Munna Sarkar | Saha Institute of Nuclear Physics (original) (raw)
Papers by Munna Sarkar
Chemical physics letters, 1991
... CHEMICAL PHYSICS LETTERS 12Apr11 1991 Volume 179, number 1,2 Munna Sarkar and Pradeep K. Seng... more ... CHEMICAL PHYSICS LETTERS 12Apr11 1991 Volume 179, number 1,2 Munna Sarkar and Pradeep K. Sengupta Saha Institute of Nuclear Physics, 1 AF, Bidhannagar, Calcutta 700 064, India Received 1 November 1990; in final ... [2] A. Nag and K. Bhattacharyya, J. Photochem. ...
The Journal of Physical Chemistry B, 2016
Colloids and Surfaces B: Biointerfaces, 2009
Journal of the …, 1996
... Sebastian Tomac, † Munna Sarkar, † Tommi Ratilainen, ‡ Pernilla Wittung, ‡ Peter E. Nielsen, ... more ... Sebastian Tomac, † Munna Sarkar, † Tommi Ratilainen, ‡ Pernilla Wittung, ‡ Peter E. Nielsen, § Bengt Nordén, ‡ and Astrid Gräslund* †. Contribution from the Department of Biophysics, Arrhenius Laboratories, Stockholm University ...
Journal of inorganic biochemistry, 2006
The rigidity and flexibility of homologous psychrophilic (P), mesophilic (M) and thermophilic (T)... more The rigidity and flexibility of homologous psychrophilic (P), mesophilic (M) and thermophilic (T) proteins have been investigated at the global and local levels in terms of ‘packing factor’ and ‘atomic fluctuations’ obtained from B-factors. For comparison of atomic fluctuations, correction of errors by considering errors in B-factors from all sources in a consolidated manner and conversion of the fluctuations to the same temperature have been suggested and validated. Results indicate no differences in the global values like average packing factor among the three classes of protein homologs but at local levels there are differences. Comparison of homologous proteins triplets show that the average atomic fluctuations at a given temperature obey the order P > M >T. Packing factors and the atomic fluctuations are anti-correlated suggesting that altering the rigidity of the active site might be a potential strategy to make tailor made psychrophilic or thermophilic proteins from the...
Journal of luminescence, 2002
Long acting non-steroidal anti-inflammatory drugs (NSAIDs) belonging to the oxicam group have att... more Long acting non-steroidal anti-inflammatory drugs (NSAIDs) belonging to the oxicam group have attracted special interest because of their diverse biological functions. In this study we present the influence of microenvironment on the spectral properties of two oxicam drugs viz. piroxicam and meloxicam. For the two drugs, a high energy shift of the UV absorption maxima was observed with increasing drug concentrations both in protic solvent like ethanol and aprotic solvent like dimethyl sulfoxide (DMSO). Studies involving variation of percentage volume of water as well as pH, using absorption and steady state fluorescence spectroscopy, allow us to identify the principal species present at different concentrations of the drugs. It is found that even trace quantity of water present in the solvent becomes significant at low concentration of the drug making the water/drug ratio sufficiently large to support the formation of anion. As the concentration of the drug increases, the number of water molecules available per drug molecule decreases and most of the drug molecules face a relatively apolar environment in which zwitterionic/neutral species become predominant. This results in a concentration-dependent high-energy shift of the absorption maximum. This study demonstrates how microenvironments of these drugs guide the nature of the predominant form present in solution.
Chemical Physics Letters, 2010
Photo physical and spectral property of indomethacin has been harnessed to sense the cluster stru... more Photo physical and spectral property of indomethacin has been harnessed to sense the cluster structures that exist at the microscopic level in binary mixtures of 1-propanol-water. The ability of indomethacin to switch from a fluorescent complex with alcohol self-association cluster at low water content, to a nonfluorescent complex with hydrogen-bonded water cluster at high water content, imparts the drug with its unique microheterogeneity sensing property. Similar results are obtained for methanol-water and 1-butanol-water binary mixtures.
