Studies on isolation and characterization of starch from oat (Avena nuda) grains

Starch from AC Hill oat grains (Avena nuda) was isolated and some of the characteristics determined. The yield of starch was 23·4% on a whole grain basis. The shape of the granule was polyhedral to irregular, with granules 6–10 μm in diameter. Lipids were extracted by acid hydrolysis and by selective solvent extraction with chloroform-methanol 2:1 v/v (CM) at ambient temperature, followed by n-propanol-water 3:1 v/v (PW) at 90–100°C. The acid hydrolyzed extracts which represented the total starch lipids (TSL) was 1·13%. The free lipids in the CM extract (1% TSL) was 6·2%, whereas the free and bound lipids in the PW extracts was 93.0%. Neutral lipids formed the major lipid class in the CM and PW extracts. The monoacyl lipid content in both CM and PW extracts was 61·0%. The total amylose content was 19·4%, of which 13·9% was complexed by native lipids. X-ray diffraction was of the ‘A’ type. Oat starch differed from wheat starch in showing a higher swelling factor, decreased amylose leaching, coleaching of a branched starch component and amylose during the pasting process, higher peak viscosity and set-back, low gel rigidity, greater susceptibility towards acid hydrolysis, greater resistance to -amylase action and a higher freeze-thaw stability. Furthermore, in comparison to wheat starch, the amylose chains of oat starch appear to be more loosely arranged in the amorphous regions, whereas in crystalline regions, oat starch chains are more compactly packed. Lipid removal from oat and wheat starches decreased their swelling factor, peak viscosity, set-back, gelatinization temperatures, freeze-thaw stability and paste clarity (at pH > 4·0), and increased their thermal stability, amylose leaching, enthalpy of gelatinization, susceptibility towards -amylase and paste clarity (at pH < 4·0). The results also showed that the properties of AC Hill oat starch is not representative of oat starch in general.     

β-Glucan extracts inhibit the in vitro intestinal uptake of long-chain fatty acids and cholesterol and down-regulate genes involved in lipogenesis and lipid transport in rats

BackgroundDietary fiber reduces the intestinal absorption of nutrients and the blood concentrations of cholesterol and triglycerides.AimWe wished to test the hypothesis that high-viscosity (HV) and low-viscosity preparations of barley and oat β-glucan modify the expression of selected genes of lipid-binding proteins in the intestinal mucosa and reduce the intestinal in vitro uptake of lipids.MethodsFive different β-glucan extracts were separately added to test solutions at concentrations of 0.1–0.5% (wt/wt), and the in vitro intestinal uptake of lipids into the intestine of rats was assessed. An intestinal cell line was used to determine the effect of β-glucan extracts on the expression of intestinal genes involved in lipid metabolism and fatty acid transport.ResultsAll extracts reduced the uptake of 18:2 when the effective resistance of the unstirred water layer was high. When the unstirred layer resistance was low, the HV oat β-glucan extract reduced jejunal 18:2 uptake, while most extracts reduced ileal 18:2 uptake. Ileal 18:0 uptake was reduced by the HV barley extract, while both jejunal and ileal cholesterol uptakes were reduced by the medium-purity HV barley extract. The inhibitory effect of HV barley β-glucan on 18:0 and 18:2 uptake was more pronounced at higher fatty acid concentrations. The expression of genes involved in fatty acid synthesis and cholesterol metabolism was down-regulated with the HV β-glucan extracts. β-Glucan extracts also reduced intestinal fatty-acid-binding protein and fatty acid transport protein 4 mRNA.ConclusionsThe reduced intestinal fatty acid uptake observed with β-glucan is associated with inhibition of genes regulating intestinal uptake and synthesis of lipids. The inhibitory effect of β-glucan on intestinal lipid uptake raises the possibility of their selective use to reduce their intestinal absorption.     

Evaluation of biomolecular interactions of sulfated polysaccharide isolated from Grateloupia filicina on blood coagulation factors

An edible marine red alga, Grateloupia filicina, collected from Jeju Island of Korea was hydrolyzed by cheap food-grade carbohydrases (Viscozyme, Celluclast, AMG, Termamyl, and Ultraflo) to investigate its anticoagulant activity. Among the tested enzymatic extracts of G. filicina, a Termamyl extract showed the highest anticoagulant activity. Anion-exchange chromatography on DEAE-cellulose and gelpermeation chromatography on Sepharose-4B were used to purify the active polysaccharide from the crude polysaccharide fraction of G. filicina. The purified sulfated polysaccharide (0.42 sulfate/total sugar) showed approximately 1,357 kDa molecular mass and was comprised mainly of galactose (98%) and 1-2% of glucose. The sample showed potential anticoagulant activity on activated partial thromboplastin time (APTT) and thrombin time (TT) assays. The purified G. filicina anticoagulant (GFA) inhibited the coagulation factor X (92%), factor II (82%), and factor VII (68%) of the coagulation cascade, and the molecular interaction (protein-polysaccharide) was highly enhanced in the presence of ATIII (antithrombin III). The dissociation constant of polysaccharide towards serine proteins decreased in the order of FXa (58.9 nM) >FIIa (74.6 nM) >FVII (109.3 nM). The low/less cytotoxicity of the polysaccharide benefits its use in the pharmaceutical industry; however, further studies that would help us to elucidate the mechanism of its activity are needed.     

