Subarna Karmaker

Jahangirnagar University, Mujib City, Dhaka, Bangladesh

Are you Subarna Karmaker?

Claim your profile

Publications (14)31.54 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The adsorption of reactive orange 13 (RO13) onto jackfruit seed flakes was investigated in aqueous solution at different pHs, initial concentration of dye solutions, ionic strengths and temperatures, respectively. The adsorbent and dye adsorption were characterized by diffuse reflectance electronic absorption and Fourier transformation infrared (FTIR) spectra. The adsorption of RO13 increased largely with decreasing solution pH or with increasing initial dye concentration. Pseudo first-, second-order, intraparticle, and film diffusion kinetic models were used to evaluate experimental data obtained from batch studies, and thereby elucidate the kinetics and mechanism of adsorption process. The results showed that the adsorption of RO13 follows pseudo second-order kinetics very well. The intraparticle diffusion and film diffusion are the rate limiting steps. The equilibrium adsorption data were analyzed by Temkin, Freundlich and Langmuir isotherm models, respectively. The best fit to the data was obtained from the Langmuir model. The monolayer adsorption capacity of jackfruit seed flakes was found to be 64.10 μmol/g at pH 2. The values of activation and thermodynamic parameters were calculated and obtained results revealed that the present adsorption is a spontaneous and endothermic physisorption process.
    Journal of Environmental Chemical Engineering. 01/2014;
  • Tapan Kumar Saha, Md. Farhad Mahmud, Subarna Karmaker
    [Show abstract] [Hide abstract]
    ABSTRACT: The adsorption behavior of [meso-tetrakis(4-carboxylatophenyl)porphyrinato]oxovanadium(IV) tetrasodium, [VO(tcpp)]Na4, in aqueous solution onto chitosan 7B has been investigated. The factors affecting the sorption process such as solution pH, initial concentration of [VO(tcpp)]Na4 solution and temperature were determined in batch mode. Adsorption kinetic data obtained from different batch experiments was tested using pseudo first-, second-order, Elovich, intraparticle, and film diffusion kinetic models. Langmuir, Temkin, and Freundlich isotherm models were used for the description of equilibrium adsorption data. The best results were achieved with the pseudo second-order kinetic and Freundlich isotherm equilibrium models, respectively. The film diffusion and intraparticle diffusion were the rate-limiting steps. The equilibrium adsorption capacity (q e) increased with increasing the initial concentration of [VO(tcpps)]Na4 solution, showing maximum adsorption capacity of 69.35 μmol/g. The activation energy (E a) of sorption kinetics was estimated to be 46.21 kJ/mol in the temperature range 25–40 °C. Thermodynamic parameters such as changes in free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were also evaluated by applying the Van’t Hoff equation. The values of thermodynamic parameters for [VO(tcpp)]Na4 adsorption onto chitosan 7B indicate that it was spontaneous and endothermic nature.
    Polymer Bulletin 01/2013; 70(7). · 1.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Adsorption of [meso-tetrakis(4-sulfonatophenyl)porphyrinato]oxovanadate(IV)(4–), [VO(tpps)], onto chitosan 7B in aqueous solution was investigated in a batch system. The effects of solution pH, initial concentration of [VO(tpps)], and temperature were studied. Adsorption kinetic data obtained from different batch experiments was modeled using both pseudo first- and second-order kinetic equations. Freundlich, Tempkin, and Langmuir models were used for the description of adsorption equilibrium data. The best results were achieved with the pseudo second-order kinetic and Langmuir isotherm equilibrium models, respectively. The equilibrium adsorption capacity (q e) increased with increasing the initial concentration of [VO(tpps)], showing maximum adsorption capacity of 441.21 μmol/g. The activation energy (E a) of sorption kinetics was estimated to be 19.84 kJ/mol in the temperature range 25–40 °C. Thermodynamic parameters such as changes in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) were also evaluated by applying the Van’t Hoff equation. The values of thermodynamic parameters of [VO(tpps)] adsorption onto chitosan 7B indicate its spontaneous and endothermic nature. The present work provides a first example for the preparation of chitosan–[VO(tpps)] complex in aqueous solution.