… et Biophysica Acta (BBA …, 2007
Modulation of surface properties of biomembranes by any ligand leading to permeabilization, fusio... more Modulation of surface properties of biomembranes by any ligand leading to permeabilization, fusion, rupture, etc. is a fundamental requirement for many biological processes. In this work, we present the interaction of piroxicam, a long acting ...
Biophysical chemistry, 2008
Membrane fusion is an important event in many biological processes and is characterized by severa... more Membrane fusion is an important event in many biological processes and is characterized by several intermediate steps of which content mixing between the two fusing vesicles signals the completion of the process. Fusion induced solely by small drug molecules is not a ...
Biophysical chemistry, 2007
Small unilamellar vesicles (SUVs) formed from a mixture of dimyristoylphosphatidylcholine (zwitte... more Small unilamellar vesicles (SUVs) formed from a mixture of dimyristoylphosphatidylcholine (zwitterionic lipid with bulkier headgroup) and dimyristoylphosphatidylglycerol (anionic lipid with relatively smaller headgroup) allows better modulation of the physical properties of lipid bilayers ...
Biophysical chemistry, 2005
Molecules, whose pK a values can be easily fine-tuned by their microenvironment, are expected to ... more Molecules, whose pK a values can be easily fine-tuned by their microenvironment, are expected to be profoundly affected by the heterogeneous environments of membranes. Membrane parameters can have a strong effect in choosing a particular structural form of a molecule for ...
Chemistry and physics of lipids, 2005
Small unilamellar vesicles (SUVs) formed by the dimyristoylphosphatidylcholine (DMPC), a phosphol... more Small unilamellar vesicles (SUVs) formed by the dimyristoylphosphatidylcholine (DMPC), a phospholipid; serve as a membrane mimetic system that can be used to study the effect of absence of net surface charges on drugmembrane interaction. The targets of non-steroidal anti-...
Biophysical chemistry, 2003
Non-steroidal anti-inflammatory drugs (NSAIDs) of oxicam group are not only effective as anti-inf... more Non-steroidal anti-inflammatory drugs (NSAIDs) of oxicam group are not only effective as anti-inflammatory agents but also show diverse functions. Their principal targets are cyclooxygenases, which are membrane-associated enzymes. To bind with the targets ...
Membrane fusion is a key event in many biological processes. The fusion process, both in vivo and... more Membrane fusion is a key event in many biological processes. The fusion process, both in vivo and in vitro, is induced by different agents which include mainly proteins and peptides. For protein- and peptide-mediated membrane fusion, conformational reorganization serves as a driving force. Small drug molecules do not share this advantage; hence, drug induced membrane fusion occurring in absence of any other fusogenic agent and at physiologically relevant concentration of the drugs is a very rare event. To date, only three drugs, namely, meloxicam (Mx), piroxicam (Px), and tenoxicam (Tx), belonging to the oxicam group of non steroidal anti-inflammatory drugs (NSAIDs), have been shown by us to induce fusion at very low drug to lipid ratio without the aid of any other fusogenic agent. In our continued effort to understand the interplay of different physical and chemical parameters of both the participating drugs and the membrane on the mechanism of this drug induced membrane fusion, we present here the effect of increase in orientational order of the lipid chains and increase in head group spacing. This is achieved by studying the effect of low concentration cholesterol (<10 mol %) at temperatures above the chain-melting transition. Low concentration cholesterol (<10 mol %), above the gel to fluid transition temperature, is mainly known to increase orientational order of the lipid chains and increase head group spacing. To isolate the effect of these parameters, small unilameller vesicles (SUVs) formed by dimyristoylphosphatidylcholine (DMPC) with an average diameter of 50-60 nm were used as simple model membranes. Fluorescence assays were used to probe the time dependence of lipid mixing, content mixing, and leakage and also used to determine the partitioning of the drugs in the membrane bilayer. Differential scanning calorimetry (DSC) was used to study the effect of drugs in the presence of cholesterol on the chain-melting temperature which reflects the fluidization effect of the hydrophobic tail region of the bilayer. Our results show contradictory effect of low concentration cholesterol on the fusion induced by the three drugs, which has been explained by parsing the effect of orientational order and increase in head group spacing on the fusion process.
