Preparation of a novel expandable konjac fiber at different freezing temperatures and exploration of its digestion regulation functions

A new form of konjac fiber was successfully prepared, and it could instantaneously expand when in contact with the digestive fluid. The expanded konjac fiber could inhibit the digestion of the ingested food by competing with the substrate for digestive enzymes and space. The konjac fiber with desirable physical properties was obtained at 4 different freezing temperatures (-20 °C, -40 °C, -80 °C, and -196 °C), and the digestion regulation mechanisms of these fibers were systematically explored. The results showed that the konjac fiber prepared at -20 °C displayed an outstanding performance in delaying gastric emptying and preventing intestinal starch hydrolysis, while the fiber prepared under liquid nitrogen conditions (-196 °C) showed the weakest digestion regulation ability. However, the digestion regulation ability of this novel fiber was highly related to the food rheological property, and it exhibited a stronger interference effect on high-viscosity food. Our novel konjac fibers exhibited a great digestion regulation potential. Our findings provide valuable references for the development of dietary fiber-based satiety-enhancing functional foods.

Comparative study on the effect of inhibitory methods on the color and gelation properties of alkali induced heat-set konjac gel from Amorphophallus bulbifer

As a newly superior konjac variety, the Amorphophallus bulbifer (A. bulbifer) was easily browning during the alkali-induced process. In this study, five different inhibitory methods, such as citric-acid heat pretreatment (CAT), mixed with citric acid (CA), mixed with ascorbic acid (AA), mixed with L-cysteine (CYS), and mixed with potato starch (PS, containing TiO2), were separately used to inhibit the browning of alkali-induced heat-set A. bulbifer gel (ABG). The color and gelation properties were then investigated and compared. Results showed that the inhibitory methods had significant influences on the appearance, color, physicochemical properties, rheological properties, and microstructures of ABG. Among them, the CAT method not only significantly inhibited the browning of ABG (ΔE value dropped from 25.74 to 14.68) but also improved the water-holding capacity, moisture distribution, and thermal stability without damaging the textural properties of ABG. Moreover, SEM revealed that both CAT and adding PS methods could exhibit the more dense gel network structures of ABG than other methods. It was reasonable to conclude that ABG-CAT offered a superior method to prevent browning compared to the other methods based on the texture, microstructure, color, appearance, and thermal stability of the product.

Properties of plant-derived soluble dietary fibers for fiber-enriched foods: A comparative evaluation

Plant-derived soluble dietary fibers (SDF) have many important physiological functions and the applications of SDF vary based on their properties, which are worth further investigating for fiber-enriched food production. In this study, SDF derived from konjac, apple, chicory, flaxseed, orange, psyllium seed, soybean and oat were purified, and their structural, physicochemical and functional properties were systematically evaluated. Monosaccharide composition analysis showed that these SDF belonged to heteropolysaccharides, of which konjac, psyllium seed, apple, soybean and oat SDF were glucomannan, arabinoxylan, pectin, arabinogalactan and glucan, respectively. The molecular weight of konjac glucomannan (KGM, 5.22 × 10⁶ Da) was the highest, and inulin, soybean arabinogalactan (SA) and oat glucan (OG) had higher water solubility. Moreover, KGM, apple pectin (AP), flaxseed SDF (FS) and psyllium seed arabinoxylan (PA) exhibited better water-holding capacity, swelling capacity, emulsifying activity and stability. Rheological studies and texture profile analysis suggested that KGM had the best viscosity and gelation ability. In addition, AP and orange SDF (OS) showed better α-amylase inhibitory activity, while OS and KGM had higher pancreatic lipase inhibitory activity. Also, KGM and FS displayed fine cholesterol absorption capacity. To summary, these functional properties illustrated the feasibility of SDF to regulate blood sugar and blood lipid levels.

Sodium caseinate enhances the effect of konjac flour on delaying gastric emptying based on a dynamic in vitro human stomach-IV (DIVHS-IV) system

BACKGROUND

In the context of the increasing prevalence of overweight and obesity worldwide, satiety-enhancing foods may help people control their energy intake and weight. In this study, an advanced near-real human gastric simulator equipped with a dynamic in vitro human stomach-IV (DIVHS-IV) system was used to determine the gastric digestion and gastric retention ratio of konjac flour (KF)/sodium caseinate (SC) mixtures with different ratios.

RESULTS

The apparent viscosity, viscoelastic properties, confocal laser scanning microscopy (CLSM) of the digested products were collected and analyzed to further study the effect of SC on the physical properties of KF during digestion. The results showed that the addition of SC could enhance the effect of KF on delaying gastric emptying in vitro. Besides, the addition of SC was shown to weaken the effect of gastric juice on the dilution of gastric contents by forming SC gel blocks in the acid environment. In particular, the synergistic gastric emptying delaying effect was the strongest in the KF/SC mixture containing 1% KF and 8% SC, and obvious massive aggregates were observed.

CONCLUSION

The combination of 1% KF and 8% SC was shown to synergistically delay gastric emptying and potentially enhance the sense of fullness. © 2022 Society of Chemical Industry.

Amorphophalli Rhizoma inhibits breast cancer growth, proliferation, migration, and invasion via the PI3K/AKT pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Amorphophalli Rhizoma (APR) is widely used as an adjuvant treatment for advanced and metastatic triple-negative breast cancer (TNBC), but its effects, potential active ingredients, and mechanism of action on estrogen receptor-positive (ER+) and human epidermal growth factor receptor-positive (HER2+) breast cancer cells were not reported.

AIM OF THE STUDY

The present study investigated the effects and mechanism of APR on ER+ and HER2+ breast cancer cells.

MATERIALS AND METHODS

Rotary evaporation was used to prepare different extracts of APR. Cell activity was assessed using the cell counting kit-8 (CCK-8) method. Wound healing assays were used to assess cell migration, and a cell invasion assay was performed using a Transwell chamber with Matrigel matrix. A xenograft model was used to analyze the inhibitory effects of APR on tumor growth. Bioinformatics analyses were used to explore the potential mechanism of APR in breast cancer. RT-qPCR and Western blotting were performed to reveal the molecular mechanism.

RESULTS

The ethyl acetate extract of APR showed the strongest tumor inhibitory effect on ER+ and HER2+ breast cancer cells compared to petroleum ether or N-butanol extracts. APR inhibited ER+ and HER2+ breast cancer cell growth, proliferation, migration, and invasion via the phosphatidylinositol-3 kinase (PI3K)/AKT pathway.

CONCLUSIONS

APR had a significant inhibitory effect on ER+ and HER2+ breast cancer cells via the PI3K/AKT signaling pathway. Therefore, APR may be useful for preventing ER+ and HER2+ breast tumor growth, proliferation, migration, and invasion.

