Paramahans V. Salimath

Carbohydrate composition of wheat, wheat bran, sorghum and bajra with good chapati/roti (Indian flat bread) making quality

Varieties of wheat, sorghum and bajra having good chapati/roti making quality were studied for carbohydrate profile. Polysaccharide fractions (water-soluble, barium hydroxide-soluble, alkali-soluble and insoluble) were isolated from these cereals and wheat bran and their carbohydrate profiles were studied. Arabinoxylans were the major polysaccharides, other than starch and cellulose. The ratio of arabinose to xylose in whole-wheat flour and wheat bran was nearly 1.25:1 but the hemicellulose A in wheat flour was mainly xylan-type. Among the pentosans in barium hydroxide extract of sorghum, the hemicellulose A had more arabinose than xylose, but the hemicellulose B contained nearly equal amounts of arabinose and xylose. Bajra had arabinose and xylose in nearly equal amounts in both the barium hydroxide extract and alkali-soluble fractions. The alkali-insoluble residues were complexes of pentosans with cellulose and were strongly bound. Contents of dietary fibre varied between the cereals. Wheat bran had the highest among the four.

Structural features of an arabinoxylan and a rhamno-galacturonan derived from linseed mucilage

Abstract The mucilage, obtained (6%) by aqueous extraction of linseed on fractionation with Cetavlon gave precipitable (CeP, 58%) and non-precipitable (CeNP, 28%) fractions. Further fractionation on DEAE-cellulose furnished a series of fractions of which the water-eluted neutral fraction of CeNP and the 0.2 m ammonium carbonate-eluted acidic fraction of CeP were homogeneous. The neutral fraction contained l -arabinose, d -xylose, and d -galactose (3.5:6.2:1), and the acidic fraction contained l -rhamnose, l -fucose, l -galactose, and d -galacturonic acid (2.6:1:1.4:1.7). The neutral fraction was an arabinoxylan having a (1→4)-β- d -xylan backbone to which arabinose and galactose side-chains were attached at positions 2 and/or 3. The acidic fraction had a backbone of (1→2)-linked α- l -rhamnopyranosyl and (1→4)-linked d -galactopyranosyluronic acid residues, with side-chains of fucose and galactose residues, the former essentially at the non-reducing end.

Structural features of arabinoxylans from sorghum having good roti-making quality

Abstract Arabinoxylans (AX) from an Indian variety of sorghum (M354) having good roti(Indian flat bread)-making quality were isolated with barium hydroxide and 10% sodium hydroxide (Hemicellulose B). Arabinoxylans from both fractions were further purified by alcohol precipitation at acidic pH and glucoamylase digestion. Structural features of the purified arabinoxylans were studied by a combination of methylation analysis involving GC–MS, 13C NMR, oxidation studies and FT-IR spectroscopy. The results indicated a xylan backbone in β-1,4 linkage, which is occasionally branched at O-3 or at O-2 and O-3. The branches contained arabinosyl residues in furanose form, linked mainly by α-1,3. Fully branched arabinosyl residues were also present.

ARABINANS FROM CAJANUS CAJAN COTYLEDON

Abstract Two arabinans were isolated in pure form, from the water-soluble extract of red gram cotyledons. Their structures were determined by a combination of methods including GC-MS and NMR. Both the arabinans were highly branched, with a backbone of α- l -arabinose units joined by 1 → 5 linkages and branched through 0 → 2 and/or O → 3 linkage. Terminal sugar residues in arabinan I were exclusively arabinofuranose, while in arabinan II, both furanose and pyranose forms of arabinose were present. These differences may account for the differences in their solubility.

Carbohydrate composition and characterization of two unusual sugars from the blue green alga Spirulina platensis

Abstract Spirulina platensis contains 13.6% carbohydrate, the sugar composition of which is comprised principally of glucose along with rhamnose, mannose, xylose, galactose and two unusual sugars. The latter were identified by a combination of GC-MS, NMR and de- O -methylation as 2- O -methyl- L -rhamnose and 3- O -methyl- L -rhamnose. Water-soluble polysaccharides were complex and heterogeneous, while the acid-soluble polysaccharide was a homogeneous glucan.

