Efficacy of hydroxypropyl-guar drops in improving tear film index and ocular surface dynamics using two treatment methods under a controlled desiccating environment.

AIM: This study aimed to assess the efficacy of hp-guar eye drops on tear film index and ocular surface dynamics under desiccating conditions using protection and relief treatment modalities. METHODOLOGY: The 12 normal, non-dry eye participants were subjected to adverse environmental conditions using a Controlled Environment Chamber (CEC) where the relative humidity (RH) was 5% and the ambient temperature was 21 °C. The participants were screened for ocular symptoms, tear osmolarity, ocular surface temperature (OST), tear production using the Ocular Surface Disease Index questionnaire (OSDI), OcuSense TearLab Osmometer, FLIR System ThermaCAM P620, and Schirmer strips. Tear production was calculated by the Tear Function Index test (TFI). RESULTS: The mean tear film osmolarity decreased significantly from 296 mOsm/L at 40% RH to 285 mOsm/L at 5% RH (p = 0.01). Conflicting responses were seen for osmolarity in protection and relief. Mean tear osmolarity was significantly higher in the protection method in comparison to the relief method (p = 0.005). The mean TFI increased from 557 at 40% to 854 at 5% (p = 0.02). A significant increase in TFI was observed in the relief method in comparison with both 40% (p = 0.001) and 5% (p = 0.04). In the relief method, the mean TFI score went up to 1139 when hp-guar was installed. A significant improvement in ocular comfort was experienced in both the protection (p = 0.041) and relief (p = 0.010) methods at 5% RH. The instillation of hp-guar drops in the relief method resulted in a significant reduction in OST. The mean OST dropped to 33.01 ºC, significantly lower than the recorded OST for both normal (p = 0.040) and dry (p = 0.014) environmental conditions. CONCLUSION: Hp-guar drops significantly improve tear film parameters under a desiccating environment, however, tear film parameters respond differently to the management modalities. In the protection method, tear film osmolarity was protected against a dry environment, while in the relief mode, an improvement in tear production and a decrease in ocular surface temperature were seen. Hp-guar performance could be maximized for the management of exposure to adverse environments by using a treatment protocol that targets the most affected parameters in each group of patients. Using CEC has the potential to provide researchers with a readily available method to evaluate the efficiency of tear supplementation.

Microwave irradiation of guar seed flour: Effect on anti-nutritional factors, phytochemicals, in vitro protein digestibility, thermo-pasting, structural, and functional attributes.

Guar seed flour (GSF) has a high amount of carbohydrates, proteins, phytochemicals, and anti-nutritional factors (ANFs), which limits its use. To address this issue, the current study was undertaken to understand the effect of microwave (MW) irradiation on ANFs, phytochemicals, in vitro protein digestibility (IVPD), and functional attributes of GSF at varying power density (Pd: 1-3 W/g) and duration (3-9 min). The ANFs were determined using a colorimetric assay and a Fourier transform infrared spectrum. At 3 Pd-9 min, the maximum reduction in ANFs (tannin, phytic acid, saponin, and trypsin inhibitor activity) was observed. Higher Pd and treatment duration increased antioxidant activity and total phenolic content, except for total flavonoid content. Furthermore, compared to the control sample (78.38%), the IVPD of the GSF samples increased to 3.28% (3 Pd-9 min). An increase in Pd and duration of MW treatment improved the thermal and pasting properties of GSF samples up to 2 Pd-9 min. Due to inter- and intramolecular hydrogen bonding degradation, the relative crystallinity of the 3 Pd-9 min treated GSF sample was 30.58%, which was lower than that of the control (40.08%). In MW-treated samples, SEM images revealed smaller clusters with rough and porous structures. However, no noticeable color (ΔE) changes were observed in MW-treated samples. Aside from water absorption capacity and water solubility index, MW treatment reduced oil absorption capacity, foaming capacity, and emulsifying capacity. As demonstrated by principal component analysis, MW irradiation with moderate Pd (2-3) was more effective in reducing ANFs, retaining nutritional contents, and improving the digestible properties of GSF, which could be a potential ingredient for developing gluten-free products.

Effect of extraction pH on amino acids, nutritional, in-vitro protein digestibility, intermolecular interactions, and functional properties of guar germ proteins.