Chemical Profiling and Evaluation of Antioxidant and Anticancer Potential of Tuber Crop Amorphophallus commutatus var. wayanadensis

Cancer and cancer-related diseases are a global health concern in the present scenario. Functional food and nutraceuticals are considered as a boon towards cancer management. Amorphophallus commutatus var. wayanadensis (ACW) is an herbaceous plant used by the local communities of Wayanad, India, for food and primary healthcare. Various radical scavenging and reducing power assays were undertaken to evaluate the antioxidant activity of methanolic extract of ACW (MEAC). In vitro anticancer activity was evaluated against HT-29 cell line by MTT assay, morphological analysis, DNA fragmentation assay and cell cycle analysis. Caspase and COX-2 enzyme assays were conducted to examine the underlying mechanism. Studies on Ehrlich Ascites Carcinoma (EAC) transplanted mice models was carried out to evaluate the in-vivo antioxidant and anticancer potential of MEAC. The major bioactive nutraceutical compound present in MEAC was isolated by bioactivity-guided fractionation. MEAC showed significant in vitro antioxidant activity. Further, MEAC promoted cytotoxicity against HT-29 cells by activating caspase-3 dependent apoptotic pathway with a cell cycle arrest at the G1/S phase and subsequent down regulation of COX-2 pathway. The potential antitumor activity of MEAC was further confirmed in EAC tumor bearing mice models in which treatment with MEAC increased the levels of antioxidant enzymes, improved the hematological profile towards normal and also augmented the life span of tumor bearing mice. β-sitosterol isolated from ACW induces anticancer activity via caspase-dependent pathway. Our study confirmed the antioxidant and anticancer activities of ACW, which proposes the medicinal importance of this plant as a preventive and supportive therapy for arising tumors.

Effects of konjac glucomannan on the long-term retrogradation and shelf life of boiled wheat noodles

BACKGROUND

Starch retrogradation and moisture migration of boiled wheat noodles (BWNs) result in quality deterioration and short shelf life. The objective of this research was to investigate whether konjac glucomannan (KGM) could improve the quality of BWNs and further establish the shelf-life prediction model.

RESULTS

The moisture distribution, recrystallization, and thermal properties of BWNs during refrigerated or ambient temperature storage were determined. Low-field nuclear magnetic resonance data showed that KGM addition induced left-shifts of T₂₁ and T₂₂ values, indicating that KGM limited the mobility of bound and immobile water among noodle matrices. X-ray diffraction spectra revealed that KGM did not change the crystal patterns of BWNs but could inhibit the starch recrystallization after refrigerated storage. The T_p and ΔH values of retrograded samples notably (P < 0.05) decreased with the increase of KGM addition, suggesting the hinderance of starch retrogradation behavior by KGM. The shelf life of BWNs was predicted by accelerated storage test combined with the Arrhenius equation. The present data displayed that the predicted shelf life of vacuum-packed and sterilized BWNs with 10 g kg^-1 KGM at 25 °C was 733 days, 2.4-fold that of the control group.

CONCLUSION

BWNs with KGM addition could inhibit starch retrogradation and improve the storage stability, consequently promoting noodle quality. © 2021 Society of Chemical Industry.

Characterization of silver carp myosin glycated with phosphorylated konjac oligo-glucomannan

BACKGROUND

Myosin (Ms) is abundant in fish meat, but it has limited application in the food industry because of its low solubility and thermal stability. Our previous reports found that these functional properties of Ms can be significantly improved after glycation with konjac oligo-glucomannan (KOG). However, the effects of phosphorylated KOG (PKOG) on physicochemical, structural and functional properties of silver carp Ms are still unknown.

RESULTS

This study characterized the silver carp Ms protein glycated with PKOG at 50 °C and 75% relative humidity for 48 h. As degree of phosphorylation increased, free amino content increased, whereas degree of grafting decreased. Meanwhile, isoelectric point (pI) reduced, however, PKOGs showed no differences in pI. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis suggested the formation of glycoconjugates, and scanning electron microscopy revealed thinner flakes and uneven appearance of glycoconjugates. Fourier transform infrared spectroscopy indicated that the amide I, II and III bands of Ms were changed by the glycation. Ms became highly soluble in 0.5 mol L^-1 NaCl with increased phosphate addition in PKOGs. Thermal stability of Ms was effectively improved when heated at 80 °C for 60 min.

CONCLUSION

Glycation with appropriate PKOG might be a promising method for Ms modification because of the resulting improvement in solubility and thermal stability. © 2021 Society of Chemical Industry.

An innovative konjac glucomannan/κ-carrageenan mixed tensile gel

BACKGROUND

Konjac glucomannan (KGM) showed a synergistic interaction with κ-carrageenan (CAR), which led to the formation of a promising compound hydrocolloid gel in the food field (such as jelly). Nevertheless, the mixed gels formed by adding KGM to CAR still displayed defects in gel strength and syneresis, and would hardly meet the quality requirements of some gel foods. However, deacetylated KGM and maltodextrin (MD) have always been used in gel foods and affect their viscosity and rheological properties.

RESULTS

In our paper, different amounts of MD were first used to alter the textural properties, and the results showed that both tensile strength and elongation exhibited first an increasing and then a decreasing trend with the increasing MD proportion and achieved a maximum at a final maltodextrin proportion of 4 g kg^-1 in the KGM/CAR/MD system. Based on the above results, we further explored the effects of deacetylation degree of KGM on the gel properties of mixed gel system. The results revealed that, compared to the native KGM, the partial deacetylated KGM was capable of significantly improving the tensile strength and elongation of KGM/CAR mixed gel.

CONCLUSION

Our study found that the appropriate addition of MD (0.4%) and DKGM were able to alter the tensile properties of KGM/CAR mixed gel, with potential to meet the needs of consumers and further design innovative tensile gel products in the soft gel industry. © 2021 Society of Chemical Industry.

Complex wall materials of polysaccharide and protein effectively protected numb-taste substance degradation of Zanthoxylum bungeanum

BACKGROUND

Hydroxyl-sanshools are mainly responsible for the numb taste and biological activities of Zanthoxylum bungeanum, but they show low water solubility, high volatility and easy degradation, which limit their application in the catering and food industries. Thus microcapsules of Z. bungeanum essential oil (ZBEO) were prepared to prevent numb-taste substance attenuation.

RESULTS

The complex effects of hydroxypropyl-β-cyclodextrin (HPCD) with other materials, such as konjac glucomannan octenyl succinate (KGOS), octenyl succinic anhydride-modified starch (OSAS), soy protein isolate (SPI) and gum arabic (GA), on the protection of the main numb-taste substance of ZBEO were investigated. Scanning electron microscopy and Fourier transform infrared spectroscopy analysis indicated that ZBEO was successfully encapsulated in the complex wall materials. X-ray diffraction indicated that the loaded essential oil did not affect the crystalline form of the wall material. The stability of the numb-taste substance α-sanshool in the microcapsules prepared with the complex microcapsule wall materials was higher than that in single-wall microcapsules. Storage stability evaluation indicated that microcapsules prepared with a combination of HPCD and SPI showed the greatest effect in maintaining the stability of the main numb-taste substance α-sanshool in ZBEO at room temperature, low pH and in high-salt conditions.

CONCLUSION

Complex wall materials of polysaccharide and protein could effectively protect the numb-taste substance degradation of Z. bungeanum during processing and storage. © 2021 Society of Chemical Industry.

