Pradyot K. Ghosal

University of Burdwan, Burdwān, Bengal, India

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Publications (15)10.48 Total impact

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    ABSTRACT: Enhydra fluctuans leaves are traditionally sold on Indian markets for various health benefits. However no phytochemical study on its high molecular weight compound has so far been performed. Chemical, chromatographic, ESI-TOF-MS and NMR analyses of the water extracted carbohydrate polymer (CP) of E. fluctuans leaves showed the presence of a 24 kDa arabinogalactan having a (1,3)-linked β-D-Galp main chain, substituted at O-6 by (1,6)-linked β-D-Galp side chains. The latter residues were substituted at O-3 by (1,3)-, (1,5)- and (1,3,5)-linked α-L-Araf chains, and nonreducing end-units of α-L-Araf and β-D-Galp. This polymer contained esterified phenolic acids. Biochemical analysis revealed similarity in antioxidative potential between the identified carbohydrate polymer and known standard antioxidants. The highly branched side chains and the phenolic acid residues of the arabinogalactan might be the functional sites. Fluorimetric and ultraviolet spectrometric analyses showed that the studied carbohydrate polymer can form complex with bovine serum albumin having binding constant K=2.42×10(6)/M and changes its microenvironment. Thus, traditional aqueous extraction method provides a carbohydrate polymer, which stimulates a fair biological response: this could represent an interesting approach in phytotherapeutic treatments.
    Biomacromolecules 05/2013; · 5.37 Impact Factor
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    ABSTRACT: The water-extracted carbohydrate polymers (WE) of Phyllanthus emblica are analyzed using chemical, chromatographic, and spectroscopic methods. Anion-exchange-chromatography of WE yielded four fractions (F1-F4) with different chemical compositions and all of them contain phenolics. The major fraction F4 possesses 50% polysaccharide and 26% phenol, and is a glycoconjugate. The antioxidant capacities of WE and F4 are comparable to standard anti-oxidants. Notably, activities of F1-F4 correlate with their phenol content. Evidence for the complexation of F4 with bovine serum albumin is presented by fluorescence quenching measurement. The results also indicate conformational change of protein at high carbohydrate polymer concentration.
    International journal of biological macromolecules 06/2011; 49(4):637-42. · 2.37 Impact Factor
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    ABSTRACT: Senna (Cassia angustifolia) is widely used in Indian folk medicine for the prevention of various disorders. Herein, we have demonstrated that water extracted arabinogalactan protein (AGP) rich fraction possesses strong antioxidative activity. The AGP rich fraction was analyzed using chemical, chromatographic, and spectroscopic methods. Effect of water extracted polymers on bovine serum albumin spectrum was determined using excitation wavelength of 282 nm. The antioxidant capacity of this fraction was studied by ferric reducing antioxidant power (FRAP) and DPPH radical assays. This polymeric fraction, ≥88% of which gets precipitated with Yariv reagent, consisted mainly of (1→5)-/(1→3,5)-linked α-arabinosyl, (1→3)-/(1→3,6)-linked-galactosyl residues and terminal arabinofuranosyl residues. Its in vitro antioxidant capacity is comparable to that of standard antioxidants. Fluorescence quenching studies furnishes evidence for the interaction of the arabinogalactan protein with bovine serum albumin. Keywordssenna leaf (Cassia angustifolia)–arabinogalactan protein–fluorescence quenching–antioxidant activity
    Food science and biotechnology 01/2011; 20(4):1005-1011. · 0.70 Impact Factor
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    ABSTRACT: Sulfated fucans, the complex polysaccharides from brown seaweeds, possess various biological activities. To understand the structure activity relationship of sulfated fucans, we have investigated the structural features of one such polymer from Padina tetrastromatica using standard methods of carbohydrate structural analysis. We report a novel structural motif for this polymer. The average structure of this macromolecule that has a molecular mass of 25 kDa differs from the previous models in three respects. First, the core region of this macromolecule is composed primarily of α-(1 → 2)- and α-(1 → 3)-linked fucopyranosyl residues. Sulfate groups, when present are located at position 4 and 2 of fucosyl residues. Secondly, fucose and xylose is attached to this polymer to form branch points, one for every two residues within the chain. Finally, this macromolecule contained smaller amount of sulfate (0.21 mol of sulfate per mol of deoxyhexose).