The chemical compositions, intermolecular interactions, and functional properties of guar germ proteins (GGP) were investigated at different extraction pH (7 to 11). The protein efficiency ratio, essential amino acid index (46.53), predicted biological value (39.02), nutritional index (42.67), and protein purity (91.69 %) were found to be highest at pH 9. The in-vitro protein digestibility of GGP sample was highest at pH 11. From SDS-PAGE, the band intensity (<10 kDa) became thinner with an increase in extraction pH from 7 to 9 and then thicker. Meanwhile, smallest particle size and weaker ionic and hydrogen bonds were found at pH 11. The ß-sheet content was more dominating in GGP samples. Moreover, higher denaturation temperatures of GGP samples indicated that protein molecules had a compact tertiary structure. Furthermore, the GGP extracted at pH 7 showed better functional properties. The principal component analysis suggested that pH 9 was more suitable for isolating GGP.

A preliminary study on heavy metal monitoring in soil and guar (Cyamopsis tetragonoloba) biomass amended with sewage sludge.

Applying sewage sludge in agricultural soils is an interesting source of organic matter. This study aimed to monitor concentrations of heavy elements in soil and guar plants, which can pose a risk to the health of humans and animals if they enter the food chain through the soil-plant system. The experiment revealed that applying sludge increased the amount of organic matter, total nitrogen, potassium, and phosphorus in the soil. Additionally, the concentration of heavy metals such as Pb, Co, Cr, Ni, Cu, and Zn in all treatments remained below the permissible limits for soil. The highest plant height and plant dry weight were recorded in the sludge and sludge + fertilizer treatments. The dry weight of the guar varied from 629 g m-1 in the control treatment to 1050 g m-1 in the sludge + fertilizer plots. The use of sludge increased the accumulation of heavy metals in the above-ground parts of the guar plant compared to the control. However, the level of heavy metal remained within the normal range and below the toxic concentration. Our results also showed that the application of sludge along with fertilizer improved the quality of the guar forage by increasing the levels of crude protein, digestible dry matter and water-soluble carbohydrates. Overall, the results indicated that using sludge as organic fertilizer can improve soil properties, reduce the use of inorganic fertilizers, and decrease the harmful effects of heavy metals on the environment and health in the research area.

Guar-based aerogels with oriented lamellar structure and lightweight properties for flame-retardant and thermal insulation.

In this study, a multi-functional guar gum aerogel with the oriented lamellar structure, which introduced sodium silicate (Na2O·nSiO2) and phytic acid (PA) as thermal insulation additives and flame-retardant agents, respectively, was fabricated via freeze drying. Our aerogel's chemical structure, morphology, and thermal and mechanical properties were analyzed. The oriented lamellar structure was attributed to the orientated growth of ice crystals, which was induced by the "silicate-guar, guar-phytate, and phytate-silicate" multiple hydrogen bonds formed between Na2O·nSiO2, PA, and guar gum. The density of the sample with 2 wt% PA could reach 0.0335 g·cm-3, and the porosity was 5 %, along with a specific pore volume of 0.8144 cm3·g-1. The mechanical properties and thermal insulation performed significant differences in the radial and axial direction of the oriented lamella (nearly 100 % resilience while 50 % deformation quantity and 0.0235 W/(m*K) of thermal conductivity in the radial direction, up to 0.079 MPa of compressive strength in the axial direction). The presence of PA attached a good flame-retardant ability to our aerogel (The Limiting Oxygen Index (LOI) was 30.77 %). This work provides a novel and promising method for developing anisotropic aerogel with excellent potential in building energy efficiency and flame-retardant.

The effects of microbial fertilizers application on growth, yield and some biochemical changes in the leaves and seeds of guar (Cyamopsis tetragonoloba L.).