A Purified Glucomannan Oligosaccharide from Amorphophallus konjac Improves Colonic Mucosal Barrier Function via Enhancing Butyrate Production and Histone Protein H3 and H4 Acetylation

A structurally defined konjac glucomannan oligosaccharide (KGMOS) with a relatively high molecular weight and narrow molecular weight distribution (molecular weight ranging from 3000 to 4000 Da, degree of polymerization (dp) 8-11) was prepared from native konjac glucomannan (KGM), and the beneficial effects and molecular mechanisms of KGMOS on colonic functions were investigated in C57BL/6 mice. The results are the first to reveal that KGMOS regulated intestinal microflora composition to facilitate the production of colonic butyrate. Elevated butyrate production further increased the acetylation of histone proteins H3 and H4 and thus enhanced the transcription of the major colonic mucin gene Muc2 and the secretion of mucin elements, which represents a new molecular mechanism of KGM oligosaccharide consumption. The findings indicate that KGM oligosaccharides with specific molecular sizes have highly desirable functional properties and potentially could improve gut health by promoting the barrier function of the colonic mucosa.

Effects of dietary fibers with different physicochemical properties on fermentation kinetics and microbial composition by fecal inoculum from lactating sows in vitro

BACKGROUND

Efficient utilization of dietary fibers (DFs) is important for optimizing feed resource utilization and animal health. The aim of the current study was to assess the effects of DFs with varying physicochemical properties (bulky, viscous, and fermentable) on fermentation kinetics and microbial composition during in vitro fermentation by fecal inoculum from lactating sow. According to the physicochemical properties, three different DFs, lignocellulose (LC), modified cassava starch (MCS) and konjac flour (KF) were selected as bulky fiber, fermentable fiber and viscous fiber respectively. Gas production, short-chain fatty acids (SCFAs) profiles and microbial composition were monitored during the fermentation.

RESULTS

Results showed that the gas production in 72 h (GP_72h ) ranked as: KF > MCS > LC (P < 0.05). The halftime of asymptotic gas production ranked as: KF < MCS = LC (P < 0.001). At 36 h of fermentation, MCS group showed higher concentrations of formic acid and lactate than LC and KF groups, whereas KF group showed higher concentrations of propionate and butyrate than LC and MCS groups (P < 0.05). At 72 h of fermentation, KF group showed higher concentrations of formic acid, lactate and propionate than LC and MCS groups, whereas MCS group showed higher concentrations of acetate and butyrate than LC and KF groups (P < 0.05). At 36 h of fermentation, Anaerovibrio and Erysipelatoclostridium abundances were higher in KF group, whereas Proteiniclasticum abundance was higher in MCS group. At 72 h of fermentation, the abundance of Fibrobacter in LC group was higher than that in MCS and KF groups. In addition, we also observed that the abundances of certain specific bacteria (Anaerovibrio and Erysipelatoclostridium) were closely related to the SCFAs production (propionate and butyrate) at different fermentation times.

CONCLUSION

Collectively, the present study revealed that KF is a fast fermentation fiber which could produce propionate and butyrate rapidly, whereas LC is difficult to be fermented by bacteria. In addition, the fermentation of DFs with different physicochemical properties had divergent impacts on microbial composition and SCFA production. These findings deepen our understanding of the mechanisms of interaction between DFs and intestinal microbiota, and provide new ideas for the rational use of fiber resources in lactating sows. © 2020 Society of Chemical Industry.

Green Synthesis of Gold and Silver Nanoparticles by Using Amorphophallus paeoniifolius Tuber Extract and Evaluation of Their Antibacterial Activity

In this report, we discussed rapid, facile one-pot green synthesis of gold and silver nanoparticles (AuNPs and AgNPs) by using tuber extract of Amorphophallus paeoniifolius, and evaluated their antibacterial activity. AuNPs and AgNPs were synthesized by mixing their respective precursors (AgNO₃ and HAuCl₄) with tuber extract of Amorphophallus paeoniifolius as the bio-reducing agent. Characterization of AuNPs and AgNPs were confirmed by applying UV-vis spectroscopy, field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDS). From UV-vis characterization, surface plasmon resonance spectra were found at 530 nm for AuNPs and 446 nm for AgNPs. XRD data confirmed that both synthesized nanoparticles were face-centered cubic in crystalline nature, and the average crystallite sizes for the assign peaks were 13.3 nm for AuNPs and 22.48 nm for AgNPs. FTIR data evaluated the characteristic peaks of different phytochemical components of tuber extract, which acted as the reducing agent, and possibly as stabilizing agents. The antibacterial activity of synthesized AuNPs and AgNPs were examined in Muller Hinton agar, against two Gram-positive and four Gram-negative bacteria through the disc diffusion method. AuNPs did not show any inhibitory effect, while AgNPs showed good inhibitory effect against both Gram-positive and Gram-negative bacteria.

Is elephant foot yam (Amorphophallus paeoniifolius) tuber detrimental to patients with diabetes? (Or a myth?)

Elephant foot yam is widely consumed as a vegetable and locally known as 'Ol' in Bangladesh. However, taboos regarding elephant foot yam are the prominent barrier for diabetic patients to consume this tuber. The study aims to judge the concept scientifically. The literature review showed that elephant foot yam tuber is a good source of carbohydrates, protein, fiber, and minerals but low in fat. Secondary metabolites viz. phytochemicals of this tuber had a significant anti-hyperglycemic effect. In conclusion, elephant foot yam tuber is safe and beneficial for patients with diabetes.

Quality characteristics of duck jerky: combined effects of collagen and konjac

The effects of curing solution prepared using various ratios of a combination of collagen and konjac (100/0, 80/20, 60/40, 40/60, 20/80, and 0/100) on the quality characteristics of duck jerky were investigated. The moisture, processing yield, water activity, tenderness score, and overall acceptability score of duck jerky were the highest when the ratio of added collagen and konjac was 60/40. The rehydration ratio of duck jerky increased due to the addition of collagen and konjac combinations in curing solution, and was higher for the 60/40 and 40/60 combinations than for the others. The shear force of duck jerky was the highest for the untreated jerky, and the lowest for the jerky formulated with the 60/40 combination of collagen and konjac solution. No significant differences were observed in lightness and yellowness between jerky treated with combinations of collagen and konjac. Taken together, our results indicate that addition of a combination of collagen and konjac at a 60/40 ratio results in good quality characteristics of duck jerky. Thus, we suggest that the use of combinations of collagen and konjac in duck jerky processing is beneficial for improving the quality characteristics of the jerky.

Konjaku flour reduces obesity in mice by modulating the composition of the gut microbiota

BACKGROUND

Changes in the intestinal flora composition is referred to as dysbiosis, which is related to obesity development, thus supporting the potential roles of nutrients acting on intestinal flora to exert salutary effects on energetic metabolism of host. Dietary fiber has been known to affect the composition of intestinal flora. The aim of the present study was to investigate the functional effects of konjac flour (KF) on obesity control in respect to improving inflammation, metabolism, and intestinal barrier function, and the possible association of the effects with intestinal flora composition changes.

METHODS

Mice (n = 30) were randomly divided into control group (n = 10), high-fat-diet (HFD) group (n = 10), and KF intervention group (n = 10), followed by feeding for 12 weeks and with adding a KF daily supplementation for the treatment group. Body weight, fat accumulation, inflammation, and energetic metabolism markers in multiple tissues and the gut microbiota of the mice were examined at the end of the experiment.

