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Cereals such as wheat, rice, sorghum, pearl millet and finger-millet are the staple diets for majority of population in India and are used to prepare various types of flat unleavened breads (Chapati /rotis), malt and various pasta products. Pentosans (arabinoxylans) are the major non-starch polysaccharides located in the cell walls of cereal grains. Textural and functional properties are influenced by pentosans and proteins. Arabinoxylans (pentosans) from pearl millet, sorghum, finger millet and durum wheat are more branched than those from bread wheat and rice. Higher branching pattern of pentosans along with associated ferulic and uronic acid linkages could be responsible for changes in the physicochemical properties of dough which in turn lead to their good flat bread/pasta-making qualities. This review discusses, pentosans in cereals, isolation, chemical composition, structure-function relationship of pentosans from the major cereals. A relationship of pentosans in cereals to their Indian flat bread/roti-making quality is also discussed. [ABSTRACT FROM AUTHOR]

Hypercholesterolemia is one of the factors contributing to cardiovascular problems. Erythrocytes are known to contribute its cholesterol to atherosclerotic plaque. Our earlier study showed that erythrocytes overexpress chondroitin sulphate/dermatan sulphate (CS/DS), a linear co-polymer, during diabetes which resulted in increased cytoadherence to extracellular matrix (ECM) components. This study was carried out to determine whether diet-induced hypercholesterolemia had any effect on erythrocyte CS/DS and impacted cytoadherence to ECM components. Unlike in diabetes, diet-induced hypercholesterolemia did not show quantitative changes in erythrocyte CS/DS but showed difference in proportion of un-sulphated and 4-Osulphated disaccharides. Erythrocytes from hypercholesterolemic rats showed increased adhesion to ECM components which was abrogated to various extents when subjected to chondroitinase ABC digestion. However, isolated CS/DS chains showed a different pattern of binding to ECM components indicating that orientation of CS/DS chains could be playing a role in binding. [ABSTRACT FROM AUTHOR]

Wheat varieties, viz., N1AW-34 (Triticum aestivum) and DWR-2006 (Triticum durum), known for good chapan and pasta making characteristics, respectively, were studied for the nature of various non-starch polysaccharides fibers present in the flour. The water-soluble, barium hydroxide soluble and the alkali-soluble polysaccharide fractions were isolated from these two wheat varieties and their carbohydrate composition was determined by gas liquid chromatography. Glucose was the major sugar, along with small amounts of arabinose and xylose in the whole-wheat flours. The water and barium hydroxide extracts mainly consisted of arabinose and xylose, along with small amounts of glucose. While the hemicellulose A fraction from aestivum contained mainly xylose and could therefore be a mixture of xylan. arabinoxylan and xyloglucan. the durum wheat hemicellulose A contained higher amounts of arabinose and xylose along with glucose, indicating preponderance of the arabinoxylan-type polysaccharides. On the other hand, hemicellulose B from both the durum and aestivum flours had arabinose. xylose and glucose as the major sugars. The alkali-insoluble residue was basically cellulosic in nature and was strongly associated with arabin-oxylans. Arabinose and xylose were the major components of both soluble and insoluble dietary fibers, which were present in comparatively higher amounts in the durum flour. The particular chemical composition of non-starch polysaccharides, mainly consisting of pentosans, could be responsible for their good chapan and pasta making quality as have been noted in traditional cooking. [ABSTRACT FROM AUTHOR]