    Carbohydrate Polymers. 01/2009;
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    ABSTRACT: Heteroglycan and xyloglucan rich fractions were extracted from Indian samples of Enteromorpha compressa in 25% yield by sequential extractions with water and alkali. This heteroglycan is sulfated and has an apparent molecular mass of 55 kDa. Chemical structural analysis of this polysaccharide revealed a branched structure having 1,4- and 1,2,4-linked rhamnose 3-sulphate, 1,4-linked glucose, 1,3- and 1,6- linked galactose, 1,4- and terminally linked glucuronic acid and 1,4-linked xylose partially sulfated on O-2. Chemical and spectroscopic analysis showed that the 4-M KOH extracted hemicellulosic fraction contained an unusual β-(1,4)-linked linear xyloglucan. Enzyme hydrolysis and analysis of the resulting fragments by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) showed that this linear polymer contained partially sulfated Glc3Xyl2 or Glc4Xyl2 as oligomeric building subunits.
    Food Chemistry. 01/2007;
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    ABSTRACT: Polysaccharides were isolated from the fruits of Limonia acidissima by sequential extraction with water, and 1M and 4M KOH. The water extract contained pectic polymers substituted with side chains comprising mainly of 1,5-, 1,3,5-linked arabinose together with 1,4-, 1,6-, 1,3,6-linked galactose, and lesser amounts of 1,2,4- and 1,3-linked galactose residues. Galactosyl and arabinofuranosyl groups terminated most of the branched residues. The alkaline extracts contained both pectic and hemicellulosic polymers. The insoluble material consists mainly of cellulose-rich material.
    Carbohydrate Polymers - CARBOHYD POLYM. 01/2002; 48(2):209-212.
  • Srabani Das, Bimalendu Ray, Pradyot K. Ghosal
    Carbohydrate Research - CARBOHYD RES. 01/1992; 224:331-335.
  • Srabani Das, Pradyot K. Ghosal, Bimalendu Ray
    Carbohydrate Research. 10/1990; 207(2):336–339.
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    ABSTRACT: An acidic polysaccharide isolated from the defatted seeds of Acacia auriculaeformis contained l-arabinose, d-xylose, d-galactose, d-glucose, and d-glucuronic acid in the molar ratios 1.5:2:2.2:1:3. Autohydrolysis of an aqueous solution of the polysaccharide yielded an electrophoretically homogeneous, degraded polysaccharide consisting of d-xylose, d-galactose, d-glucose, and d-glucuronic acid in the molar ratios 1:3.9:1.9:6.7. Methylation analysis, periodate oxidation, and Smith degradation of the native and degraded polysaccharide and their carboxyl-reduced derivatives indicated that the polysaccharide is branched with 3,6-linked galactosyl and 2,4-linked glucosyl residues at the branch points to which are attached chains comprised of arabinose, xylose, glucose, galactose, and glucuronic acid residues via different linkages. Oxidation of the acetylated polysaccharide with chromium trioxide indicated that most of the glucose and arabinose residues were α, while xylose, galactose, and glucuronic acid were mostly β. A d.p. of ∼89 was established for the polysaccharide by end-group analysis.
    Carbohydrate Research. 01/1989; 185(1):105–112.
  • Carbohydrate Research. 05/1988; 176(2):324–328.
  • Nanda G. Basu, Pradyot K. Ghosal, Swapnadip Thakur
    Carbohydrate Research - CARBOHYD RES. 01/1986; 146(2):350-351.
  • Nanda G. Basu, Pradyot K. Ghosal, Swapnadip Thakur
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    ABSTRACT: The neutral polysaccharide isolated from the fruits of Cordia dichotoma was separated into two fractions, I and II, by gel filtration using Sephadex G-100. The major fraction, II, was found to contain d-glucose and l-arabinose in the molar ratio of 21:4. The results of complete hydrolysis with acid, permethylation studies, periodate oxidation, and Smith degradation suggested it to be an arabinoglucan, and the backbone of the polysaccharide to be composed of (1→6)-linked d-gluco-pyranosyl and (1→2)-linked l-arabinofuranosyl residues. The average degree of polymerization, determined through end-group analysis, was found to be ∼144.
