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

Recent updates on guar gum derivatives in colon specific drug delivery

Colon specific delivery of therapeutics have gained much attention of pharmaceutical researchers in the recent past. Colonic specific targeting of drugs is used not only for facilitating absorption of protein or peptide drugs, but also localization of therapeutic agents in colon to treat several colonic disorders. Among various biopolymers, guar gum (GG) exhibits pH dependent swelling, which allows colon specific release of drug. GG also shows microbial degradation in the colonic environment which makes it a suitable excipient for developing colon specific drug delivery systems. The uncontrolled swelling and hydration of GG can be controlled by structural modification or by grafting with another polymeric moiety. Several graft copolymerized guar gum derivatives are investigated for colon targeting of drugs. The efficacy of various guar gum derivatives are evaluated for colon specific delivery of drugs. The reviewed literature evidenced the potentiality of guar gum in localizing drugs in the colonic environment. This review focuses on the synthesis of several guar gum derivatives and their application in developing various colon specific drug delivery systems including matrix tablets, coated formulations, nano or microparticulate delivery systems and hydrogels.

Jatobá-do-cerrado (Hymenaea stigonocarpa Mart.) pulp positively affects plasma and hepatic lipids and increases short-chain fatty acid production in hamsters fed a hypercholesterolemic diet

This study aimed to assess the impact of jatobá pulp, in its fresh (FJ) and extruded (EJ) forms, on lipid metabolism and intestinal fermentation parameters in hamsters. In a 21-day experiment, we determined the parameters of the animal lipid metabolism and colonic production of short chain fatty acids in four different groups. Control (C), fresh pulp (FJ) and extruded pulp (EJ) were fed using hypercholesterolemic diets, and the reference (R) was fed using AIN93 meal. R and C diets contained cellulose, FJ and EJ were added by jatobá pulp as a fiber source. The results showed that FJ and EJ exhibited lower levels of triglycerides, total cholesterol, LDL-c, non-HDL-c serum levels, liver lipids, and liver weight compared to C. The EJ had higher bile acid excretion in stool than the C. EJ and FJ exhibited lower excreted fiber compared to R and C, implying greater fermentation. Furthermore, the production of short-chain fatty acids (SCFA) in the cecum of FJ and EJ animals exceeded that of the C. Acetic and propionic acids were more abundant in the FJ and EJ diets, with FJ producing more butyric acid than the other groups.In conclusion, jatobá pulp maintained at normal levels of total cholesterol, LDL and HDL-associated cholesterol, non-HDL cholesterol, and serum triglycerides, while also reducing the accumulation of hepatic lipids. Jatobá also promoted SCFA formation and fermentation, making it a valuable ingredient for preventing chronic diseases.

ITC study on the interaction of some bile salts with tragacanth, Arabic, and guar gums with potential cholesterol-lowering ability

Introduction

The urge of designing new safe and natural functional foods to control blood lipids and dispensable without the need of physician supervision, has increased especially after the coming into effect of the recent EU Commission regulation 2022/860, that regulates the consumption of "red yeast rice," made by fermentation of rice with Monascus purpureus, and perceived as a natural functional food, due to a health risk for frail consumers. The results of the present work are a part of the systematic study we are carrying out of the binding ability of some soluble dietary fibers (SDF) from different natural sources toward selected bile salts (BS).

Methods

Measurements were carried out by isothermal titration calorimetry (ITC) with the idea to shed light on the mechanism, if any, by which they show cholesterol-lowering activity.

Results and discussion

Epidemiological studies are sometimes conflicting and offer only hypothesis about the mechanism of action, the most accredited being the reduction of reabsorption of BS in the gut. Previous measurements done on negatively charged pectin and alginate, showed specific binding interaction with monomer NaDC for pectin and no interaction at all for alginate. Chitosan, positively charged and soluble only at low pH, in 100 mM acetate buffer at pH = 3 shows strong exothermic interactions with NaTC and NaTDC. Here we considered two plant exudates (Arabic gum and tragacanth gum) and guar gum, extracted from guar beans, and their interaction with the same bile salts. ITC measurements do not evidence specific interactions between gums and the studied BS, so that their cholesterol lowering ability, if any, is due to a different mechanism very probably bound to the viscosity increase. Moreover, the addition of NaC, the most abundant BS in the bile, at very low concentration (under the cmc) causes a structural change of the solution. The obtained results seem to corroborate the hypothesis that the cholesterol lowering activity is related to the increase in viscosity of guar solution favored by NaC, the major component of the bile.

Effects of hydrocolloids as fat-replacers on the physicochemical and structural properties of salt-soluble protein isolated from water-boiled pork meatballs

Konjac glucomannan (KGM), xanthan gum (XG), guar gum (GG), and κ-carrageenan (KC), as substituent, are commonly used in ground pork products. Here, the content of these (0.5, 1.0, 1.5, and 2.0%, w/w) on the gel properties, thermal properties, and interaction forces of salt-soluble protein (SSP) isolated from water-boiled pork meatballs were investigated. We found 1.0% KGM, 0.5% XG, 0.5-2.0% GG, and 0.5-2.0% KC to water-boiled pork meatballs exerted a positive effect on the denaturation temperature, hydrogen bonds, hydrophobic interactions, disulfide bonds, α-helix, and β-sheet content of SSP, as well as the strength and storage modulus of the modified protein gel. The addition of these hydrocolloids with the addition of 1.0% aggregated myosin and actin, led to the enhancement of the bands corresponding to myosin heavy chain and actin. The prediction model of gel strength showed that the gel strength was negatively correlated with Tpeak1, Tpeak2, and ionic bond. This study provides theoretical guidance for improving the application of hydrocolloids in pork-based foods.

The effects of guar gum supplementation on glycemic control, body mass and blood pressure in adults: A GRADE-assessed systematic review and meta-analysis of randomized clinical trials

BACKGROUND

This systematic review and meta-analysis sought to evaluate the effects ofguar gum supplementation on glycemic control, blood pressure, and body mass in adults.