RESULTS

The KF supplementation significantly reduced the gains in weight, fat mass, as well as adipocyte size of HFD mice and lowered the serum TC, leptin (LEP), thiobarbituric acid-reacting substance (TBARS), IL-6, and lipopolysaccharide (LPS) levels in HFD mice. KF also upregulated the expression of intestinal mucosa protein gene Intection and tight junction ZO-1 in HFD mice, as well as upregulate the expression of energy metabolism genes PPARα and CPT-1 as well as the fat metabolism gene HLS in livers and fat tissues, and downregulate that of fat synthesis gene PPARγ (p < 0.05). The KF treatment increases the α-diversity and change the β-diversity of the intestinal microflora in HFD mice and boosted the abundances of some obesity-related beneficial microorganisms (such as Megasphaera elsdenii) in the intestinal microflora of HFD mice, while reduced those of harmful microorganisms (such as Alistipes, Alloprevotella, Bacteroides acidifaciens, and Parabacteroides goldsteinii). The abundance of Alistipes was positively correlated with weight, fat mass, serum TC, TG, LEP, IL-6, and LPS contents as well as PPARγ gene expression; while notably and negatively related to the expression of CPT-1 and HLS genes (p < 0.01). KF remarkably increased the abundance of Aerococcaceae, while reduced that of Alistipes finegoldii (p < 0.01).

CONCLUSIONS

Supplementation with KF achieves favorable effects on treating obesity, improving inflammatory response, metabolism, and intestinal barrier function, by regulating intestinal microfloral structure in HFD-fed mice.

Genomic and GeneChip expression profiling reveals the inhibitory effects of Amorphophalli Rhizoma in TNBC cells

ETHNOPHARMACOLOGICAL RELEVANCE

Amorphophalli Rhizoma has been widely used as an adjuvant treatment for advanced or metastatic breast cancer, pancreatic cancer, hepatoma, and malignant lymphoma, but its molecular mechanism of action for treatment of metastatic triple-negative breast cancer (TNBC) is generally poorly understood.

AIM OF THE STUDY

To investigate genomic changes related to the inhibitory effect of Amorphophalli Rhizoma and to elucidate the molecular mechanism of this inhibition in MDA-MB-231 TNBC cells.

MATERIALS AND METHODS

Gene chip analysis was employed to explore genomic changes caused by Amorphophalli Rhizoma in TNBC cells. Potential classical signaling pathways, upstream regulators, functions, regulatory effects and gene interaction networks were analyzed by Ingenuity Pathway Analysis (IPA). Real-time quantitative PCR (RT-qPCR) and RNA interference (RNAi) assays were used to clarify the roles of potential target genes.

RESULTS

In total, 536 significantly upregulated and 648 significantly downregulated genes were identified between the group treated with Amorphophalli Rhizoma extract and that treated with vehicle. Many of these differentially expressed genes (DEGs) in TNBC cells are involved in DNA replication, recombination and repair, the cell cycle, and cellular assembly and organization. Attenuation of KNL1, OLFML2A, RTKN2 and SGO1 gene expression by Amorphophalli Rhizoma significantly induced cell cycle arrest and suppressed cell proliferation and migration.

CONCLUSIONS

The inhibitory effects of Amorphophalli Rhizoma in TNBC cells likely occur through regulation of the spindle checkpoint, chromosomal and centrosomal instability, and cell membrane stability.

Hypoglycemic and Hypolipidemic Effects of Glucomannan Extracted from Konjac on Type 2 Diabetic Rats

Diabetes and its complications are one of the most concerned metabolic diseases worldwide and threaten human health severely. Hypoglycemic and hypolipidemic effects of glucomannan extracted from konjac on high-fat diet and streptozocin-induced type 2 diabetic rats were evaluated in this study. Administration of konjac glucomannan significantly decreased the levels of fasting blood glucose, serum insulin, glucagon-like peptide 1, and glycated serum protein. The concentrations of serum lipids, including total cholesterol, triacylglycerols, low-density lipoprotein cholesterol, and non-esterified fatty acid, were notably reduced by konjac glucomannan treatment. In addition, antioxidant capacity, pancreatic injury, and adipose cell hypertrophy were ameliorated by konjac glucomannan administration in type 2 diabetic rats. Besides, ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry-based lipidomics analysis was used to explore the improvement of lipid metabolic by konjac glucomannan treatment. The disturbance of glycerolipid (diacylglycerol, monoacylglycerol, and triacylglycerol), fatty acyl (acylcarnitine and hydroxyl fatty acid), sphingolipid (ceramide and sphingomyelin), and glycerophospholipid (phosphatidylcholine) metabolism were attenuated by the glucomannan treatment. This study provided new insights for investigating the anti-diabetic effects of konjac glucomannan and suggests that konjac glucomannan may be a promising nutraceutical for treating type 2 diabetes.

Konjac glucomannan octenyl succinate (KGOS) as an emulsifier for lipophilic bioactive nutrient encapsulation

BACKGROUND

Konjac glucomannan octenyl succinate (KGOS) has excellent emulsification properties and can potentially be used in the food industry as an emulsifier, stabilizer and microcapsule wall material. In the present study, the in vitro digestion properties and emulsification capability and stability of KGOS were studied to evaluate the transport and encapsulation characteristics of KGOS with insoluble bioactive nutrients.

RESULTS

Confocal scanning laser microscopy (CSLM) suggested that oil droplets could be encapsulated by KGOS into regular spheres. In vitro digestion properties showed that KGOS is effective for colon-targeted transport. β-Carotene was selected as a representative lipophilic bioactive compound to evaluate the emulsification characteristics of KGOS. The loading capacity of the 0.4 mg mL^-1 KGOS solution for β-carotene was 3.26%, and transmission electron microscopy suggested that the self-aggregate particles of KGOS/β-carotene (KGOSC) were more uniform than KGOS. With a composition of 0.03% β-carotene, 0.3% KGOS and 10% medium-chain triglycerides, the emulsification yield of the KGOSC nanoemulsion was more than 95%. After 30 days of storage, the particle size and polydispersity index of the KGOSC nanoemulsion were less than 5 nm and 0.5, respectively, and the sensitivity of KGOSC nanoemulsions to storage conditions decreased in the order temperature, oxygen and light.

CONCLUSION

The results of this study suggested that KGOS is a good potential emulsifier and stabilizer for lipophilic bioactive nutrient encapsulation. © 2018 Society of Chemical Industry.

Metagenomic Mining and Functional Characterization of a Novel KG51 Bifunctional Cellulase/Hemicellulase from Black Goat Rumen

A novel KG51 gene was isolated from a metagenomic library of Korean black goat rumen and its recombinant protein was characterized as a bifunctional enzyme (cellulase/hemicellulase). In silico sequence and domain analyses revealed that the KG51 gene encodes a novel carbohydrate-active enzyme that possesses a salad-bowl-like shaped glycosyl hydrolase family 5 (GH5) catalytic domain but, at best, 41% sequence identity with other homologous GH5 proteins. Enzymatic profiles (optimum pH values and temperatures, as well as pH and thermal stabilities) of the recombinant KG51 bifunctional enzyme were also determined. On the basis of the substrate specificity data, the KG51 enzyme exhibited relatively strong cellulase (endo-β-1,4-glucanase [EC 3.2.1.4]) and hemicellulase (mannan endo-β-1,4-mannosidase [EC 3.2.1.78] and endo-β-1,4-xylanase [EC 3.2.1.8]) activities, but no exo-β-1,4-glucanase (EC 3.2.1.74), exo-β-1,4-glucan cellobiohydrolase (EC 3.2.1.91), and exo-1,4-β-xylosidase (EC 3.2.1.37) activities. Finally, the potential industrial applicability of the KG51 enzyme was tested in the preparation of prebiotic konjac glucomannan hydrolysates.

