controlled amount of calcium should maximise colonie specificity by providing optimal protection of a drug during its transit to the colon and a high susceptibility to enzymic attack.

An opportunity for simultaneous purification and deesterification of pectic substances

The possibility of simultaneous purification and deesterification of apple pectin under conditions of acid chromatographic elution in a column filled with the pectic substances subjected to purification was investigated. Elution was done with diluted hydrochloric solutions of ethanol and isopropanol and the effect of temperature, acid concentration and process duration was studied. Two types of commercial pectins with different degrees of esterification were used. The dependence between purity, degree of esterification (DE) and the gel strength (GS) of the purified pectic preparations was investigated. It was shown that the gel strength increases with increasing purity, but only to a finite value of DE. The GS maximum as a function of DE depends on the type of initial pectin. The process of deesterification was studied kinetically and the rate constants were calculated on the basis of an equation describing reactions of the first order. The results obtained indicate that deesterification takes place faster in an isopropanol medium than in an ethanol medium for both types of pectin. The rate constants of deesterification also depend on the initial degree of esterification, deesterification taking place more quickly with highly esterified pectins than with moderately esterified ones.

Separation, isolation and characterization of acidic polysaccharides from the inner bark of Ulmus glabra Huds

Pectin type polysaccharides were extracted from the inner bark of Ulmus glabra Huds., using water at 50°C. After redissolving the product by boiling, fractionation into 9 polymers was achieved by a combination of two different ion exchange columns. The three most abundant polymers were isolated and characterized. The polysaccharides appeared to have structural differences. The two fractions A fplc and B fplc contain galacturonic acid, galactose and rhamnose, while C fplc in addition contains 3- O-methylgalactose, glucuronic acid and acetyl groups. The backbone of all three polysaccharides consists of 4-linked α- D-galactopyranosyl-uronic acid interspersed with 2-linked α- L-rhamnopyranosyl residues. The side chains on A fplc and B fplc consist of galactose units attached to C-3 of the rhamnose, while the side chains of C fplc are mainly linked through C-4 of rhamnose. These include 4-linked 3- O-methylgalactose. After weak acid hydrolysis, 5 acidic oligosaccharides were isolated and characterized.

Biosynthèse des pectines et différenciation des fibres cellulosiques au cours de la croissance du lin

During the first stage of flax growth, stem elongation reaches 2.4 cm per day and the percentage of cell wall remains quite constant (4–15%). Cellulosic fibres develop principally during capsule formation and seed maturation. During the latter stage, the proportion of walls increases from 15 to 60% and the elongation is diminished to 0.5 cm per day. The lowering of the cation exchange capacity and of the pectin content of the cell walls during growth results principally from increased cellulose deposition in the fibre cells. The changes in the cation exchange capacity and in the percentage of cell wall show that when cellulose biosynthesis predominates, there is a continuous synthesis of pectins (10–15%) during the development of the plant. Methylated pectins are synthesized during the elongation phase. During maturation, the relative amounts of highly and less methylated pectins remain the same and thus it is not possible to determine what type of pectin is preferentially synthesized.

Calcium in the Vacuoles and Cell Walls of Plant Tissue )

