Guar Gum: A Miracle Therapy for Hypercholesterolemia, Hyperglycemia and Obesity

Guar gum as a promising starting material for diverse applications: A review

Guar gum is the powdered endosperm of the seeds of the Cyamopsis tetragonolobus which is a leguminous crop. The endosperm contains a complex polysaccharide called galactomannan, which is a polymer of d-galactose and d-mannose. This hydroxyl group rich polymer when added to water forms hydrogen bonding imparting significant viscosity and thickening to the solution. Due to its thickening, emulsifying, binding and gelling properties, quick solubility in cold water, wide pH stability, film forming ability and biodegradability, it finds applications in large number of industries. In last few decades a lot of research has been done on guar gum to fit it into particular application, as such or by its structural modifications. This review gives an overview of the nature, chemistry and properties of guar gum and discusses recent developments in its modifications and applications in major industries like hydraulic fracturing, explosives, food, agriculture, textile, paper, cosmetics, bioremediation, drug delivery, medical and pharmaceuticals. This article would help researchers engaged in biopolymer area and other end-users who want to begin research in natural polysaccharides.

Non-cereal ingredients for the attenuation of glycaemic response to bread: a review of the clinical evidence

Enrichment of bread with non-cereal ingredients could favourably influence postprandial glucose response to bread.

Cholesterol-lowering effects and potential mechanisms of different polar extracts from Cyclocarya paliurus leave in hyperlipidemic mice

ETHNOPHARMACOLOGICAL RELEVANCE

Cyclocarya paliurus Batal., native only to China, is widely consumed as a Chinese traditional folk medicine for the prevention and treatment of hyperlipidemia, obesity, and diabetes. The aim of the study is to investigate the cholesterol-lowering effect and potential mechanisms of different polar extracts from Cyclocarya paliurus leaves in mice fed with high-fat-diet.

MATERIALS AND METHODS

Cyclocarya paliurus leaves extracts were orally administered to diet-induced hyperlipidemic mice for 4 weeks. Simvastatin was used as a positive control. Body weight, food intake, histopathology of liver and adipose tissues, hepatic and renal function indices, lipid profiles in the serum and liver were evaluated. Total bile acid concentrations of the liver and feces were also measured. Furthermore, the activities and mRNA expression of cholesterol metabolism-related enzymes including 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, cholesterol 7α-hydroxylase (CYP7A1) and acyl-CoA cholesterol acyltransferase 2 (ACAT2) in the livers of the mice were analyzed. LC-MS detection was performed to identify the components in the active fraction of Cyclocarya paliurus extracts.

RESULTS

Different Cyclocarya paliurus polar extracts, especially ChE reduced the levels of serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and hepatic TC and TG, enhanced the level of serum high-density lipoprotein cholesterol (HDL-C), restored hepatic and renal function indices and histomorphology. HMG-CoA reductase activity and mRNA expression were decreased, while CYP7A1 activity and mRNA expression as well as the level of fecal and hepatic bile acid were increased by ChE. LC-MS analysis of ChE revealed the presence of six main triterpenoids, which might be responsible for its antihyperlipidemic bioactivity.

CONCLUSIONS

Evidently ChE possesses the best antihyperlipidemic activity, and the cholesterol-lowering effect is at least partly attributed to its role in promoting the conversion of cholesterol into bile acids by upgrading the activity and mRNA expression of CYP7A1 and inhibiting those of HMG-CoA reductase to lower the cholesterol biosynthesis.

The short-chain fatty acid uptake fluxes by mice on a guar gum supplemented diet associate with amelioration of major biomarkers of the metabolic syndrome