Guar (Cyamopsis tetragonoloba L.) is a summer legume that is becoming a crucial industrial crop because of its high gum and protein content. Thus far, the combined effects of arbuscular mycorrhizal fungi (AMF) and Bradyrhizobium on the yield and chemical composition of guar plants are not well studied. Therefore, the current investigation was designed to estimate the individual as well as the combined effects of AMF and Bradyrhizobium on plant growth, yield and nutritional quality of seeds and leaves of guar. AMF and/or Bradyrhizobium inoculation improved chemical composition of guar seeds and its morpho-physiological (plant height, fresh weight, dry weight, and yield production) traits. In addition to increased guar growth and yield production, the inoculation of AMF and/or Bradyrhizobium increased guar leaf and seed minerals, fiber, lipids, crude protein and ash contents. At primary metabolites, there were increases in sugar levels including raffinose stachyose, verbascose and galactomannan. These increases in sugar provided a route for organic acids, amino acids and fatty acids production. Interestingly, there was an increase in essential amino acids and unsaturated fatty acids. At the bioactive secondary metabolite levels, biofertilizers improved phenols and flavonoids levels and anthocyanin and polyamines biosynthesis. In line with these increases, precursors of anthocyanin (phenylalanine, p-coumaric acid, and cinnamic acid) and the levels of polyamines (diaminopropane, putrescine, cadaverine, spermidine, spermine, and agmatine) were increased. Overall, for the first time, our study shed the light on how AMF and Bradyrhizobium improved guar yield and metabolism. Our findings suggested that the combined inoculation of AMF and Bradyrhizobium is an innovative approach to improve guar growth, yield production and yield quality.

Effects of basil seed and guar gums coatings on sensory attributes and quality of dehydrated orange slices using osmotic-ultrasound method.

In this work, the effects of gum coating (basil seed and guar gums), ultrasonic power, sonication time, and sucrose concentration on the osmosis dehydration parameters (water loss, solid gain, and rehydration rate), sensory attributes, color changes, and surface shrinkage of dehydrated orange slices using osmotic-ultrasound method were studied. The moisture loss and sucrose gain increased when the ultrasonic duration and sucrose level increased. The edible coating reduced solids absorption, with the lowest sucrose absorption in the basil seed gum-coated slices. Also, the coating increased rehydration rate of dried orange slices, with the highest rehydration ratio in the basil seed gum-coated slices (225.91 %). Edible coating with basil seeds gum improved the sensorial attributes of dried orange slices. The total color difference (ΔE) and surface shrinkage of osmotic dehydrated, dried, and rehydrated orange slices decreased with edible coating pretreatment and increasing in the sonication intensity. As the ultrasound duration enhanced from 5 to 15 min, the average surface shrinkage values of dried and rehydrated orange slices increased from 22.74 % to 26.36 %, and 12.18 % to 15.50 %, respectively. The current work confirmed that the gum coating has the potential to enhance appearance quality and sensorial attributes of osmotic-ultrasound dehydrated orange slices.

Alterations in plant anatomy and higher lignin synthesis provides drought tolerance in cluster bean [Cyamopsis tetragonoloba (L.) Taub.].

Four contrasting varieties of guar, RGC-1002 and RGC-1038, drought tolerant, while, Sarada and RGC-936, drought sensitive, were monitored in watered and drought. The water status, phenolics, plant anatomy and transcript level of genes related to anatomical traits were assessed. The study aimed to decipher the anatomical adaptations of guar plants in response to water stress. The physiological determinants, relative water content (RWC), water potential (ψ), and leaf membrane damage, declined under drought in all four varieties although, the decrement was lesser in the tolerant varieties. Furthermore, the tolerant cultivars subjected to water stress recorded higher accumulation of total phenolic content, anthocyanin and lignin, which efficiently scavenge the reactive oxygen species. The results suggest that the cultivars RGC-1002 and RGC-1038 are better able to resist drought-induced oxidative stress than Sarada and RGC-936. Moreover, leaf, petiole, stem and root anatomical traits viz. size of epidermal cell, parenchyma, width of cortex layer, and diameter of xylem vessels were narrowed in all the varieties although, the decrement was lesser in the tolerant varieties under drought. The expression analysis of genes revealed that drought-tolerant varieties showed enhanced mechanical support for water conduction by up-regulation of genes, Phenylalanine ammonia-lyase1 (PAL1), cinnamate-4-hydroxylase (C4H), 4-coumarate-CoA ligase (4CL), cinnamoyl-CoA reductase (CCR), caffeoyl-CoA O-methyltransferase (CCOMT), and cinnamyl-alcohol dehydrogenase (CAD6) in water stress conditions. The alterations in physio-anatomical, biochemical and gene expression traits in tolerant guar varieties enabled them to maintain steady nutrient transport while reducing the risk of embolisms and increasing water-flow resistance for better survival in water stressed conditions.

