Dietary Pulverized Konjac Glucomannan Suppresses Scratching Behavior and Skin Inflammatory Immune Responses in NC/Nga Mice

Respirable konjac glucomannan microparticles as antitubercular drug carriers: Effects of in vitro and in vivo interactions

Pulmonary delivery of drugs is potentially beneficial in the context of lung disease, maximising drug concentrations in the site of action. A recent work proposed spray-dried konjac glucomannan (KGM) microparticles as antitubercular drug (isoniazid and rifabutin) carriers to treat pulmonary tuberculosis. The present work explores in vitro and in vivo effects of these microparticles, focusing on the ability for macrophage uptake, the exhibited antibacterial activity and safety issues. Efficient uptake of KGM microparticles by macrophages was demonstrated in vitro, while the antitubercular activity of the model drugs against Mycobacterium bovis was not affected by microencapsulation in KGM microparticles. Despite the good indications provided by the developed system, KGM is not yet approved for pulmonary applications, which is a limiting characteristic. To reinforce the available data on the performance of the material, safety parameters were evaluated both in vitro and in vivo, showing promising results. No significant cell toxicity was observed at concentrations considered realistic for lung delivery approaches (up to 125 μg/mL) when lung epithelial cells and macrophages were exposed to KGM microparticles (both drug-loaded and unloaded). Finally, no signs of systemic or lung inflammatory response were detected in mice after receiving 10 administrations of unloaded KGM microparticles.

A Poly-D-Mannose Synthesized by a One-Pot Method Exhibits Anti-Biofilm, Antioxidant, and Anti-Inflammatory Properties In Vitro

In this study, D-mannose was used to synthesize poly-D-mannose using a one-pot method. The molecular weight, degree of branching, monosaccharide composition, total sugar content, and infrared spectrum were determined. In addition, we evaluated the safety and bioactivity of poly-D-mannose including anti-pathogen biofilm, antioxidant, and anti-inflammatory activity. The results showed that poly-D-mannose was a mixture of four components with different molecular weights. The molecular weight of the first three components was larger than 410,000 Da, and that of the fourth was 3884 Da. The branching degree of poly-D-mannose was 0.53. The total sugar content was 97.70%, and the monosaccharide was composed only of mannose. The infrared spectra showed that poly-D-mannose possessed characteristic groups of polysaccharides. Poly-D-mannose showed no cytotoxicity or hemolytic activity at the concentration range from 0.125 mg/mL to 8 mg/mL. In addition, poly-D-mannose had the best inhibition effect on Salmonella typhimurium at the concentration of 2 mg/mL (68.0% ± 3.9%). The inhibition effect on Escherichia coli O157:H7 was not obvious, and the biofilm was reduced by 37.6% ± 2.9% at 2 mg/mL. For Staphylococcus aureus and Bacillus cereus, poly-D-mannose had no effect on biofilms at low concentration; however, 2 mg/mL of poly-D-mannose showed inhibition rates of 33.7% ± 6.4% and 47.5% ± 4%, respectively. Poly-D-mannose showed different scavenging ability on free radicals. It showed the best scavenging effect on DPPH, with the highest scavenging rate of 74.0% ± 2.8%, followed by hydroxyl radicals, with the scavenging rate of 36.5% ± 1.6%; the scavenging rates of superoxide anion radicals and ABTS radicals were the lowest, at only 10.1% ± 2.1% and 16.3% ± 0.9%, respectively. In lipopolysaccharide (LPS)-stimulated macrophages, poly-D-mannose decreased the secretion of nitric oxide (NO) and reactive oxygen species (ROS), and down-regulated the expression of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). Therefore, it can be concluded that poly-D-mannose prepared in this research is safe and has certain biological activity. Meanwhile, it provides a new idea for the development of novel prebiotics for food and feed industries or active ingredients used for pharmaceutical production in the future.