Studies with dietary supplementation of various types of fibers have shown beneficial effects on symptoms of the metabolic syndrome. Short-chain fatty acids (SCFAs), the main products of intestinal bacterial fermentation of dietary fiber, have been suggested to play a key role. Whether the concentration of SCFAs or their metabolism drives these beneficial effects is not yet clear. In this study we investigated the SCFA concentrations and in vivo host uptake fluxes in the absence or presence of the dietary fiber guar gum. C57Bl/6J mice were fed a high-fat diet supplemented with 0%, 5%, 7.5% or 10% of the fiber guar gum. To determine the effect on SCFA metabolism, ¹³C-labeled acetate, propionate or butyrate were infused into the cecum of mice for 6 h and the isotopic enrichment of cecal SCFAs was measured. The in vivo production, uptake and bacterial interconversion of acetate, propionate and butyrate were calculated by combining the data from the three infusion experiments in a single steady-state isotope model. Guar gum treatment decreased markers of the metabolic syndrome (body weight, adipose weight, triglycerides, glucose and insulin levels and HOMA-IR) in a dose-dependent manner. In addition, hepatic mRNA expression of genes involved in gluconeogenesis and fatty acid synthesis decreased dose-dependently by guar gum treatment. Cecal SCFA concentrations were increased compared to the control group, but no differences were observed between the different guar gum doses. Thus, no significant correlation was found between cecal SCFA concentrations and metabolic markers. In contrast, in vivo SCFA uptake fluxes by the host correlated linearly with metabolic markers. We argue that in vivo SCFA fluxes, and not concentrations, govern the protection from the metabolic syndrome by dietary fibers.

Sonication-based improvement of the physicochemical properties of Guar Gum as a potential substrate for modified drug delivery systems

Guar Gum is a natural polysaccharide that, due to its physicochemical properties, is extensively investigated for biomedical applications as a matrix for modified drug delivery, but it is also used in the food industry as well as in cosmetics. A commercial sample of Guar Gum was sonicated for different periods of time, and the reduction in the average molecular weight was monitored by means of viscometric measurements. At the same time, the rheological behaviour was also followed, in terms of viscoelasticity range, flow curves, and mechanical spectra. Sonicated samples were used for the preparation of gels in the presence of borate ions. The effect of borax on the new samples was investigated by recording mechanical spectra, flow curves, and visible absorption spectra of complexes with Congo Red. The anisotropic elongation, observed in previous studies with tablets of Guar Gum and borax, was remarkably reduced when the sonicated samples were used for the preparation of the gels.

Effect of guar gum on glucose and lipid metabolism in white sea bream Diplodus sargus

The aim of this study was to assess the role of soluble non-starch polysaccharide (guar gum) on white sea bream Diplodus sargus, glucose and lipid metabolism. A control diet was formulated to contain 40 % crude protein, 14 % crude lipids and 35 % pregelatinized maize starch, and three other diets were formulated similar to the control diet except for guar gum, which was included at 4 % (diet GG4), 8 % (diet GG8) or 12 % (diet GG12). Diets were fed to the fish for 9 weeks on a pair-feeding scheme. Guar gum had no effect on growth performance, feed efficiency, glycaemia, cholesterolaemia and plasma triacylglyceride levels. Hepatic glucokinase and pyruvate kinase activities, liver glycogen content and liver insulin-like growth factor-I gene expression were not affected by dietary guar gum, while fructose-1,6-bisphosphatase activity was lower in fish fed guar gum-supplemented diets. Hepatic glucose-6-phosphate dehydrogenase activity was higher in fish fed diets GG4 and GG8 than in the control group. Overall, data suggest that in contrast to mammals guar gum had no effect on white sea bream glucose utilization and in lowering plasma cholesterol and triacylglyceride levels. However, it seems to contribute to lower endogenous glucose production.

Nutritional supplements and their effect on glucose control

As diabetes mellitus (DM) continues to be a growing health concern, many people have been turning to natural health products (NHPs) in order to manage this condition, adjunctive to, or even in place of conventional therapies. In order to keep up with this trend, research focussing on the efficacy and mechanisms behind the most common NHPs has been growing amongst the scientific community. The purpose of this chapter is to search and compile scientific literature focussing on the most commonly used NHPs in diabetes treatment, so to educate health professionals on the efficacy, safety and dosage of these products. From our findings, it is apparent that there are promising results from many studies on the potential benefit of NHPs in the treatment of diabetes. Nonetheless, many of the herbs and single nutraceuticals still require further studies in order to confirm safety, dosage and potential interactions with standard conventional therapies. Soluble fibre, alpha lipoic acid, milk thistle, prickly pear cactus and pycnogenol appear to be the most beneficial in the treatment of diabetes.

