Plant Gums Research Articles

Assessment of Pituitary Response to Nasal Application of Synthetic Gonadotropin-Releasing Hormone in Men

An attempt has been made to assess the pituitary response to the nasal application of synthetic gonadotropin-releasing hormone (GnRH) in three oligospermic and two azoospermic men. Intranasal administration of 3 mg of GnRH in aqueous or natural plant gum solution produced a pituitary response pattern similar to that produced by the intramuscular injection of 100 microng, with respect to plasma concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). No technical difficulties or side effects were observed. GnRH in a nasal drop preparation seems to be effective in releasing LH and FSH in men. These findings may have a practical application in those cases where long-term therapy with the hormone is indicated.

Interior chains of glucuronomannan from extracellular polysaccharides of suspension-cultured tobacco cells.

Methylation analyses and partial acid hydrolysis have indicated the similarity of the interior chains of the glucuronomannan, obtained from extracellular polysaccharides of tobacco cells to those of plant gums such as leiocarpan A and ghatti which contain contiguous 2-O-linked D-mannopyranose and 4-O-linked D-glucopyranosyluronic acid residues. Evidence also suggests that about 56% of 2-linked D-mannopyranose residues are substituted at position-3 with L-arabinofuranose residues as a single side chain.

An investigation and identification of polysaccharides isolated from archeological specimens

Polymeric compounds have been isolated from archeological specimens (fragments of Central Asian paintings of the 2nd-19th centuries). A comparison of their IR spectra with the spectra of plant gums has shown that they are polysaccharides which have remained undestroyed for up to 1800 yr. In some cases it has been possible from the IR spectra and composition of the extracted polysaccharides to provisionally identify sourcherry or apricot gum, of which these polysaccharides were components.

ON THE TECHNOLOGY OF CENTRAL ASIAN WALL PAINTINGS: THE PROBLEM OF BINDING MEDIA

Organic components of paint layers and grounds in specimens of late antique and early medieval Central Asian wall paintings were studied. Quantitative analysis of amino acids isolated from specimens of Mansur-Depe wall paintings, second to first century B.C., has demonstrated that gelatin was used for the preparation of painting media and grounds—proline, glycine and alanine were revealed to a high percentage while hydroxyproline was not detected. In other wall paintings of the second to the eighth century the use of plant gums was inferred since polysaccharides isolated from the specimens had infrared spectra resembling those of polysaccharides from the Prunoideae sub-family. The gum used in the Toprak-Kala wall paintings, third to fourth century, and in a nineteenth-century painting from Khiva could be identified precisely: it was either apricot or cherry gum. The technique used for the preparation of paints and grounds in Mansur-Depe and Kara-Tepe, second to fourth century, resembles those described in medieval Indian manuscripts.

Composition of gum exudates from Anacardium occidentale

The composition and solution properties of Indian and Papuan specimens of the gum from Anacardium occidentale have been studied and found to be closely similar. Contrary to earlier reports by Indian workers, this gum does not contain galacturonic acid. It does, however, contain glucose; this appears to be the first report of the presence of this sugar in a plant gum exudate. A freeze-dried sample of the gum was examined at intervals over a period of 2 months; its weight-average MW increased by a factor of three in that time, and molecular-sieve chromatography showed that self-association occurred with the formation of a small proportion of a very high MW component.

Studies of the aberrant eumenine wasp,Xenorhynchium nitidulum (Fabr.)

The females of theXenorhynchium nitidulum can provide for their larvae either by mass provisioning or by progressive provisioning. They can also reuse cells that they have built themselves. At least during progressive provisioning and cell reusing behaviour, the wasps journies to collect mud for wall building, to collect plant gum for daubing and to collect holometabolous insect larvae to provision the cell, are much less grouped than is usual in the solitary wasps; the egg is not laid at one characteristic stage in the building of a cell; prey may or may not be present when an egg hatches; and may or may not be present when a cell is sealed. After metamorphosis the imagines have taken several hours to complete the gnawing away of the lid of their cell, before emerging and flying.

Structural studies of sapote ( Sapota achras) gum

Sapote gum contains residues of L-arabinose (pyranose and furanose), D-xylose, D-glucuronic acid, and 4- O-methyl- D-glucuronic acid in the ratio 1.0:2.8:0.48:0.52. The two uronic acids were conveniently determined by reducing the carboxyl functions with lithium borohydride and measuring the ratio of D-glucose to 4- O-methyl- D-glucose. Periodate oxidation of the carboxyl-reduced gum gave inter alia 2- O-methyl- D-erythritol and 4- O-methyl- D-glucose in amounts suggesting that 37% of the 4- O-methyl- D-glucuronic acid residues are unsubstituted in the polysaccharide. Acetolysis of the carboxyl-reduced gum gave O-α- D-glucopyranosyl-(1→2)-(4- O-β- D-xylopyranosyl) 0,1,2,- D-xylose, a hitherto undescribed series of oligosaccharides, together with 2- O-(4- O-methyl-α- D-glucopyranosyl)- D-xylose. Methylation confirmed that sapote gum has a highly branched structure, and commercial xylanases did not depolymerize the gum. An α- L-arabinofuranosidase liberated a substantial part of the arabinose residues. Sapote gum is a member of the uncommon class of plant gums having a D-xylose backbone and structurally resembles brea gum.

