Cassia spectabilis DC seed galactomannan: structural, crystallographical and rheological studies

Phyto-complexation of galactomannan-stabilized calcium hydroxide and selenium-calcium hydroxide nanocomposite to enhance the seed-priming effect in Vigna radiata

The evaluation of nano-priming effect with galactomannan stabilized Phyto-complexed calcium hydroxide (Ca(OH)₂), selenium oxyanion‑calcium hydroxide SeO-(Ca(OH)₂), and selenium‑calcium hydroxide Se-(Ca(OH)₂) nanocomposites was carried out in Vigna radiata (Green gram) seeds. The green source Cassia angustifolia seed rich in galactomannan and other phytoconstituents was detected experimentally and characterized with GC-MS, UV, FT-IR, NMR, XRD, and SEM studies. The highly active galactomannan and other biomolecules, enable their terminal oxygen and hydroxide groups to bind with calcium and selenium ions through bidentate and monodentate chelation, followed by bio-reduction. On the mild-thermal agitation, bio-stabilized (Ca(OH)₂), SeO-(Ca(OH)₂), and Se-(Ca(OH)₂) nanocomposite coated with seed-derived biomolecules were precipitated under an alkaline condition. The size and morphological parameters of bio-fabricated nanocomposites were characterized to exhibit the spherical and hexagonal shape in nanoscale images of size 17.9 nm for (Ca(OH)₂), 56.2 nm for SeO-(Ca(OH)₂), and 69.3 nm Se-(Ca(OH)₂). The sub-standard seed lot of Vigna radiata (Green gram) seeds (71%) was examined using synthesized nanocomposites at various concentrations, and the obtained physiological parameters in seedlings were compared with hydro-primed seeds. The nano-priming action of all the Phyto-complexed nanocomposites was predicted with a positive response, where the porous Se-(Ca(OH)₂) possess high efficacy interaction on seed embryos and beneficially results at 90% germination.

Galactomannan from the seeds of Caesalpinia pulcherrima prevents indomethacin-induced gastrointestinal damage via neutrophil migration

Galactomannans are neutral polysaccharides isolated from the endosperm of some Leguminosae seeds. They consist of a (1 → 4) linked β-mannopyranosyl backbone partially substituted at O-6 with α-d-galactopyranosyl side groups. C. pulcherrima have anti-inflammatory and muco-adhesive proprieties. Acute gastritis is an inflammatory disease triggered by use of non-steroidal anti-inflammatory drugs. We investigated the gastroprotective effect of galactomannan obtained from the seeds of Caesalpinia pulcherrima L. (GM-CP) in acute gastritis model induced by indomethacin. Gastritis was induced with indomethacin (30 mg/kg, P.·O.) in female Swiss mice. Animal groups (n = 7) were pretreated with saline-dissolved GM-CP (3 mg/kg, 10 mg/kg, 30 mg/kg, P.O.) or vehicle 1 h before gastritis induction. Mice were euthanized seven hours after the induction. The stomach and blood samples were collected for analysis. At 10 mg/kg, GP-CP reduced the extension of macroscopic lesion and the loss of superficial cells by alleviating inflammatory symptoms (neutrophil infiltration, migration and adhesion of mesenteric leukocytes, production of TNF-α and thiobarbituric acid reactive species (TBARS) and helping to maintain mucin labeling of the tissue. Thus, the findings of the study suggest that GM-CP exhibits gastroprotective effects.

Extraction, purification and characterization of water soluble galactomannans from Mimosa pudica seeds

Water soluble galactomannans from seed endosperm of Mimosa pudica L. was extracted and characterized (Fig. 1). Nuclear magnetic resonance spectroscopy and Gas Chromatography results revealed the presence of 4-linked mannose backbone with galactose side chains linked at the C6 position. Scanning Electron Micrographs showed smooth, elongated and irregular granular structure of galactomannan. Structural analysis by Attenuated total reflection infrared spectroscopy presented the Mannose to Galactose ratio while the X-ray diffraction studies showed the presences of A-type crystalline pattern of the galactomannan. Thermo Gravitimetric Analysis showed the three steps weight loss event and determined the thermal stability. The results showed that the extracted polysaccharides are typically amorphous, thermally stable and have desirable properties for industrial applications.

Characterization and rheological study of the galactomannan extracted from seeds of Cassia grandis

Galactomannan extracted from seeds of Cassia grandis with 0.1M NaCl, followed by ethanol precipitation, presented a yield of 36 ± 8%. The polysaccharide has a constant mannose/galactose ratio (2.44:1). Methylation analysis, one and two dimensional NMR spectroscopy confirmed that the polysaccharide has a central core composed of 4-linked β-mannose units, with branches of galactose, linked to the carbohydrate core through α(1-6) linkage. The amorphous nature of the galactomannan was confirmed by X-ray diffraction. Rheological characterization exhibited Newtonian plateaus followed by shear-thinning zones characteristic of polymer solutions up to 1.5% (w/v) and above this value the system exhibited yield stress associated with a weak gel. Adjusting stress-strain curves confirmed a 1.6% (w/v) as the galactomannan concentration value for the sol-gel transition. These results indicate that the galactomannan extracted from C. grandis seeds presents rheological characteristics suitable for applications in pharmaceutical, biomedical, cosmetic and food industries.

