Compendio degli studi più significativi con riferimento a proprietà, assunzione, effetti.

Jakóbik-Kolon A, Bok-Badura J, Milewski A, Karoń K. Long Term and Large-Scale Continuous Studies on Zinc(II) Sorption and Desorption on Hybrid Pectin-Guar Gum Biosorbent. Polymers (Basel). 2019 Jan 8;11(1):96. doi: 10.3390/polym11010096.

Abstract. Pectin-guar gum biosorbent was tested for zinc(II) ions removal in column process. Sorption⁻desorption experiments were performed in laboratory and at larger scale. The breakthrough and elution curves were obtained for various conditions. The Bed Depth Service Time model was tested for utility in data estimation. Possibility of sorbent reuse and its lifetime was examined in 20 repeated sorption⁻desorption cycles. Finally, tests were repeated for real wastewater from galvanizing plant, giving satisfactory results. The effectiveness of Zn(II) sorption happened to be dependent on process parameters; tests have proved that it increased with increasing bed height and with decreasing flow rate or grain size. For an initial zinc concentration of 30 mg/L, even 2096 mL of zinc solution could be purified in small scale experiment (2 g of fine grain sorbent and flow rate 60 mL/h) or 5900 L in large-scale (16 kg of large grain sorbent and flow rate 45 L/h). This allowed for 40-fold or 49-fold zinc increases in concentration in one sorption⁻desorption cycle. The most successful results are meant that at least 20 sorption⁻desorption cycles could be performed on one portion of biosorbent without loss of its effectiveness, large-scale tests for real wastewater from galvanizing plant gave satisfactory results, and that the form and mechanical stability of our sorbent is suitable for column usage with flow rates applicable in industry.

Inoue R, Sakaue Y, Kawada Y, Tamaki R, Yasukawa Z, Ozeki M, Ueba S, Sawai C, Nonomura K, Tsukahara T, Naito Y. Dietary supplementation with partially hydrolyzed guar gum helps improve constipation and gut dysbiosis symptoms and behavioral irritability in children with autism spectrum disorder. J Clin Biochem Nutr. 2019 May;64(3):217-223. doi: 10.3164/jcbn.18-105.

Abstract. Prebiotic dietary water-soluble fiber obtained from partially hydrolyzed guar gum was added to diets of children with autism spectrum disorders who presented constipation symptoms. Supplementation with partially hydrolyzed guar gum altered gut microbiota and significantly increased the frequency of defecation per week and altered the gut microbiota. In addition, supplementation with partially hydrolyzed guar gum significantly (p<0.05) decreased and tended to decrease (p = 0.07) the concentrations of serum interleukin-1β and tumor necrosis factor-α, respectively. More importantly, supplementation with partially hydrolyzed guar gum significantly ameliorated behavioral irritability as per the Aberrant Behavior Checklist, Japanese Version. The present study demonstrated that supplementation with partially hydrolyzed guar gum to diets of constipated autism spectrum disorders children helped improve constipation and gut dysbiosis symptoms, which in turn helped attenuate the level of serum inflammation cytokines and behavioral irritability.

Cliffe L, Hernandez-Becerra N, Boothman C, Eden B, Lloyd JR, Nixon SL. Guar Gum Stimulates Biogenic Sulfide Production in Microbial Communities Derived from UK Fractured Shale Production Fluids. Microbiol Spectr. 2022 Dec 21;10(6):e0364022. doi: 10.1128/spectrum.03640-22. 