    Carbohydrate Research. 08/1984; 131(1):149–155.
  • Pradyot K. Ghosal, Swapnadip Thakur
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    ABSTRACT: The acidic polysaccharide isolated from the gum exudate of Swietenia mahogany, and the degraded polysaccharide obtained by its mild hydrolysis with acid, are composed of residues of d-galactose, l-arabinose, l-rhamnose, and d-galacturonic acid. The products of methylation of these two polysaccharides and their carboxyl-reduced derivatives were characterized. The results of the methylation and periodate-oxidation experiments showed that these polysaccharides are extensively branched, and that their backbone is a (1 → 3)-linked d-galactan chain. The periodate consumption was in accord with the linkage distributions proposed. End-group analysis showed that the polysaccharide has a high value of average degree of polymerization.
    Carbohydrate Research 02/1983; 112(2):253-259. · 2.04 Impact Factor
  • Pradyot K. Ghosal, Swapnadip Thakur
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    ABSTRACT: The purified, homogeneous, acidic polysaccharide isolated from the gum exudate of Spondias pinnata, and its degraded product prepared by controlled autohydrolysis, were found to contain d-galactose, l-arabinose, and d-galacturonic acid. Complete methylation followed by hydrolysis, both before and after reduction with lithium aluminum hydride, revealed the probability of a (1 →3)-linked, galactan backbone. The linkages of the interior parts were confirmed by methylation studies, and by the results of periodate oxidation and Smith degradation.
    Carbohydrate Research - CARBOHYD RES. 01/1981; 98(1):75-83.
  • Partha Ghosh, Pradyot Ghosal, Bimalendu Ray
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    ABSTRACT: Hemicellulo sic po lysaccharides obtained from depectinated and delignified mus tard meal by extraction with 1 KOH (1OH-M) is fractionated by anio n exchange chromatography yielding a neutral xylogluc an rich population (1OH-N). The latter fraction is further characterized by size exclusio n chro matography, which resulted in one broad peak between Kav. 0.3 0.7, c orrespo nding to an ap parent molecular weight of 90 30 kDa. S ugar co mpositional analysis and d egradation stud ies with spec ific enzymes were performed to obtain information about the s tructure. The results obtained show that the xylo glucan present in 1OH-N fractio n contained a hepta ()-, an octa ()-, a no na ()-and a deca ()-sac charid es as the majo r building sub-units. The structures o f these oligo saccharides were determined. Hydrolysis of 1O H-M fraction with end o--(1 4)-D-xylanase and analysis o f the xylan d erived oligos accharides by chromatograp hy and mass sp ectrometry show that mustard meal xylan is compo sed of a -(1 4)-linked-D-xylopyrano se bac kbone s ubstituted with D-glucuro nic acid residue and its 4--methyl derivative. : Mustard meal, enzyme hydrolysis, oligosaccharides, MALDI-TOF-MS, HPAEC In a preceding paper 1 it was shown that 43% of the defatted mustard meal (DMM) could be solubilised during sequential extraction with dil HCl (HCl-M), dil KOH (OH-M), sodium chlorite (SC-M), 1 KOH (1OH-M) and 4 KOH (4OH-M), leaving an insoluble residue. Partial chemical characterizations of the polysaccharides present in HCl-M, OH-M, SC-M and 4OH-M fractions revealed the presence of arabinan, rham nogalacturonan I, arabinogalac tan protein, xyloglucan and xylans. The present study reports the structural features of polysaccharides present in 1 KOH extracte d fraction (1OH-M). In particular, structure of oligomers generated by endo-cellulase digestion of a xyloglucan rich pool (1OH-N) obtained by anion exchange chromatography of 1OH-M fraction is described (). Structural analysis of the r es ultin g oligo sa cc ha rid es w as ca rr ie d o ut b y combination of chemical, chromatographic and Matrix Assisted Laser Desorption Ionisation-Time of Flight-mass spectrometric techniques. In addition, structural features of xylans present in 1OH-M fraction will also be reported.