Environmental Control of Vanadium Haloperoxidases and Halocarbon Emissions in Macroalgae

Vanadium-dependent haloperoxidases (V-HPO), able to catalyze the reaction of halide ions (Cl^?, Br^?, I^-) with hydrogen peroxide, have a great influence on the production of halocarbons, which in turn are involved in atmospheric ozone destruction and global warming. The production of these haloperoxidases in macroalgae is influenced by changes in the surrounding environment. The first reported vanadium bromoperoxidase was discovered 40 years ago in the brown alga Ascophyllum nodosum. Since that discovery, more studies have been conducted on the structure and mechanism of the enzyme, mainly focused on three types of V-HPO, the chloro- and bromoperoxidases and, more recently, the iodoperoxidase. Since aspects of environmental regulation of haloperoxidases are less well known, the present paper will focus on reviewing the factors which influence the production of these enzymes in macroalgae, particularly their interactions with reactive oxygen species (ROS).     

Modulating effects of hesperidin on circadian pattern indices of rotenone induced redox homeostasis in clock mutant (cryb) of Drosophila melanogaster

The circadian timing system controls drug metabolism and cellular processes over the 24 h period in every cell. Impaired redox homeostasis is a casual factor for a number of diseases and it is desirable to understand the orchestration of circadian clock under oxidative stress in the model organism, Drosophila melanogaster. This study evaluates the effect of hesperidin on the circadian rhythms of lipid peroxidation products and antioxidants during rotenone-induced oxidative stress in fruit fly. The characteristics of temporal rhythms (acrophase, amplitude, and mesor) of glutathione peroxides (GPx), reduced glutathione (GSH)), were markedly declined in rotenone-treated flies when compared to other groups. Treatment of hesperidin to rotenone-treated flies significantly increased the mesor and modified the amplitudes of antioxidants. Further, delays in acrophase in rotenone-induced flies were reversed by hesperidin treatment. Thus, treatment of hesperidin results in normalization of the altered rhythms of these indices plausibly by its cytoprotective and antioxidant effects. Impairment of 24 h rhythms in oxidative stress markers and antioxidants were observed during rotenone treatment and the impairment is severe in circadian clock mutant cry^b flies. A reversibility of rhythms was prominent consequent to hesperidin treatment in wild-type flies than cry^b flies. These findings revealed a role of circadian clock in redox homeostasis and the use of Drosophila model in screening putative antioxidative phytomedicines earlier to their use in mammalian systems.     

Dietary medicinal plant extracts improve growth, immune activity and survival of tilapia Oreochromis mossambicus

The effects of supplementing diets with acetone extract (1% w/w) from four medicinal plants (Bermuda grass Cynodon dactylon, H₁, beal Aegle marmelos, H₂, winter cherry Withania somnifera, H₃ and ginger Zingiber officinale, H₄) on growth, the non‐specific immune response and ability to resist pathogen infection in tilapia Oreochromis mossambicus were assessed. In addition, the antimicrobial properties of the extract were assessed against Vibrio alginolyticus, Vibrioparahaemolyticus, Vibrio mimicus, Vibrio campbelli, Vibrio vulnificus, Vibrio harveyi and Photobacterium damselae. Oreochromis mossambicus were fed 5% of their body mass per day for 45 days, and those fed the experimental diets showed a greater increase in mass (111–139%) over the 45 days compared to those that received the control diet (98%). The specific growth rate of O. mossambicus fed the four diets was also significantly greater (1·66–1·93%) than control (1·52%) diet‐fed fish. The blood plasma chemistry analysis revealed that protein, albumin, globulin, cholesterol, glucose and triglyceride levels of experimental fish were significantly higher than that of control fish. Packed cell volume of the blood samples of experimental diet‐fed fish was also significantly higher (34·16–37·95%) than control fish (33·0%). Leucocrit value, phagocytic index and lysozyme activity were enhanced in fish fed the plant extract‐supplemented diets. The acetone extract of the plants inhibited growth of Vibrio spp. and P. damselae with extracts from W. somnifera showing maximum growth inhibition. A challenge test with V. vulnificus showed 100% mortality in O. mossambicus fed the control diet by day 15, whereas the fish fed the experimental diets registered only 63–80% mortality at the end of challenge experiment (30 days). The cumulative mortality index for the control group was 12 000, which was equated to 1·0% mortality, and accordingly, the lowest mortality of 0·35% was registered in H₄‐diet‐fed group.     