Preparation of konjac glucomannan/casein blending gels optimized by response surface methodology and assessment of the effects of high-pressure processing on their gel properties and structure

BACKGROUND

In order to improve the compatibility of polysaccharide-protein mixtures and enhance their performance, a response surface methodology was used to optimize the preparation conditions of konjac glucomannan/casein blend gel. Moreover, the effects of high-pressure processing (HPP) on the gel properties and structure were also investigated.

RESULTS

The optimal preparation parameters were a temperature of 60 °C, a total concentration 40 g kg^-1 , and a dietary alkali concentration 5 g kg^-1 . Under these conditions, the experimental value of hardness was 38.7 g, which was close to the predicted value. HPP increased gel hardness by 161-223% and led to a more compact structure at 200-600 MPa/10 min, while a hardness increase of ∼120% and damaged structure were observed at 600 MPa/30 min. Fourier transform infrared spectroscopy showed that noncovalent interactions are likely the most important factor in the modification of gel hardness; indeed, hydrogen bonding interactions in the gels are enhanced when subjected to HPP, but are weakened at 600 MPa/30 min.

COUCLUSION

Protein-polysaccharide complexes with excellent properties could be obtained through this method, with broad application prospects in the food industry. © 2018 Society of Chemical Industry.

Beneficial effect of Amorphophallus paeoniifolius tuber on experimental ulcerative colitis in rats

CONTEXT

The tuber of Amorphophallus paeoniifolius (Dennst.) Nicolson (Araceae), commonly called Suran or Jimmikand, has high medicinal value and is used ethnomedicinally for the treatment of different gastrointestinal and inflammatory disorders.

OBJECTIVE

The present study evaluated the effects of extracts of Amorphophallus paeoniifolius tubers on acetic acid-induced ulcerative colitis (UC) in rats.

MATERIALS AND METHODS

Wistar rats were orally administered methanol extract (APME) or aqueous extract (APAE) (250 and 500 mg/kg) or standard drug, prednisolone (PRDS) (4 mg/kg) for 7 days. On 6th day of treatment, UC was induced by transrectal instillation of 4% acetic acid (AA) and after 48 h colitis was assessed by measuring colitis parameters, biochemical estimations and histology of colon.

RESULTS

APME or APAE pretreatment significantly (p < .05-.001) prevented AA-induced reduction in body weight and increase in colitis parameters viz. stool consistency, colon weight/length ratio and ulcer score, area and index. Extracts treatment attenuated (p < .001) increase in alkaline phosphatase and lactate dehydrogenase in serum and myeloperoxidase activity and cytokines in colon tissue due to AA administration. Extracts treatment prevented AA-induced elevation in lipid peroxidation and decline in activities of superoxide dismutase and catalase and reduced-glutathione content (p < .05-.001) along with histopathological alterations. PRDS also showed similar ameliorative effect on colitis.

DISCUSSION AND CONCLUSION

APME and APAE showed a preventive effect on UC, and ameliorated inflammation and oxidative damage in colon. The effects may be attributed to presence of phytochemicals, betulinic acid, β-sitosterol, and glucomannan. In conclusion, the tuber of Amorphophallus paeoniifolius exhibited an anticolitic effect through anti-inflammatory and antioxidant action.

Phylogenetic trends in the evolution of inflorescence odours in Amorphophallus

The chemical composition of inflorescence odours of 80 species of Amorphophallus (Araceae) were determined by headspace-thermal desorption GC-MS. When compared to published molecular phylogenies of the genus, the data reveal evidence both of phylogenetic constraint and plasticity of odours. Dimethyl oligosulphides were found as common constituents of Amorphophallus odours and were the most abundant components in almost half of the species studied. Odours composed mainly of dimethyl oligosulphides, and perceived as being 'gaseous', were only found among Asian species, and some of these species clustered in certain clades in molecular phylogenies; e.g. in two clades in Amorphophallus subgenus Metandrium. However, some species with gaseous odours were found to be closely related to species producing odours more reminiscent of rotting meat in which various minor components accompany the dominant dimethyl oligosulphides. These two broad types of odours have co-evolved with other inflorescence characteristics such as colour, with species with rotting meat odours having darker inflorescences. Species producing pleasant odours characterised by benzenoid compounds constitute two broad groups that are not related in published phylogenies. Species having fruity odours containing 1-phenylethanol derivatives mainly occur in a clade in subgenus Metandrium while those with anise odours composed almost solely of the 2-phenylethanol derivative 4-methoxyphenethyl alcohol are restricted to a clade in subgenus Scutandrium. Phylogenetic mapping of odours also indicates that the evolution of some odour types is likely to have been influenced by ecological factors. For example, species producing fishy odours dominated by trimethylamine and occurring in N and NE Borneo are not all closely related. Conversely, two sister species, A. mossambicensis and A. abyssinicus, which are morphologically very similar and have overlapping geographical distribution, produce odours which are very different chemically. The pressure of pollinator resource has therefore been a factor influencing the evolution of odours in Amorphophallus, driving both the divergence of odour types in some taxa and the convergence of odour types in others.

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.

Deacetylated Konjac Glucomannan Is Less Effective in Reducing Dietary-Induced Hyperlipidemia and Hepatic Steatosis in C57BL/6 Mice

Konjac gel foods that mainly consist of deacetylated konjac glucomannan (Da-KGM) are considered to have the same health benefits as native konjac glucomannan (KGM); however, no definitive data support this notion. The objective of this study was to compare the effects of Da-KGM and KGM on the hyperlipidemia and liver steatosis induced by high-fat diet feeding and to investigate the underlying molecular mechanisms. C57BL/6 mice were fed (1) normal chow diet, (2) high-fat diet, (3) HFD with KGM, or (4) HFD with Da-KGM for 10 weeks. KGM, but not Da-KGM, showed decreased fat accumulation, improved blood and liver lipid profiles, and prevention of liver lipid droplet deposition compared with HFD. Compared with Da-KGM, KGM increased the outputs of fecal bile acid (KGM 22.5 ± 2.34 mg/g vs Da-KGM 19.3 ± 1.87 mg/g), fat (KGM 5.56 ± 0.68 mg/g vs Da-KGM 4.42 ± 0.57 mg/g) and cholesterol (KGM2.67 ± 0.43 mg/g vs Da-KGM 1.78 ± 0.28 mg/g), fecal concentrations of total short-chain fatty acids (KGM 103 ± 14.8 μmol/g vs Da-KGM 74.5 ± 8.49 μmol/g), and improved hepatic antioxidant status and upregulated CYP7A1 and LDLR gene expression. These findings suggest that deacetylation of KGM negatively affects its fermentation characteristics and its inhibition of lipid absorption, which thereby reduces Da-KGM's health benefits.

Curative effect of Amorphophallus paeoniifolius tuber on experimental hemorrhoids in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Amorphophallus paeoniifolius (Dennst.) Nicolson (Family- Araceae) is a crop of south East Asian origin. In India, its tuber is widely used in ethnomedicinal practices by different tribes for the treatment of piles (hemorrhoids).