    Polymer Bulletin 01/2012; 68(5). · 1.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Adsorption of reactive black 5 (RB5) from aqueous solution onto chitosan was investigated in a batch system. The effects of solution pH, initial dye concentration, and temperature were studied. Adsorption data obtained from different batch experiments were modeled using both pseudo first- and second-order kinetic equations. The equilibrium adsorption data were fitted to the Freundlich, Tempkin, and Langmuir isotherms over a dye concentration range of 45–100 µmol/L. The best results were achieved with the pseudo second-order kinetic and Langmuir isotherm equilibrium models, respectively. The equilibrium adsorption capacity (qe) was increased with increasing the initial dye concentration and solution temperature, and decreasing solution pH. The chitosan flakes for the adsorption of the dye was regenerated efficiently through the alkaline solution and was then reused for dye removal. The activation energy (Ea) of sorption kinetics was estimated to be 13.88 kJ/mol. Thermodynamic parameters such as changes in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) were evaluated by applying the van't Hoff equation. The thermodynamics of reactive dye adsorption by chitosan indicates its spontaneous and endothermic nature.
    CLEAN - Soil Air Water 09/2011; 39(10):984 - 993. · 2.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In developing new insulin-mimetic vanadyl complexes with various ligands including biodegradable polymers, we prepared and characterized three VO(γ γ γ γ-pga) complexes in solution and evaluated their in vitro insulin-mimetic activities and in vivo anti-diabetic effects in streptozotocin (STZ)-induced type 1 like diabetic mice (STZ-mice). All three VO(γ γ γ γ-pga) complexes normalized the hyperglycemia in STZ-mice within 14 d when administered orally at doses of 10 mg V kg –1 body mass for 28 d. In addition, the impaired glucose tolerance, elevated HbA 1c levels and metabolic syndromes were significantly improved in VO(γ γ γ γ-pga) complexes-treated STZ-mice relative to those administrated with saline and VS. Vanadium was distributed in the tissues examined in the following decreasing order: bones, liver, muscles, spleen, heart, kidneys, brain, lungs and pancreas. VO(γ γ γ γ-pga) complexes in which γ γ γ γ-pga having average molecular weight 480 – 4700 kDa are promising oral therapeutic agents for the treatment of type 1 diabetic animals.
    African journal of pharmacy and pharmacology 04/2010; 4:235-243. · 0.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In developing new insulin-mimetic zinc(II) complexes with various ligands including a biodegradable polymer, we prepared and characterized a Zn(gamma-pga) complex in solution as well as in solid, and investigated its in vitro insulin-mimetic activity and in vivo antidiabetic effect in type-2 diabetic KKA(y) mice. The in vitro insulin-mimetic activity of the Zn(gamma-pga) complex was considerable better than that of ZnSO(4). The Zn(gamma-pga) complex normalized the hyperglycemia in KKA(y) mice within 21 d when administrated orally at doses of 10-20 mg (0.15-0.31 mmol) Zn per kg body mass for 30 d. In addition, the impaired glucose tolerance, elevated HbA(1c) levels and metabolic syndromes were significantly improved in Zn(gamma-pga)-treated KKA(y) mice relative to those administrated with saline and ZnSO(4).