Glucomannan as a Dietary Supplement for Treatment of Breast Cancer in a Mouse Model

Konjac glucomannan (KGM) is a water-soluble polysaccharide derived from the Amorphophallus’s tuber and, as herbal medicine has shown, can suppress tumor growth or improve health. However, there has been no investigation into the effects of KGM on breast tumor-bearing mice. Therefore, in two cohort experiments, we assessed the effect of glucomannan at daily doses of 2 and 4 mg for 28 days as a dietary supplement and also glucomannan in combination with tumor lysate vaccine as an adjuvant. Tumor volume was monitored twice weekly. In addition, TNF-α cytokines and granzyme B (Gr–B) release were measured with ELISA kits, and IL-2, IL-4, IL-17, and IFN-γ were used as an index for cytotoxic T lymphocyte activity. Moreover, TGF-β and Foxp3 gene expression were assessed in a real-time PCR test. The results show that glucomannan as a dietary supplement increased the IFN-γ cytokine and Th1 responses to suppress tumor growth. Glucomannan as a dietary supplement at the 4 mg dose increased the IL-4 cytokine response compared to control groups. In addition, cell lysate immunization with 2 or 4 mg of glucomannan suppressed tumor growth. As an adjuvant, glucomannan at both doses showed 41.53% and 52.10% tumor suppression compared with the PBS group. Furthermore, the administration of glucomannan as a dietary supplement or adjuvant reduced regulatory T cell response through decreasing TGF-β and Foxp3 gene expression in the tumor microenvironment. In conclusion, glucomannan as a dietary supplement or adjuvant enhanced the immune responses of tumor-bearing mice and decreased immune response suppression in the tumor milieu, making it a potentially excellent therapeutic agent for lowering breast tumor growth.

A γ-PGA/KGM-based injectable hydrogel as immunoactive and antibacterial wound dressing for skin wound repair

Injectable hydrogels, of which the cover area and volume can be flexibly adjusted according to the shape and depth of the wound, are considered to be an ideal material for wound dressing. Konjac glucomannan (KGM) is a natural polysaccharide with immunomodulatory capability, while γ-polyglutamic acid (γ-PGA) is a single chain polyamino acid with moisturizing, water-retention and antibacterial properties. This work intended to combine the advantages of the two materials to prepare an injectable hydrogel (P-OK) by mixing the adipic acid dihydrazide (ADH) modified γ-PGA with oxidized KGM. The chemical structures, the physical and chemical properties, and the biological properties of the P-OK hydrogel were evaluated. The optimal conditions to form the P-OK hydrogel were fixed, and the cytotoxicity, qPCR, antibacterial and animal experiments were performed. Results showed that the P-OK hydrogel had a fast gelation time, good water-retention rate, little cytotoxicity, good immunomodulating and antibacterial capabilities, and could shorten the healing period in the rat full-thickness defect model, which makes it a potential candidate for wound repair dressing.

A Systematic Review Exploring the Anticancer Activity and Mechanisms of Glucomannan

Glucomannan, long recognized as the active ingredient of the traditional Chinese medicinal herb Konjac glucomannan, is a naturally occurring polysaccharide existing in certain plant species and fungi. Due to its special property to also serve as a dietary supplement, glucomannan has been widely applied in clinic to lower body weight and circulation cholesterol level and to treat constipation, diabetes, and arterial sclerosis. Besides the regulatory role engaged with gastroenterological and metabolic syndrome, recently, its therapeutic effect and the underlying mechanisms in treating cancerous diseases have been appreciated by mounting researches. The present review aims to emphasize the multifaceted aspects of how glucomannan exerts its anti-tumor function.

Health-promoting effects of konjac glucomannan and its practical applications: A critical review

Konjac glucomannan (KGM) is a dietary fiber hydrocolloidal polysaccharide isolated from the tubers of Amorphophallus konjac. Over the last few decades, the purified KGM has been offered as a food additive as well as a dietary supplement in many countries. Also, a diet containing konjac flour or KGM is considered as healthier, and these foods are popular in many Asian and European markets. Further, due to the adhesive property of KGM, it can form a defensive covering on the surface of the intestine. Additionally, KGM can reduce the levels of glucose, cholesterol, triglycerides, and blood pressure and can enable weight loss. Its wide-ranging effects prevent many chronic diseases through the regulation of metabolism. In this review, the recent studies on the health benefits such as anti-diabetic, anti-obesity, laxative, prebiotic, and anti-inflammatory activities of KGM were discussed. Also, this review deals with the applications of KGM and its derivatives in bio-technical, pharmaceutical, tissue engineering, fine chemical fields, etc.