Durably dual superlyophobic cationic guar gum­calcium complex decorated cellulose fabrics for on-demand oil/water separation.

The removal to oils from water has become a global issue because of the growing of wastewater discharge and unceasing appearance of oil leaks. Herein, a kind of durably dual superlyophobic (superhydrophobic under oil and superoleophobic under water) cotton fabric (CF) was fabricated via simple assembly route that introduced guar hydroxypropyltrimonium chloride­calcium (GHTC-Ca) chelate compound on the fabric surface. The coated CF exhibits good resistance to mechanical abrasion, corrosive aqueous solution, high temperature, and organic solvent immersion. Furthermore, due to prewetting-caused superoleophobicity underwater and superhydrophobicity underoil, the as-prepared CF can selectively separate both heavy oils and light oils in water under extremely harsh conditions with separation efficiencies as high as 98.7 % and 98.4 %, respectively. More importantly, the as-prepared fabrics are able to remove dispersed oil droplets from oil-in-water emulsions and water droplets from water-in-oil emulsions with separation efficiency of over 89 % and 91.4 %, respectively. Hence, this prominent separation performance suggests a good application prospect of GHTC-Ca functionalized CF in oily water purification.

Identification and characterization of the Cyamopsis tetragonoloba transcription factor MYC (CtMYC) under drought stress.

The MYC transcription factor (TF) has a variety of roles in abiotic stress responses of plants. In the present work, MYC TF named CtMYC (Cymopsis tetragonoloba) from guar plant, which is induced by drought stress, was identified. The mature leaves of guar were employed to detect the full-length CtMYC TF on the 8th day of drought stress. The CtMYC gene showed tissue-specific expression and up regulated under drought stress conditions as compared to the control and maximum expression was observed in mature leaves. Additionally, CtMYC TF was cloned and expressed in E. coli Rosetta cells and CtMYC protein was purified. The circular dichroism (CD) analysis revealed the presence of helical content and beta sheets and in the presence of genomic DNA the conformational changes were observed in secondary structure, which showed DNA binding potential of CtMYC. These results were analyzed by CD and fluorescence studies. In silico studies reveal the presence of conserved bHLH domain and DNA-binding amino acid residues His, Glu and Arg in CtMYC. This is first report on CtMYC TF with DNA binding potential that is responsive to drought. This study provides the structure and characterization of CtMYC TF and DNA binding ability in drought tolerance mechanism in guar.

The chromosome-scale genome assembly of cluster bean provides molecular insight into edible gum (galactomannan) biosynthesis family genes.

Cluster bean (Cyamopsis tetragonoloba (L.) Taub 2n = 14, is commonly known as Guar. Apart from being a vegetable crop, it is an abundant source of a natural hetero-polysaccharide called guar gum or galactomannan. Here, we are reporting a chromosome-scale reference genome assembly of a popular cluster bean cultivar RGC-936, by combining sequencing data from Illumina, 10X Genomics, Oxford Nanopore technologies. An initial assembly of 1580 scaffolds with an N50 value of 7.12 Mb was generated and these scaffolds were anchored to a high density SNP linkage map. Finally, a genome assembly of 550.31 Mb (94% of the estimated genome size of ~ 580 Mb (through flow cytometry) with 58 scaffolds was obtained, including 7 super scaffolds with a very high N50 value of 78.27 Mb. Phylogenetic analysis using single copy orthologs among 12 angiosperms showed that cluster bean shared a common ancestor with other legumes 80.6 MYA. No evidence of recent whole genome duplication event in cluster bean was found in our analysis. Further comparative transcriptomics analyses revealed pod-specific up-regulation of genes encoding enzymes involved in galactomannan biosynthesis. The high-quality chromosome-scale cluster bean genome assembly will facilitate understanding of the molecular basis of galactomannan biosynthesis and aid in genomics-assisted improvement of cluster bean.

Evaluation of different treatment modalities on the efficacy of hydroxypropyl Guar (HP-Guar) formulation on tear film stability (TFS) in subjects exposed to adverse environmental conditions.