METHODS

Relevant studies were obtained by searching the PubMed, SCOPUS, Embase, and Web of Science databases (from inception to January 2022). Weighted mean differences (WMD) and 95% confidence intervals (CIs) were pooled using a random-effects model. Heterogeneity, sensitivity analysis, and publication bias were reported using standard methods.

RESULTS

Pooled analysis of 14 randomized controlled trials (RCTs) revealed that guar gum supplementation led to significant reductions in hemoglobin A1c (HbA1c) (WMD: -0.47 mg/dL, 95% CI: -0.75, -0.18, p = 0.001). However, there was no effect on fasting blood sugar (FBS), systolic and diastolic blood pressure, and body mass among adults in comparison with the control group. A subgroup analysis demonstrated that intervention in patients with type 2 diabetes (T2DM), and high supplementation dosages (>15 g/d) significantly decreased FBS concentrations, but not in other subgroups.

CONCLUSION

Guar gum supplementation may yield a beneficial effect on glycemic control in T2DM patients. However, the extant clinical trials, thus far, are not sufficient enough to form guidelines for clinical practice.

Guar gum-based nanoformulations: Implications for improving drug delivery

Poorly soluble drugs are reported to easily degrade in the gastrointestinal tract and contribute in limiting the effect of drug to its targeted site. Oral administration of drug is one of the prominent ways to deliver a drug, although, it experiences barriers like acidic pH, presence of microflora and enzymes in the gastrointestinal tract. Collectively all of these participate in the degradation of drug before it reaches its target site and thus, they impede the sustained effect of drug. A quest of choosing a polymer with good stability profile and releasing the drug to its targeted site is always been a challenge for the scientists worldwide. Many polymers have been reported to prevent the degradation of drug and one such naturally occurring biocompatible polymer is guar gum. Guar gum-based nanoformulations have been extensively used in past decades to achieve controlled drug release which defines its importance. The coating of guar gum over the drug improves the bioavailability of the drug and thus helps in minimizing the risk of drug degradation. This review intends to highlight the beneficial role of guar gum-based nanoformulations to improve drug delivery by ameliorating the bioavailibility.

Effect of partially hydrolyzed guar gum on the composition and metabolic function of the intestinal flora of healthy mice

Partially hydrolyzed guar gum (PHGG), a water-soluble dietary fiber, has shown beneficial physiological effects in various disease models and is used as a prebiotic to regulate intestinal function. However, its role in healthy states remains unclear. The purpose of this study was to investigate the effects of PHGG on gut flora composition and predict metabolic function in healthy mice. Our study showed that PHGG supplementation had significant duration-dependent effects on the composition and function of the intestinal flora of healthy mice. In specific, although the long-term supplementation of PHGG may increase the abundance of some beneficial bacterial species and promote beneficial phenotypes, it may also cause increased body weight and decreased abundance and diversity of gut microorganisms. Therefore, the long-term use of PHGG as a nutritional product still requires further investigation. PRACTICAL APPLICATIONS: As the importance of the gut microbiota has become more widely recognized, interventions that modulate the microbiome and its interaction with the host have gained much attention. While the capability of some prebiotics has largely been shown to have many beneficial effects, the evidence leaves much desirable, and microbiota regulation is explored differently in healthy or diseased states. Currently, the scientific community and regulatory authorities are beginning to pay attention to these unregulated and over-the-counter products claiming to possess probiotic and prebiotic properties. Studies exploring the rationality of these prebiotics as nutraceuticals for use in health states are essential. This study focuses on the effects of PHGG, a prebiotic, on intestinal flora, metabolism, and function when used in a healthy state over a long period. It is helpful to have a clearer understanding of the effect of PHGG on intestinal flora and the possible mechanisms of action to exert effects, which are indicative for the future application of PHGG as a nutraceutical or therapeutic agent..

Effects of Different Viscous Guar Gums on Growth, Apparent Nutrient Digestibility, Intestinal Development and Morphology in Juvenile Largemouth Bass, Micropterus salmoides

An 8-week feeding trial was conducted to investigate the effects of different viscous guar gums on the growth performance, apparent nutrient digestibility, intestinal development and morphology of juvenile largemouth bass. Four isoproteic and isolipidic diets (crude protein 42.5%, crude lipid 13.7%) were formulated to contain 8% cellulose (Control group), 8% low viscous guar gum with 2,500 mPa s (Lvs-GG group), 8% medium viscous guar gum with 5,200 mPa s (Mvs-GG group) and 8% high viscous guar gum with 6,000 mPa s (Hvs-GG group), respectively. Each diet was fed to quadruplicate groups of 40 fish (6.00 ± 0.01 g) per repetition. Dietary guar gum inclusion significantly decreased the weight gain rate, specific growth rate, protein efficiency ratio, protein productive value and lipid deposition rate, and these parameters decreased considerably with increasing guar gum viscous and were lowest in the Hvs-GG group. Dietary guar gum inclusion significantly decreased the apparent digestibility of dry matter, crude protein and crude lipid, and these parameters decreased considerably with increasing guar gum viscous and were lowest in the Hvs-GG group. Intestinal protease, lipase and creatine kinase activities in the guar gum groups were significantly lower than those in the control group, and intestinal protease and lipase activities decreased considerably with increased guar gum viscous. Intestinal alkaline phosphatase activity in the Hvs-GG group and intestinal Na⁺/K⁺-ATPase activity in the Mvs-GG and Hvs-GG groups were significantly lower than those in the Lvs-GG and control groups. Serum high-density lipoprotein, total cholesterol and triglyceride concentrations and superoxide dismutase activity in the guar gum groups were significantly lower than those in the control group. Intestinal villus height and muscular thickness in the guar gum groups were considerably higher than those in the control group, whereas the goblet cell relative number in the Mvs-GG and Hvs-GG groups and the microvillus height in the Lvs-GG and Hvs-GG groups were significantly lower than those in the control group. The expression level of IGF-1 in the guar gum groups and the expression level of GLP-2 in the Mvs-GG and Hvs-GG groups were significantly higher than those in the control group. These results indicated that guar gum diets adversely affected intestinal morphology, decreased intestinal digestive and absorptive enzyme activities, and caused poor nutrient digestibility and growth performance in juvenile largemouth bass. Moreover, the adverse effects of guar gum are closely related to its viscous, and high viscous guar gum produces more extreme negative impacts on juvenile largemouth bass.