Biopolymers, 2004
Encapsulation of drugs in different host systems not only serves as an effective tool for deliver... more Encapsulation of drugs in different host systems not only serves as an effective tool for delivering drugs to appropriate targets, but in some cases is also known to increase their therapeutic efficacy. A detailed understanding of the basic principles that govern the interaction of ...
Mini reviews in …, 2008
Non-steroidal anti-inflammatory drugs and aureolic acid group of anti-cancer drugs belong to the ... more Non-steroidal anti-inflammatory drugs and aureolic acid group of anti-cancer drugs belong to the class of generic drugs. Research with some members of these two groups of drugs in different laboratories has unveiled functions other than those for which they were primarily developed as drugs. Here we have reviewed the molecular mechanism behind the multiple functions of these drugs that might lead to employ them for treatment of diseases in addition to those they are presently employed.
Spectrochimica Acta Part A: …, 2003
Oxicam group of non steroidal anti-inflammatory drugs has been chosen as a prototype molecular gr... more Oxicam group of non steroidal anti-inflammatory drugs has been chosen as a prototype molecular group that shows diverse biological functions and dynamic structural features. Photophysical studies of three drugs from this group viz., piroxicam, meloxicam and tenoxicam have ...
New Journal of Chemistry
Lornoxicam forms inclusion complexes with all cyclodextrins but for their hydroxy-propyl derivati... more Lornoxicam forms inclusion complexes with all cyclodextrins but for their hydroxy-propyl derivatives, the drug also interacts with their outer surfaces.
Chemical physics letters, 1991
... CHEMICAL PHYSICS LETTERS 12Apr11 1991 Volume 179, number 1,2 Munna Sarkar and Pradeep K. Seng... more ... CHEMICAL PHYSICS LETTERS 12Apr11 1991 Volume 179, number 1,2 Munna Sarkar and Pradeep K. Sengupta Saha Institute of Nuclear Physics, 1 AF, Bidhannagar, Calcutta 700 064, India Received 1 November 1990; in final ... [2] A. Nag and K. Bhattacharyya, J. Photochem. ...
The Journal of Physical Chemistry B, 2016
Colloids and Surfaces B: Biointerfaces, 2009
Journal of the …, 1996
... Sebastian Tomac, † Munna Sarkar, † Tommi Ratilainen, ‡ Pernilla Wittung, ‡ Peter E. Nielsen, ... more ... Sebastian Tomac, † Munna Sarkar, † Tommi Ratilainen, ‡ Pernilla Wittung, ‡ Peter E. Nielsen, § Bengt Nordén, ‡ and Astrid Gräslund* †. Contribution from the Department of Biophysics, Arrhenius Laboratories, Stockholm University ...
Journal of inorganic biochemistry, 2006
The rigidity and flexibility of homologous psychrophilic (P), mesophilic (M) and thermophilic (T)... more The rigidity and flexibility of homologous psychrophilic (P), mesophilic (M) and thermophilic (T) proteins have been investigated at the global and local levels in terms of ‘packing factor’ and ‘atomic fluctuations’ obtained from B-factors. For comparison of atomic fluctuations, correction of errors by considering errors in B-factors from all sources in a consolidated manner and conversion of the fluctuations to the same temperature have been suggested and validated. Results indicate no differences in the global values like average packing factor among the three classes of protein homologs but at local levels there are differences. Comparison of homologous proteins triplets show that the average atomic fluctuations at a given temperature obey the order P > M >T. Packing factors and the atomic fluctuations are anti-correlated suggesting that altering the rigidity of the active site might be a potential strategy to make tailor made psychrophilic or thermophilic proteins from the...