Summary: Background & aims: Diabetes causes impairment of various enzyme activities in the physiological system, including lysosomal enzymes. The effect of feeding curcumin, quercetin and aminoguanidine on lysosomal enzyme activities viz., N-acetyl-β-d-glucosaminidase, β-d-glucuronidase, β-d-galactosidase and acid phosphatase were studied in different tissues of streptozotocin-induced diabetic rats. Method: Rats were divided into four control groups and four diabetic groups. Experimental groups were fed with diet supplemented with curcumin (0.5%) or quercetin (0.1%) or aminoguanidine (0.05%). Lysosomal enzyme activities were determined in various tissues. Results: The specific activity of N-acetyl-β-d-glucosaminidase in liver of diabetic rats was decreased when compared to control rats and was ameliorated with curcumin and quercetin treatment by 67% and 78%, respectively. On the other hand, β-d-glucuronidase activity was higher in the brain of diabetic rats (0.90 ± 0.04 nmol/mg protein/min), when compared to control rats (0.45 ± 0.02 nmol/mg protein/min) and was decreased in curcumin (0.75 ± 0.05 nmol/mg protein/min) and quercetin (0.74 ± 0.11 nmol/mg protein/min) treated rats. β-d-galactosidase activity in spleen of curcumin and quercetin fed diabetic group rats was ameliorated by 68% and 58%, respectively, in comparison to diabetic rats. Acid phosphatase activity in diabetic rats decreased in testis when compared to control. Conclusion: Curcumin and quercetin feeding modulated lysosomal enzyme activities in different tissues during diabetes and the effect was comparable to well-known anti-glycative agent - aminoguanidine. [ABSTRACT FROM AUTHOR]

Reactive oxygen metabolites, which are constant products of normal aerobic cell metabolism, play a key role in worsening the pathophysiological complications of diabetes. The present investigation was aimed at understanding the effect of butyric acid supplementation along with wheatbran and guar gum on serum and renal antioxidant enzyme activities and lipid peroxidation in streptozotocin (STZ)-induced diabetic rats. Activities of superoxide dismutase, catalase, glutathione peroxidase were evaluated in serum and kidney of control and experimental rats. Results clearly showed that the altered activity of the enzymes during diabetes was significantly ameliorated by butyric acid (500 mg/kg body weight/day) supplementation compared with other experimental groups. Further, the increased lipid peroxidation in serum and kidney of diabetic rats was also significantly reduced in butyric acid-supplemented diabetic rats. The study led us to conclude that butyric acid exert antioxidant property, thereby minimizing oxidative stress induced diabetes and its related complications. PRACTICAL APPLICATIONS Butyric acid – a product of dietary fiber fermentation – is a four-carbon fatty acid, which has wide range of application in disease management. This product is involved in various physiological functions of body like cell differentiation, apoptosis, colonic homeostasis, histone acetylation, etc. It is also known to decrease the incidence of bowel cancer and some of its analogues are shown to selectively improve glucose-stimulated insulin release and glucose tolerance in both normal and diabetic rats. This study aims to evaluate the beneficial effects of butyric acid supplementation on oxidative stress-induced diabetic complications in rats. [ABSTRACT FROM AUTHOR]

Glycosaminoglycans (GAGs) such as chondroitin sulphate/dermatan sulphate (CS/DS) are complex molecules that are widely expressed on the cell membrane and extracellular matrix (ECM). They play an important role in wide range of biological activities especially during pathological conditions. Diabetes, a metabolic disorder characterized by sustained hyperglycemia, is known to affect GAGs in different tissues and affect erythrocyte adhesion. The present investigation was aimed at exploring the nature of GAGs present in erythrocytes and its role on adhesion of erythrocytes from control and diabetic rats to major extracellular matrix components. GAGs isolated from erythrocytes were demonstrated to be CS/DS and a 2-fold increase was observed in erythrocytes from diabetic rats. Disaccharide composition analysis by HPLC after depolymerization by the enzyme, chondroitinase ABC showed the presence of 4-O sulphated disaccharide units with small amounts of non-sulphated disaccharides, in both control and diabetic erythrocytes. Erythrocytes from diabetic rats, however, showed significantly increased binding to poly-l-ornithine (P-orn), type IV collagen, laminin and fibronectin, which was abrogated on treatment with chondroitinase ABC to various degrees. This study sheds new light on CS/DS in erythrocytes and its likely biological implications in vivo., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Diabetic nephropathy (DN) is one of the serious secondary complications of diabetes, which results in end-stage renal failure. Reports on the progressive nature of early phase DN especially with respect to kidney parameters such as kidney weight, type IV collagen excretion, total kidney and urinary glycosaminoglycans (GAGs) are few. This work was undertaken to determine systematically the progression of early phase DN in relation to various kidney-related parameters for a period of four months. Experimentally-induced diabetic rats were grouped based on fasting blood glucose levels. Various basic and kidney-related parameters such as kidney weight, microalbuminuria, urinary excretion of GAGs and type IV collagen, total kidney GAGs, histopathology, glomerular area and glomerular volume were examined in control and diabetic rats. There was a progressive increase in fasting blood sugar, urine sugar, kidney weight, microalbuminuria, urine glycosaminoglycans, urine type IV collagen, glomerular area and glomerular volume but there was a progressive decrease in kidney glycosaminoglycans. Glomerular sclerotic condition was aggravated with the increase in duration of diabetes from 1 to 4 months. Onset of DN in rats begins subtly after one month of diabetes but gets vitiated and more pronounced at the end of four months.