The Impact of Waxy Wheat Flour, Inulin and Guar Gum on Post-Prandial Glycaemic and Satiety Indices, Sensory Attributes and Shelf Life of Tandoori and Pita Breads

The purpose of this study was to develop two different functional breads (Pita and Tandoori) supplemented with novel functional ingredients: waxy wheat flour (15%), inulin (8%) and guar gum (2%) independently and in combination. The breads were submitted to sensory characteristics, shelf life, glycaemic and satiety indices assessments. Both guar gum and inulin independently and in combination significantly (p < 0.05) decreased post-prandial blood glucose and glycemic response of Pita (GI of guar gum bread was 55%, inulin 57%) and Tandoori (GI of guar gum bread was 57% and inulin bread was 60%) compared to the control breads (GI 100%). Moreover, the results of the area under the curve of satiety showed that the addition of functional ingredients increased satiety levels as follows: for Pita, control was 355, a combination of all ingredients was 418, inulin was 451 and guar gum was 452; for Tandoori, control was 329, a combination of all ingredients was 420, inulin was 381 and guar gum was 390. The results showed that all sensory characteristics were improved, and breads were acceptable (all obtained more than five points) when the highest proportions of ingredients were added. Similarly, the shelf life of supplemented Pita and Tandoori breads was improved with the addition of ingredients. Therefore, the functional ingredients such as inulin and guar gum can be used independently and in combination to reduce GI and increase satiety of Pita and Tandoori bread with acceptable quality and shelf life.

Effects of guar gum supplementation on the lipid profile: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Guar gum can be used as an adjuvant in the treatment of dyslipidemia. However, based on data from different studies, the effectiveness of this product is not uniform. Therefore, we conducted a dose-response meta-analysis between guar gum supplementation and lipid profile.

METHODS AND RESULTS

Five databases (Scopus, Web of Science, PubMed/Medline, Embase, and Google Scholar) were searched to identify relevant articles published up to July 2020. The weighted mean difference (WMD) was derived based on the random-effects model. Overall findings were generated from 25 eligible trials. Patients' conditions included hyperlipidemia, diabetes, metabolic syndrome, hypertension, overweight, carotid endarterectomy, and menopausal women. Prescribed gum dose varied between 100 mg/d and 30 g/d for 1-24 months. Compared with control groups, guar gum supplementation decreased total cholesterol (TC) by -20.41 mg/dL (95% CI: -26.76 to -14.07; P < 0.001) and low-density lipoprotein-cholesterol (LDL-C) by -17.37 mg/dL (95% CI: -23.60 to -11.13; P < 0.001), but did not change triglycerides (TG) (WMD: -6.53 mg/dL, 95% CI: -16.03 to 2.97; P = 0.178) and high-density lipoprotein-cholesterol (HDL-C) (WMD: -0.62 mg/dL, 95% CI: -1.68 to 0.44, P = 0.252).

CONCLUSIONS

Guar gum supplementation significantly reduced serum LDL-C and TC levels in patients with cardiometabolic problems, but had neutral effects on TG and HDL-C levels.

Guar (Cyamopsis tetragonoloba L.) plant gum: From biological applications to advanced nanomedicine

Natural polymers are an efficient class of eco-friendly and biodegradable polymers, because they are readily available, come from natural sources, inexpensive and can be chemically modified with the correct reagents. Guar gum (GG) is a natural polymer with great potential to be used in pharmaceutical formulations due to its unique composition and lack of toxicity. GG can be designed to suit the needs of the biological and medical engineering sectors. In the development of innovative drug delivery systems, GG is commonly utilized as a rate-controlling excipient. In this review, different properties of GG including chemical composition, extraction methods and its usefulness in diabetes, cholesterol lowering, weight control, tablet formulations as well as its food application were discussed. The other purpose of this study is to evaluate potential use of GG and its derivatives for advanced nanomedicine such as drug delivery, tissue engineering and nanosensing. It should be noted that some applicable patents in medical area have also been included in the rest of this survey to extend knowledge about guar gum and its polymeric nature.

Soluble Dietary Fiber Significance against Obesity in a Western China Population

Objectives

This study aimed to investigate whether soluble dietary fibers (SDFs) could protect against obesity by influencing weight, body mass index (BMI), body fat rate (BFR), visceral fat rate (VFR), or waistline.

Methods

We examined obese adult patients from western China at 0 and 3 weeks after an SDF diet. Index assessments of obesity including height, weight, BMI, BFR, VFR, and waistline were carried out. We used the Mann-Whitney U test to examine the difference between the usual diet and the SDF group.

Results

Weight, BMI, BFR, and waistline were reduced in both the control group and the SDF group (P < 0.001). The reduction of the four indices in the SDF group was significantly higher than in the control group (P < 0.001). Higher intake of various SDFs has significantly reduced the weight, BMI, BFR, and waistline than the usual diet group in obesity.

Conclusion

Our results indicated that increased intake of SDFs in the diet of obese patients would protect against obesity in the first 3 weeks.