AIM

The present study evaluated the effect of methanolic and aqueous extract of Amorphophallus paeoniifolius tuber on croton oil induced hemorrhoids in rats.

MATERIALS AND METHODS

The methanolic extract was standardized with the major phenolic compound, betulinic acid, by HPLC. The hemorrhoids were induced by applying 6% croton oil preparation in the ano-rectal region. Rats were orally administered methanolic and aqueous extract at doses of 250 and 500mg/kg, each for 7 days. Pilex (200mg/kg) was used as reference anti-hemorrhoidal drug. Hemorrhoids were assessed on eighth day by measuring hemorrhoidal and biochemical parameters along with histology of ano-rectal tissue.

RESULTS

Croton oil application caused induction of hemorrhoids as indicated by significant (p<0.001) increase in plasma exudation of Evans blue in ano-rectal tissue, macroscopic severity score and ano-rectal coefficient as compared to normal rats. It significantly (p<0.001) elevated lactate dehydrogenase and cytokines (TNF-α and IL-6) levels in serum and increased myeloperoxidase activity and lipid peroxidation in ano-rectal tissue along with marked histological damage as compared to normal rats. Treatment with tuber extracts and pilex significantly (p<0.05-p<0.001) ameliorated Evans blue exudation, hemorrhoidal parameters and other biochemical parameters with attenuation of tissue damage compared to hemorrhoid control rats. The results indicate that tuber extracts exhibited curative action on hemorrhoids. The aqueous extract showed more pronounced effect than methanolic extract. The effects may be attributed to anti-inflammatory and antioxidant properties.

CONCLUSION

Results indicate that tuber of Amorphophallus paeoniifolius exhibited curative action on hemorrhoids through anti-inflammatory and antioxidant properties. The study validates the ethnomedicinal use of tuber in hemorrhoids and implicates its therapeutic potential as an anti-hemorrhoidal agent.

Soluble Fiber with High Water-Binding Capacity, Swelling Capacity, and Fermentability Reduces Food Intake by Promoting Satiety Rather Than Satiation in Rats

To understand whether soluble fiber (SF) with high water-binding capacity (WBC), swelling capacity (SC) and fermentability reduces food intake and whether it does so by promoting satiety or satiation or both, we investigated the effects of different SFs with these properties on the food intake in rats. 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 (PWMS) plus guar gum (PG), and PWMS starch plus xanthan gum (PX) for three weeks, with the measured values of SF, WBC, and SC in the four diets following the order of PG > KF > PX > control. Food intake, body weight, meal pattern, behavioral satiety sequence, and short-chain fatty acids (SCFAs) in cecal content were evaluated. KF and PG groups reduced the food intake, mainly due to the decreased feeding behavior and increased satiety, as indicated by decreased meal numbers and increased inter-meal intervals. Additionally, KF and PG groups increased concentrations of acetate acid, propionate acid, and SCFAs in the cecal contents. Our results indicate that SF with high WBC, SC, and fermentability reduces food intake—probably by promoting a feeling of satiety in rats to decrease their feeding behavior.

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.

Organochlorine (chlordecone) uptake by root vegetables

Chlordecone, an organochlorine insecticide, continues to pollute soils in the French West Indies. The main source of human exposure to this pollutant is food. Root vegetables, which are staple foods in tropical regions, can be highly contaminated and are thus a very effective lever for action to reduce consumer exposure. We analyzed chlordecone contamination in three root vegetables, yam, dasheen and sweet potato, which are among the main sources of chlordecone exposure in food in the French West Indies. All soil types do not have the same potential for the contamination of root vegetables, allophanic andosols being two to ten times less contaminating than non-allophanic nitisols and ferralsols. This difference was only partially explained by the higher OC content in allophanic soils. Dasheen corms were shown to accumulate more chlordecone than yam and sweet potato tubers. The physiological nature of the root vegetable may explain this difference. Our results are in good agreement with the hypothesis that chlordecone uptake by root vegetables is based on passive and diffusive processes and limited by transport and dilution during growth.

acoustic assessment of a konjac–carrageenan tissue-mimicking material aT 5–60 MHZ

The acoustic properties of a robust tissue-mimicking material based on konjac–carrageenan at ultrasound frequencies in the range 5–60 MHz are described. Acoustic properties were characterized using two methods: a broadband reflection substitution technique using a commercially available preclinical ultrasound scanner (Vevo 770, FUJIFILM VisualSonics, Toronto, ON, Canada), and a dedicated high-frequency ultrasound facility developed at the National Physical Laboratory (NPL, Teddington, UK), which employed a broadband through-transmission substitution technique. The mean speed of sound across the measured frequencies was found to be 1551.7 ± 12.7 and 1547.7 ± 3.3 m s21, respectively. The attenuation exhibited a non-linear dependence on frequency, f (MHz), in the form of a polynomial function: 0.009787f2 1 0.2671f and 0.01024f2 1 0.3639f, respectively. The characterization of this tissue-mimicking material will provide reference data for designing phantoms for preclinical systems, which may, in certain applications such as flow phantoms, require a physically more robust tissuemimicking material than is currently available.

Biogenic amines in low- and reduced-fat dry fermented sausages formulated with konjac gel

Biogenic amines in low- and reduced-fat dry fermented sausages made with konjac gel (KG) as pork backfat replacer were studied. An increase (P < 0.05) was observed in the microbial count during the fermentation process, reaching levels of over 8 Log cfu/g of total viable microorganisms and lactic acid bacteria. However, no significant differences were observed in the microbiota evolution as a function of the reformulation process (fat and konjac gel content). High levels of physiological amines (spermidine, spermine, and agmatine) were observed in the raw material. From day 2 of the fermentation process an increase (P < 0.05) was observed in tyramine and putrescine, which were the predominant amines at the end of the storage period. The increase in these amines was proportional to the presence of KG and fat reduction. This can also be seen for spermine, with agmatine showing the inverse. The biogenic amine levels in these products reformulated with KG are not considered to pose a health risk to consumers.

[Physico-chemical properties of microbial and plant polysaccharides structurants]

The comparative investigation of physico-chemical properties of plant (guar gum, konjac-mannan) and microbial (xanthan gum) origin structurants have been carried out. Among them, xanthan sigma (1544 mPa) and konjac-mannan (5000 mPa) have the best initial viscosity. It has been shown that due to molecular-mass characteristics xanthan (74.3%) gum, ksampan (39%) and konjac-mannan (42.1%) have the highest percentage of high-weight fractions. It has been established that mannose, glucose and galactose as well as unidentified substances are presented in different concentrations in the structure of structurants.

Adsorption-desorption properties and characterization of crosslinked Konjac glucomannan-graft-polyacrylamide-co-sodium xanthate

A new flocculant, based on Konjac-graft-poly (acrylamide)-co-sodium xanthate (CKAX), was synthesized in aqueous solution using epichlorohydrin (ECH) as the cross-linker and ceric ammonium nitrate (CAN) as the initiator. X-ray diffraction indicated the existence of strong interaction between KGM and reactant, including intermolecular and intramolecular hydrogen bonds. Microscopy images exhibited the appropriate pore size and distribution, which might be related to a higher capacity of flocculation and adsorption. Thermo gravimetric analysis showed that the synthetic polymer could improve the thermo-stability of the natural polysaccharides, and there was a positive correlation between polymer residual weight and flocculation. The adsorption and desorption properties for copper ions indicated that the adsorption rate could be described by a pseudo-second-order rate model, and the Freundlich model provides the best fit for the resulting adsorption isotherm. The flocculant can be regenerated in HNO(3) solution.