Differential expression of basal microRNAs’ patterns in human dental pulp stem cells

MicroRNAs (miRNAs) are small non‐coding RNAs that regulate translation of mRNA into protein and play a crucial role for almost all biological activities. However, the identification of miRNAs from mesenchymal stem cells (MSCs), especially from dental pulp, is poorly understood. In this study, dental pulp stem cells (DPSCs) were characterized in terms of their proliferation and differentiation capacity. Furthermore, 104 known mature miRNAs were profiled by using real‐time PCR. Notably, we observed 19 up‐regulated miRNAs and 29 significantly down‐regulated miRNAs in DPSCs in comparison with bone marrow MSCs (BM‐MSCs). The 19 up‐regulated miRNAs were subjected to ingenuity analysis, which were composed into 25 functional networks. We have chosen top 2 functional networks, which comprised 10 miRNA (hsa‐miR‐516a‐3p, hsa‐miR‐125b‐1‐3p, hsa‐miR‐221‐5p, hsa‐miR‐7, hsa‐miR‐584‐5p, hsa‐miR‐190a, hsa‐miR‐106a‐5p, hsa‐mir‐376a‐5p, hsa‐mir‐377‐5p and hsa‐let‐7f‐2‐3p). Prediction of target mRNAs and associated biological pathways regulated by each of this miRNA was carried out. We paid special attention to hsa‐miR‐516a‐3p and hsa‐miR‐7‐5p as these miRNAs were highly expressed upon validation with qRT‐PCR analysis. We further proceeded with loss‐of‐function analysis with these miRNAs and we observed that hsa‐miR‐516a‐3p knockdown induced a significant increase in the expression of WNT5A. Likewise, the knockdown of hsa‐miR‐7‐5p increased the expression of EGFR. Nevertheless, further validation revealed the role of WNT5A as an indirect target of hsa‐miR‐516a‐3p. These results provide new insights into the dynamic role of miRNA expression in DPSCs. In conclusion, using miRNA signatures in human as a prediction tool will enable us to elucidate the biological processes occurring in DPSCs.     

In vitro antioxidant studies of Sphaeranthus indicus (Linn)

The free radical scavenging potential of the plant S. indicus was studied by using different antioxidant models of screening. The ethanolic extract at 1000 microg/ml showed maximum scavenging of the radical cation, 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonate) (ABTS) observed upto 41.99% followed by the scavenging of the stable radical 1,1-diphenyl, 2-picryl hydrazyl (DPPH) (33.27%), superoxide dismutase (25.14%) and nitric oxide radical (22.36%) at the same concentration. However, the extract showed only moderate scavenging activity of iron chelation (14.2%). Total antioxidant capacity of the extract was found to be 160.85 nmol/g ascorbic acid. The results justify the therapeutic applications of the plant in the indigenous system of medicine, augmenting its therapeutic value.     

Development of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fibers for skin tissue engineering: effects of topography, mechanical, and chemical stimuli

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a biodegradable polyester, was electrospun to form defect-free fibers with high surface-area-to-volume ratio for skin regeneration. Several parameters such as solvent ratio, polymer concentration, applied voltage, flow rate, and tip-to-target distance were optimized to achieve defect-free morphology. The average diameter of the PHBV fibers was 724 ± 91 nm. PHBV was also solvent-cast to form 2-D films, and its mechanical properties, porosity, and degradation rates were compared with PHBV fibers. Our results demonstrate that PHBV fibers exhibited higher porosity, increased ductility, and faster degradation rate when compared with PHBV 2-D films (p < 0.05). In vitro studies with PHBV fibers and 2-D films were carried out to evaluate the adhesion, viability, proliferation, and gene expression of human skin fibroblasts. Cells adhered and proliferated on both PHBV fibers and 2-D films. However, the proliferation of cells on the surface of PHBV fibers was comparable to tissue culture polystyrene (TCPS, control) (p > 0.05). The gene expression of collagen I and elastin was significantly up-regulated when compared with TCPS control, whereas collagen III was down-regulated on PHBV fibers and 2-D film after 14 days in culture. The less ductile PHBV 2-D films showed higher levels of elastin expression. Furthermore, the PHBV fibers in the presence and absence of an angiogenesis factor (R-Spondin 1) were evaluated for their wound healing capacity in a rat model. The wound contracture in R-Spondin-1-loaded PHBV fibers was found to be significantly higher when compared with PHBV fibers alone after 7 days (p < 0.05). Furthermore, the presence of fibers promoted an increase in collagen and aided re-epithelialization. Thus our results demonstrate that the topography and mechanical and chemical stimuli have a pronounced influence on the cell proliferation, gene expression, and wound healing.