The study aimed to assess the efficacy of hydroxypropyl guar (HP) formulation (Systane) to protect tear film parameters under desiccating environment using protection and relief treatment modalities. The subjects were exposed to adverse environmental conditions using a Controlled Environment Chamber (CEC) where the relative humidity (RH) was 5% and the ambient temperature was 21 °C and screened for Tear break-up time (TBUT), Tear film evaporation rate (TFER) and lipid layer thickness (LLT) using the HIRCAL grid, Servomed EP3 Evaporimeter and Keeler's TearScope-Plus respectively. Significant improvement in LLT was noticed in the protection modality. The mean tear film evaporation rate doubled after exposure to the humidity of 5% to a value of 105.37 g/m2/h (0.29 µl/min). All subjects displayed a significant reduction in non-invasive tear break-up time (NITBUT) with a mean NITBUT of 7.7 s after exposure to a desiccating environment for 15 min. A significant increase in NITBUT after the instillation of the drops was recorded in both methods. The results obtained from this study showed that a solution containing HP-Guar significantly improves tear film parameters under a desiccating environment. Apart from the tear evaporation rate, all tear parameters showed improvement after the use of HP-Guar eye drops. It is evident that tear film parameters respond differently to the management modalities and using CEC has the potential to provide researchers with a readily available method to evaluate the efficiency of tear supplementation.

Atmospheric cold plasma induced nutritional & anti-nutritional, molecular modifications and in-vitro protein digestibility of guar seed (Cyamopsis tetragonoloba L.) flour.

The present study was carried out to investigate the effect of atmospheric cold plasma treatment on the nutritional, anti-nutritional, functional, morphological, and digestibility of guar seed (Cyamopsis tetragonoloba L.) flour. Here, guar seed flour was kept inside the plasma reactor for 5 to 20 min at different power levels (10 & 20 kV). The cold plasma treatment (CPT) significantly (p < 0.05) reduced the carbohydrate (46.87 - 36.81 %), protein (27.15 - 25.88 %), and increased the WAC (1.89 - 2.91 g/g), OAC (1.18 - 2.17 g/g), FC (113 - 186.17 %), and pasting properties of guar seed flour. High-intensity plasma-treated samples (20 kV-20 min) contained lesser tannin, phytic acid, and saponin with reduced the nutritional value. The FTIR spectrum suggested that functional group formation or destruction might have occurred in the plasma-treated samples. Additionally, the crystallinity is reduced with increasing applied voltage or duration. The SEM analysis reveals that CPT resulted in the formation of rough surfaces with highly porous structures. On the other hand, CPT significantly reduced the trypsin inhibitor activity and had a minor impact on in-vitro protein digestibility except for the 20 kV-20 min treated sample. In PCA analysis, 10 kV-15 min treated samples exhibited better nutritional value, functional, and pasting properties with maximum impact of anti-nutritional factors. From the results, it can be concluded that treatment duration rather than the applied voltage plays a significant role in preserving the nutritional content.

A structure-property study for konjac glucomannan and guar galactomannan: Selective carboxylation and scale inhibition.

The effect of structural difference for konjac glucomannan (KGM) and guar galactomannan (GGM) on their physicochemical properties including selective carboxylation, biodegradation and scale inhibition was firstly investigated. Compared with GGM, KGM can be specially modified by amino acid to prepare carboxyl-functionalized polysaccharides. The structure-activity relationship explaining the difference in carboxylation activity and the anti-scaling abilities of polysaccharides and carboxylated derivatives were explored by static anti-scaling, iron oxide dispersion and biodegradation tests coupled with structural and morphological characterizations. KGM with linear structure was preferred for carboxylated modification by glutamic acid (KGMG) and aspartic acid (KGMA) while GGM with branched structure failed to accomplish that due to steric hindrance. GGM and KGM showed limited scale inhibition performance, which was probably attributed to the moderate adsorption and isolation effect of macromolecular stereoscopic structure. While KGMA and KGMG performed as effective and degradable inhibitors for CaCO3 scale with inhibitory efficiencies > 90 %.

Biodegradable Guar-Gum-Based Super-Porous Matrices for Gastroretentive Controlled Drug Release in the Treatment of Helicobacter pylori: A Proof of Concept.