The effect of guar gum consumption on the lipid profile in type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials

Dyslipidemia is a common encounter in type 2 diabetes mellitus (T2DM) and the current strategies to manage it are still suboptimal. Subsequently, identifying newer molecules with lipid-lowering effects is necessary. A great deal of attention has been given in recent years to fiber supplements, e.g., guar gum. Thus, we screened and evaluated the quality of the evidence regarding the benefits of guar gum supplementation in T2DM and conducted a meta-analysis to assess the effects of this compound on serum lipids in T2DM. We conducted a comprehensive search in PubMed/Medline, Web of Science, Scopus, Google Scholar and Embase, from the inception of these databases until January 2021. In total, 11 papers were included based on the eligible criteria in our meta-analysis. The meta-analysis of the eligible trials demonstrated a significant reduction of total cholesterol (TC) (WMD: -20.32 mg/dL, 95% CI: -27.02, -13.62, P < 0.001) and low-density lipoprotein cholesterol (LDL-C) (WMD: -14.52 mg/dL, 95% CI: -20.69, -8.35, P < 0.001) following guar gum supplementation in T2DM patients. The subgroup analysis based on the dosage (g/day) of this compound revealed that ≥20 g/day of guar gum led to a notable decrease in triglyceride (TG) levels (WMD: -12.55 mg/dL, 95% CI: -23.72, -1.37, P = 0.02) versus < 20 g/day (WMD: -1.84 mg/dL, 95% CI: -32.18, 28.49, P = 0.90). Guar gum supplementation had no effects on high-density lipoprotein cholesterol (HDL-C) (WMD: 0.66 mg/dL, 95% CI: -0.95, 2.28, P = 0.42). Guar gum consumption has lipid-lowering effects when administered to patients with type 2 diabetes mellitus and it is particularly able to reduce TC, LDL-C and TG levels. Further research is however needed to confirm our findings.

Effects of three different mannans on obesity and gut microbiota in high-fat diet-fed C57BL/6J mice

To compare the effects of three mannans, Konjac glucomannan (KGM), guar gum (GG) and locust bean gum (LBG), on obesity and obesity-related metabolic disorders in mice fed with high-fat diet (HFD), and to investigate the potential modulation of gut microbiota, we performed a 14 week study on C57BL/6J mice fed a HFD with/without mannan supplementation. The results showed that supplementing 8% KGM, GG, and LBG to a HFD dramatically reduced the body weight gain and adipose accumulation, attenuated liver injury, and antagonized glycolipid metabolism and inflammation-related parameters of HFD-fed mice in different degrees. However, only LBG had such roles when the supplement dose was reduced to 2%. In addition, it was found that LBG required more time to exert its impacts on weight control and lipid metabolism. Furthermore, 16S rRNA gene sequencing of gut microbiota indicated that mannans with different structures and supplement doses affected the overall structure of the gut microbiota to a varying extent and specifically changed the abundance of some OTUs. Moreover, several OTUs belonging to the genera Muribaculum, Staphylococcus, [Eubacterium] fissicatena group, and Christensenella had a high correlation with obesity and obesity-related metabolic disorders of the host. In summary, all the three mannans had the potential to be used as alternative dietary supplements or functional foods to prevent obesity and obesity-related metabolic disorders induced by a HFD, but the effects of the dose and time varied, and the functions of the mannans were associated with their ability to regulate the gut microbiota.

Current Evidence to Propose Different Food Supplements for Weight Loss: A Comprehensive Review

The use of food supplements for weight loss purposes has rapidly gained popularity as the prevalence of obesity increases. Navigating through the vast, often low quality, literature available is challenging, as is providing informed advice to those asking for it. Herein, we provide a comprehensive literature revision focusing on most currently marketed dietary supplements claimed to favor weight loss, classifying them by their purported mechanism of action. We conclude by proposing a combination of supplements most supported by current evidence, that leverages all mechanisms of action possibly leading to a synergistic effect and greater weight loss in the foreseen absence of adverse events. Further studies will be needed to confirm the weight loss and metabolic improvement that may be obtained through the use of the proposed combination.

SCFAs-Induced GLP-1 Secretion Links the Regulation of Gut Microbiome on Hepatic Lipogenesis in Chickens

The impact of gut microbiota and its metabolites on fat metabolism have been widely reported in human and animals. However, the critical mediators and the signal transductions are not well demonstrated. As ovipara, chicken represents a specific case in lipid metabolism that liver is the main site of lipid synthesis. The aim of this study is to elucidate the linkage of gut microbiota and fat synthesis in broiler chickens. The broilers were subjected to dietary treatments of combined probiotics (Animal bifidobacterium: 4 × 10⁸ cfu/kg; Lactobacillus plantarum: 2 × 10⁸ cfu/kg; Enterococcus faecalis: 2 × 10⁸ cfu/kg; Clostridium butyrate: 2 × 10⁸ cfu/kg, PB) and guar gum (1 g/kg, GG), respectively. Results showed that dietary supplementation of PB and GG changed the cecal microbiota diversity, altered short chain fatty acids (SCFAs) contents, and suppressed lipogenesis. In intestinal epithelial cells (IECs), SCFAs (acetate, propionate, and butyrate) up-regulated the expression of glucagon-like peptide-1 (GLP-1) via mitogen-activated protein kinase (MAPK) pathways, mainly via the phospho - extracellular regulated protein kinase (ERK) and phospho-p38 mitogen activated protein kinase (p38 MAPK) pathways. GLP-1 suppressed lipid accumulation in primary hepatocytes with the involvement of (AMP)-activated protein kinase/Acetyl CoA carboxylase (AMPK/ACC) signaling. In conclusion, the result suggests that SCFAs-induced GLP-1 secretion via MAPK pathway, which links the regulation of gut microbiota on hepatic lipogenesis in chickens.