Potentiation of hypolipidemic and weight-reducing influence of dietary tender cluster bean (Cyamopsis tetragonoloba) when combined with capsaicin in high-fat-fed rats

Soluble fiber-rich tender cluster bean pod (Cyamopsis tetragonoloba) (CB) and a combination of CB and capsaicin, a thermogenic spice compound, were evaluated for weight-reducing effect in high-fat-fed Wistar rats. Freeze-dried CB and capsaicin were included at 15 and 0.015%, respectively, in the high-fat (30%) diet for 8 weeks. Excretion of dietary fat, fat deposition in adipose, and activities of enzymes involved in lipolysis and lipogenesis were examined. CB and capsaicin additively decreased weight gain in high-fat-fed rats, without affecting feed intake. The antiobesity potential of CB was through impeding fat accumulation in adipose and enhancing fat excretion. Decrease in adipose triglyceride by the combination was higher than their individual effects and was accompanied by enhanced activity of hormone-sensitive lipase-facilitating mobilization of depot fat. Increased fecal excretion of triglycerides by the combination of CB and capsaicin was additive. Whereas the hypolipidemic effect of the combination was higher than their individual effects, the decrease in hepatic cholesterol and triglycerides produced by the combination was additve. Thus, dietary CB significantly checked weight gain and adverse changes in lipid profile in high-fat-fed condition amounting to a cardioprotective effect. These beneficial effects were potentiated by coadministration of capsaicin.

Partially hydrolyzed guar gums reduce dietary fatty acid and sterol absorption in guinea pigs independent of viscosity

This study investigated the effect of two partially hydrolyzed guar gums (PHGG) on fatty acid and sterol excretion. PHGG were obtained by chemical hydrolysis of guar gum (GG) with H(2)O:EtOH (1:1) at 100 °C for 1 h (PHGG1) or 2 h (PHGG2). The viscosity of the PHGG in a 1 % (w/v) aqueous solution corresponded to that of a pseudoplastic fluid and was higher for PHGG1 than PHGG2. Guinea pigs (n = 8 per group) were fed high fat diets (17/100 g) that contained 12/100 g of cellulose, PHGG1, or PHGG2 for 4 weeks. Despite the differences in viscosity, the two PHGG exerted similar physiological effects. Compared to the control cellulose group, the body weight gain was lower in animals fed PHGG, although no effect on food consumption was observed. PHGG increased the excretion of fatty acids and neutral sterols, but not bile acids. Consumption of PHGG did not alter the fecal fatty acid profile, while intestinal bioconversion of sterols tended to increase in response to PHGG2. A reduction in the viscosity within the range tested did not correlate with losses in the hypocholesterolemic capacity of PHGG as both were effective in reducing plasma cholesterol. Thus, we conclude that the chemical hydrolysis of guar gum renders the gum suitable for inclusion in food products without significantly altering its beneficial health effects.

Optimization of enzymatic hydrolysis of guar gum using response surface methodology

Guar gum is a polysaccharide obtained from guar seed endosperm portion. Enzymatically hydrolyzed guar gum is low in viscosity and has several health benefits as dietary fiber. In this study, response surface methodology was used to determine the optimum conditions for hydrolysis that give minimum viscosity of guar gum. Central composite was employed to investigate the effects of pH (3-7), temperature (20-60 °C), reaction time (1-5 h) and cellulase concentration (0.25-1.25 mg/g) on viscosity during enzymatic hydrolysis of guar (Cyamopsis tetragonolobus) gum. A second order polynomial model was developed for viscosity using regression analysis. Results revealed statistical significance of model as evidenced from high value of coefficient of determination (R(2) = 0.9472) and P < 0.05. Viscosity was primarily affected by cellulase concentration, pH and hydrolysis time. Maximum viscosity reduction was obtained when pH, temperature, hydrolysis time and cellulase concentration were 6, 50 °C, 4 h and 1.00 mg/g, respectively. The study is important in optimizing the enzymatic process for hydrolysis of guar gum as potential source of soluble dietary fiber for human health benefits.