Abstract. Shale gas production fluids offer a window into the engineered deep biosphere. Here, for the first time, we report on the geochemistry and microbiology of production fluids from a UK shale gas well in the Bowland shale formation. The composition of input fluids used to fracture this well were comparatively lean, consisting only of water, sand, and polyacrylamide. This formation therefore represents an interesting comparison to previously explored fractured shales in which more additives were used in the input fluids. Here, we combine cultivation and molecular ecology techniques to explore the microbial community composition of hydraulic fracturing production fluids, with a focus on the potential for common viscosity modifiers to stimulate microbial growth and biogenic sulfide production. Production fluids from a Bowland Shale exploratory well were used as inocula in substrate utilization experiments to test the potential for polyacrylamide and guar gum to stimulate microbial metabolism. We identified a consortium of thiosulfate-reducing bacteria capable of utilizing guar gum (but not polyacrylamide), resulting in the production of corrosive and toxic hydrogen sulfide. Results from this study indicate polyacrylamide is less likely than guar gum to stimulate biogenic sulfide production during shale gas extraction and may guide planning of future hydraulic fracturing operations. IMPORTANCE Shale gas exploitation relies on hydraulic fracturing, which often involves a range of chemical additives in the injection fluid. However, relatively little is known about how these additives influence fractured shale microbial communities. This work offers a first look into the microbial community composition of shale gas production fluids obtained from an exploratory well in the Bowland Shale, United Kingdom. It also seeks to establish the impact of two commonly used viscosity modifiers, polyacrylamide and guar gum, on microbial community dynamics and the potential for microbial sulfide production. Not only does this work offer fascinating insights into the engineered deep biosphere, it could also help guide future hydraulic fracturing operations that seek to minimize the risk of biogenic sulfide production, which could reduce efficiency and increase environmental impacts of shale gas extraction.

Wu C, Liu J, Tang Y, Li Y, Yan Q, Jiang Z. Hepatoprotective Potential of Partially Hydrolyzed Guar Gum against Acute Alcohol-Induced Liver Injury in Vitro and Vivo. Nutrients. 2019 Apr 27;11(5):963. doi: 10.3390/nu11050963. 

Abstract. Natural polysaccharides, particularly galactomannans, are potential candidates for treatment of alcoholic liver diseases (ALD). However, applications are restricted due to the physicochemical properties associated with the high molecular weight. In this work, guar gum galactomannans were partially hydrolyzed by β-mannanase, and the molecular mechanisms of hepatoprotective effects were elucidated both in vitro and in vivo. Release of lactate dehydrogenase and cytochrome C were attenuated by partially hydrolyzed guar gum (PHGG) in HepG2 cells, due to protected cell and mitochondrial membrane integrity. PHGG co-administration decreased serum amino transaminases and cholinesterase levels of acute alcohol intoxicated mice, while hepatic pathologic morphology was depleted. Activity of superoxide dismutase, catalase, and glutathione peroxidase was recovered to 198.2, 34.5, 236.0 U/mg protein, respectively, while malondialdehyde level was decreased by 76.3% (PHGG, 1000 mg/kg∙day). Co-administration of PHGG induced a 4.4-fold increment of p-AMPK expression, and lipid metabolism was mediated. PHGG alleviated toll-like-receptor-4-mediated inflammation via the signaling cascade of MyD88 and IκBα, decreasing cytokine production. Moreover, mediated expression of Bcl-2 and Bax was responsible for inhibited acute alcohol-induced apoptosis with suppressed cleavage of caspase 3 and PARP. Findings gained suggest that PHGG can be used as functional food supplement for the treatment of acute alcohol-induced liver injury.

Liu Y, Rao L, Zhang H, Cen Y, Cheng K. Conjugation of vitamin E-TPGS and guar gum to carry borneol for enhancing blood-brain barrier permeability. J Biomater Appl. 2018 Oct;33(4):590-598. doi: 10.1177/0885328218799551. 

Abstract. Herb borneol is usually used in clinics for the treatment of central nervous system illness, for its ability of blood-brain barrier permeability, although its poor water solubility and poor bioavailability limit its clinical application to some degree. In this study, we developed a novel nanoparticle combining the benefits of vitamin E d-ɑ-tocopheryl poly(ethylene glycol) succinate (E-TPGS) (or TPGS) and guar gum to get TPGS-g-guar gum as a drug delivery system to carry borneol, which could improve the solubility of borneol and increase the drug-loading capacity efficiently. The results showed that TPGS-g-guar gum nanoparticles delivery system was suitable to carry borneol and release the drug effectively, and TPGS-g-guar gum/borneol nanoparticles would be a potential platform for improving the treatment of central nervous system illness and cerebrovascular disease.