Flow behavior and linear viscoelasticity of cellulose 1-allyl-3-methylimidazolium formate solutions

The rheological properties of α-cellulose 1-allyl-3-methylimidazolium formate solutions were investigated using shear viscosity and dynamic rheological measurements in a large range of concentrations (0.1-10 wt%) at 25 °C. In steady shear measurement, the overlap concentration (c*) and the entanglement concentration (c(e)) were determined to be 0.5 and 2.0 wt% respectively, and the exponents of the specific viscosity (η(sp)) versus the concentration (c) were determined as 1.0, 2.0 and 4.7 for dilute, semidilute unentangled and entangled regimes respectively, which were in accordance with the scaling prediction for neutral polymer in θ solvent. The slopes of the relaxation time (τ) against the concentration for semidilute unentangled and entangled regimes were observed as 1.0 and 2.5 respectively. In dilute and semidilute unentangled regimes, failure of the Cox-Merz rule with steady shear viscosity larger than complex viscosity was observed; while the deviation from the Cox-Merz rule disappeared in semidilute entangled regime.

Sterilization of exopolysaccharides produced by deep-sea bacteria: impact on their stability and degradation

Polysaccharides are highly heat-sensitive macromolecules, so high temperature treatments are greatly destructive and cause considerable damage, such as a great decrease in both viscosity and molecular weight of the polymer. The technical feasibility of the production of exopolysaccharides by deep-sea bacteria Vibrio diabolicus and Alteromonas infernus was previously demonstrated using a bioproduct manufacturing process. The objective of this study was to determine which sterilization method, other than heat sterilization, was the most appropriate for these marine exopolysaccharides and was in accordance with bioprocess engineering requirements. Chemical sterilization using low-temperature ethylene oxide and a mixture of ionized gases (plasmas) was compared to the sterilization methods using gamma and beta radiations. The changes to both the physical and chemical properties of the sterilized exopolysaccharides were analyzed. The use of ethylene oxide can be recommended for the sterilization of polysaccharides as a weak effect on both rheological and structural properties was observed. This low-temperature gas sterilizing process is very efficient, giving a good Sterility Assurance Level (SAL), and is also well suited to large-scale compound manufacturing in the pharmaceutical industry.

Rheological behaviors in the regimes from dilute to concentrated in cellulose solutions dissolved at low temperature

Cellulose was dissolved rapidly in 9.5 wt.-% NaOH/4.5 wt.-% thiourea aqueous solution pre-cooled to -5 degrees C to prepare cellulose solution with different concentrations. The rheological properties of the cellulose solutions in wide concentration regimes from dilute (0.008 wt.-%) to concentrated (4.0 wt.-%) at 25 degrees C were investigated. On the basis of data from the steady-shear flow test, the critical overlap (c*), the entanglement (c(e)) and the gel (c(g)) concentrations of the cellulose solution at 25 degrees C were determined, respectively, to be 0.10 wt.-%, 0.53 wt.-% and 2.50 wt.-%, in accordance with the results of storage modulus (G') versus c by dynamic test. Moreover, the Cox-Merz deviation at relatively low concentrations was in good agreement with the micro-gel particles in dilute regime. As the cellulose concentration increased, a homogeneous 3-dimensional network formed in the cellulose solution in the concentrated regime, and further increasing of the concentration led to micro-phase separation as determined by the time-temperature superposition (tTS). So far, this complex cellulose solution has been successfully described by the concentration regime theory for the first time, and the relatively molecular morphologies in each regime have been determined, providing useful information for the applications of the cellulose solution systems.

Structure elucidation and properties of a non-ionic galactomannan derived from the Cassia pleurocarpa seeds

A non-ionic water soluble galactomannan made up of d-galactose and d-mannose was isolated from the seed endosperm of Cassia pleurocarpa. Acid catalyzed fragmentation, periodate oxidation, methylation and selective enzymatic hydrolysis revealed that the repeating unit of the heteropolysaccharide had a backbone of beta(1-->4) linked d-mannopyranosyl units to which D-galactopyranosyl units are linked as side chains through alpha(1-->6) linkages. The properties such as viscosity, water/saline retention, gelling behavior, and shelf life of the galactomannan indicated that the material may be exploited in biomedical applications for example drug delivery and tissue engineering fields.

