Konjac Oligosaccharides Alleviated Ovariectomy-Induced Bone Loss through Gut Microbiota Modulation and Treg/Th17 Regulation

Oligosaccharides from the plant Amorphophallus konjac were potentially effective in menopausal osteoporosis due to their prebiotic attributes. The present work mainly studied the regulation of konjac oligosaccharides (KOS) on menopausal bone loss. Experiments were carried out in ovariectomized (OVX) rats, and various contents of KOS were correlated with diet. After 3 months of treatment, the degree of osteoporosis was determined by bone mineral density and femoral microarchitecture. The research data showed that the 8% dietary KOS significantly alleviated bone loss in OVX rats, as it promoted the bone trabecular number by 134.2% and enhanced the bone bending stiffness by 103.1%. From the perspective of the gut-bone axis, KOS promoted gut barrier repair and decreased pro-inflammatory cytokines. Besides, KOS promoted the growth of Bifidobacterium longum and restored Treg/Th17 balance in bone marrow. The two aspects contributed to decreased osteoclastogenic activity and thus inhibited inflammation-related bone loss. This work extended current knowledge of prebiotic inhibition on bone loss and provide an alternative strategy for osteoporosis prevention.

Study on the interaction and gel properties of pork myofibrillar protein with konjac polysaccharides

BACKGROUND

Natural myofibrillar protein (MP) is sensitive to changes in the microenvironment, such as pH and ionic strength, and therefore can adversely affect the final quality of meat products. The aim of this study was to modify natural MP as well as to improve its functional properties. Therefore, the quality improvement effect of konjac polysaccharides with different concentrations (0, 1.5, 3, 4.5 and 6 g kg-1 protein) on MP gels was investigated.

RESULTS

With a concentration of konjac polysaccharides of 6 g kg-1 protein, the composite gel obtained exhibited a significant improvement of water binding (water holding capacity increased by 7.71%) and textural performance (strength increased from 29.12 to 37.55 N mm, an increase of 8.43 N mm). Meanwhile, konjac polysaccharides could help to form more disulfide bonds and non-disulfide covalent bonds, which enhanced the crosslinking of MP and maintained the MP gel network structure. Then, with the preservation of α-helix structure (a significant increase of 8.11%), slower protein aggregation and formation of small aggregates, this supported the formation of a fine and homogeneous network structure and allowed a reduction in water mobility.

CONCLUSION

During the heating process, konjac polysaccharides could absorb the surrounding water and fill the gel system, which resulted in an increase in the water content of the gel network and enhanced the gel-forming ability of the gel. Meanwhile, konjac polysaccharides might inhibit irregular aggregation of proteins and promote the formation of small aggregates, which in turn form a homogeneous and continuous gel matrix by orderly arrangement. © 2023 Society of Chemical Industry.

Effects of konjac glucan-nan/low-acyl gellan edible coatings loaded thymol-β-cyclodextrin microcapsules on postharvest blueberry

This study developed an edible antimicrobial coating using a blend of konjac glucomannan (KGM) and low acyl gellan gum (LAG) hydrogel to incorporate thymol nanoparticles (TKL). The optimized TKL formulation (TKL60) comprised 0.22% thymol microcapsules (TMs), 0.075% total polysaccharide content (KGM:LAG = 1:2), and 99.63% distilled water. When applied to blueberries, TKL60 significantly extended their shelf life to 42 d at 2 ± 0.5 °C, tripling that of control fruit. TKL60 reduced decay rate, weight loss, and respiration rate, delayed softening and senescence during cold storage. It preserved the outer epidermis by retaining cuticular waxes, curbing lipid oxidation, and sustaining defense-related enzyme activities. Flavor analysis revealed altered volatile compound concentrations in TKL60-treated berries, including decreased terpenes and benzaldehyde, and increased esters and aldehydes like 2-methylbutanol, 3-methylbutanol, and linalool. Discriminant Analysis highlighted TKL60's efficacy in delaying aroma deterioration by over 21 d. TKL60 exhibits potential as a substitute for synthetic coatings and chemical insecticides.