Nutritionist and obesity: brief overview on efficacy, safety, and drug interactions of the main weight-loss dietary supplements

Over the past 20 years the use of dietary supplements as adjuvant therapy for weight loss gained growing favor among consumers and dietician-nutritionists, with the subsequent astounding increase in health costs. Despite the reassuring label of natural remedy for losing weight, dietary supplements contain a wide variety of ingredients on which available information is rather scanty and scientifically incomplete. Currently, there is little evidence that weight-loss supplements offer effective aids to reduce weight and meet criteria for recommended use. Robust, randomized, placebo-controlled studies to provide clear-cut scientific evidence of their efficacy and potential side effects in clinical practice are still lacking. Understanding the evidence for the efficacy, safety, and quality of these supplements among nutritionists and physicians is critical to counsel patients appropriately, especially considering the risk of serious adverse effects and interference with concomitant therapies. Detailed information on the efficacy and safety of the most commonly used weight-loss dietary supplements has been recently published by the National Institutes of Health (NIH). However, in this report the thorny issue that may result from drug interactions with weight-loss dietary supplements has been not sufficiently addressed. The aim of this review was to provide a synthetic, evidence-based report on efficacy and safety of the most commonly used ingredients in dietary supplements marketed for weight loss, particularly focusing on their possible drug interactions.

Impact of molecular interactions with phenolic compounds on food polysaccharides functionality

Commercial trends based of the emergence of plant-based functional foods lead to investigate the structure-function relationship of their main bioactive constituents and their interactions in the food matrix and throughout the gastro-intestinal tract. Among these bioactive constituents, dietary polysaccharides and polyphenols have shown to interact at the molecular level and these interactions may have consequences on the polysaccharides physical and nutritional properties. The methods of investigation and mechanisms of interactions between polysaccharides and polyphenols are reviewed in light of their respective technological and nutritional functionalities. Finally, the potential impact of the co-occurrence or co-ingestion of polyphenols and polysaccharides on the technological and nutritional functionality of the polysaccharides are investigated.

Nondigestible carbohydrates, butyrate, and butyrate-producing bacteria

Nondigestible carbohydrates (NDCs) are fermentation substrates in the colon after escaping digestion in the upper gastrointestinal tract. Among NDCs, resistant starch is not hydrolyzed by pancreatic amylases but can be degraded by enzymes produced by large intestinal bacteria, including clostridia, bacteroides, and bifidobacteria. Nonstarch polysaccharides, such as pectin, guar gum, alginate, arabinoxylan, and inulin fructans, and nondigestible oligosaccharides and their derivatives, can also be fermented by beneficial bacteria in the large intestine. Butyrate is one of the most important metabolites produced through gastrointestinal microbial fermentation and functions as a major energy source for colonocytes by directly affecting the growth and differentiation of colonocytes. Moreover, butyrate has various physiological effects, including enhancement of intestinal barrier function and mucosal immunity. In this review, several representative NDCs are introduced, and their chemical components, structures, and physiological functions, including promotion of the proliferation of butyrate-producing bacteria and enhancement of butyrate production, are discussed. We also describe the strategies for achieving directional accumulation of colonic butyrate based on endogenous generation mechanisms.

Identification and characterization of SSR, SNP and InDel molecular markers from RNA-Seq data of guar (Cyamopsis tetragonoloba, L. Taub.) roots

Background

Guar [Cyamopsis tetragonoloba, L. Taub.] is an important industrial crop because of the commercial applications of the galactomannan gum contained in its seeds. Plant breeding programmes based on marker-assisted selection require a rich resource of molecular markers. As limited numbers of such markers are available for guar, molecular breeding programmes have not been undertaken for the genetic improvement of this important crop. Hence, the present work was done to enrich the molecular markers resource of guar by identifying high quality SSR, SNP and InDel markers from the RNA-Seq data of the roots of two guar varieties.

Results

We carried out RNA-Seq analysis of the roots of two guar varieties, namely, RGC-1066 and M-83. A total of 102,479 unigenes with an average length of 1016 bp were assembled from about 30 million high quality pair-end reads generated by an Illumina HiSeq 2500 platform. The assembled unigenes had 86.55% complete and 97.71% partially conserved eukaryotic genes (CEGs). The functional annotation of assembled unigenes using BLASTX against six databases showed that the guar unigenes were most similar to Glycine max. We could assign GO terms to 45,200 unigenes using the UniProt database. The screening of 102,479 unigenes with MISA and SAMtools version 1.4 softwares resulted in the identification of 25,040 high-confidence molecular markers which consisted of 18,792 SSRs, 5999 SNPs and 249 InDels. These markers tagged most of the genes involved in root development, stress tolerance and other general metabolic activities. Each of the 25,040 molecular markers was characterized, particularly with respect to its position in the unigene. For 71% of the molecular markers, we could determine the names, products and functions of the unigenes. About 80% of the markers, from a random sample of molecular markers, showed PCR amplification.

Conclusions

We have identified and characterized 25,040 high confidence SSR, SNP and InDel molecular markers in guar. It is expected that these markers will be useful in molecular breeding programmes and will also be helpful in studying molecular mechanisms of root development, stress tolerance and gum synthesis in guar.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5205-9) contains supplementary material, which is available to authorized users.

A proof-of-concept study to evaluate the efficacy and safety of BTI320 on post-prandial hyperglycaemia in Chinese subjects with pre-diabetes

BACKGROUND

Galactomannan(s) are plant-derived fiber shown to reduce post-prandial blood glucose by delaying intestinal absorption of carbohydrates and slowing down gastric emptying. We examined glucose-lowering effects of BTI320, a propriety fractionated mannan(s) administered as a chewable tablet before meal in a proof-of-concept study in Chinese subjects with prediabetes.

METHODS

Sixty Chinese adults aged 18-70 years with either impaired fasting glucose, impaired glucose tolerance, or glycated haemoglobin 5.7-6.4% (39-46 mmol/mol), were randomly assigned in 2:2:1 ratio to either BTI320 8 g (high dose), BTI320 4 g (low dose) or matching-placebo three times daily before meal for 16 weeks. The primary endpoint was change in fructosamine in subjects treated with BTI320 compared with placebo from baseline to week 4. Indices of glycaemic variability based on continuous glucose monitoring (CGM) and standard meal tolerance test were explored in secondary analyses.