Journal of luminescence, 2002
Long acting non-steroidal anti-inflammatory drugs (NSAIDs) belonging to the oxicam group have att... more Long acting non-steroidal anti-inflammatory drugs (NSAIDs) belonging to the oxicam group have attracted special interest because of their diverse biological functions. In this study we present the influence of microenvironment on the spectral properties of two oxicam drugs viz. piroxicam and meloxicam. For the two drugs, a high energy shift of the UV absorption maxima was observed with increasing drug concentrations both in protic solvent like ethanol and aprotic solvent like dimethyl sulfoxide (DMSO). Studies involving variation of percentage volume of water as well as pH, using absorption and steady state fluorescence spectroscopy, allow us to identify the principal species present at different concentrations of the drugs. It is found that even trace quantity of water present in the solvent becomes significant at low concentration of the drug making the water/drug ratio sufficiently large to support the formation of anion. As the concentration of the drug increases, the number of water molecules available per drug molecule decreases and most of the drug molecules face a relatively apolar environment in which zwitterionic/neutral species become predominant. This results in a concentration-dependent high-energy shift of the absorption maximum. This study demonstrates how microenvironments of these drugs guide the nature of the predominant form present in solution.
Chemical Physics Letters, 2010
Photo physical and spectral property of indomethacin has been harnessed to sense the cluster stru... more Photo physical and spectral property of indomethacin has been harnessed to sense the cluster structures that exist at the microscopic level in binary mixtures of 1-propanol-water. The ability of indomethacin to switch from a fluorescent complex with alcohol self-association cluster at low water content, to a nonfluorescent complex with hydrogen-bonded water cluster at high water content, imparts the drug with its unique microheterogeneity sensing property. Similar results are obtained for methanol-water and 1-butanol-water binary mixtures.
… et Biophysica Acta (BBA …, 2007
Modulation of surface properties of biomembranes by any ligand leading to permeabilization, fusio... more Modulation of surface properties of biomembranes by any ligand leading to permeabilization, fusion, rupture, etc. is a fundamental requirement for many biological processes. In this work, we present the interaction of piroxicam, a long acting ...
Biophysical chemistry, 2008
Membrane fusion is an important event in many biological processes and is characterized by severa... more Membrane fusion is an important event in many biological processes and is characterized by several intermediate steps of which content mixing between the two fusing vesicles signals the completion of the process. Fusion induced solely by small drug molecules is not a ...
Biophysical chemistry, 2007
Small unilamellar vesicles (SUVs) formed from a mixture of dimyristoylphosphatidylcholine (zwitte... more Small unilamellar vesicles (SUVs) formed from a mixture of dimyristoylphosphatidylcholine (zwitterionic lipid with bulkier headgroup) and dimyristoylphosphatidylglycerol (anionic lipid with relatively smaller headgroup) allows better modulation of the physical properties of lipid bilayers ...
Biophysical chemistry, 2005
Molecules, whose pK a values can be easily fine-tuned by their microenvironment, are expected to ... more Molecules, whose pK a values can be easily fine-tuned by their microenvironment, are expected to be profoundly affected by the heterogeneous environments of membranes. Membrane parameters can have a strong effect in choosing a particular structural form of a molecule for ...
Chemistry and physics of lipids, 2005
Small unilamellar vesicles (SUVs) formed by the dimyristoylphosphatidylcholine (DMPC), a phosphol... more Small unilamellar vesicles (SUVs) formed by the dimyristoylphosphatidylcholine (DMPC), a phospholipid; serve as a membrane mimetic system that can be used to study the effect of absence of net surface charges on drugmembrane interaction. The targets of non-steroidal anti-...