Bacterial community structure in the rhizosphere of fungi-infected Amorphophallus titanum

The rhizosphere is a narrow soil area directly affected by plant root exudates. Microbes inhabiting the rhizosphere have been widely studied for their beneficial effects on plant nutrition, growth, and disease prevention. Many factors affect the rhizosphere microbial composition, including plant pathogen infection. Here, we analyzed the bacterial community structure in the rhizosphere of fungi-infected Amorphophallus titanum. Soil samples were collected from rhizosphere and non-rhizosphere areas of fungi-infected A. titanum. The 16S metagenomic analysis was conducted to investigate the bacterial community of the samples by amplifying the V3-V4 region. The results showed that the phylum Firmicutes was prevalent in the rhizosphere, whereas the phyla Proteobacteria, Acidobacteria, and Actinobacteria were limited. Some major fungal genera were isolated from infected tubers and rhizosphere soil of A. titanum, including Trichoderma sp., Aspergillus sp., Perenniporia sp., and Cerrena sp. The fungal-isolate Aspergillus spp. is a well-known agricultural pest in several reports. While Cerrena sp. was reported to be pathogenic in plants, including the family of Arecaceae. Overall, the data revealed a potential relationship between fungal infections and the dominant bacterial community in the rhizosphere of A. titanum. Additionally, this research may contribute to the development of microbe-based technology to mitigate diseases in A. titanum.

Konjac glucomannan-based hydrogels with health-promoting effects for potential edible electronics applications: A mini-review

Konjac glucomannan (KGM), a dietary fiber hydrocolloid polysaccharide isolated from Amorphophallus konjac tubers, has potential applications in various fields. However, the use of KGM-based hydrogels has mainly focused on the food, biomedical, and water treatment industries. KGM possesses several health benefits and could be a promising candidate for use in edible electronics. This paper presents the first review of KGM-based hydrogels as edible electronics and their potential health benefits. The paper initially focuses on the health-promoting effects of KGM-based hydrogels, such as prebiotic effects, antiobesity, antioxidant, and antibacterial properties. Then, it discusses the feasible design strategies for KGM-based hydrogels as edible electronics, considering their flexibility, mechanical properties, response to stimuli, degradability aspects, their role as electronic device components, and the retention period of the devices. Finally, this review outlines future directions for developing KGM-based hydrogels for use in edible electronics.

Patterns and drivers of heat production in the plant genus Amorphophallus

Thermogenesis - the ability to generate metabolic heat - is much more common in animals than in plants, but it has been documented in several plant families, most prominently the Araceae. Metabolic heat is produced in floral organs during the flowering time (anthesis), with the hypothesised primary functions being to increase scent volatilisation for pollinator attraction, and/or to provide a heat reward for invertebrate pollinators. Despite in-depth studies on the thermogenesis of single species, no attempts have yet been made to examine plant thermogenesis across an entire clade. Here, we apply time-series clustering algorithms to 119 measurements of the full thermogenic patterns in inflorescences of 80 Amorphophallus species. We infer a new time-calibrated phylogeny of this genus and use phylogenetic comparative methods to investigate the evolutionary determinants of thermogenesis. We find striking phenotypic variation across the phylogeny, with heat production in multiple clades reaching up to 15°C, and in one case 21.7°C above ambient temperature. Our results show that the thermogenic capacity is phylogenetically conserved and is also associated with inflorescence thickness. Our study paves the way for further investigations of the eco-evolutionary benefits of thermogenesis in plants.

Selection and Evaluation of Reference Genes for RT-qPCR Analysis in Amorphophallus Konjac Based on Transcriptome Data

Combined with the Konjac transcriptome database of our laboratory and internal reference genes commonly used in plants, the eight candidate internal reference genes were screened and detected. They are the 25S ribosomal RNA gene (25S rRNA), 18S ribosomal RNA gene (18S rRNA), actin gene (ACT), glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH), ubiquitin gene (UBQ), β-tubulin gene (β-TUB), eukaryotic elongation factor 1-αgene(eEF-1α), and eukaryotic translation initiation factor 4α-1 gene (eIF-4α). The results of GeNorm, Normfinder, and BestKeeper were analyzed comprehensively. The data showed that the expression levels of 25S rRNA, 18S rRNA, and ACT at the reproductive periods, eEF-1α and eIF-4α at the nutritional periods, and eEF-1α, UBQ, and ACT at different leaf developmental periods were stable. These identified and stable internal reference genes will provide the basis for the subsequent molecular biology-related studies of Konjac.