RESULTS

Of 60 subjects randomized, 3 subjects discontinued study treatment prematurely. In intention-to-treat analysis, no significant differences in change in serum fructosamine between low or high dose BTI320 and placebo were observed. Using random effect models, adjusted for variability by meals, treatment with low dose BTI320 was associated with reduction in 1-h (p < 0.01), 2-h (p = 0.01) and 3-h (p = 0.02) post-prandial incremental glucose area-under-curve and post-meal maximum glucose (p = 0.03) compared with placebo. Subjects receiving low dose BTI320 had greater body weight reduction than placebo group.

CONCLUSIONS

BTI320 did not change fructosamine levels compared with placebo. BTI320 reduced glycaemic variability based on CGM indices.

TRIAL REGISTRATION

The study was registered at www.clinicaltrials.gov , reference number NCT02358668 (9 February 2015).

Effects of Fiber Purified Extract of Carob Fruit on Fat Digestion and Postprandial Lipemia in Healthy Rats

Increased postprandial lipemia is a cardiovascular disease (CVD) risk factor. Carob fruit extract (CFE) contains condensed tannins, and their intake has been inversely related to CVD. The objective was to evaluate the in vitro pancreatic lipase activity in the presence of CFE and the in vivo effect of CFE on postprandial lipemia of healthy Wistar rats in acute and subchronic digestibility studies and to relate it with changes in fat digestion and absorption. CFE significantly reduced pancreatic lipase activity. A peak delay and a dose-dependent decrease in plasma triglyceride and cholesterol areas under the curve were observed, effects that increased after the subchronic treatment. The levels of nondigested, nonabsorbed triglycerides of the remaining intestinal lumen fat were significantly higher in the maximum dose of CFE administrated versus the control ( P < 0.05). This study demonstrates for the first time the hypolipemic properties of CFE from the first administration, modifying postprandial lipemia by reducing the extents of fat digestion and absorption.

Marine polysaccharides attenuate metabolic syndrome by fermentation products and altering gut microbiota: An overview

Marine polysaccharides (MPs), including plant, animal, and microbial-derived polysaccharides, can alleviate metabolic syndrome (MetS) by different regulation mechanisms. MPs and their derivatives can attenuate MetS by vary cellular signal pathways, such as peroxisome proliferator-activated receptor, 5' adenosine monophosphate-activated protein kinase, and CCAAT/enhancer binding protein-α. Also, most of MPs cannot be degraded by human innate enzymes, but they can be degraded and fermented by human gut microbiota. The final metabolic products of these polysaccharides are usually short-chain fatty acids (SCFAs), which can change the gut microbiota ecology by altering the existing percentage of special microorganisms. In addition, the SCFAs and changed gut microbiota can regulate enteroendocrine hormone secretion, blood glucose, lipid metabolism levels, and other MetS symptoms. Here, we summarize the up-to-date findings on the effects of MPs, particularly marine microbial-derived polysaccharides, and their metabolites on attenuating MetS.

Partially hydrolyzed guar gum as a potential prebiotic source

Guar galactomannan was enzymatically hydrolyzed to obtain partially hydrolyzed guar gum which can be utilized as prebiotic source. In present study, growth of probiotics (Lactic Acid Bacteria strains) were studied with glucose, partially hydrolyzed guar gum and native guar gum. All the six strains were galactose &/or mannose positive using the API CHl 50 test. Almost all these strains showed an ability to assimilate partially hydrolyzed guar gum with respect to increase in optical density and viable cell count with concomitant decrease in the pH of the growth medium. Streptococcus thermophilus MD2 exhibited higher growth (7.78 log cfu/ml) while P. parvulus AI1 showed comparatively less growth (7.24 log cfu/ml) as compared to used lactobacillus and Weissella strains. Outcomes of the current study suggest that partially hydrolyzed guar can be considered as potential prebiotic compound that may further stimulate the growth of potentially probiotic bacteria or native gut microflora.

Effects of isolated soluble fiber supplementation on body weight, glycemia, and insulinemia in adults with overweight and obesity: a systematic review and meta-analysis of randomized controlled trials

Background: There is strong epidemiologic evidence that dietary fiber intake is protective against overweight and obesity; however, results of intervention studies have been mixed. Soluble fiber beneficially affects metabolism, and fiber supplementation may be a feasible approach to improve body composition and glycemia in adults with overweight and obesity.Objective: We evaluated randomized controlled trials (RCTs) of isolated soluble fiber supplementation in overweight and obese adults on outcomes related to weight management [body mass index (BMI; in kg/m²), body weight, percentage of body fat, and waist circumference] and glucose and insulin metabolism (homeostasis model assessment of insulin resistance and fasting insulin) through a systematic review and meta-analysis.Design: We searched PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature and Cochrane Library databases. Eligible studies were RCTs that compared isolated soluble fiber with placebo treatments without energy-restriction protocols. Random-effects models were used to estimate pooled effect sizes and 95% CIs. Meta-regressions were performed to assess outcomes in relation to the intervention duration, fiber dose, and fiber type. Publication bias was assessed via Begg's and Egger's tests and funnel plot inspection.Results: Findings from 12 RCTs (n = 609 participants) from 2 to 17 wk of duration are summarized in this review. Soluble fiber supplementation reduced BMI by 0.84 (95% CI: -1.35, -0.32; P = 0.001), body weight by 2.52 kg (95% CI: -4.25, -0.79 kg; P = 0.004), body fat by 0.41% (95% CI: -0.58%, -0.24%; P < 0.001), fasting glucose by 0.17 mmol/L (95% CI: -0.28, -0.06 mmol/L; P = 0.002), and fasting insulin by 15.88 pmol/L (95% CI: -29.05, -2.71 pmol/L; P = 0.02) compared with the effects of placebo treatments. No publication bias was identified. Considerable between-study heterogeneity was observed for most outcomes.Conclusions: Isolated soluble fiber supplementation improves anthropometric and metabolic outcomes in overweight and obese adults, thereby indicating that supplementation may improve fiber intake and health in these individuals. However, the interpretation of these findings warrants caution because of the considerable between-study heterogeneity. This trial was registered at clinicaltrials.gov as NCT03003897.