Aravindaraj N, Suresh J, Krishnaswami V, Alagarsamy S, Kandasamy R. Guar gum based oral films for hypertensive urgencies. Nat Prod Res. 2022 Dec;36(24):6470-6473. doi: 10.1080/14786419.2022.2039919. 

Abstract.  Guar gum (GG) is a natural film forming biopolymer used as a drug delivery media for Telmisartan (TS). TS is a poorly water-soluble anti-hypertensive agent with low bioavailability.The present work has been hypothesized by converting TS into nanocrystals by high shear homogenisation to enhance the solubility thereby the bioavailability is expected to get enhanced. TS-NC-GG-OF was formulated by solvent casting method using GG by varying the disintegrant ratio.Telmisartan nanocrystals showed particle size of 441.70 ± 35.28 nm, surface charge of -20.86 ± 0.55 mV and reduced crystalline pattern. The amount of TS present per mg ofnanocrystals is 0.33 mg. The developed TS-NC-GG-OF was circular, creamy white colour with desired physicochemical properties. The in vitro release studies performed by beaker model showed an immediate release pattern.This proof of concept specifies that the TS-NC-GG-OF may be a better choice for hypertensive emergencies using the natural excipient Guar gum.

Todd PA, Benfield P, Goa KL. Guar gum. A review of its pharmacological properties, and use as a dietary adjunct in hypercholesterolaemia. Drugs. 1990 Jun;39(6):917-28. doi: 10.2165/00003495-199039060-00007. 

Abstract. Guar gum is a dietary fibre advocated for use in lowering serum total cholesterol levels in patients with hypercholesterolaemia. Its mechanism of action is proposed to be similar to that of the bile-sequestering resins. Although guar gum is also employed as an adjunct in non-insulin-dependent diabetic patients this review is restricted to its efficacy as a hypolipidaemic agent. Clinical trials indicate that, when used alone, guar gum may reduce serum total cholesterol by 10 to 15%, although some studies show no significant response. An attenuation of this effect during longer term treatment has been seen but evidence of this effect is equivocal. As an adjunct to established therapies (bezafibrate, lovastatin or gemfibrozil) guar gum has shown some promise: it may produce a further reduction in total cholesterol of about 10% in patients not responding adequately to these drugs alone. Gastrointestinal effects, notably flatulence, occur relatively frequently and may be considered unacceptable by some patients. Standardization of formulations and methods of administration of guar gum is required to clarify its pharmacological and clinical properties. Thus, on the basis of presently available evidence guar gum as monotherapy may be considered at most modestly effective in reducing serum cholesterol levels. Nonetheless, further investigation of guar gum is warranted, particularly its use as an adjunct to produce additional reductions in serum cholesterol in patients not responding optimally to other lipid-lowering agents.

Slavin JL, Greenberg NA. Partially hydrolyzed guar gum: clinical nutrition uses. Nutrition. 2003 Jun;19(6):549-52. doi: 10.1016/s0899-9007(02)01032-8. 

Abstract. Objective: This paper provides a review of research on partially hydrolyzed guar gum that is relevant to clinical nutrition practice....Results: Partially hydrolyzed guar gum (PHGG) is a water-soluble dietary fiber with a wide range of uses in clinical nutrition. Its low viscosity allows its use in enteral products and beverages. PHGG can be added to enteral formulas and food products as a dietary fiber source. PHGG provides the benefits associated with dietary fiber ingestion. Addition of PHGG to the diet reduced laxative dependence in a nursing home population. PHGG also reduced the incidence of diarrhea in septic patients receiving total enteral nutrition and reduced symptoms of irritable bowel syndrome. PHGG also increased production of Bifidobacterium in the gut. Conclusion: The ease of use of PHGG and its clinical effectiveness make it a good choice in clinical nutrition practice.