Evaluation of konjac noodle as a microsurgery training model: learning curve analysis

BACKGROUND

classical models of microsurgical anastomosis training are expensive and have ethical implications. Some alternatives join low cost and easiness to store. However, the translation of knowledge acquired by training in these methods into the traditional ones is not clear. This project aims to assess the feasibility of konjac noodles as a reliable microsurgery-training model.

METHODS

10 neurosurgery residents performed an end-to-end anastomosis in a 2-3mm placenta artery. The anastomoses were evaluated quantitatively, recording time; and qualitatively, applying a validated score (Anastomosis Lapse Index - ALI) by three experienced neurosurgeons and verifying the presence of gross leakage through the infusion of fluorescein. Subsequently, they performed 10 non-consecutive sessions of anastomosis training in the konjac noodle. Eventually, a final anastomosis in the placenta model was performed and the same parameters were scored.

RESULTS

we observed a 17min reduction in the mean time to perform the anastomosis in the placenta model after the training in the konjac (p<0.05). There was a non-significant 20% reduction in gross leakage, but the training sessions were not able to consistently improve the ALI score.

CONCLUSIONS

we demonstrate a reduction in anastomosis performing time in placental arteries after training sessions in the konjac noodle model, which can be regarded as a feasible low-cost method, particularly useful in centers with surgical microscopes only in the operation room.

Thermal and Rheological Performances Evaluation of a Modified Biopolymer for Fracturing Fluid System

Developing an efficient fracturing fluid system is an enduring hot topic in the petrochemical industries, especially regarding the exploitation of limited oil. Biopolymers, especially polysaccharides (e.g., konjac gum, guar gum), are widely applied as fracturing fluids in fracturing as a result of their advantages. Herein, we propose an easy method of modifying konjac gum (KGM) using isopropanol, sodium hydroxide, and chloroacetic acid to obtain modified konjac glum (MKGM). The MKGM and KGM gels were also obtained by using the self-prepared organic titanium high-temperature stabilizer and organic borate cross-linker. The prepared MKGM was characterized by multiscale techniques, including attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and rheology properties. The ATR-FTIR results showed that the etherification modification reaction occurred as designed. The XRD results showed that the regularity of KGM was destroyed after modification. The TGA and DSC results showed that the thermal stability improved. Rheology measurements illustrated that the temperature and shear resistance of MKGM were better than those of KGM. The MKGM gel could be applied in fracturing fluid systems at a lower frequency through viscoelastic measurements.

The Effect of κ-Carrageenan Proportion and Hot Water Extract of the Pluchea indica Less Leaf Tea on the Quality and Sensory Properties of Stink Lily (Amorphophallus muelleri) Wet Noodles

The study aims to determine the effect of the proportion of κ-carrageenan and the hot water extract of pluchea leaf tea on the quality and sensory properties of stink lily wet noodles. The research design is a randomized block design with two factors, i.e., the difference in the proportion of κ-carrageenan (K) (0, 1, 2, and 3% w/w) and the addition of the hot water extract of the Pluchea indica Less leaf tea (L) (0, 15, and 30% w/v), with 12 treatment levels (K0L0, K0L1, K0L2, K1L0, K1L1, K1L2, K2L0, K2L1, K2L2, K3L0, K3L1, K3L2). The data are analyzed by the ANOVA at p < 5% and continued with the Duncan’s multiple range test at p < 5%, and the best treatment was determined by the spider web method based on sensory assay by a hedonic method. The proportions of κ-carrageenan and the concentration of pluchea tea extract had a significant effect on the cooking quality and sensory properties. However, the interaction of the two factors affected the swelling index, yellowness (b*), chroma (C), hue (h), total phenol content (TPC), total flavonoid content (TFC), and DPPH free radical scavenging assay (DPPH). The best treatment of wet noodles was K2L0, with a preference score of 15.8. The binding of κ-carrageenan and phenolic compounds to make a networking structure by intra- and inter-disulfide bind between glucomannan and gluten was thought to affect the cooking quality, sensory properties, bioactive compounds (TPC and TFC), and DPPH.