Dietary fibres ameliorate decreased synthesis of heparan sulphate in streptozotocin induced diabetic rats

The role of dietary fibers in diabetes has been studied by several workers. Long term dietary treatment with increased amounts of fiber-rich low-glycaemic index natural foods improves blood glucose and reduces the number of hypoglycemic events in type I diabetic patients. On the other hand Rohrbach and Martin and Cohen and Surma described changes in the general and biochemical structure of renal tissues such as the glomerular basement membranes. One of these changes was the reduction and undersulfation of the glycoconjugate and glycosaminoglycan heparan sulfate, which plays an important role in renal structure and function. The purpose of the present study was to determine specific effects of two types of dietary fiber on the composition of kidney glycoconjugates in an animal model of diabetes type I. Streptozotocin-treated diabetic rats were fed either a control diet or diets containing 10% wheat bran (insoluble dietary fiber) or 5% guar gum (soluble dietary fiber). Effects of these fibers on glycaemic control and nephropathy were assessed using previously described methodologies. The effect of dietary fiber in the glycoconjugate composition of kidneys of control and diabetic animals was studied by estimating their total hexose content, sulfated glycosaminoglycans, hexosamines and uronic acids. The activities of enzymes that participate in the synthesis of saccharides and glycoconjugates (L-glutamine-fructose-6-phosphate aminotransferase) and their degradation (N-acetyl-beta-glucosaminidase and beta-glucuronidase) were also evaluated. Results indicated that both soluble and insoluble dietary fibers ameliorated a significant increase in the activity of GFAT. Heparan sulfate was also isolated and quantified. Results indicated that the renal content of heparan sulfate decreased in diabetic animals and that this decrement was ameliorated by the ingestion of both soluble and insoluble fiber in the diet.

Effect of curcumin and quercetin on lysosomal enzyme activities in streptozotocin-induced diabetic rats.

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.

Modulatory effect of butyric acid-a product of dietary fiber fermentation in experimentally induced diabetic rats.

The effect of feeding of butyric acid on alleviation of diabetic status was studied. Diabetes was induced in rats using streptozotocin. Rats were fed with basal diet containing wheat bran (5%) as a source of insoluble dietary fiber and guar gum (2.5%) as a source of soluble dietary fiber. The experimental group received butyric acid at 250, 500 and 750 mg/kg body weight/day. The diabetic animals lost weight in spite of high diet consumption. The levels of water intake, urine output, urine sugar, fasting blood sugar increased during diabetic condition compared to control and these were reduced by nearly 20% in the fiber-fed diabetic group. Further supplementation of butyric acid at 500 mg/kg body weight/day ameliorated the diabetic status by nearly 40%. Urine sugar level during the diabetic state was reduced from 7.2 g/day to 3.6 g/day and fasting blood glucose from 270 mg/dl to 180 mg/dl. Butyric acid feeding at 500 mg/kg body weight/day was most effective in controlling the diabetic status.

Anti-diabetic effect of dietary mango (Mangifera indica L.) peel in streptozotocin-induced diabetic rats

BACKGROUND In the present study, the composition of mango peel powder (MPP) collected from the mango pulp industry was determined and the effect of MPP on ameliorating diabetes and its associated complications was studied. RESULTS Mango peel was rich in polyphenols, carotenoids and dietary fibre. Peel extract contained various bioactive compounds and was found to be rich in soluble dietary fibre. Peel extract exhibited antioxidant properties and protected against DNA damage. Therefore, the effect of peel on ameliorating diabetes was investigated in a rat model of diabetes. A significant increase in urine sugar, urine volume, fasting blood glucose, total cholesterol, triglycerides and low density lipoprotein, and decrease in high density lipoprotein were observed in the rats; however, these parameters were ameliorated in diabetic rats fed with diet supplemented with mango peel at 5% and 10% levels in basal diet. Treatment of diabetic rats with MPP increased antioxidant enzyme activities and decreased lipid peroxidation in plasma, kidney and liver compared to untreated diabetic rats. Glomerular filtration rate and microalbuminuria levels were ameliorated in MPP treated diabetic group. CONCLUSIONS Mango peel, a by-product, can be used as an ingredient in functional and therapeutic foods.

Effect of dietary fibre on intestinal and renal disaccharidases in diabetic rats

Diabetes was induced in rats with streptozotocin. They were fed either with wheat bran as a source of insoluble dietary fibre or guar gum as soluble dietary fibre. The effect of these fibres on intestinal and renal disaccharidases in diabetic rats was studied. Activities of intestinal maltase, sucrase and lactase increased during diabetes, which was ameliorated to a considerable extent in fibre fed groups. The activities of disaccharidases in renal tissue was decreased in diabetic rats and there was an improvement in fibre fed group.