    Macromolecular Bioscience 12/2008; 9(3):279-86. · 3.74 Impact Factor
  • Subarna Karmaker, Tapan Kumar Saha, Hiromu Sakurai
    [Show abstract] [Hide abstract]
    ABSTRACT: Newly synthesized vanadyl-poly(gamma-glutamic acid) complex (VO-gamma-PGA) with a VO(O4) coordination mode was found to have potent antidiabetic activity in streptozotocin (STZ)-induced type 1 diabetic mice (STZ-mice), compared with that of a solution containing only vanadyl sulfate, VOSO4. This was the first example of orally active vanadyl complex of gamma-PGA for treating STZ-mice. To better define its efficacy, we examined here the effects of VO-gamma-PGA treatment in STZ-mice by oral administration at the dose of 10 mg V/kg body mass for a longer period time than our previous study. The improvement in diabetic states in STZ-mice compared with saline-treated nondiabetic normal Std ddY mice. It was found that the elevated blood glucose levels in STZ-mice significantly decreased after 3 days and sustained the normalized blood glucose level around 180-200 mg/dL (10-11.1 mM) for the last 14 days, which is close to the blood glucose levels 100-200 mg/dL (5.6-11.1 mM) in nondiabetic normal Std ddY mice. The improvement in diabetes was strongly corelated by the improvement in oral glucose tolerance ability, glycosylated hemoglobin (HbA1c) levels and blood pressure, and serum parameters. The present results confirmed that VO-gamma-PGA complex is a promising, orally active insulin-mimetic agent to treat type 1 diabetic mice.
    Journal of Biomaterials Applications 04/2008; 22(5):449-64. · 2.64 Impact Factor
  • Subarna Karmaker, Tapan K Saha
    [Show abstract] [Hide abstract]
    ABSTRACT: The naturally occurring edible biopolymer poly(gamma-glutamic acid) (gamma-PGA) is shown to be an efficient chelating agent of vanadium(IV). The structure of poly(gamma-glutamic acid)oxovanadium(IV) (VO-gamma-PGA) complex in solution has been analyzed by electron spin resonance and UV-visible absorption spectra. The equatorial coordination sphere of vanadium(IV) is proposed to be [2 x carboxylate (2O)-VO-(OH2)2]. The binding isotherm is determined for suspensions of gamma-PGA in vanadium(IV) oxide sulfate (VS) solutions of different concentrations, and the data have been adjusted to fit the modified Langmuir equation. The maximum amount of vanadium bound per gram of gamma-PGA is estimated to be 141 mmol . g(-1) with a binding constant of 22 L . g(-1) at pH 3.
    Macromolecular Bioscience 03/2008; 8(2):171-6. · 3.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recently, we found that poly(gamma-glutamic acid)oxovanadium(IV) complex (VO(gamma-pga)) exhibits a potent antidiabetic activity in streptozotocin (STZ)-induced type 1 diabetic mice. This result prompted us to examine its ability to treat the type 2 diabetic model KKA(y) mice with insulin resistance. We studied the in vivo antidiabetic activity of VO(gamma-pga), compared with that of vanadium(IV) oxide sulfate (VS) as control. Both compounds were orally administered at doses of 5-10 mg (0.1-0.2 mmol) V kg(-1) body mass to the KKA(y) mice for 30 days. VO(gamma-pga) normalized the hyperglycemia within 21 days, whereas VS lowered the blood glucose concentration only by a small degree. In addition, the glucose intolerance, HbA(1c) level, hyperinsulinemia, hypercholesterolemia, and hyperleptinemia were significantly improved in VO(gamma-pga)-treated KKA(y) mice compared with those treated with VS. Based on these observations, VO(gamma-pga) is proposed to be the first orally active oxovanadium(IV)-polymer complex for the efficacious treatment of not only type 2 diabetes but also metabolic syndrome in animals.
    ChemMedChem 12/2007; 2(11):1607-12. · 2.84 Impact Factor
  • Subarna Karmaker, Tapan K Saha, Hiromu Sakurai
    [Show abstract] [Hide abstract]
    ABSTRACT: The complexation between cupric ions (Cu(II)) and poly(gamma-glutamic acid) (gamma-PGA) in aqueous solutions (pH 3-11) has been studied by UV-visible absorption and electron spin resonance (ESR) techniques. Formation of the Cu(II)-gamma-PGA complex is confirmed by the observation of the blue shift of the absorption band in the visible region, anisotropic line shapes in the ESR spectrum at room temperature, and a computer simulation of the visible absorption spectrum of the complex. The structure of the Cu(II)-gamma-PGA complex, depending on the pH, has been determined. The in vitro insulin-mimetic activity of the Cu(II)-gamma-PGA complex is examined by determining both inhibition of free fatty acid release and glucose uptake in isolated rat adipocytes treated with epinephrine, in which the concentration of the Cu(II)-gamma-PGA complex for 50% inhibition of free fatty acid release is very similar to that of CuSO4. However, it is significantly lower than that of a previously reported insulin-mimetic bis(3-hydroxypicolinato)copper(II), [Cu(3hpic)2], complex.