Konjac Glucomannan (KGM), Deacetylated KGM (Da-KGM), and Degraded KGM Derivatives: A Special Focus on Colloidal Nutrition

Konjac flour, mainly obtained and purified from the tubers ofAmorphophallus konjac C. Koch, yields a high molecular weight (M_w) and viscous hydrocolloidal polysaccharide: konjac glucomannan (KGM). KGM has been widely applied in the food industry as a thickening and gelation agent as a result of its unique colloidal properties of effective viscosity enhancement and thermal-irreversible gelling. This review first narrates the typical commercial KGM source species, the industrial production, and the purification process of KGM flour. The structural information on native KGM, gelation mechanisms of alkali-induced deacetylated KGM (Da-KGM) hydrogel, progress on degraded KGM derivatives, cryoprotection effect, and colloidal nutrition are highlighted. Finally, the regulatory requirements of konjac flour and KGM among different countries are briefly introduced. The fine structure and physicochemical properties of KGM can be regulated in a great range via the deacetylation or degradation reaction. Here, the relationship between the physicochemical properties, such as viscosity, solubility, gelation, and nutritional effects, of native KGM, Da-KGM, and degraded KGM derivatives was preliminary established, which would provide theoretical guidance for designing KGM-based products with certain nutritional needs.

Konjac Oligosaccharides Modulate the Gut Environment and Promote Bone Health in Calcium-Deficient Mice

This study aimed to investigate the beneficial effect of konjac oligosaccharides (KOS) on bone health in calcium-deficient mice. During the experimental period, low-calcium diet-fed mice were administered with calcium chloride to simulate daily calcium supplementation. Meanwhile, different levels of KOS intervened by adding them into the diet. After 8 weeks, the calcium balance status, bone mass parameters, and gut environment modulation were evaluated. The results showed that dietary KOS intervention alleviated the negative calcium balance, significantly promoted the trabecular number and cortical thickness, and remarkably enhanced the skeletal mechanical strength. Moreover, Pearson's correlation analysis among significantly changed gut microbiota, gut metabolites, and relevant physiological indexes showed that the microbial genera of Lactobacillus, Bifidobacterium, Mucispirillum, Alistipes, and unidentified Clostridia and gut metabolites of kynurenine and testosterone were significantly associated with increased bone mass. These findings provided a new insight into the effect of prebiotics on bone health.

High-efficiency expression of a superior β-mannanase engineered by cooperative substitution method in Pichia pastoris and its application in preparation of prebiotic mannooligosaccharides

β-mannanase with high specific activity is a prerequisite for the industrial preparation of prebiotic mannooligosaccharides. Three mutants, namely MEI, MER, and MEIR, were constructed by cooperative substitution based on three predominant single-point site mutations (K291E, L211I, and Q112R, respectively). Heterologous expression was facilitated in Pichia pastoris and the recombinase was characterized completely. The specific activities of MER (7481.9 U mg^-1) and MEIR (9003.1 U mg^-1) increased by 1.07- and 1.29-fold from the initial activity of ME (6970.2U mg^-1), respectively. MEIR was used for high-cell-density fermentation to further improve enzyme activity, and the expression levels achieved in the 10-L fermenter were significantly high (105,836 U mL^-1). The prebiotic mannooligosaccharides (<2000 Da) were prepared by hydrolyzing konjac gum and locust bean gum with MEIR, with 100% and 76.40% hydrolysis rates, respectively. These characteristics make MEIR highly attractive for prebiotic development in food and related industries.

Protective Effects of Konjac and Inulin Extracts on Type 1 and Type 2 Diabetes

OBJECTIVE

The present study was designed to determine whether konjac and inulin extracts or their combination, konjac-inulin (KI) composition, as diet supplementary, can exert beneficial effects against type 1 diabetes and type 2 diabetes using animal models.