Adsorption of tannin from aqueous solution by deacetylated konjac glucomannan

Konjac glucomannan treated by alkali solution through deacetylated reaction was used as a new water insoluble adsorbent to remove tannin from aqueous solution. A comprehensive study on adsorption of tannin by deacetylated konjac glucomannan (DKGM) was conducted regarding the effects of initial pH, adsorbent dosage, contact time, temperature and initial tannin concentration. The adsorption process was much dependent on the pH and temperature and was found to follow pseudo-second-order kinetics. The optimum pH value was at pH ranging from 2 to 6. The maximum removal efficiency of tannin from aqueous solution was 90%. Increasing the adsorption temperature would result in lower adsorption capacity, suggesting that adsorption of tannin onto DKGM was exothermic in nature. The adsorption isotherms were measured at various temperatures and correlated to Freundlich isotherms. Adsorption mechanism was confirmed that the interaction of DKGM and tannin was through hydrogen bonding. It was also observed that DKGM possesses excellent reusability for tannin removal.

Lead and other elemental content of normal and Erwinia carotovora infected Amorphallus konjac corms

Amorphallus konjac corms are important agriculture products in Yichang, Hubei Province, China. The Erwinia carotovora infected Amorphallus konjac corms are processed to food as normal corms. The contents of elements and L: -Proline in the normal and infected Amorphallus konjac corms are analyzed for food safety. Even growing in the almost same soil condition, the contents of Pb, Cd, Mn and L: -Proline in infected corms are significantly higher than those of normal corms (show data as suggestion by peers). Our study suggested that the infected corms are not suitable for food purpose.

Antioxidant potential of Amorphophallus paeoniifolius in relation to their phenolic content

The present study evaluates the antioxidative and radical scavenging potential of the tuber extract of Amorphophallus paeoniifolius (Dennst.) Nicolson, (Araceae). The ethanol extract of A. paeoniifolius (APE) was studied for the inhibition of lipid peroxidation estimated in terms of thiobarbituric acid reactive substances (TBARS) and the levels were reduced by 4.3% to 67.2% in a dose-dependent manner. Further, APE was analyzed for scavenging capacities based on 1,1-diphenyl-2-picrylhydrazyl-2-radical (DPPH) assay and percentage inhibition activity based on 2,2-azinobis-(-3-ethyl) benzo-thiozoline-6-sulfonate (ABTS+) and H2O2. The A. paeoniifolius extract showed a maximum of 68.6% of DPPH scavenging activity and the maximum inhibition of 74% and 67.2% in the case of ABTS and H2O2, respectively. The antioxidant efficiency and inhibition of oxidation of the extract was found to be dose-dependent at the tested concentrations of 1-50 microg/mL. High-performance thin layer liquid chromatography (HPTLC) profile of the extract suggests the presence of polyphenols such as gallic acid, resveratrol, quercetin and two unidentified compounds. The results suggest that the ethanol extract of A. paeoniifolius has a potent antioxidant activity in vitro and can be utilized as an effective and safe source of antioxidants.

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.

Antioxidant and hepatoprotective activity of ethanolic and aqueous extracts of Amorphophallus campanulatus Roxb. tubers

In the present study, the hepatoprotective activity of ethanolic and aqueous extracts of Amorphophallus campanulatus (Roxb.) tubers were evaluated against carbon tetrachloride (CCl4) induced hepatic damage in rats. The extracts at a dose of 500 mg/kg were administered orally once daily. The substantially elevated serum enzymatic levels were significantly restored towards normalization by the extracts. Silymarin was used as a standard reference and exhibited significant hepatoprotective activity against carbon tetrachloride induced haptotoxicity in rats. The biochemical observations were supplemented with histopathological examination of rat liver sections. The results of this study strongly indicate that Amorphophallus campanulatus (Roxb.) tubers have potent hepatoprotective action against carbon tetrachloride induced hepatic damage in rats. The ethanolic extract was found hepatoprotective more potent than the aqueous extract. The antioxidant activity was also screened and found positive for both ethanolic and aqueous extracts. This study suggests that possible mechanism of this activity may be due to free radical scavenging potential caused by the presence of flavonoids in the extracts.

[Effect of konjac polysaccharide on levels of leptin and Na+ -K+-ATPase of mice treated with high fat]

OBJECTIVE

To investigate the effect of konjac polysaccharide on serum leptin and intestinal mucosa Na+ -K+-ATPase activity of mice treated with high fat.

METHODS

Mice were divided into normal control, high-fat control, and high, middle, low dose of konjac polysaccharide combining high fat groups. The mice were feed for twenty days. The levels of serum leptin were determined by ELISA method, and intestinal mucosa Na+ -K+-ATPase activities were determined by spectrophotometry. The body weight, adipose tissue and blood glucose were also examined.

RESULTS

At the 10th day, body weight and postprandial blood glucose of high-fat control group were (31.3 +/- 2.11) g and (7.5 +/- 1.15) mmol/L, those of high dose konjac polysaccharide combining high fat group were(28.0 +/- 2.06) g and (4.8 +/- 0.73) mmol/L. At the 20th day, concentrations of serum leptin and Na+ -K-ATPase activities of high-fat control group were (1078.5 +/- 61.69) pg/ml and (16.2 +/- 1.48) micromol Pi/(mg pro x h), those of high dose konjac polysaccharide combining high fat group were (820.5 +/- 58.52) pg/ml and (11.2 +/- 1.10) micromol Pi/(mg pro x h). All differences between two groups were significant (P < 0.05).

CONCLUSION

Konjac polysaccharide could decrease level of body weight, postprandial blood glucose, serum leptin and intestinal mucosa Na -K+-ATPase activity of mice treated with high fat.

Konjac glucomannan and konjac glucomannan/xanthan gum mixtures as excipients for controlled drug delivery systems. Diffusion of small drugs

Konjac glucomannan (KGM), alone or in combination with xanthan gum (XG), was evaluated as main component of systems capable of controlling the diffusion of small molecules with a view of their use in drug delivery. To provide the study with enough general character, KGM batches were obtained from the three main areas of excipient harmonization (Europe, USA and Japan). The rheological evaluation at physiological temperature of KGM (0.5%, w/v) aqueous dispersions, with or without XG at different ratios, showed significant variability among the three KGMs owing to differences in the acetylation degree. The Japanese and European varieties of KGM synergically interact with XG giving rise to gel formation; the synergism being maximum at a 1:1 ratio. By contrast, the American KGM does not show such effect forming only viscous solutions. Drug diffusion coefficients of theophylline and diltiazem HCl, with different molecular size and net charge, were evaluated in systems containing KGM/XG ratio 1:1. KGM/XG systems were more efficient than the XG alone dispersion for controlling drug diffusion of small molecules because of the gel formation. These results point out the potential of mixtures of some KGM types with XG to develop delivery systems capable of maintaining physical integrity and drug release control for up to 8-h period.