An increase in resistance to key antibiotics has made the need for novel treatments for the gastric colonization of Helicobacter pylori (H. pylori) a matter of the utmost urgency. Recent studies tackling this topic have focused either on the discovery of new compounds to ameliorate therapeutic regimes (such as vonoprazan) or the synthesis of gastroretentive drug delivery systems (GRDDSs) to improve the pharmacokinetics of oral formulations. The use of semi-interpenetrating polymer networks (semi-IPNs) that can act as super-porous hydrogels for this purpose is proposed in the present work, specifically those displaying low ecological footprint, easy synthesis, self-floating properties, high encapsulation efficiency for drugs such as amoxicillin (AMOX), great mucoadhesiveness, and optimal mechanical strength when exposed to stomach-like fluids. To achieve such systems, biodegradable synthetic copolymers containing acid-labile monomers were prepared and interpenetrated with guar gum (GG) in a one-pot polymerization process based on thiol-ene click reactions. The resulting matrices were characterized by SEM, GPC, TGA, NMR, and rheology studies, and the acidic hydrolysis of the acid-sensitive polymers was also studied. Results confirm that some of the obtained matrices are expected to perform optimally as GRDDSs for the sustained release of active pharmaceutical ingredients at the gastrointestinal level, being a priori facilitated by its disaggregation. Therefore, the optimal performance of these systems is assessed by varying the molar ratio of the labile monomer in the matrices.

The formaldehyde treated guar meal and prill fat, agro industrial by-products as dietary rumen protected protein and energy source: improves growth performance, feed conversion, nutrient utilization, microbial protein synthesis, blood metabolites and economic efficiency in growing dairy buffalo (Bubalus bubalis) calves.

The study investigated the effects of protein replacement with formaldehyde-treated guar meal (FTGM) and prill fat (PF) in the diet on performance of growing dairy buffalo calves. Thirty-two feedlots Surti breed dairy buffalo calves (age, 7.31 ± 0.34 months and body weight, 90.69 ± 6.19 kg) were assigned into four dietary treatments (n-8 calves/each): (1) control group, supplied basal diet as per ICAR (2013) nutrient requirements; (2) FTGM group, 30% crude protein (CP) requirement of concentrate mixture (dry matter basis (DMB)) replaced with FTGM in basal diet; (3) PF group, supplied basal diet + 100 g PF; and (4) FTGM + PF group, 30% CP requirement of concentrate mixture (DMB) replaced with FTGM in the basal diet + 100 g PF for 280 days. All the treatment diets were isonitrogenous. Growth performance was improved in FTGM + PF and FTGM groups. Apparent digestibility (%) of CP was increased in FTGM and FTGM + PF diet, while digestibility (%) of ether extract (EE) was increased in PF group. Serum total protein, albumen, urea nitrogen, and creatinine concentrations were higher in FTGM + PF and FTGM groups, whereas total cholesterol and triglycerides levels were greater in FTGM + PF and PF groups. Calculated methane emission had a discernible influence of treatment in FTGM and FTGM + PF. The overall cost of feeding per kilogram gain was lowest in FTGM and FTGM + PF groups. In conclusion, 30% CP replacement with FTGM with or without PF improved the growth performance, feed conversion ratio, and nutrient utilization; supported efficient utilization of resources; and economized the rearing of growing dairy buffalo calves.

The solution properties of galactomannan after simulated digestion of guar fortified bread predict the extent of postprandial insulin reduction in healthy adult overweight subjects.

Coil overlap occurs when random coil polysaccharides such as cereal beta-glucan or galactomannan in solution are abundant enough and large enough to entangle with one another to form networks. It was recently shown that this concept applied to in vitro digested cereal-based foods could predict the efficacy of the food to reduce postprandial glycaemia. In the current study we further investigate the role of coil overlap for prediction of glycaemic and insulinaemic responses using four guar fortified breads (10-15% wheat flour replacement level) with galactomannans of different weight-average molecular weight (Mw). The breads, including a wheat flour control, were tested in a randomised crossover study in 12 overweight adults. Addition of guar reduced postprandial serum insulin, but not glucose responses. The extent of postprandial insulin reduction correlated with the solution properties of galactomannan after in vitro digestion. A significantly greater reduction in insulin response was observed for two of the breads where the galactomannan Mw and concentration in solution after in vitro digestion was above coil overlap, in contrast to two other breads, which resulted in digests containing galactomannan below coil overlap and a significantly lower reduction of postprandial insulin. Further in vitro digestion experiments focusing on amylolysis of starch with kinetic modelling showed a greater proportion of slowly digested starch in breads with galactomannan above coil overlap than below. A combination of the molecular weight of dietary fibre in a food and its soluble concentration are key parameters explaining its physiological efficiency in the upper gastrointestinal tract.