METHODS

A total of 60 diabetic (type 1) rats induced by streptozotocin (STZ) were randomly assigned to five groups: vehicle control (STZ group), KI combination at low dose group (KI-L group), KI combination at medium dose group (KI-M group), KI combination at high dose group (KI-H group), konjac extract group (konjac group), and inulin extract group (inulin group). A sham group (without STZ) was also included. Levels of blood glucose were monitored at each week. After continuous treatment of each diet for 24 days, a glucose tolerance test was performed. After 28 days of treatment, plasma biochemical indicators including glycated serum proteins, total cholesterol, and triglycerides were measured and immunohistochemistry staining of the rat pancreas was performed, to study the insulin expressions. Type 2 diabetes was developed in db/db mice. A total of 28 db/db mice were divided into 4 groups: vehicle control (db/db group), KI composition group (KI group), konjac extract group (konjac group), and inulin extract group (inulin group). A wild-type control group (wild-type group) for db/db mice was also included. Levels of blood glucose, body weight, and blood triglycerides were monitored at each week.

RESULTS

Daily use of the KI composition significantly decreased levels of blood glucose and blood triglycerides, as well as improved the insulin production in islets or reduced development of obesity in STZ-induced diabetic rats or in db/db mice. Such effects from KI composition were better than single ingredient of konjac or inulin extract.

CONCLUSION

The results of this study suggest that daily use of KI composition has a protective role on type 1 and 2 diabetes and provided experimental basis for further development of KI composition as a food supplement for diabetic or diabetic high-risk population.

A simply enzymatic hydrolysis pretreatment for β-mannanase production from konjac powder

Currently, the traditional fermentation using konjac powder for β-mannanase production presents operational difficulties and high energy consumption, because of the individual hot air sterilization for konjac powder. A simply enzymatic hydrolysis pretreatment for konjac powder was developed to solve the problems of the traditional process in a 7-L fermenter. In the new process, when hydrolysis yield of konjac powder was above 50%, the media became liquid state from gelatinous state and could be sterilized immediately, avoiding the hot air sterilization and solving the operational difficulties. Interestingly, the new process didn't have negative influence on β-mannanase production. Additionally, it could save close to 23% of power consumption during the whole fermentation. For another example, it did work well using locust bean gum for β-mannanase production in a 7-L fermenter. Therefore, the new process might be scaled up for industrial production using mannan-based bioresource as substrate.

Rhizoma Amorphophalli inhibits TNBC cell proliferation, migration, invasion and metastasis through the PI3K/Akt/mTOR pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Triple-negative breast cancer (TNBC) often presents with a high histological grade and high malignancy, which greatly contribute to patient morbidity and mortality. Rhizoma Amorphophalli exhibits many biological and pharmacological activities, but its potential as a therapeutic agent for the treatment of metastatic TNBC patients remains poorly understood.

AIM OF THE STUDY

The aim of this study was to determine whether Rhizoma Amorphophalli inhibits metastasis in the human TNBC MDA-MB-231 cell line.

MATERIALS AND METHODS

CCK-8 and colony formation assays were adopted for the analysis of cell activity and cell proliferation, respectively. Flow cytometry was used for cell cycle analysis. Wound healing and transwell assays were performed to assess cell migration and invasion, respectively. PI3K/Akt/mTOR signaling pathways were analyzed through western blotting. Breast cancer cell metastasis to the lung in a xenograft model was evaluated by in vivo fluorescence imaging. A GC-MS analysis was performed to determine the main components of the petroleum ether fraction from the ethanol extract of Rhizoma Amorphophalli (abbreviated RhA).

RESULTS

RhA significantly reduced breast cancer cell viability and proliferation. The flow cytometry analysis indicated that RhA induced MDA-MB-231 cell arrest at the S phase. Additionally, RhA decreased MDA-MB-231 cell migration and invasion and inhibited the PI3K/Akt/mTOR signaling pathway. In addition, mice treated with RhA exhibited a significant reduction in tumor infiltration and a decrease in breast cancer cell metastasis to the lung. The GC-MS analysis results showed that RhA contained a large number of unsaturated fatty acids, such as octadecadienoic acid (linoleic acid), octadecatrienoic acid (linolenic acid), and oleate, which might represent the anticancer components of the extract.