Summary Current knowledge of Ca uptake and modes of transport in higher plants were discussed. The relationships of Ca both within the cell and in relation to metabolic movement along transport paths throughout the plant were considered. It was stressed that Ca flows into the plant for the most part passively with the water flow of transpiration. The deposition of this often surplus amount of Ca is accomplished by various means in different physiological types of plant. The following results of the author’s research group were presented in a coordinated form: 1. Ca found outside the cytoplasm is partly in the vacuoles and partly in the cell walls. In the latter case, it is not only bound to the anionic constituents of the cell walls (pectins), but may also be present, in some plant species, in considerable quantities as CaCO 3 . 2. Ca may be present in different fractions and different conditions in the vacuoles: a) Plants which produce oxalate will always contain Ca-oxalate. When there is more oxalate than Ca, then all of the Ca in the vacuole will be in the insoluble form of Ca-oxalate except for a very small quantity of free Ca 2+ ions which can exist in the presence of excess oxalate (4.2 • 10 −5 mol/l at the most). Plants where this occurs are well established and follow taxonomic groupings. Some of these “oxalate types” are stimulated to oxalate production by an influx of Ca so that dissolved Ca will never be stored. b) Ca is present in dissolved form to a lesser extent than other cations such as K and Mg in the majority of plant families and species. However, Poaceae and Cyperaceae have an especially large surplus of dissolved K in comparison to dissolved Ca. c) Ca is stored in appreciably large amounts in the vacuoles of a group of plants where certain plant families predominate. This “calciotrophic type” has a K/Ca ratio below 1 in the water soluble fraction of its leaves. 3. Current analytical methods for determination of water-soluble Ca do not reveal what fraction is present as free Ca 2+ ions. Investigation with an ion sensitive electrode showed only part of the Ca to be in this form: a) Several Brassicaceae contain an oversaturated, but stabile solution of CaSO 4 which is only partly ionized. b) The vacuoles of most Boraginaceae have pectin type poly-anions that Ca binds to. c) Generally if the cell sap contains ions of hydroxy-carbon acids such as malate and citrate, an appreciable part of Ca may be complexed by them. 4. In vacuoles of plant types mentioned in sub 2.b., ionized Ca 2+ may range from a few mmol to about 20mmol/l. The total of dissolved Ca may be more than double these values. In calciotrophic types (2.c.), relations in press saps allow us to infer that the vacuoles may have up to 140mmol/l dissolved Ca and more than 50mmol/l ionized Ca 2+ . The special types mentioned in sub. 3.a. may contain 50−100mmol/l dissolved Ca and 10−15mmol/l ionized Ca. The Boraginaceae (3.b.) have been estimated to contain 2−37mmol/l dissolved Ca and 0.25 − 1 mmol/1 ionized Ca 5. The consequences of these observations for our concept of the compartmentalization of Ca within the plant cell and the transport modes between cell compartments were discussed.

On the molecular weight of pectic substances and its relation to their gel strengths

A study has been made on the possibility of determining the molecular weight M w , the second virial coefficient A 2 and the radius of gyration by measuring the light scattering of pectin aqueous solutions. The experimental data were processed on a computer by using an algorithm, accounting for the effect of microgel formations in the pectic solution. A tendency towards a decrease in M w when decreasing the degree of esterification for a certain type of pectin was established and was confirmed by the change in the intrinsic viscosity [η]. This fact is explained by degradation during deesterification. The dependence of the gel strength of the pectic preparations on their degree of esterification, molecular weight M w and purity (p%) was also studied as well as the dependence of the gel strength on the intrinsic viscosity [η], the degree of esterification and the purity p%. The passive multifactor experiment method was used to obtain regression models which were tested for an optimum in the factors influencing the gel strength. The optimal value for the degree of esterification was obtained at 57–58% which confirmed the view that within this range the pectin macromolecules possess maximum conformational flexibility.

Optimum Conditions for the Interaction of Food Gums with the Anthrone Reagent

SUMMARYOptimum conditions for the reaction of food gums with the anthrone reagent vary from one gum to another. The sulfated, carboxylic acid type and mixed polysaccharides produced colors with absorption maxima at 620 mμ. The uranic acid type of polysaccharides, pectin and sodium alginate (Kelco Gel HV), produced colors exhibiting absorption maxima at 520 mμ. In all cases, color intensity increased with increasing temperature. The heating time necessary for maximum color development at 99°C varied from 4 to 10‐min, depending on the hydrocolloid in question. With pectin and sodium alginate, although color intensity increased with heating time at 99°C, no definite heating time for maximum color development was observed up to 60 min. In most cases, aging led to a rapid decrease in color intensity, except for pectin and sodium alginate, in which cases color intensity increased.

Critical Aspects of an Acidic Germicidal Lotion

Experiments on desirable modifications of an acidic germicidal lotion are described. The basic emulsification system of water phase, pectin, cetyl trimethyl ammonium bromide, and oleaginous phase is so modified as to improve shelf storage stability, enhance germicidal activity, decrease irritation, and improve emolliency. Critical physical, bacteriological, and pharmacological effects of ingredients such as pectin type and level, mineral oil and lanolin type and level, and bodying agents are discussed.

Pectin therapy and pectin types

Commercial pectins are commonly adjusted as to “Grade” by dilution with cerelose, glycerine, etc. The physician should know whether his preparation is all pectin, the grade of the pectin, and what diluents are present. In addition he needs to know ash content and the chief ash constituents, as well as the combining weight. With this knowledge pectin therapy will become more of an exact science.