Guar gum: processing, properties and food applications-A Review

Guar gum is a novel agrochemical processed from endosperm of cluster bean. It is largely used in the form of guar gum powder as an additive in food, pharmaceuticals, paper, textile, explosive, oil well drilling and cosmetics industry. Industrial applications of guar gum are possible because of its ability to form hydrogen bonding with water molecule. Thus, it is chiefly used as thickener and stabilizer. It is also beneficial in the control of many health problems like diabetes, bowel movements, heart disease and colon cancer. This article focuses on production, processing, composition, properties, food applications and health benefits of guar gum.

Arabinoxylans and arabinogalactans: a comprehensive treatise

The functional and nutraceutical importance of various foods is often attributed to the bioactive molecules present in them. A number of components have been studied but dietary fiber and its different constituents are of prime consideration. Among these, arabinoxylan (AX) and arabinogalactan (AG) are of significant importance in that they hold potential in improving the quality of the baked products along with providing health benefits against various ailments. However, the improvements are dependent on their molecular weights, cross linkages, and solubility. Water-Extractable Arabinoxylan (WEAX) is more effective as compared to Water-Unextractable Arabinoxylan (WUEAX). In this review article, efforts were directed to describe the structural and molecular conformations of these functional ingredients. The discussion has been made regarding the functional properties of AX and AG, for example, improvements in water absorption capacities, dough stability time, and viscosity. They also improve the baking absorption of flour that is positively correlated with bread volume, the most important criterion for stakeholders. The arguments are also provided on the detrimental effects on gluten quality with some possible solutions. Their role in improving the quality and extending the shelf life of bread by reducing the process of staling and retrogradation is the main idea presented in the article. The nutraceutical perspectives were also highlighted as they are helpful in regulating blood cholesterol which thereby protect the body from cardiovascular disorders like atherosclerosis. Additionally, they act as prebiotics for microorganisms residing in the gastrointestinal tract.

Comprehensive review on herbal medicine for energy intake suppression

The obesity drug development is present not a bright and successful story. So far, drugs reported to be effective, either from synthetic or natural sources, mostly stimulated controversy because of serious adverse effects, which ended with stopping clinical trials or even withdrawal from the market. However, obesity and its comorbidities have become rapidly a major problem in both developed and developing countries. This has encouraged pharmaceutical companies and academia to keep on struggling on developing novel effective but safe obesity drugs, and on characterizing novel obesity drug targets. From existing scientific work on obesity drug discovery and commercial slimming preparations, compounds originating from nature, especially from plants, seem to be the first choice. Traditional belief that herbal medicine is safer than synthetic ones is one of the classical arguments, although scientifically this is not always true (e.g. ban on Ephedra). But in general, it has been widely acknowledged that a plant compound, with its unique scaffolds and rich diversity is an unlimited source of novel lead compounds. This paper aims to summarize all works focused on screening plant materials by targeting important pathways related to energy intake regulation, either by in vivo or in vitro experiments.

Dietary sources of fiber intake and its association with socio-economic factors among Flemish preschool children

The objectives were to assess total dietary fiber intake, identify the major sources of dietary fiber, and examine its association with socio-economic factors among Flemish preschoolers. Three-day estimated dietary records were collected from a representative sample of preschoolers 2.5-6.5 years old (n = 661; 338 boys, 323 girls). The mean dietary fiber intake (13.4 g/d) was lower than the intake level recommended by the Belgian Superior Health Council (70% boys and 81% girls below the guidelines). The most important contributor was the group of bread and cereals (29.5%), followed by fruits (17.8%), potatoes and grains (16.0%), energy-dense, low-nutritious foods (12.4%), and vegetables (11.8%). Multiple linear regression analyses showed that total fiber intake was associated with maternal education and parents' employment. Overall, fiber intakes from high-nutritious foods (vegetables and fruits) were higher in preschoolers of higher educated mothers and those with one or both parents being employed. In conclusion, the majority of the preschoolers had dietary fiber intakes below the recommended level. Hence, dietary fiber should be promoted among parents of preschoolers and low socio-economic status families should be addressed in particular.

