The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Umesh R. Desai - One of the best experts on this subject based on the ideXlab platform.
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Capillary electrophoresis of highly sulfated Flavanoids and flavonoids.
Analytical biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5-10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (+/-)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% beta-cyclodextrin, a chiral selector, but not with alpha- or gamma-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (-)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.
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capillary electrophoresis of highly sulfated Flavanoids and flavonoids
Analytical Biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Abstract Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5–10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (±)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% β-cyclodextrin, a chiral selector, but not with α- or γ-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (−)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.
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interaction of designed sulfated Flavanoids with antithrombin lessons on the design of organic activators
Journal of Medicinal Chemistry, 2002Co-Authors: Gunnar T. Gunnarsson, Umesh R. DesaiAbstract:Recently, we designed (−)-epicatechin sulfate (ECS), the first small nonsaccharide molecule, as an activator of antithrombin for the accelerated inhibition of factor Xa, a key proteinase of the coagulation cascade (Gunnarsson, G. T.; Desai, U. R. J. Med. Chem. 2002, 45, 1233−1243). Although sulfated Flavanoid ECS was found to bind antithrombin with an affinity (∼10.7 μM) comparable to the reference trisaccharide DEF (∼4.5 μM), it accelerated the inhibition of factor Xa only 10-fold as compared to the ∼300-fold observed with DEF. To determine whether this conformational activation of the inhibitor is dependent on the structure of the organic activator and to probe the basis for the deficiency in activation, we studied the interaction of similar sulfated Flavanoids with antithrombin. (+)-Catechin sulfate (CS), a chiral stereoisomer of ECS, bound plasma antithrombin with a 3-fold higher affinity (KD = 3.5 μM) and a 2-fold higher second-order rate constant for factor Xa inhibition (kACT = 6750 M-1 s-1). On th...
Gunnar T. Gunnarsson - One of the best experts on this subject based on the ideXlab platform.
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Capillary electrophoresis of highly sulfated Flavanoids and flavonoids.
Analytical biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5-10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (+/-)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% beta-cyclodextrin, a chiral selector, but not with alpha- or gamma-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (-)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.
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capillary electrophoresis of highly sulfated Flavanoids and flavonoids
Analytical Biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Abstract Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5–10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (±)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% β-cyclodextrin, a chiral selector, but not with α- or γ-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (−)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.
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interaction of designed sulfated Flavanoids with antithrombin lessons on the design of organic activators
Journal of Medicinal Chemistry, 2002Co-Authors: Gunnar T. Gunnarsson, Umesh R. DesaiAbstract:Recently, we designed (−)-epicatechin sulfate (ECS), the first small nonsaccharide molecule, as an activator of antithrombin for the accelerated inhibition of factor Xa, a key proteinase of the coagulation cascade (Gunnarsson, G. T.; Desai, U. R. J. Med. Chem. 2002, 45, 1233−1243). Although sulfated Flavanoid ECS was found to bind antithrombin with an affinity (∼10.7 μM) comparable to the reference trisaccharide DEF (∼4.5 μM), it accelerated the inhibition of factor Xa only 10-fold as compared to the ∼300-fold observed with DEF. To determine whether this conformational activation of the inhibitor is dependent on the structure of the organic activator and to probe the basis for the deficiency in activation, we studied the interaction of similar sulfated Flavanoids with antithrombin. (+)-Catechin sulfate (CS), a chiral stereoisomer of ECS, bound plasma antithrombin with a 3-fold higher affinity (KD = 3.5 μM) and a 2-fold higher second-order rate constant for factor Xa inhibition (kACT = 6750 M-1 s-1). On th...
Mandakini Dantuluri - One of the best experts on this subject based on the ideXlab platform.
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Capillary electrophoresis of highly sulfated Flavanoids and flavonoids.
Analytical biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5-10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (+/-)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% beta-cyclodextrin, a chiral selector, but not with alpha- or gamma-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (-)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.
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capillary electrophoresis of highly sulfated Flavanoids and flavonoids
Analytical Biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Abstract Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5–10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (±)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% β-cyclodextrin, a chiral selector, but not with α- or γ-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (−)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.
Huyen Nguyen - One of the best experts on this subject based on the ideXlab platform.
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Capillary electrophoresis of highly sulfated Flavanoids and flavonoids.
Analytical biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5-10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (+/-)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% beta-cyclodextrin, a chiral selector, but not with alpha- or gamma-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (-)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.
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capillary electrophoresis of highly sulfated Flavanoids and flavonoids
Analytical Biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Abstract Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5–10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (±)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% β-cyclodextrin, a chiral selector, but not with α- or γ-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (−)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.
Muhammad Riaz - One of the best experts on this subject based on the ideXlab platform.
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Capillary electrophoresis of highly sulfated Flavanoids and flavonoids.
Analytical biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5-10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (+/-)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% beta-cyclodextrin, a chiral selector, but not with alpha- or gamma-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (-)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.
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capillary electrophoresis of highly sulfated Flavanoids and flavonoids
Analytical Biochemistry, 2005Co-Authors: Mandakini Dantuluri, Gunnar T. Gunnarsson, Muhammad Riaz, Huyen Nguyen, Umesh R. DesaiAbstract:Abstract Flavanoids and flavonoids are natural products present in our diet and known to possess multiple biological activities. Sulfated species of these natural products represent highly charged water-soluble organic molecules that possess unique biochemical properties. We describe here the first studies on capillary electrophoresis of these highly charged molecules. Fully sulfated Flavanoids and flavonoids can be electrophoresed and resolved under reverse polarity at pH 3.5 using 5–10 kV in less than 20 min. In contrast, at high pH under normal polarity these species can be electrophoresed only if a pressurized capillary is employed. (±)-Catechin sulfate, a racemic sulfated Flavanoid, was resolved into its enantiomers using 15% β-cyclodextrin, a chiral selector, but not with α- or γ-cyclodextrins. Yet, the high charge density of these molecules challenges the resolving capability of capillary electrophoresis as diastereomers (−)-epicatechin sulfate and (+)-catechin sulfate do not resolve, even in the presence of cyclodextrins or chiral positively charged amino acids. Overall, capillary electrophoresis of highly sulfated Flavanoids and flavonoids is expected to be useful in rapid structure analysis of sulfated flavonoids, either synthetic or natural.