Rheological characterization of galactomannans extracted from seeds of Caesalpinia pulcherrima

Influence of 3-chloropropyl) triethoxysilane and pH on the properties of modified guar gum film

Guar gum (GG) as a polymer biopolymer is widely used in the field of bio-based packaging. However, its poor mechanical properties, barrier properties and high viscosity greatly hinder its use as an effective packaging material. Therefore, this study introduced CPTES to improve the mechanical (16.58-27.39 MPa) and tensile properties (26.80 %-30.67 %). The FTIR and XRD results indicated a strong interaction between the biofilm fractions modified by CPTES, CPTES bound to the hydroxyl groups on GG and formed a dense polysiloxane network through adsorption and grafting. OM and AFM reflect a denser and flatter film structure on the surface of the G30 film, which has the best film formation. Based on this, the pH of the solution was further adjusted to reach an alkaline environment, disrupting the intermolecular binding through electrostatic repulsion. The rheological behavior indicates that the viscosity and viscoelasticity of film solution gradually decrease with the increase in pH. OM and AFM results show that the G30/8 film has the best compact properties, while the nonporous compact film structure further improves the mechanical, barrierand and thermodynamic properties of the film. Accordingly, the findings of this study had a certain value for regulating the low viscoelasticity of GG emulsion and enhancing the stability of film formation.

On rheological properties of disc-shaped cellulose nanocrystals

The rheological properties of a substance depend greatly on its morphology, and rod-shaped cellulose nanocrystals (RCNCs) and cellulose nanofibrils (CNFs) have been extensively studied for their rheological properties. Nevertheless, the rheological properties of disc-shaped cellulose nanocrystals (DCNCs) with crystalline allomorph II derived from mercerized cellulose remain unknown yet. This work investigated the DCNCs' rheological properties in depth using steady-shear and oscillation measurements. At the same concentration, DCNC's suspension viscosity is lower than that of RCNC; RCNC has an instinct viscosity of 258.2, while DCNC has 187.9. Comparing RCNC suspensions with cellulose nanorods, DCNC has a lower aspect ratio and exhibits a distinct steady shear behavior. Under polarized film, DCNC suspension cannot self-assemble into chiral or liquid crystal phases, and with increasing concentrations, the system transitions from an isotropic phase to a gel phase. Oscillation sweeps demonstrate that the gel transition occurs at 7 %-8 %. Based on thixotropic recovery sweep outcomes, the high-stress oscillations enhance the network structure of DCNC suspensions, which is significantly different from that of RCNC suspensions. Results demonstrate the unique properties of DCNC, highlighting its application as a rheological modifier.

Extraction, Purification and Electrical Characterization of Gross Galactomannan and Purified Galactomannan Obtained from Adenanthera pavonina L. Seeds

Aiming of self-sustainable production, the search for biodegradable and biocompatible materials has brought with it the need to know the physicochemical and dielectric characteristics of polysaccharide-based composite structures, which can be used as important and promising raw materials for biotechnology and electronic industries. Galactomannans are polysaccharides, extracted from seeds and microbiological sources, consisting of mannose and galactose. In this context, this work aimed to extract, purify and characterize by XRD, FTIR and impedance spectroscopy galactomannan obtained from seeds of Adenanthera pavonina L. The purification process was made with ethyl alcohol at concentrations of 70, 80 and 90 %. Polymeric films were prepared by solvent slow evaporation at low temperatures. XRD measurements revealed that Galactomannan from Adenanthera pavonina L., after purification, has a semi-crystalline structure due to the identification of two peaks the first between 5.849° and 6.118° and the second between 20.011° and 20.247°. FTIR spectra showed the functional groups associated with monosaccharides of the galactomannan from Adenanthera pavonina L. seeds, as well as the typical polysaccharide bands and peaks, confirmed by literature data. The impedance results give an increment on the state-of-the-art of this biomaterial by showing the existence of dielectric relaxations, independent of the degree of purification, using the dielectric modulus formalism. The permittivity analysis reveals the presence of water in the structure of the film, whose dipoles contribute to the relatively high value of the dielectric constant. From the results obtained, it can be concluded that purified galactomannan has the potential for possible applications in the electronics industry as a green and eco-friendly dielectric material.

Rheological properties of Sesbania cannabina galactomannan as a new source of thickening agent

The present study evaluated the rheological properties of galactomannan from Sesbania cannabina. The intrinsic viscosity of galactomannan was determined to be 8.63 ± 0.06 dl/g. Moreover, the onset of galactomannan coil overlap occurred at 5.12 ± 0.13 g/L. With increasing concentration, galactomannan showed a more distinct shear-thinning behavior, which was well characterized by the Cross model. Notably, the viscosity of polysaccharide showed a negative relationship with the temperature, while the activation energy decreased with increasing polysaccharide concentration. Furthermore, at high concentrations, the galactomannan solution showed stability after heating or freezing, as well as over the wide pH range of 5.0-9.0. Dynamic viscoelasticity measurements reveal a gradual transition from viscous to elastic behavior of galactomannans with an increasing frequency. It is anticipated that S. cannabina galactomannan will find interesting applications as a natural thickener due to the comprehensive description of its rheological properties presented herein. PRACTICAL APPLICATION: The investigated S. cannabina galactomannan has shown a higher viscosity and heat stability at high concentration, as well as a good stability at the pH range of 5-9. The S. cannabina galactomannan may be employed as stabilizers in the food field.