Immunomodulatory Activity of Octenyl Succinic Anhydride Modified Porang (Amorphophallus oncophyllus) Glucomannan on Mouse Macrophage-Like J774.1 Cells and Mouse Primary Peritoneal Macrophages

Porang is a local plant of Indonesia, which has a high content of glucomannan. In this study, porang glucomannan (PG) was esterified with octenyl succinic anhydride (OSA) to enhance emulsion properties to be widely used in food industry. OSA-modified PG (OSA-PG) enhanced the phagocytosis activity of macrophage-like J774.1 cells and mouse peritoneal macrophages. In addition, OSA-PG increased the production of IL-6 and TNF-α by enhancing their gene expression. Immunoblot analysis displayed that OSA-PG tended to activate both nuclear factor-κB and mitogen-activated protein kinase cascades. Treatment of OSA-PG with polymyxin B revealed that cytokine production induced by OSA-PG was not caused by endotoxin contamination. Our findings also indicated that OSA-PG activates macrophages through not only Toll-like receptor (TLR) 4, but another receptor. Overall findings suggested that OSA-PG has a potential as an immunomodulatory food factor by stimulating macrophages.

Re-evaluation of konjac gum (E 425 i) and konjac glucomannan (E 425 ii) as food additives

The present opinion deals with the re-evaluation of konjac (E 425), comprising konjac gum (E 425 i) and konjac glucomannan (E 425 ii) when used as food additives. Following the conceptual framework for the risk assessment of certain food additives re-evaluated under Commission Regulation (EU) No 257/2010, the Panel considered that current use of konjac (E 425) was limited in all food categories to maximum permitted level (MPL) of 10 g/kg, and that the calculated indicative refined exposure assessment for all population groups was below 0.1 mg/kg body weight (bw) per day for the general population (mean and high level). Konjac gum and konjac glucomannan were unlikely to be absorbed intact and were significantly fermented by intestinal microbiota. The available database on toxicological studies was considered limited, however, no relevant adverse effects were seen in rats and dogs in 90-day feeding studies according to the SCF, the no-observed-effect level (NOEL) in rats being 1,250 mg konjac glucomannan/kg bw per day. Konjac gum and konjac glucomannan were of no concern with respect to the genotoxicity. After a daily dosage of 3,000 mg in adults for 12 weeks, several individuals experienced abdominal discomfort including diarrhoea or constipation. The Panel concluded that there was no need for a numerical acceptable daily intake (ADI) and that there was no safety concern for the general population at the refined exposure assessment for the reported uses of konjac gum (E 425 i) and konjac glucomannan (E 425 ii) as food additives under the current conditions of use of 10 g/kg. The Panel agreed with the conclusions of the SCF (1997) that the uses of konjac (E 425) as an additive at the levels up to 10 g/kg in food are acceptable, provided that the total intake from all sources stays below 3 g/day.

Manufacture and Properties of Glucomannans and Glucomannooligosaccharides Derived from Konjac and Other Sources

Glucomannans (GM) are polymers that can be found in natural resources, such as tubers, bulbs, roots, and both hard- and softwoods. In fact, mannan-based polysaccharides represent the largest hemicellulose fraction in softwoods. In addition to their structural functions and their role as energy reserve, they have been assessed for their healthy applications, including their role as new source of prebiotics. This paper summarizes the scientific literature regarding the manufacture and functional properties of GM and their hydrolysis products with a special focus on their prebiotic activity.

Glucomannan- and glucomannan plus spirulina-enriched pork affect liver fatty acid profile, LDL receptor expression and antioxidant status in Zucker fa/fa rats fed atherogenic diets