A thermostable extracellular beta-mannanase from the culture supernatant of a fungus Aspergillus niger gr was purified to homogeneity. SDS-PAGE of the purified enzyme showed a single protein band of molecular mass 66 kDa. The beta- mannanase exhibited optimum catalytic activity at pH 5.5 and 55 degrees C. It was thermostable at 55 degrees C, and retained 50% activity after 6 h at 55 degrees C. The enzyme was stable at a pH range of 3.0 to 7.0. The metal ions Hg(2+), Cu(2+), and Ag(2+) inhibited complete enzyme activity. The inhibitors tested, EDTA, PMSF, and 1,10-phenanthroline, did not inhibit the enzyme activity. N-Bromosuccinimide completely inhibited enzyme activity. The relative substrate specificity of enzyme towards the various mannans is in the order of locust bean gum>guar gum>copra mannan, with K(m) of 0.11, 0.28, and 0.33 mg/ml, respectively. Since the enzyme is active over a wide range of pH and temperature, it could find potential use in the food-processing industry.

Aim: Changes in glycoconjugate metabolism during the development of diabetic complications and their modulation by feeding bitter gourd and spent turmeric as fiber-rich source., Method: This was studied by measuring the contents of total sugar, uronic acid, amino sugar, and sulfate in the streptozotocin-induced diabetic rats., Results: Total sugar content decreased in liver, spleen, and brain, while an increase was observed in heart and lungs. Uronic acid content in liver, spleen, and brain decreased, and marginal increase was observed in testis. Amino sugar content decreased in liver, spleen, lungs and heart during diabetes, and augmentation was observed to different extents. Decrease in sulfation of glycoconjugates was observed in liver, spleen, lungs and heart during diabetes and was significantly ameliorated by bitter gourd and spent turmeric, except brain. Protein content decreased in liver, while an increase was observed in brain. The studies clearly showed alteration in glycoconjugate metabolism during diabetes and amelioration to different extents by feeding bitter gourd and spent turmeric., Conclusion: Improvement is due to slow release of glucose by fiber in the gastrointestinal track and short-chain fatty acid production from fiber by colon microbes.

Glycoconjugates in the kidney play an important role in the maintenance of glomerular filtration barrier. Thickening of the glomerular basement membrane (GBM) is well characterized in diabetic nephropathy. Changes in GBM mainly include reduction and undersulfation of heparan sulfate, and laminin with accumulation of type IV collagen leading to kidney dysfunction and there is a need to identify therapies that arrest disease progression to end-stage renal failure. In the present investigation, effect of bitter gourd on streptozotocin-induced diabetic rats with particular emphasis on kidney heparan sulfate (HS) was studied. Earlier, our study showed partial reversal of all the diabetes-induced effects by bitter gourd. Increase in the components of glycoconjugates during diabetes was significantly decreased by bitter gourd feeding. Diabetes associated elevation in the activities of enzymes involved in the synthesis and degradation of glycosaminoglycans (GAGs) were significantly lowered by bitter gourd supplementation. GAGs composition revealed decrease in amino sugar, and uronic acid contents during diabetes and bitter gourd feeding was effective in countering this reduction. Decrease in sulfate content in the GAGs during diabetes was ameliorated by bitter gourd feeding. HS decreased by 43% in diabetic rats while bitter gourd feeding to diabetic rats showed 28% reduction. These results clearly indicate beneficial role of bitter gourd in controlling glycoconjugate and heparan sulfate related kidney complications during diabetes thus prolonging late complications of diabetes.