Seed mucilage from Ipomoea dasysperma

A non-ionic water-soluble galactomannan, having galactose and mannose in 1:6 molar ratio, was isolated from endosperm of the seeds of Ipomoea dasysperma. The seed mucilage was found to have a structure having a linear chain of beta (1-->4) linked mannopyranosyl units with D-galactose side chains attached through alpha (1-->6) linkage to the main chain. I. dasysperma seed gum possesses non-ionic characteristics of commercial seed gums and has potential to be used in food and pharmaceutical industries.

Role of Substituents on the Properties of Some Polysaccharides

This paper concerns the influence of the chemical structure on the physical properties of some polysaccharides. Especially, we proposed to discuss the role of the substituents on these properties. In some cases, non-carbohydrate substituents play a minor role on rheological properties in the presence of a salt excess as shown on xanthan and succinoglycan. The rheology of aqueous solution of these stereoregular polysaccharides is controlled by the conformation (helical conformation) whose stability is not largely influenced by these substituents. On the other hand, the interaction between galactomannan and xanthan depends on the presence of acetyl substituents on xanthan but also on the xanthan conformation. However, for polymers such as gellan, XM-6 or BEC 1615, complete deacetylation induces the ability to form physical gels in given thermodynamic conditions. The presence of carbohydrate substituents or short side chains was also examined. Especially in the gellan family, the role of position of substitution (position 3 on the glucose unit C or position 6 on the A glucose) was presented. It is concluded that the substituents giving the higher stability for the helical conformation (higher DeltaH and Tm values) also cause a lower salt sensitivity for the helical stability. The role of the substituents on the properties is also described for natural polymers and their chemically or enzymatically modified derivatives.

Rheological characterization of schizophyllan aqueous solutions after denaturation-renaturation treatment

Schizophyllan (SPG) with a molecular weight of 2.6x10(6), designated SPG-1, is denatured and then renatured at a concentration of 1.8 wt % by alkalization-neutralization. The prepared denatured-renatured samples (DRSPG-1) are diluted to various concentrations and equilibrated for 10 days before rheological and intrinsic viscosity measurements. When concentration (C(p)) is above 0.75 wt %, DRSPG-1 aqueous systems have weak gel-type rheological properties. However, for 0.28 wt % <or= C(p) <or= 0.65 wt % and C(p) <or= 0.19 wt %, DRSPG-1 aqueous systems behave as power law fluids and Newtonian fluids, respectively, which are attributed to the moderate isotropy degree of DRSPG-1 chains. Furthermore, a critical overlap parameter of c*[eta] = 1.2 is determined for DRSPG-1 in aqueous solutions, which is close to that of 1 for intact SPG in water while far smaller than that of 4.3 for SPG in DMSO. This is considered to be due to the strong interactions of DRSPG-1 chains in water, further confirmed by the intrinsic viscosity measurements in which the DRSPG-1 aqueous solution shows an abnormally large value of Huggins constant. Regarding the structure of DRSPG-1 weak gels, multiruns of dynamic strain sweep measurements suggest that the dominant structures are aggregates formed by hydrogen-bonding associations of DRSPG-1 chains rather than the permanent three-dimensional network. In addition, the step-shear rate tests are performed to study the thixotropic properties of DRSPG-1 aqueous systems.

Cassia grandis Linn. f. seed galactomannan: structural and crystallographical studies

Cassia grandis is a small or medium sized tree, found in abundance throughout India. The seeds contain about 50% endosperm gum and possess the characteristics of becoming a potential source of seed gum. The purified polysaccharide has been characterized as a pure galactomannan having a mannose-galactose ratio of 3.15; molecular weight (Mw) 80,200; polydispersity (Mw/Mn), 1.35 and intrinsic viscosity [eta], 848 mL/g. Methylation, periodate oxidation, Smith degradation and 13C NMR studies confirm that the polysaccharide has the basic structure of legume galactomannans consisting of a beta-(1-->4)-linked main mannan backbone to which galactose units are attached at O-6. The orthorhombic lattice constants of the hydrated gum are as follows: a=9.00, b=24.81, c=10.30 A. The crystallographic data establish that the probable space group symmetry of the unit cell is P2(1)2(1)2. The results are in contradiction to earlier reports (Indian J. Chem. 16B (1978) 966; J. Indian Chem. Soc. 55 (1978) 1216) in which a non-galactomannan polysaccharide structure has been assigned having a main chain of (1-->4)-linked galactose and mannose units in the molar ratio 6:3, where 50% of the galactose units branched with two galactose and one mannose through 1-->3 linkage.

A non-ionic water-soluble seed gum from Ipomoea campanulata

A non-ionic water-soluble galactomannan, having galactose and mannose in 2:3 molar ratio was isolated from endosperm of the seeds of Ipomoea campanulata. The seed gum was found to have linear chain of beta (1-->4) linked mannopyranosyl units with D-galactose side chains attached through alpha (1-->6) linkage to the main chain. This structure is similar to many commercial gums like Guar, Carob and Locust bean gum. Various physical properties of the gum were studied in order to explore the possibility of commercial exploitation of the seed gum.