    Macromolecular Bioscience 05/2007; 7(4):456-66. · 3.74 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Insulin-mimetic vanadyl-poly(gamma-glutamic acid) complex, VO-gamma-PGA, is proposed as a novel drug delivery system for treating type 1 diabetic animals. The structure of VO-gamma-PGA in solution as well as in solid state was analyzed by electronic absorption, infra-red, and electron spin resonance spectra, and proposed that the equatorial coordination mode of VO(2+) is in either carboxylate(O)-VO-(OH(2))(3) or 2 carboxylate(O(2))-VO-(OH(2))(2). In vitro insulin-mimetic activity, metallokinetic feature in the blood of healthy rats, and in vivo normoglycemic effect of the complex prepared in solution were evaluated in streptozotocin(STZ)-induced type 1 diabetic mice, and these effects were compared with those of a solution containing only VOSO(4) as a positive control. The in vitro insulin-mimetic activity of VO-gamma-PGA was examined by determining both inhibition of free fatty acid (FFA) release and glucose uptake in isolated rat adipocytes, in which the concentration of VO-gamma-PGA for 50% inhibition of FFA release was significantly lower than that of VOSO(4). Metallokinetic study suggested that the bioavailability of VO-gamma-PGA complex was much higher than that of VOSO(4). The complex showed a significant hypoglycemic activity within at least 4h after a single oral administration, the effect being sustained for at least 24h. Furthermore, VO-gamma-PGA normalized the hyperglycemia in STZ-mice within 3 days when it was given orally at doses of 5-10mgVkg(-1) body mass for 16 days. The improvement in diabetes was also supported by the results on oral glucose tolerance test, HbA(1c) levels, and blood pressure.
    Journal of Inorganic Biochemistry 10/2006; 100(9):1535-46. · 3.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Chitosan, a naturally abundant biopolymer, has widely been studied for metal adsorption from various solutions, but the extension of chitosan as an adsorbent to remove organic substances from water and wastewater has seldom been explored. In this study, the adsorption of an azo dye, trisodium 2-hydroxy-1,1'-azonaphthalene-3,4',6-trisulfonate (1), from aqueous solution onto the various degrees of deacetylated chitosan has been investigated. Equilibrium studies have been carried out to determine the capacity of chitosan for dye. The experimental data were analyzed using two isotherm correlations, namely, Langmuir and Freundlich equations. The linear correlation coefficients were determined for each isotherm and the Langmuir provided the best fit. The experimental adsorption isotherms were perfectly reproduced in the simulated data obtained from numerical analysis on the basis of the Langmuir model and the isotherm constants. Adsorption of (1) onto the chitosan flakes was found to be strongly depending on degrees of deacetylation in chitosan and temperatures. Significant amounts of (1) were adsorbed by chitosan 8B (higher degree of deacetylated chitosan), but the adsorption capacity was reduced remarkably with increasing solution temperatures. Thermodynamic parameters such as change in free energy (DeltaG), enthalpy (DeltaH), and entropy (DeltaS) were also determined. In addition, kinetic study indicated that the adsorption process mechanisms were both transport- and attachment-limited.