Physical characterization of high methoxyl pectin and sunflower oil wax emulsions: A low-field 1 H NMR relaxometry study

Pectin-wax-based emulsion systems could be used to form edible films and coatings with desired water permeability characteristics. Pectin is often used in food industry due to its gelling and viscosity increasing properties. Physical properties of pectin are highly dependent on its esterification degree. Waxes are commonly used as edible coatings to enhance the water barrier properties of food products. This study focuses on preparing emulsions with sunflower oil wax (SFW) and high methoxyl pectin (HMP) at different concentrations for any possible edible film or coating formulations. Sunflower oil (SFO) was added as the dispersed oil phase to these emulsions. Characterization of the emulsions was performed by using particle size, rheology, and time domain nuclear magnetic resonance (NMR) relaxometry measurements. Effects of HMP concentration and the presence of SFO in the emulsion formulations were explored. Mean particle size values were recorded between 1 and 3 µm. Rheology measurements showed that increasing HMP concentrations and presence of SFO in emulsions resulted in more pseudoplastic behavior. NMR transverse relaxation times (T₂ ) were measured to detect the differences between the emulsions. Relaxation spectrum analysis was also conducted for a detailed understanding of the transverse relaxations. Addition of SFO and higher HMP concentrations decreased the T ₂ values of the emulsion systems (P < 0.05). However, T₂ decreasing effect of SFO was compensated at 10% (w/w) HMP concentration showing that SFO was well dispersed in this particular emulsion formulation. Changes in the rheological behavior and relaxation times provided insight on the formation and stability of the emulsions. PRACTICAL APPLICATION: Findings of this study can be utilized and integrated to produce edible films and coatings with different water permeability characteristics. This study showed that NMR relaxometry parameters were also effective in monitoring and determining the physical characteristics of the pectin-wax-based emulsion systems as other conventional techniques including rheology and particle size measurements. Our NMR relaxometry findings were in correlation with the flow behavior and particle size results of the investigated emulsion systems.

Isolation, qualitative and quantitative evaluation of galactomannan during germination of Trigonella persica (Fabaceae) seed

Galactomannan extracted from Trigonella persica endosperm like to other galactomannans is useful in the medicine and pharmaceutical industry such as drug delivery due to its unique physicochemical properties. As soon as germination takes place, the hydrolysis of galactomannan begins and its structure changes. Evaluation of galactomannan content extracted from the germinating seeds (GEGS) and the non-germinated seeds (GENGS) showed that the amount of galactomannan was highest at 24 h after imbibition and was completely consumed approximately 48 h after imbibition. It seems that galactomannan is used for storage reserve synthesis in the cotyledon during germination. Based on the quantitative assessment, FT-IR, macroscopic and microscopic observations, galactomannan of T. persica seeds have high an M/G ratio (approximately 5:1) and this ratio does not alter during germination. Therefore, changes in galactomannan structure (functional group and band) caused that GEGS have different physicochemical properties than GENGS. Based on the results, GENGS with a high M/G ratio may be suitable for drug delivery system due to some properties such as high viscosity and gelling.

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.

Bioavailability enhancement of ondansetron after nasal administration of Caesalpinia pulcherrima-based microspheres

CONTEXT

Natural polymers have attracted a great deal of attention for use as potential carriers in site-specific delivery over past decades. Mucoadhesive microspheres are useful tools for nasal drug delivery.

OBJECTIVES

To prepare and evaluate mucoadhesive microspheres as mode for nasal delivery of ondansetron using Caesalpinia pulcherrima galactomannan (CPG).

MATERIALS AND METHODS

Conventional spray-dried CPG nasal microspheres loaded with ondansetron for intranasal drug delivery in order to avoid the first pass metabolism with improved therapeutic efficiency in treatment of nausea and vomiting as an alternative therapy to parenterals. Developed microspheres were evaluated for characteristics like particle size, entrapment efficiency, zeta potential, swelling ability, in-vitro mucoadhesion, in-vitro drug release, DSC, XRD study and histopathological evaluation of tissue. CPG-based ondansetron microspheres were studied in rabbits for screening nasal absorption potential of nasal formulation.

RESULTS

Developed nasal microspheres possess entrapment efficiency of 80-89%, higher mucoadhesion of 72-84% across goat nasal mucosa. In-vivo study showed that microspheres based on mucoadhesive polymer were able to promote quick drug absorption as well as enhanced bioavailability of drug.

DISCUSSION

Histopathological studies evaluated biocompatible and nontoxic nature of CPG in nasal cavity. Developed mucoadhesive microspheres by nasal route showed enhancement of bioavailability as compared to oral route in rabbits.

CONCLUSION

CPG-based mucoadhesive microspheres can successfully deliver ondansetron intranasally, sustain its effect, avoid first pass effect, an alternative route of administration to injection and thus enhance systemic bioavailability of ondansetron hydrochloride.