Support of drug therapy using functional foods and dietary supplements: focus on statin therapy

Functional foods and dietary supplements might have a role in supporting drug therapy. These products may (1) have an additive effect to the effect that a drug has in reducing risk factors associated with certain conditions, (2) contribute to improve risk factors associated with the condition, other than the risk factor that the drug is dealing with, or (3) reduce drug-associated side effects, for example, by restoring depleted compounds or by reducing the necessary dose of the drug. Possible advantages compared with a multidrug therapy are lower drug costs, fewer side effects and increased adherence. In the present review we have focused on the support of statin therapy using functional foods or dietary supplements containing plant sterols and/or stanols, soluble dietary fibre, n-3 PUFA or coenzyme Q10. We conclude that there is substantial evidence that adding plant sterols and/or stanols to statin therapy further reduces total and LDL-cholesterol by roughly 6 and 10 %, respectively. Adding n-3 PUFA to statin therapy leads to a significant reduction in plasma TAG of at least 15 %. Data are insufficient and not conclusive to recommend the use of soluble fibre or coenzyme Q10 in patients on statin therapy and more randomised controlled trials towards these combinations are warranted. Aside from the possible beneficial effects from functional foods or dietary supplements on drug therapy, it is important to examine possible (negative) effects from the combination in the long term, for example, in post-marketing surveillance studies. Moreover, it is important to monitor whether the functional foods and dietary supplements are taken in the recommended amounts to induce significant effects.

Dietary fiber supplements: effects in obesity and metabolic syndrome and relationship to gastrointestinal functions

Dietary fiber is a term that reflects a heterogeneous group of natural food sources, processed grains, and commercial supplements. Several forms of dietary fiber have been used as complementary or alternative agents in the management of manifestations of the metabolic syndrome, including obesity. Not surprisingly, there is a great variation in the biological efficacy of dietary fiber in the metabolic syndrome and body weight control. Diverse factors and mechanisms have been reported as mediators of the effects of dietary fiber on the metabolic syndrome and obesity. Among this array of mechanisms, the modulation of gastric sensorimotor influences appears to be crucial for the effects of dietary fiber but also quite variable. This report focuses on the role, mechanism of action, and benefits of different forms of fiber and supplements on obesity and the metabolic syndrome, glycemia, dyslipidemia, and cardiovascular risk and explores the effects of dietary fiber on gastric sensorimotor function and satiety in mediating these actions of dietary fiber.

Health benefits of dietary fiber

Dietary fiber intake provides many health benefits. However, average fiber intakes for US children and adults are less than half of the recommended levels. Individuals with high intakes of dietary fiber appear to be at significantly lower risk for developing coronary heart disease, stroke, hypertension, diabetes, obesity, and certain gastrointestinal diseases. Increasing fiber intake lowers blood pressure and serum cholesterol levels. Increased intake of soluble fiber improves glycemia and insulin sensitivity in non-diabetic and diabetic individuals. Fiber supplementation in obese individuals significantly enhances weight loss. Increased fiber intake benefits a number of gastrointestinal disorders including the following: gastroesophageal reflux disease, duodenal ulcer, diverticulitis, constipation, and hemorrhoids. Prebiotic fibers appear to enhance immune function. Dietary fiber intake provides similar benefits for children as for adults. The recommended dietary fiber intakes for children and adults are 14 g/1000 kcal. More effective communication and consumer education is required to enhance fiber consumption from foods or supplements.

Removal of chromium (VI) using poly(methylacrylate) functionalized guar gum

Using persulfate/ascorbic acid redox pair, poly(methylacrylate) was grafted on to guar gum and the conditions for the grafting were optimized. The copolymer sample having maximum %G was evaluated for the removal of Cr(VI) and the sorption conditions were optimized. The sorption was found pH dependent, pH 1.0 being the optimum value. Sorption data at pH 1.0 were modeled using both the Langmuir and Freundlich isotherms where the data fitted better to Freundlich isotherm. The equilibrium sorption capacity of 29.67mg/g was determined from the Langmuir isotherm. The sorption followed a pseudo-second-order kinetics with a rate constant 2.5x10(-4)gmg(-1) min(-1). The grafted product was also evaluated for Cr(VI) removal from local electroplating industrial waste water. The regeneration experiments revealed that the guar-graft-poly(methylacrylate) could be successfully reused for five cycles. In the present study conductivity measurements were used instead of conventional photometric method for determining Cr(VI) concentration in the equilibrium solutions and the results obtained have been compared with photometric method. Optimum Cr(VI) binding under highly acidic conditions indicated significant contribution of non electrostatic forces in the adsorption process.