    Journal of Colloid and Interface Science 07/2005; 286(2):433-9. · 3.55 Impact Factor
  • Tapan Kumar Saha, Subarna Karmaker, Keietsu Tamagake
    [Show abstract] [Hide abstract]
    ABSTRACT: High-valent oxo-iron(IV) species are commonly proposed as the key intermediates in the catalytic mechanisms of iron enzymes. Water-soluble iron(III) tetrakis-5,10,15,20-(N-methyl-4-pyridyl)porphyrin (Fe(III)TMPyP) has been used as a model of heme-enzyme to catalyse the hydrogen peroxide (H(2)O(2)) oxidation of various organic compounds. However, the mechanism of the reaction of Fe(III)TMPyP with H(2)O(2) has not been fully established. In this study, we have explored the kinetic simulation of the reaction of Fe(III)TMPyP with H(2)O(2) and of the catalytic reactivity of FeTMPyP in the luminescent peroxidation of luminol. According to the mechanism that has been established in this work, Fe(III)TMPyP is oxidized by H(2)O(2) to produce (TMPyP)(*+)Fe(IV)[double bond]O (k1 = 4.5 x 10(4)/mol/L/s) as a precursor of TMPyPFe(IV)[double bond]O. The intermediate, (TMPyP)(*+)Fe(IV)[double bond]O, represented nearly 2% of Fe(III)TMPyP but it does not accumulate in sufficient concentration to be detected because its decay rate is too fast. Kinetic simulations showed that the proposed scheme is capable of reproducing the observed time courses of FeTMPyP in various oxidation states and the decay profiles of the luminol chemiluminescence. It also shows that (TMPyP)(*+)Fe(IV)[double bond]O is 100 times more reactive than TMPyPFe(IV)[double bond]O in most of the reactions. These two species are responsible for the initial sharp and the sustained luminol emissions, respectively.
    Luminescence 09/2003; 18(5):259-67. · 1.27 Impact Factor
  • Tapan Kumar Saha, Subarna Karmaker, Keietsu Tamagake
    [Show abstract] [Hide abstract]
    ABSTRACT: The reaction of iron(III) tetrakis-5,10,15,20-(N-methyl-4-pyridyl)porphyrin (Fe(III)TMPyP) with hydrogen peroxide (H(2)O(2)) and the catalytic activity of the reaction intermediates on the luminescent peroxidation of luminol in aqueous solution were studied by using a double-mixing stopped-flow system. The observed luminescence intensities showed biphasic decay depending on the conditions. The initial flashlight decayed within <1 s followed by a sustained emission for more than 30 s. Computer deconvolution of the time-resolved absorption spectra under the same conditions revealed that the initial flashlight appeared during the formation of the oxo-iron(IV) porphyrin, TMPyPFe(IV) = O, which is responsible for the sustained emission. The absorption spectra 0.0-0.5 s did not reproduce well by a simple combination of the two spectra of Fe(III)TMPyP and TMPyPFe(IV) = O, indicating that transient species was formed at the initial stage. Addition of uric acid (UA) caused a significant delay in the initiation of the luminol emission as well as in the formation of the TMPyPFe(IV) = O. Both of them were completely diminished in the presence of UA equimolar with H(2)O(2), while mannitol had no effect at all. The delay of the light emission as well as the appearance of TMPyPFe(IV) = O was directly proportional to the [UA](0) but other kinetic profiles were not changed significantly. Based on these observations and the kinetic analysis, we confirmed the involvement of the oxo-iron(IV) porphyrin radical cation, (TMPyP)(.+)Fe(IV) = O, as an obligatory intermediate in the rate-determining step of the overall reaction, Fe(III)TMPyP + H(2)O(2) --> TMPyPFe(IV) = O, with a rate constant of k = 4.3 x 10(4)/mol/L/s. The rate constants for the reaction between the (TMPyP)(.+)Fe(IV) = O and luminol, and between the TMPyPFe(IV) = O and luminol were estimated to be 3.6 x 10(6)/mol/L/s and 1.31 x 10(4)/mol/L/s, respectively.
    Luminescence 01/2003; 18(3):162-72. · 1.27 Impact Factor

Publication Stats

68 Citations
31.54 Total Impact Points

Institutions

  • 2011–2013
    • Jahangirnagar University
      • Department of Chemistry
      Mujib City, Dhaka, Bangladesh
  • 2008
    • Primeasia University
      Mujib City, Dhaka, Bangladesh
  • 2006–2008
    • Kyoto Pharmaceutical University
      • Laboratory of Analytical and Bioinorganic Chemistry
      Kioto, Kyōto, Japan