Biophysical chemistry, 2003
Non-steroidal anti-inflammatory drugs (NSAIDs) of oxicam group are not only effective as anti-inf... more Non-steroidal anti-inflammatory drugs (NSAIDs) of oxicam group are not only effective as anti-inflammatory agents but also show diverse functions. Their principal targets are cyclooxygenases, which are membrane-associated enzymes. To bind with the targets ...
Membrane fusion is a key event in many biological processes. The fusion process, both in vivo and... more Membrane fusion is a key event in many biological processes. The fusion process, both in vivo and in vitro, is induced by different agents which include mainly proteins and peptides. For protein- and peptide-mediated membrane fusion, conformational reorganization serves as a driving force. Small drug molecules do not share this advantage; hence, drug induced membrane fusion occurring in absence of any other fusogenic agent and at physiologically relevant concentration of the drugs is a very rare event. To date, only three drugs, namely, meloxicam (Mx), piroxicam (Px), and tenoxicam (Tx), belonging to the oxicam group of non steroidal anti-inflammatory drugs (NSAIDs), have been shown by us to induce fusion at very low drug to lipid ratio without the aid of any other fusogenic agent. In our continued effort to understand the interplay of different physical and chemical parameters of both the participating drugs and the membrane on the mechanism of this drug induced membrane fusion, we present here the effect of increase in orientational order of the lipid chains and increase in head group spacing. This is achieved by studying the effect of low concentration cholesterol (<10 mol %) at temperatures above the chain-melting transition. Low concentration cholesterol (<10 mol %), above the gel to fluid transition temperature, is mainly known to increase orientational order of the lipid chains and increase head group spacing. To isolate the effect of these parameters, small unilameller vesicles (SUVs) formed by dimyristoylphosphatidylcholine (DMPC) with an average diameter of 50-60 nm were used as simple model membranes. Fluorescence assays were used to probe the time dependence of lipid mixing, content mixing, and leakage and also used to determine the partitioning of the drugs in the membrane bilayer. Differential scanning calorimetry (DSC) was used to study the effect of drugs in the presence of cholesterol on the chain-melting temperature which reflects the fluidization effect of the hydrophobic tail region of the bilayer. Our results show contradictory effect of low concentration cholesterol on the fusion induced by the three drugs, which has been explained by parsing the effect of orientational order and increase in head group spacing on the fusion process.
Biopolymers, 2004
Encapsulation of drugs in different host systems not only serves as an effective tool for deliver... more Encapsulation of drugs in different host systems not only serves as an effective tool for delivering drugs to appropriate targets, but in some cases is also known to increase their therapeutic efficacy. A detailed understanding of the basic principles that govern the interaction of ...
Mini reviews in …, 2008
Non-steroidal anti-inflammatory drugs and aureolic acid group of anti-cancer drugs belong to the ... more Non-steroidal anti-inflammatory drugs and aureolic acid group of anti-cancer drugs belong to the class of generic drugs. Research with some members of these two groups of drugs in different laboratories has unveiled functions other than those for which they were primarily developed as drugs. Here we have reviewed the molecular mechanism behind the multiple functions of these drugs that might lead to employ them for treatment of diseases in addition to those they are presently employed.
Spectrochimica Acta Part A: …, 2003
Oxicam group of non steroidal anti-inflammatory drugs has been chosen as a prototype molecular gr... more Oxicam group of non steroidal anti-inflammatory drugs has been chosen as a prototype molecular group that shows diverse biological functions and dynamic structural features. Photophysical studies of three drugs from this group viz., piroxicam, meloxicam and tenoxicam have ...
New Journal of Chemistry
Lornoxicam forms inclusion complexes with all cyclodextrins but for their hydroxy-propyl derivati... more Lornoxicam forms inclusion complexes with all cyclodextrins but for their hydroxy-propyl derivatives, the drug also interacts with their outer surfaces.