We evaluated the effects of glucomannan or glucomannan plus spirulina-restructured pork (RP) on liver fatty acid profile, desaturase/elongase enzyme activities and oxidative status of Zucker fa/fa rats for seven weeks. Control (C), glucomannan (G) and glucomannan/spirulina (GS)-RP; HC (cholesterol-enriched control), HG and HGS (cholesterol-enriched glucomannan and glucomannan/spirulina-RP) experimental diets were tested. Increased metabolic syndrome markers were found in C, G and GS rats. Cholesterol feeding increased liver size, fat, and cholesterol and reduced antioxidant enzyme levels and expressions. Cholesterolemia was lower in HG and HGS than in HC. GS vs. G showed higher stearic but lower oleic levels. SFA and PUFA decreased while MUFA increased by cholesterol feeding. The arachidonic/linoleic and docosahexaenoic/alpha-linolenic ratios were lower in HC, HG, and HGS vs. C, G, and GS, respectively, suggesting a delta-6-elongase-desaturase system inhibition. Moreover, cholesterol feeding, mainly in HGS, decreased low-density-lipoprotein receptor expression and the delta-5-desaturase activity and increased the delta-9-desaturase activity. In conclusion, the liver production of highly unsaturated fatty acids was limited to decrease their oxidation in presence of hypercholesterolaemia. Glucomannan or glucomannan/spirulina-RP has added new attributes to their functional properties in meat, partially arresting the negative effects induced by high-fat-high-cholesterol feeding on the liver fatty acid and antioxidant statuses.

Beneficial health characteristics of native and hydrolysed konjac (Amorphophallus konjac) glucomannan

The impact of ingesting glucomannans on health is not limited to colonic-focused fermentation into short-chain fatty acids (SCFAs), which might have some local health benefits; it also helps in treating disease states and enhancing the body's immune system, both within the gut and in/on other parts of the body. The local and systemic roles of hydrolysed glucomannans, especially konjac glucomannans, in the mouth, oesophagus, stomach, small intestine, large intestine, gut-associated lymphoid tissue (GALT), skin and vagina, are highlighted. Therapeutic applications are discussed. © 2015 Society of Chemical Industry.

Konjac glucomannan, a promising polysaccharide of Amorphophallus konjac K. Koch in health care

In recent year, konjac glucomannan (KGM) has attracted more attention due to its non-harmful and non-toxic properties, good biocompatibility, biodegradability and hydrophilic ability. Moreover, KGM and their derivatives have several importances in the multidirectional research areas such as nutritional, biotechnological and fine chemical fields. In the previous article, we have reviewed the nutritional aspects of KGM covering the various aspects of functional foods, food additives and their derivatives. This review aims at highlighting the diverse biomedical research conducted on KGM in the past ten years, covering therapies for anti-obesity, regulation in lipid metabolism, laxative effect, anti-diabetic, anti-inflammatory, prebiotic to wound dressing applications. Moreover, this review deals with global health aspects of KGM and the disparate health related factors associated with diseases and their control measures.

Effects of konjac flour inclusion in gestation diets on the nutrient digestibility, lactation feed intake and reproductive performance of sows

This study was conducted to investigate the effects of konjac flour (KF) inclusion in gestation diets of sows on nutrients digestibility, lactation feed intake, reproductive performance of sows and preweaning performance of piglets. Two isoenergetic and isonitrogenous gestation diets were formulated: a control diet and a 2.1% KF-supplemented diet (KF diet). Both diets had the same NDF and insoluble fiber (ISF) levels, but the KF diet had higher soluble fiber (SF) level. The day after breeding, 96 multiparous sows were assigned to the two dietary treatments. Restrict-fed during gestation, in contrast, all sows were offered the same lactation diet ad libitum. Response criteria included sow BW, backfat depth, lactation feed intake, weaning-to-estrus interval, litter size and piglet's weight at parturition and day 21 of lactation. On day 60 of gestation, 20 sows were used to measure nutrient digestibility. Results showed that the digestibility of dry matter, gross energy, crude fiber and ADF were not affected by the dietary treatments. The inclusion of KF in gestation diets increased NDF digestibility (P<0.05) and tended to increase the digestibility of CP (P=0.05) compared with the control diet group. In addition, dietary treatment during gestation did not affect litter size, BW and backfat gain during gestation, lactation weight, backfat loss or weaning-to-estrus interval of sows. However, sows fed the KF diet consumed more (P<0.05) lactation diet per day than sows in the control group. Accordingly, sows fed the KF diet showed greater average piglet weights on day 21 of lactation (P=0.09), and the litter weight of sows fed the KF diet on day 21 of lactation increased by 3.95 kg compared with sows fed the control diet (not significant). In conclusion, the inclusion of KF in gestation diets increased lactation feed intake of sows and tended to improve litter performance.