CONCLUSIONS

The results of this study suggest that RhA has potential as a therapeutic candidate for metastatic TNBC treatment.

Konjac-based oil bulking system for development of improved-lipid pork patties: technological, microbiological and sensory assessment

Improved-lipid pork patties were manufactured following two different reformulation strategies: fat reduction by replacement of pork backfat with konjac gel (KG), and fat reduction/lipid improvement by replacement of pork backfat with an improved oil combination (olive, linseed and fish oils) bulking system based on konjac gel (O-KG). Technological, microbiological and sensory properties were analyzed as affected by the type of formulation and by chilled storage (9days, 2°C). Fat was reduced by between 30 and 86%. In the cases where O-KG was incorporated, 12 and 41% of total fat in patties came from the oil combination. There was no observable effect on color parameters in samples with O-K. Higher KG levels produced harder cooked patties. Animal fat replacement in patties promoted an increase in lipid oxidation, which was more pronounced in samples with an oil combination. In general, during chilled storage no major changes were observed in the studied properties as a result of the different treatments.

Effect of prebiotic konjac mannanoligosaccharide on growth performances, intestinal microflora, and digestive enzyme activities in yellow catfish, Pelteobagrus fulvidraco

In the present study, konjac mannanoligosaccharide (KMOS) was evaluated as a prebiotic in yellow catfish. The fish were fed with diets containing KMOS in four concentrations: 0 g kg(-1) (C), 1.0 g kg(-1) (KM1), 2.0 g kg(-1) (KM2), and 3.0 g kg(-1) (KM3) for 49 days, respectively. Another group fed with diets containing 3.0 g kg(-1) yeast cell wall mannanoligosaccharide (MOS) (M3) was set as positive control. The results indicated that fish receiving the diets supplemented with KMOS or MOS showed higher relative gain rate (RGR), specific growth rate (SGR), and lower feed conversion ratio (FCR) with significantly differences (P < 0.05) than those fed with the basal diets. Moreover, fish receiving the diets with 2.0 g kg(-1) KMOS inclusion showed higher RGR, SGR, and lower FCR (P < 0.05) than that feeding the diets supplemented with 3.0 g kg(-1) MOS. The quantities of Bifidobacterium spp. were significantly increased (P < 0.05). Meanwhile, Escherichia coli and Aeromonas spp. were significantly reduced (P < 0.05) in the fish-feeding diets with 2.0 g kg(-1) KMOS supplement. Compared with the control group, the significantly enhancement of protease and amylase activity (P < 0.05) in intestine and pancreas was observed in fish fed with diets containing KMOS or MOS. Collectively, an optimum level of KMOS inclusion in diets could modulate intestinal microflora, induce digestive enzyme activity, and improve the growth performance of yellow catfish significantly.

Konjac glucomannan and inulin systematically modulate antioxidant defense in rats fed a high-fat fiber-free diet

The aim of this study was to investigate the effects of konjac glucomannan (KGM) and inulin on the balance between pro-oxidative status and antioxidative defense systems in the colon, liver, and plasma of rats fed a high-fat fiber-free diet. Male Sprague-Dawley rats (n = 8 animals per group) were fed a high-fat (25% corn oil, w/w) fiber-free diet or that supplemented with KGM or inulin fiber (5%, w/w) for 4 weeks. The index of pro-oxidative status, malondialdehyde (MDA), and blood lymphocyte DNA damage; the antioxidative defense, that is, antioxidant enzymes (glutathione peroxidase, superoxide dismutase, catalase) in the colonic mucosa and liver; and the plasma antioxidant levels were determined. The fermentation of fiber was shown in fecal short-chain fatty acids. Incorporation of KGM and inulin into the high-fat fiber-free diet beneficially reduced the MDA levels of the colon and liver and DNA damage in blood lymphocytes. On the other hand, both fibers enhanced the antioxidative defense systems by up-regulating the gene expressions of glutathione peroxidase and catalase in the colonic mucosa and of superoxide dismutase and catalase in the liver. Furthermore, KGM and inulin promoted antioxidative status in the blood by elevating the α-tocopherol level. KGM and inulin were well-fermented in rats and increased the concentration and daily excretion of fecal short-chain fatty acids, especially acetate and butyrate. These results suggest that in vivo utilization of KGM and inulin stimulated both local and systemic antioxidative defense systems in rats.