Analysis of natural resins by prolysis gas chromatography. I. Classification of natural resins by pyrograms

Pyrolysis gas chromatography was applied for the analysis of (35 species of) natural resins. Benzene, toluene, xylene, styrene, and light gases (CO, CO2, CH4, C2H6, C2H4) were identified as their pyrolysis products at 800°. Siam Benzoin produced much benzene, while Sumatra Benzoin, Storax, and Peru Balsam yielded much styrene. Amber, Dammar, and Copal produced much toluene and xylene besides benzene. Rosins and gum resins showed less, and plant gums showed the least production of these compounds. Natural resins were thus classified according to their pyrograms.

The amino acid and amino sugar composition of some plant gums

The amino acid compositions of typical plant gum exudates from the genera Acacia, Araucaria, Azadirachta and Lannea are reported. The proteins involved contain large amounts of serine, threonine and aspartic acid; in addition, those of Lannea species contain major amounts of proline and leucine. There is evidence that gums from different species in a genus have very similar amino acid compositions. Glucosamine also occurs in exudates of the genera named above, but was not detected in Khaya, Fagara or Boswellia.

Electrophoresis of dyed polysaccharides on “PhoroSlides”

Polysaccharides that have been previously treated with reactive dyestuffs can be separated within 1 to 3 minutes by electrophoresis on PhoroSlides at potential gradients of 40 to 56 V cm–1. In addition to providing the required self-indicating system, dyeing increases the electrophoretic mobility of charged polysaccharides. The difficulty experienced in dyeing polysaccharides that have small proportions of primary hydroxyl groups (e.g., plant gums, pectin, alginic acid and sulphated polysaccharides) can be overcome by increasing the amount of sodium carbonate added in the dyeing process.

Infrared absorption spectra of aldobiouronic acids obtained from natural plant gums and mucilages

Infrared absorption spectra of aldobiouronic acids obtained from natural plant gums and mucilages

Plant gums of the Genus Sterculia. Part V. Degradation of carboxyreduced Sterculia urens gum

Degradation of periodate-oxidised carboxy-reduced Sterculia urens gum affords a degraded polysaccharide which contains essentially linear chains of alternating 4-O-substituted D-galactopyranose and 2-O-substituted L-rhamnopyranose residues. Oligosaccharides formed on partial acetolysis of carboxy-reduced S. urens gum and/or the degraded polysaccharide include 4-O-L-rhamnopyranosyl-D-galactose, 2-O-D-galactopyranosyl-L-rhamnose, 4-O-D-galactopyranosyl-D-galactose, 2-O-D-galactopyranosyl-D-galactose, O-D-galactopyranosyl-(1 → 2)-O-D-galactopyranosyl-(1 → 4)-D-galactose, and a series of higher oligosaccharides containing galactose and rhamnose residues in alternating sequences. The significance of these and previous results is assessed in terms of two main structural regions (A and B) in the polysaccharide.

Method for the Extraction of Light Filth from Plant Gums

Abstract A new method has been developed for the extraction of extraneous materials from plant gums. Hydrochloric acid and autoclaving are used to break down and disperse partially insoluble gums, followed by sieving and extracting using a trap flask. Collaborative studies gave reproducible recoveries of rodent hairs and insect fragments, and the method is recommended for adoption as official first action.

Structural Chemistry of Fungal Polysaccharides

This chapter discusses the structural chemistry of the polysaccharides and glycoproteins of fungal origin. The organisms considered are of the phylum Eumycophyta ; this includes the classes Phycomycetes , Ascomycetes , Basidiomycetes, and Deuteromycetes. The Myxomyceteae include the slime molds, which are not generally recognized to be true fungi, having an amebic assimilative stage. The feature of fungal polysaccharides that is most striking to the chemist is that relatively few of them are structurally similar to polysaccharides from other natural sources. Structural knowledge of fungal polymers can be of aid in such fields as taxonomy, immunochemistry, biosynthesis of polysaccharides, and enzymolysis of polysaccharides. In the commercial area, polysaccharides that form viscous solutions have many potential uses, especially as plant–gum substitutes.

Studies on uronic acid materials : Part XXV. Some unusual forms of the gum from Acacia senegal willd.