Impact of prebiotics and probiotics on skin health

This review discusses the role of pre- and probiotics with respect to improving skin health by modulating the cutaneous microbiota. The skin ecosystem is a complex environment covered with a diverse microbiota community. These are classified as either transient or resident, where some are considered as beneficial, some essentially neutral and others pathogenic or at least have the capacity to be pathogenic. Colonisation varies between different parts of the body due to different environmental factors. Pre- and probiotic beneficial effects can be delivered topically or systemically (by ingestion). The pre- and probiotics have the capacity to optimise, maintain and restore the microbiota of the skin in different ways. Topical applications of probiotic bacteria have a direct effect at the site of application by enhancing the skin natural defence barriers. Probiotics as well as resident bacteria can produce antimicrobial peptides that benefit cutaneous immune responses and eliminate pathogens. In cosmetic formulations, prebiotics can be applied to the skin microbiota directly and increase selectively the activity and growth of beneficial 'normal' skin microbiota. Little is known about the efficacy of topically applied prebiotics. Nutritional products containing prebiotics and/or probiotics have a positive effect on skin by modulating the immune system and by providing therapeutic benefits for atopic diseases. This review underlines the potential use of pre- and probiotics for skin health.

Liver oxidation and inflammation in Fa/Fa rats fed glucomannan/spirulina-surimi

The effect of high-fat squid-surimi diets enriched in glucomannan or glucomannan-spirulina on lipemia, liver glutathione status, antioxidant enzymes and inflammation biomarkers was determined in Zucker Fa/Fa rats. Groups of eight rats each received for 7weeks the squid-surimi control (C), glucomannan-enriched squid-surimi (G) and glucomannan-spirulina enriched squid-surimi (GS). Liver weight, cytochrome P450 7A1 expression and cholesterolemia were decreased in G and GS vs. C, improving glutathione red-ox index (p<0.05). G also showed increased glutathione reductase (GR) levels vs. C, but reduced the endothelial (eNOS) and increased the inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α) levels (p<0.05). The GS diet improved superoxide dismutase, catalase, glutathione peroxidase and GR activities and eNOS, iNOS and TNF-α levels (p<0.05). The glucomannan enriched surimi-diet induced hypocholesterolemic, antioxidant and proinflammatory effects, while the addition of 3g/kg spirulina kept those hypocholesterolemic and antioxidant effects but reduced the inflammation observed.

Development of mechanisms associated with neurogenic-mediated skin inflammation during the growth of rats

Neurogenic-mediated inflammation may be associated with several inflammatory skin diseases including atopic dermatitis. However, age-dependent differences in neurogenic-mediated skin responses are not fully understood. We compared skin plasma leakage in rats aged 2 and 8 wk, which was induced by topical capsaicin, topical formalin, and intracutaneous substance P, whose effects are mediated via tachykinin NK1 receptors. Evans blue dye extravasation served as an index of the increase in skin vascular permeability. Capsaicin, formalin, and substance P caused a skin response in a dose-dependent manner in both age groups. However, the skin response was much greater in adults than in pups. In addition, the localization of sensory C-fibers and tachykinin NK1 receptors in the skin was investigated by immunofluorescent staining with antisubstance P and antitachykinin NK1 receptor antibodies, respectively. Substance P-immunoreactive nerves were detected throughout the dermis and tachykinin NK1 receptors were mainly detected in blood vessel walls in the dermis in both age groups. However, they were more sparsely distributed in pups. In conclusion, the weak neurogenic-mediated skin inflammation in pups is probably because of immature neural mechanisms associated with skin inflammation such as reduced innervation of sensory C-fibers and low expression of tachykinin NK1 receptors.