Inhibitory effects of a soluble dietary fiber from Amorphophallus konjac on cytotoxicity and DNA damage induced by fecal water in Caco-2 cells

The aims of this study were to determine the effects of konjac glucomannan (KGM), a water-soluble dietary fiber from Amorphophallu konjac C. Koch, on the cytotoxicity and DNA damage of fecal water-treated Caco-2 cells, a human colon adenocarcinoma cell line, and to compare these effects with those of inulin, oligofructose (FO), cellulose and no fiber diet. In addition, the possible mechanisms by which dietary fibers modulated the toxicity of feces were investigated. Seven-week-old BALB/c mice were randomly allocated to consume an AIN-93 diet that contained no dietary fiber (FF) or 5 % (w/w) KGM, inulin, FO, or cellulose for 3 weeks. Fresh feces were collected during days 18 - 21. Our results indicated that the survival rate (%) of fecal water-treated Caco-2 cells was similarly enhanced by each dietary fiber as compared with that of FF group, respectively. The inhibition of fecal water-induced DNA damage of Caco-2 cells was in the descending order of inulin> FO> cellulose, KGM group. Cellulose significantly exerted a bulk effect, while KGM, inulin and FO significantly increased the ratio of lactobacilli and bifidobacteria in feces, respectively, as well as the ferrous ion-chelating ability of fecal water, respectively. Therefore, this study suggests that KGM, inulin and FO may reduce the toxicity of fecal water mainly by increasing the fecal probiotics and ferrous ion-chelating activities while cellulose may act mainly by increasing the fecal bulk. FF: fiber free FO: oligofructose KGM: konjac glucomannan.

Improvement of atopic dermatitis and reduction of skin allergic responses by oral intake of konjac ceramide

Although topical application of ceramide is effective in the treatment of atopic dermatitis, its effect is transient. Thus, the effect of oral intake of ceramide on atopic dermatitis was studied. Two groups of 25 children with moderate atopic dermatitis, who were allergic to house dust mite took either milk sugar (control group) or 1.8 mg/day of konjac ceramide in milk sugar (ceramide group) once a day for 2 weeks. Before and after 2 weeks, skin symptoms were assessed using the SCORAD index, while allergic skin responses to house dust mite were assessed by skin prick test. Moreover, production of allergen-specific IgE and various cytokines by mononuclear cells was measured. After 2 weeks, SCORAD index score, allergic skin responses to house dust mite and house dust mite-specific IgE production were significantly reduced in the ceramide group, but not in the control group. Moreover, house dust mite-induced cytokine production was skewed towards the Th1 type, since production of Th1 cytokine, IFN-gamma, and IL-12, was increased, while production of Th2 cytokine, IL-4, and IL-13, was decreased. In contrast, no change of these parameters was found in control group. Collectively, oral intake of konjac ceramide improved skin symptoms and reduced allergic responses with concomitant skewing of the cytokine pattern towards the Th1 type.

Synergistic interactions between the genetically modified bacterial polysaccharide P2 and carob or konjac mannan

Rheological studies have confirmed that the bacterial polysaccharide P2, a genetically modified variant of the Acetobacter xylinum polysaccharide acetan, undergoes synergistic gelation with either of the plant polysaccharides carob or konjac mannan. X-ray fibre diffraction data shows that P2 can form a 5-fold helical structure of pitch 4.7nm and an axial rise per disaccharide repeat of 0.92nm. Optical rotation data demonstrate that P2 undergoes a coil-helix transition in solution and that deacylation enhances the stability of the helical structure in solution. Studies made on mixtures prepared at different temperatures and ionic strengths suggest that denaturation of the P2 helix favours interaction and gelation. Deacetylation of P2 enhances gelation. X-ray diffraction data for oriented fibres prepared from deacetylated P2-konjac mannan mixed films reveal a 6-fold helical structure of pitch 5.54nm with an axial rise per disaccharide repeat also of 0.92nm. This mixed helix provides direct evidence for binding between the two polysaccharides. P2 contains two sites of acetylation: one on the backbone and one on the sidechain. The former site of acetylation inhibits helix formation for P2. It is suggested that this site of acetylation also inhibits formation of the mixed helix, explaining the enhanced gelation of mixtures on deacetylation.