Inhibition of Th1 activation and differentiation by dietary guar gum ameliorates experimental autoimmune encephalomyelitis.

Dietary fibers are potent modulators of immune responses that can restrain inflammation in multiple disease contexts. However, dietary fibers encompass a biochemically diverse family of carbohydrates, and it remains unknown how individual fiber sources influence immunity. In a direct comparison of four different high-fiber diets, we demonstrate a potent ability of guar gum to delay disease and neuroinflammation in experimental autoimmune encephalomyelitis, a T cell-mediated mouse model of multiple sclerosis. Guar gum-specific alterations to the microbiota are limited, and disease protection appears to be independent of fiber-induced increases in short-chain fatty acid levels or regulatory CD4+ T cells. Instead, CD4+ T cells of guar gum-supplemented mice are less encephalitogenic due to reduced activation, proliferation, Th1 differentiation, and altered migratory potential. These findings reveal specificity in the host response to fiber sources and define a pathway of fiber-induced immunomodulation that protects against pathologic neuroinflammation.

The effect of hydroxypropyl-guar nanoemulsion on signs and symptoms of dry eye.

PURPOSE: To examine the effect of hydroxypropyl-guar nanoemulsion (HP-Guar nanoemulsion, Alcon Laboratories Ltd, Fort Worth, TX, USA) versus saline (0.9% sodium chloride; Pfizer Inc., Bentley WA Australia) on the comfort and tear film properties of people with dry eye disease both in the short-term (up to 2 h post-drop instillation) and longer-term (after 4 weeks of 4-times daily use), and to examine the effect on tear inflammatory markers after 4 weeks. METHODS: This was a prospective, investigator-masked, randomised, cross-over dispensing study. Twenty participants with dry eye disease (5 males: 15 females) with average age 46.9 ± 14.4 (range 26 to 70) years were randomized to either HP-Guar nanoemulsion, or saline eye drops. Ocular symptoms, lipid layer thickness, tear evaporation, tear osmolarity and non-invasive break-up time were measured pre-drop instillation, 1 h and 2 h post-eye drop instillation, and after 4-weeks of 4-times daily drop use. Tear inflammatory mediators were measured pre-drop instillation and after 4-weeks. After 4-weeks, patients had a 4-week washout period and then crossed over to the alternate drop. RESULTS: With HP-Guar nanoemulsion, participants reported less grittiness/burning/stinging 1 h post eye drop instillation compared to baseline (79.5 ± 23.3 vs. 66.8 ± 27.7, p = 0.02); less dryness 1 h and 2 h post eye drop instillation compared to baseline (77.8 ± 23.0 and 76.2 ± 23.7 vs. 61.0 ± 27.1 respectively, p < 0.01 for both); and greater overall satisfaction 1 h post drop instillation and after 4 weeks of daily use compared to baseline (80.4 ± 21.6 and 83.4 ± 16.6 vs. 68.6 ± 26.0 respectively, p ≤ 0.011 for both). With saline, participants reported less dryness after 4 weeks of daily use compared to baseline (74.2 ± 23.8 vs. 60.2 ± 24.0, p < 0.01). For HP-Guar nanoemulsion, average lipid layer thickness was significantly thicker 2 h post drop-instillation (79.5 ± 21.7 nm) compared to baseline (63.7 ± 18.9 nm) and the 4-week assessment (62.4 ± 23.1 nm, p < 0.01 for both). For saline, average lipid layer thickness was significantly thicker at 1 h and 2 h post eye drop instillation (76.0 ± 23.8 nm and 80.4 ± 24.8 nm) compared to baseline (61.0 ± 15.6 nm, p < 0.01 for both). There was no difference in inflammatory mediators or other tear variables between drops or visits. CONCLUSION: HP-Guar nanoemulsion was more effective for improving a range of subjective dry eye symptoms both in the short and long-term compared to saline. Both HP-Guar nanoemulsion and saline transiently increased lipid layer thickness.