Guar gum and similar soluble fibers in the regulation of cholesterol metabolism: current understandings and future research priorities

The hypocholesterolemic effects associated with soluble fiber consumption are clear from animal model and human clinical investigations. Moreover, the modulation of whole-body cholesterol metabolism in response to dietary fiber consumption, including intestinal cholesterol absorption and fecal sterol and bile acid loss, has been the subject of many published reports. However, our understanding of how dietary fibers regulate molecular events at the gene/protein level and alter cellular cholesterol metabolism is limited. The modern emphasis on molecular nutrition and rapid progress in 'high-dimensional' biological techniques will permit further explorations of the role of genetic polymorphisms in determining the variable interindividual responses to soluble fibers. Furthermore, with traditional molecular biology tools and the application of 'omic' technology, specific insight into how fibers modulate the expression of genes and proteins that regulate intestinal cholesterol absorption and alter hepatic sterol balance will be gained. Detailed knowledge of the molecular mechanisms by which soluble fibers reduce plasma cholesterol concentrations is paramount to developing novel fiber-based "cocktails" that target specific metabolic pathways to gain maximal cholesterol reductions.

Effect of Shilianhua extract and its fractions on body weight of obese mice

Five commercial botanical products (Shilianhua [SLH] tablets, Shiu Huo pills, Fenulyn, Bitter Melon, and Glucose Metabolic Support), available in the US market, with reported claims for regulation of metabolism were screened for their effect on body weight gain in high-fat diet-induced obese mice. Pilot results suggested that SLH tablets attenuated body weight gain, whereas Shiu Huo pills and Fenulyn tended to promote weight gain in the mice on the high-fat diet. To investigate the bioactive components in the SLH tablet, the wild SLH plant (Sinocrassula indica Berge) was collected from China and used to make a variety of extracts including aqueous extract, ethanol extract (SLH-E), and subfraction F100. In the study of metabolic activities, the extracts were administrated through food intake by incorporating them into the diet. A rigorous evaluation of the extracts on body weight was conducted in 2 animal models. The aqueous extract and SLH-E were tested in dietary obese mice, while F100 together with SLH-E was tested in KK-Ay mice, a genetic diabetic model. In the 12- to 16-week study, body weight was not significantly altered by the SLH extracts in the 2 animal models. The results suggest that neither the total extract nor the purified components from the SLH plant have a clear effect in the regulation of body weight. The weight reduction observed with the over-the-counter SLH tablet in the pilot studies may be secondary to other components in the tablet, but not from the SLH extract.

Dietary Fiber and the Relationship to Chronic Diseases

Preventative medicine is targeting chronic diseases such as heart disease, cancer, diabetes, and obesity. Populations that consume more dietary fiber have less chronic disease. Intake of dietary fiber has beneficial effects on the risk factors for developing several chronic diseases. Dietary reference intakes recommend the consumption of 14 g of dietary fiber per 1000 kcal, or 25 g for women and 38 g for men, based on the goal of protection against cardiovascular disease. Usual intake of dietary fiber is only 16 g per day. Viscous fibers decrease the glycemic response and may assist in diabetes care. High-fiber diets provide bulk, are more satiating, and have been linked to lower body weights. Evidence that fiber decreases cancer is mixed, and further research is needed. Dietary messages to increase consumption of high-fiber foods such as whole grains, legumes, fruits, and vegetables should be broadly supported by the medical profession. Consumers are also turning to fiber supplements and bulk laxatives as additional fiber sources. As many fiber supplements have not been studied for physiological effectiveness, the best advice is to consume fiber in foods.