Konjac supplement alleviated hypercholesterolemia and hyperglycemia in type 2 diabetic subjects--a randomized double-blind trial

OBJECTIVES

The present study was designed to evaluate effects of konjac glucomannan (KGM) supplement (3.6 g/day) for 28 days on blood lipid and glucose levels in hyperlipidemic type 2 diabetic patients and the possible mechanism for the reductions in blood lipid levels.

METHODS

Twenty-two diabetic subjects (age 64.2 + 8.4 years, BMI 25.5 + 3.2 kg/m(2)) with elevated blood cholesterol levels (fasting glucose between 6.7-14.4 mmol/L), but currently not taking lipid-lowering medication, were recruited to participate in a two 28-day period, randomized, double-blind, crossover clinical trial. Fasting blood samples drawn on the initial and final days of each period were determined for plasma lipids and glucose levels. Feces collected at the end of each experimental period were analyzed for neutral sterol and bile acid contents.

RESULTS

Compared with placebo, KGM effectively reduced plasma cholesterol (11.1%, p = 0.0001, adjusted alpha = 0.006), LDL-cholesterol (20.7%, p = 0.0004, adjusted alpha = 0.006), total/HDL cholesterol ratio (15.6%, p = 0.0005, adjusted alpha = 0.007), ApoB (12.9%, p = 0.0001, adjusted alpha = 0.006) and fasting glucose (23.2%, p = 0.002, adjusted alpha = 0.008). Plasma triglyceride, HDL-cholesterol, LDL/HDL cholesterol, postprandial glucose and body weight were not significant after adjustment by the Bonferroni-Hochberg procedure. Fecal neutral sterol and bile acid concentrations were increased by 18.0% (p = 0.004) and 75.4% (p < 0.001), respectively, with KGM supplement.

CONCLUSIONS

The KGM supplement improved blood lipid levels by enhancing fecal excretion of neutral sterol and bile acid and alleviated the elevated glucose levels in diabetic subjects. KGM could be an adjunct for the treatment of hyperlipidemic diabetic subjects.

Effect of Amorphophallus Konjac oligosaccharides on STZ-induced diabetes model of isolated islets

Three oligosaccharide fractions from the root of Amorphophallus Konjac, which was reported with hypoglycemic effects on diabetes subjects, were isolated and studied using the STZ-treated diabetes model. Among them, one fraction named as KOS-A, was found with nitric oxide (NO(*)) free radical regulation effect, while the other two were not. At concentrations less than 1.5 mM, KOS-A positively decreased STZ-induced NO(*) level of islets, but normal NO(*) release for non-STZ-treated islets was not affected within the range. At 15 mM, KOS-A played a contrary role and increased NO(*) level for islets both with and without STZ-treatment. Islets insulin secretion changed corresponding to NO(*) level in the assay. Increased insulin secretion appeared parallel to the decrease of NO(*), and normal insulin release was not affected by KOS-A less than 1.5 mM. Structure determination of KOS-A shows that it is a tetrasaccharide with Mw of 666 Da and reductive end of alpha-D-mannose. These results indicate that low dosage of KOS-A, with its function on attenuating STZ-induced NO(*) level, doesn't alter normal NO(*) and insulin secretion pathways of isolated islets. The NO(*) attenuation function of KOS-A on the diabetes model is mainly resulted from environmental free radical scavenging by the oligosaccharide. Present results also imply the mechanism of clinical Amorphophallus Konjac hypoglycemic function maybe related with free radical attenuation and lower risks of islets damage from NO(*) radical.