Photosynthetic bacteria of the Rhodospirillaceae family (sulfur-free purple bacteria) possess lipopolysaccharides (LPS) that deviate markedly from the Salmonella lipopolysaccharides in the chemical makeup of the lipid A component and in their biologic properties. LPS of Rhodopseudomonas gelatinosa is highly toxic and pyrogenic, while that of Rhodospirillum tenue shows cryptic toxicity. Two LPS types are completely non-toxic. The Rhodopseudomonas sphaeroides lipid A has the same backbone as that of Salmonella, but a part of the amide-linked fatty acids has the unusual 3-oxo structure (3-oxo-14:0). The lipid A's of Rhodopseudomonas viridis and Rhodopseudomonas palustris have 2,3-diamino-2,3-dideoxy-D-glucose as the backbone sugar. This is the first demonstration of this sugar in nature. In recent studies using 16S rRNA sequencing, the nonphotosynthetic Nitrobacter strains were shown to be phylogenetically closely related to R. palustris. The R. palustris lipid A type has been identified in three Nitrobacter species, including Nitrobacter winogradskyi, the type strain. The data demonstrate the taxonomic significance of lipid A constituents and structures.

The chemical structure of the polysaccharide moiety of the lipopolysaccharide Rhodopseudomonas sphaeroides ATCC 17023 was established. Mild acetic acid hydrolysis of isolated lipopolysaccharide, followed by preparative high-voltage paper electrophoresis afforded three oligosaccharides. They were characterized by chemical and physicochemical studies to be: GlcA(alpha 1----4)dOclA8P, Thr(6') GlcA(alpha 1----4)GlcA and GlcA(alpha 1----4)dOclA, where GlcA is D-glucuronic acid and dOc1A is 3-deoxy-D-manno-octulosonic acid. Carboxyl-reduction of the lipopolysaccharide followed by acid hydrolysis gave a trisaccharide: GlcA(alpha 1----4)Glc(alpha 1----4)Glc, showing the presence of three residues of glucuronic acids in the O-specific chain and indicating that only two of them are reducible by NaBH4. The linkage between the polysaccharide and lipid A was shown to be through a single 1,4-linked residue of dOc1A attached by a 2,6'-linkage to the lipid A moiety.

The lipid A isolated from Rhodopseudomonas sphaeroides ATCC 17023 has been investigated. A sequence of analyses indicated beta-D-glucosaminyl-1,6-D-glucosamine as the sugar backbone carrying phosphate groups at C-1 of the reducing glucosamine and C-4 of the non-reducing glucosamine. Both 3-(7-tetradecenoyl)oxytetradecanoic and 3-oxotetradecanoic acid are linked to the NH2 groups. Two residues of 3-hydroxydecanoic acid are linked to hydroxy groups at C-3 of both reducing and non-reducing glucosamine, and the hydroxy group of 3-hydroxydecanoic acid is free. In free lipid A, the hydroxy group at C-4 of the reducing glucosamine and at C-6 of the non-reducing glucosamine are unsubstituted. The latter probably arises from a 3-deoxy-D-manno-octulosonate linkage. The structural similarities and dissimilarities existing between lipid A of R. sphaeroides, which is non-toxic, and lipid A types such as those from Salmonella, which are toxic, are discussed.