A comparative study, involving classical methylation and Smith-degradation techniques, has been carried out on samples of normal “tapped” gum from Acacia senegal, natural exudate gum (“Hennawi” gum) from the main trunk of the tree, and the gum exuded by a tree infested with wood-boring beetles. The studies have shown that the beetle-borer specimen was virtually identical to the specimen of normal exucate gum; the specimen of “Hennawi” gum was basically similar, but differed in two important aspects concerning some of the peripheral end-group positions involving rhamnose and glucuronic acid residues. Theories of the origin, function, precursors, and mode of biosynthesis of plant gums are examined critically in terms of the results obtained.

Studies on uronic acid materials. Part XII. The composition of Acacia gum exudates

The exudates from seven Acacia species, not hitherto studied chemically, have been examined. As a result, variation in the characteristic features of the Acacia group of plant gums can now be discussed from a more representative viewpoint. Species considered previously to have atypical features (e.g., positive optical rotation or low rhamnose content) are now seen to occur almost as frequently as those with negative rotations and unit correspondence between the rhamnose and uronic acid content.

The polynucleotide double helix as a versatile assembly template during polymer biogenesis

A hypothesis is put forward for consideration in which the ubiquitous duplex polynucleotide is given a widespread function in nature as a special kind of assembly template for the formation of all high polymers. It is envisaged as a means to an end rather than a final product, as distinct from either a metabolically active polymer such as an enzyme protein or a structurally necessary one such as cellulose for instance. In other words, its life is imagined to be essentially transitory. During its synthesis it simultaneously produces a variety of polymers depending on its fine structure format and on the nature of the polymer sub-units attached to the nucleotide monomer in the first instance. The latter in turn would depend on the nature of the substrate environment, the “activating” enzymes present, etc. The synthesis stage is imagined to take place in “ribosomal structures”; some of these would produce protein, some would be concerned with polysaccharide formation and others would synthesize polyisoprene, plant gums, etc. Indeed, the existence of “mixed” ribosomes producing mucopeptides such as the blood group substances could be just as readily imagined. The function would be mainly as an assembly “scaffolding” by which stereospecific morphological requirements could be met. The ancillary coding mechanism of polymer sub-units would require, in complex cases, additional interactions as in the instance of protein synthesis but the activation of these sub-units would be essentially similar for all polymers. It is emphasized that the theory is basically biogenetical in conception and does not seek to explain all mechanisms of limited ( in vitro) biosynthesis in the presence of primer molecules, although some of the available evidence on the matter comes, perforce, from these latter sources.

Preparation of Films for the Infrared Spectrophotometric Analysis of Plant Gums.

Preparation of Films for the Infrared Spectrophotometric Analysis of Plant Gums.

Studies on biocolloids and polyelectrolytes—the plant—gums viscosity of azrechtic acid

AbstractAzrechtic acid (ARA) has been obtained by the electrodialysis of an aqueous solution of the gum of Azadirechta indica in an acidic medium. The viscosity of this gum acid has been investigated under different experimental conditions, i.e., with dilution in aqueous and in isoionic concentration of added electrolyte (HCl), and with change in pH. It is observed that the reduced viscosity of the aqueous solutions increases rapidly with dilution and the reduced viscosity—concentration curve is concave upwards instead of being linear as in the case of linear polymers. The viscosity of aqueous ARS solutions follows the equation, ηsp/C = A/(1 + B√C) where A, B, and D are constants (A = 0.03, B = 0.1845, and D = 0.05), as well as the equation ηsp/C = aCb, in which a and b are constants and equal to 0.2113 and −0.4375, respectively. It is observed that in isoionic concentrations of added electrolyte (HCl, 2.20 × 10−4 g.‐equiv./l.), the sharp rise in the ηsp/C versus C curve vanishes, and the curves show well defined maxima which shift to higher concentrations of the gum acid as the electrolyte concentration increases and ultimately vanish at sufficiently high concentration of the added electrolyte (HCl, 2.20 × 10−3 g.‐equiv./l.), and the ηsp/C versus C curves become linear. The viscosity of azrechtic acid at constant solute concentration increases rapidly when the pH is increased by the addition of NaOH, becomes maximum at a pH of about 6, after which it falls rapidly and becomes constant after a pH of 12. The viscosity also decreases when the pH is decreased on addition of HCl and becomes constant after a pH of 2.0. All these phenomena have been explained on the basis that azrechtic acid behaves as a polyelectrolyte.

Studies on uronic acid materials : The simultaneous determination of uronic acid and alkoxyl groups in polysaccharides by reflux with hydriodic acid

A reaction period of 2.5 h is required for the decarboxylation of uronic acid groups with 19% (w/w) hydrochloric acid, but 55% (w/w) hydriodic acid gives complete decarboxylation in 1.5 h. This rapid reaction can be carried out in a standard Zeisel reaction flask and condenser. Vapour phase infra-red spectroscopy gives a specific determination of the carbon dioxide evolved, and facilitates simultaneous determinations of any alkoxyl groups present. The proposed method is particularly useful for pectins and plant gums; it gives greater sensitivity and reproducibility than previous methods.