[Studies on drug release from aminophylline konjac glucomannan matrix tablet]

OBJECTIVE

In vitro aminophylline release from matrix tablets with konjac glucomannan (KGM) were studied to elevate the feasibility of KGM used as carrier materials to prepare matrix tablets.

METHOD

KGM hydrophilic matrix tablets were prepared by direct compression method with aminophylline as the model drug. The effects of test methods, pH values, ionic strength of dissolution media and rotation speeds on drug release were studied by in vitro dissolution experiment.

RESULT

The MDT value tested by Paddle method was less than that tested by Basket method (P < 0.05). Among the rate of drug release in different dissolution media, distillded water is the fastest, pH 6. 8 PBS is the second, 0.1 mol x L(-1) HCL is the slowest. MDT increased with increasing the ionic strength of dissolution media (P < 0.05). MDT decreased with increasing the rotation speed, but the rate of drug release did not increase when the rotation speed was more than 100 r x min(-1) (P > 0.1). The mechanism of drug release were diffusion and erosion.

CONCLUSION

KGM can be used in sustained delivery systems as a good candidate of hydrophilic polymer.

[Study on in vitro colon-specific enzymatic degradation performance of carboxymethyl konjac glucomannan]

OBJECTIVE

In vitro enzymatic degradation of carboxymethy konjac glucomannan (CMKGM) were studied to evaluate the feasibility of CMKGM used as carrier materials to prepare colon-specific drug delivery systems.

METHOD

The solutions with rat gastrointestinal tract (GIT) contents or with commercial enzymes were chosen to stimulate in vivo GIT environment, respectively. Enzymatic degradation of CMKGM were studied by viscometic procedure. Degradation kinetics of CMKGM and konjac glucomannan (KGM) by enzymes, the effects of the degree of substitution (DS) of CMKGM and the pH of solution on its susceptibility to degradation were investigated.

RESULT

CMKGM were degraded mainly in the simulated cecal and colonic media, but not in the simulated gastric and enteric media. Degradation of KGM and CMKGM by enzymes obeyed Michaelis-Menton kinetics. CMKGM with lower DS were more susceptible substrates. CMKGM were more susceptible substrates in solution with pH 6. 0-6. 8.

CONCLUSION

CMKGM had colon-specific enzymatic degradation characteristics and could be used as carrier materials to prepare colon-specific drug delivery systems.

A novel method for measuring dissolution kinetics of pulverized konjac flour

The aim of the current study was to explore a novel method for measuring hydration and dissolution kinetics of the pulverized konjac flour (PK flour) from Amorphophallus albus using RVA-3D+ Rapid Visco Analyzer (RVA; Newport Scientific Pty Ltd., Australia). The results showed that RVA was a reliable fast technique for determining the hydration curve of PK flour. The test conditions determining the hydration curves were optimized at the concentration of PK flour with 1.0%, test temperature at 30+/-1oC, stirring speed at 160 RPM (Revolution Per Minute), and test time of 16 min. An empirical exponential model has also been established to describe the dis-solution kinetics of PK flour at the concentration of 1.0%: eta= 161.9343.EXP (-2.1522/tau) (R2=0.9762) Where tau is the test time (min); eta is the viscosity of the hydration process (RVU) of PK flour. The results also showed that a significant difference among the hydration curves of 1.0% PK flour when dispersed in distilled water and in different concentrations of sucrose aqueous solution.

[Study on preparation of konjac glucomannan-hydroxypropyl methyl cellulose compression coated tablets for colonic delivery and in vitro release]

OBJECTIVE

Prepare konjac glucomannan-hydroxypropyl methyl cellulose (HPMC) compression coated tablets and study the effects of the formulation, technics and in vitro dissolution condition on drug release behavior to elevate the colon-specific effects of preparation.

METHOD

Berberine hydrochloride core tablets were prepared by wet granulation technique and konjac glucomannan-HPMC mixture as the coating layer were used with compression coated technique. The effects of the formulation and technics on drug release behavior were investigated by dissolution test. The erosion of coat layer during dissolution test was investigated.

RESULT

Drug almost not released in dissolution medium stimulating gastric and intestinal condition, and released completely by coating layer erosion and rupture by enzyme in stimulating colonic condition. Drug release decreased with decreasing the ratio of konjac glucomannan-HPMC and increasing coat weight (P < 0.05), compression force was not found to be a significant factor on drug release. Drug release increased with increasing the concentration of beta-mannase in dissolution medium (P < 0.05), rotation speed has no effect on drug release. The release of drug was correlative with erosion of coat layer. The mechanism of drug release were diffusion and erosion.

CONCLUSION

The konjac glucomannan-HPMC compression coated tablets was a promising delivery system for drugs to be delivered to the colon.

Grain-size effect on the structure and antiobesity activity of konjac flour

The effect of high-frequency oscillatory type ball-mill treatment on the structure and antiobesity activity of konjac flour was investigated. The grain size of konjac flour changed from 657.3 microm (d(50)) to 23.7 microm (d(50)) after 4 h of treatment. The structural change of the konjac flour with different grain size was characterized by using X-ray diffraction (XRD) differential scanning calorimetry (DSC). The results indicated that the crystallinity decreased and the diffraction peak drifted not only by when the crystallization region was reduced but also when the crystalline structure was changed. With the decrease of the grain size and crystallinity, the konjac flour grain, especially the 4 h milled konjac flour, swelled more rapidly and led to the improvement of the antiobesity effect. Compared with the native konjac flour, the 4 h milled konjac flour could significantly decrease the body weight and total wet weight of fat of nutritional obese rats (P < 0.05) and also decreased the contents of triglyceride, glucose, and high-density lipoprotein in blood of nutritional obese rat significantly (P < 0.05), which meant the grain-size effect of konjac flour improved its antiobesity activity notably.

Analgesic activity of Amorphophallus campanulatus tuber

The methanol extract of Amorphophallus campanulatus tuber, given orally at the doses of 250 and 500 mg/kg, showed significant analgesic activity in mice.

Tensile and tear strength of carrageenan film from Philippine eucheuma species

The tensile and tear strength of carrageenan film from Philippines Eucheuma species were investigated using NEC tensilon universal-testing machine according to American Society for Testing Materials methods. These properties are important for assessing carrageenan film as packaging material. The kappa and iota types were used in the study. The effect of glycerine on the tensile and tear strength including elongation was also evaluated. Addition of glycerine tended to lower the tensile strength of the film and increase its elongation properties including the tear strength. Carrageenan film without glycerine was much stronger. Glycerine made the film more flexible and easy to deform. The composite film of carrageenan and konjac gum did not exhibit elongation. It also showed higher tensile strength than did the composite film of carrageenan and xanthan gum. Compared with iota-type carrageenan film, kappa-type carrageenan film without glycerine was more comparable to low-density polyethylene (LDPE) film in terms of tensile strength as was the composite film of carrageenan-konjac gum. The kappa-type carrageenan film with glycerine was more comparable to LDPE film in terms of tear strength. The elongation reading for carrageenan film was lower than that for LDPE film. Morphologic studies showed that the carrageenan film had sets of pores distributed randomly at different places as compared to LDPE film. It also showed that the carrageenan film was more fibrous than LDPE film.