High Quality Unigenes and Microsatellite Markers from Tissue Specific Transcriptome and Development of a Database in Clusterbean (Cyamopsis tetragonoloba, L. Taub)

Clusterbean (Cyamopsis tetragonoloba L. Taub), is an important industrial, vegetable and forage crop. This crop owes its commercial importance to the presence of guar gum (galactomannans) in its endosperm which is used as a lubricant in a range of industries. Despite its relevance to agriculture and industry, genomic resources available in this crop are limited. Therefore, the present study was undertaken to generate RNA-Seq based transcriptome from leaf, shoot, and flower tissues. A total of 145 million high quality Illumina reads were assembled using Trinity into 127,706 transcripts and 48,007 non-redundant high quality (HQ) unigenes. We annotated 79% unigenes against Plant Genes from the National Center for Biotechnology Information (NCBI), Swiss-Prot, Pfam, gene ontology (GO) and KEGG databases. Among the annotated unigenes, 30,020 were assigned with 116,964 GO terms, 9984 with EC and 6111 with 137 KEGG pathways. At different fragments per kilobase of transcript per millions fragments sequenced (FPKM) levels, genes were found expressed higher in flower tissue followed by shoot and leaf. Additionally, we identified 8687 potential simple sequence repeats (SSRs) with an average frequency of one SSR per 8.75 kb. A total of 28 amplified SSRs in 21 clusterbean genotypes resulted in polymorphism in 13 markers with average polymorphic information content (PIC) of 0.21. We also constructed a database named ‘ClustergeneDB’ for easy retrieval of unigenes and the microsatellite markers. The tissue specific genes identified and the molecular marker resources developed in this study is expected to aid in genetic improvement of clusterbean for its end use.

In Vitro Bile Acid Binding Capacities of Red Leaf Lettuce and Cruciferous Vegetables

In the present study, we tested the bile acid binding capacity of red leaf lettuce, red cabbage, red kale, green kale, and Brussels sprouts through in vitro digestion process by simulating mouth, gastric, and intestinal digestion using six bile acids at physiological pH. Green and red kale exhibited significantly higher (86.5 ± 2.9 and 89.7 ± 0.9%, respectively) bile acid binding capacity compared to the other samples. Further, three different compositions of bile acids were tested to understand the effect on different health conditions. To predict the optimal dose for bile acid binding, we established a logistic relationship between kale dose and bile acid binding capacity. The results indicated that kale showed significantly higher bile acid binding capacity (82.5 ± 2.9% equivalent to 72.06 mg) at 1.5 g sample and remained constant up to 2.5 g. In addition, minimally processed (microwaved 3 min or steamed 8 min) green kale showed significantly enhanced bile acid binding capacity (91.1 ± 0.3 and 90.2 ± 0.7%, respectively) compared to lyophilized kale (85.5 ± 0.24%). Among the six bile acids tested, kale preferentially bound hydrophobic bile acids chenodeoxycholic acid and deoxycholic acid. Therefore, regular consumption of kale, especially minimally processed kale, can help excrete more bile acids and, thus, may lower the risk of hypercholesterolemia.

Thermal and Rheological Properties of the Mucilage from the Fruit of Cordia lutea

In recent years, natural gums and mucilages have been shown to be useful in the food and pharmacological industries. In this study, the mucilage of the fruit of Cordia lueta has been extracted and characterised in order to explore its potential applications. Thermogravimetric tests were used to measure the water content of this natural mucilage. Differential scanning calorimetry allowed assessing thermal transitions and thermal degradation of the samples. Steady flow rheometry was used to measure the viscosity of the samples as a function of the shear rate. Dynamic oscillatory rheometry was used to study the variation of the storage and loss modulus of the mucilage as function of the oscillatory frequency and stress. The results showed that this mucilage is a polysaccharide network that behaves as a pseudoplastic fluid. Its storage modulus is not completely independent from the oscillation frequency. In addition, the stress sweeps showed that C. lutea mucilage has a reversible stress softening behaviour. The findings reported in the present work suggest that this mucilage can be used as a rheology modifier for commercial foods and biomedical materials.

Effects of dietary fibers with high water-binding capacity and swelling capacity on gastrointestinal functions, food intake and body weight in male rats

Objective: The aim of this study was to investigate the effects of supplementation of dietary soluble fibers with high water-binding capacity (WBC) and swelling capacity (SC) on gastrointestinal tract mass, physicochemical properties of digesta, gastrointestinal mean retention time (MRT), body weight, and food intake in male rats. Methods: Thirty-two male Sprague-Dawley rats were randomized to four equal groups and fed the control diet or diet containing 2% konjac flour (KF), pregelatinized waxy maize starch plus guar gum (PWMS+GG), andPWMS plus xanthan gum (PWMS+XG) for three weeks. Results: WBC and SC of diets followed the order of PWMS+GG > KF > PWMS + XG > control. PWMS+GG and KF groups had a lower average daily food intake than the control group, but all the groups showed no difference in final body weightand the weight gain rate. The high WBC and SC of the PWMS+GG and KF groupsled to an increase of WBC and SC in the stomach digesta, and a gain of the cecal digesta weight, due to increased cecal moisture content. Conclusion: The inclusion of the novel fiber, PWMS+GG, in the diet of male rats appears to facilitate the modulation of WBC and SC of stomach digesta and the reduction of food intake.