Traditional uses and potential health benefits of Amorphophallus konjac K. Koch ex N.E.Br

Amorphophallus konjac (konjac) has long been used in China, Japan and South East Asia as a food source and as a traditional medicine. Flour extracted from the corm of this species is used in Far Eastern cuisine to make noodles, tofu and snacks. In traditional Chinese medicine (TCM), a gel prepared from the flour has been used for detoxification, tumour-suppression, blood stasis alleviation and phlegm liquefaction; and for more than 2000 years has been consumed by the indigenous people of China for the treatment of asthma, cough, hernia, breast pain, burns as well as haematological and skin disorders. Over the past two decades, purified konjac flour, commonly known as konjac glucomannan (KGM) has been introduced on a relatively small scale into the United States and Europe, both as a food additive and a dietary supplement. The latter is available in capsule form or as a drink mix and in food products. Clinical studies have demonstrated that supplementing the diet with KGM significantly lowers plasma cholesterol, improves carbohydrate metabolism, bowel movement and colonic ecology. Standards for the classification of both konjac flour and KGM have been established by the Chinese Ministry of Agriculture, the European Commission and the U.S. Food Chemicals Codex. However, to date, there is no worldwide agreed regulatory standard for konjac flour or KGM. This highlights the need for harmonization of konjac commercial standards to assess and ensure the quality of existing and future KGM products. Despite the widespread consumption of konjac derived products in East and South East Asia, there has been limited research on the biology, processing and cultivation of this species in the West. Most studies performed outside Asia have focussed on the structural characterisation and physicochemical properties of KGM. Therefore, the objective of this monograph is to review the literature covering the ethnic uses, botany and cultivation of konjac corms, together with the health benefits of KGM with the associated requirements for quality control. Possible directions for future research and development and standardisation of production and classification of this versatile natural product will be discussed.

Peritoneal injection of fucoidan suppresses the increase of plasma IgE induced by OVA-sensitization

We previously reported that fucoidan, a dietary fiber purified from seaweed, inhibited IgE production by B cells in vitro. In this study, we examined the effect of fucoidan on IgE production in vivo. The OVA-induced increase of plasma IgE was significantly suppressed when fucoidan was intraperitoneally, but not orally, administered prior to the first immunization with OVA. The production of IL-4 and IFN-gamma in response to OVA in spleen cells isolated from OVA-sensitized mice treated with fucoidan in vivo was lower than that from mice treated without fucoidan. Moreover, the flow cytometric analysis and ELISpot assay revealed that the administration of fucoidan suppressed a number of IgE-expressing and IgE-secreting B cells, respectively. These results indicate that fucoidan inhibits the increase of plasma IgE through the suppression of IgE-producing B cell population, and the effect of fucoidan in vivo is crucially dependent on the route and timing of its administration.

Development of autoantibody responses in NC/Nga mice: its prevention by pulverized konjac glucomannan feeding

Dietary pulverized konjac glucomannan (PKGM) suppresses the development of eczema in NC/Nga mice, a model of atopic dermatitis (AD). Although NC/Nga mice were originally recognized as an autoimmune disease model, recent studies on their autoimmunity are still poorly performed. Here, we show that cervical lymphadenopathy, splenomegaly, and increases in plasma levels of anti-dsDNA, rheumatoid factor IgG autoantibodies, and B cell-activating factor of the TNF family (BAFF) were co-elicited in eczematous NC/Nga mice; however, these symptoms were all prevented in PKGM-fed mice. Our results imply the possible involvement of autoimmunity on the pathogenesis of dermatitis and hyper-IgE syndrome in NC/Nga mice. PKGM might be effective in preventing autoimmune responses in AD.

Dietary pulverized konjac glucomannan prevents the development of allergic rhinitis-like symptoms and IgE response in mice

Konjac is a traditional Japanese food with a peculiar texture, and it has been suggested that its main ingredient, konjac glucomannan (KGM), ameliorates metabolic disorders such as diabetes and hypercholesteremia. We have found that feeding with pulverized KGM (PKGM) prevents skin inflammation in a murine model of atopic dermatitis. Here, we show that dietary PKGM suppresses allergic rhinitis-like symptoms in mice upon immunization and nasal sensitization with ovalbumin (OVA). The PKGM-fed mice showed a much lower frequency of sneezing than in control animals. We also found that PKGM supplementation exclusively suppressed OVA-specific IgE response without affecting IgG1/IgG2a responses as well as systemic Th1/Th2 cytokine production. These results suggest that PKGM can be a beneficial foodstuff in preventing nasal allergy such as seasonal pollinosis.