Effect of guar gum on stability and physical properties of orange juice

The objective of current study was to determine the stability and physical properties of orange juice which was added with guar gum. The optimal formulation showed good stability and physical properties, in light of better indices on the serum cloudiness (turbidity), sensory analysis, particle size distribution, aroma concentration analysis and rheological properties. By serum cloudiness (turbidity), the viscosity of optimal guar gum used in orange juice was 584mpas; by the other four methods, the optimal formulation was determined: 0.1% guar gum (584mpas) combined with 0.03% carboxymethyl cellulose (CMC). The results indicated that the guar gum can be used to partially replaced CMC and improve the stability and physical properties of orange juice.

RNA-Seq of Guar (Cyamopsis tetragonoloba, L. Taub.) Leaves: De novo Transcriptome Assembly, Functional Annotation and Development of Genomic Resources

Genetic improvement in industrially important guar (Cyamopsis tetragonoloba, L. Taub.) crop has been hindered due to the lack of sufficient genomic or transcriptomic resources. In this study, RNA-Seq technology was employed to characterize the transcriptome of leaf tissues from two guar varieties, namely, M-83 and RGC-1066. Approximately 30 million high-quality pair-end reads of each variety generated by Illumina HiSeq platform were used for de novo assembly by Trinity program. A total of 62,146 non-redundant unigenes with an average length of 679 bp were obtained. The quality assessment of assembled unigenes revealed 87.50% of complete and 97.18% partial core eukaryotic genes (CEGs). Sequence similarity analyses and annotation of the unigenes against non-redundant protein (Nr) and Gene Ontology (GO) databases identified 175,882 GO annotations. A total of 11,308 guar unigenes were annotated with various enzyme codes (EC) and categorized in six categories with 55 subclasses. The annotation of biochemical pathways resulted in a total of 11,971 unigenes assigned with 145 KEGG maps and 1759 enzyme codes. The species distribution analysis of the unigenes showed highest similarity with Glycine max genes. A total of 5773 potential simple sequence repeats (SSRs) and 3594 high-quality single nucleotide polymorphisms (SNPs) were identified. Out of 20 randomly selected SSRs for wet laboratory validation, 13 showed consistent PCR amplification in both guar varieties. In silico studies identified 145 polymorphic SSR markers in two varieties. To the best of our knowledge, this is the first report on transcriptome analysis and SNPs identification in guar till date.

The Effectiveness of a Bioactive Food Compound in the Lipid Control of Individuals with HIV/AIDS

Cardiovascular events due to decompensated lipid metabolism are commonly found in Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) patients using anti-retroviral therapy (HAART). Thus, the aim of this study was to identify the effect of a bioactive food compound (BFC) containing functional foods on individuals with HIV undergoing HAART. Particularly, this study aims to verify the clinical outcome in the change of the lipid profile due to the use of this compound. This study includes 115 individuals with HIV on HAART. All patients received dietary guidelines; however, sixty-one consumed BFC while fifty-one did not (NO BFC). Biochemical examinations and socio-demographic and clinical profiles were evaluated. As result, in patients using hypolipidemic and/or hypoglycemic drugs, there was 28.6% decrease in triglyceride levels (p < 0.001) in the NO BFC group, and 18.3% reduction in low density lipoprotein cholesterol (LDL-C) (p < 0.001) in the BFC group. In patients who did not use hypolipidemic and/or hypoglycemic drugs in the NO BFC group, there was 30.6% increase in triglycerides, 11.3% total cholesterol and 15.3% LDL-C levels (p < 0.001) while for the BFC group there was 4.5% reduction in total cholesterol (p < 0.001). In conclusion, this study evidenced that the dietary intervention containing BFC positively affected in lipid control, since these HIV/AIDS patients using HAART are more vulnerable to lipid disorders.

Application of guar-xanthan gum mixture as a partial fat replacer in meat emulsions

The physicochemical, oxidative, texture and microstructure properties were evaluated for low fat meat emulsions containing varying levels of guar/xanthan gum mixture (1:1 ratio) as a fat substitute. Partial replacement of fat with guar/xanthan gum resulted in higher emulsion stability and cooking yield but lower penetration force. Proximate composition revealed that high fat control had significantly higher fat and lower moisture content due to the difference in basic formulation. Colour evaluation revealed that low fat formulations containing gum mixture had significantly lower lightness and higher yellowness values than high fat control formulation. However non-significant difference was observed in redness values between low fat formulations and the high fat control. The pH values of the low fat formulations containing gum mixture were lower than the control formulations (T0 and TC). The MetMb% of the high fat emulsion formulation was higher than low fat formulations. The significant increase of TBARS value, protein carbonyl groups and loss of protein sulphydryl groups in high fat formulation reflect the more oxidative degradation of lipids and muscle proteins during the preparation of meat emulsion than low fat formulations. The SEM showed a porous matrix in the treatments containing gum mixture. Thus, the guar/xanthan gum mixture improved the physicochemical and oxidative quality of low fat meat emulsions than the control formulations.

The role of alginates in regulation of food intake and glycemia: a gastroenterological perspective

Regulation of food intake through modulation of gastrointestinal responses to ingested foods is an ever-growing component of the therapeutic approaches targeting the obesity epidemic. Alginates, viscous and gel-forming soluble fibers isolated from the cell wall of brown seaweeds and some bacteria, are recently receiving considerable attention because of their potential role in satiation, satiety, and food intake regulation in the short term. Enhancement of gastric distension, delay of gastric emptying, and attenuation of postprandial glucose responses may constitute the basis of their physiological benefits. Offering physical, chemical, sensorial, and physiological advantages over other viscous and gel-forming fibers, alginates constitute promising functional food ingredients for the food industry. Therefore, the current review explores the role of alginates in food intake and glycemic regulation, their underlying modes of action and their potential in food applications.

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.