Adenosine deaminase (ADA) can discriminate between two distinct (North and South), conformational... more Adenosine deaminase (ADA) can discriminate between two distinct (North and South), conformationally rigid substrate conformers. (N)-methanocarba-2′dA (4) is deaminated 100 times faster than the antipodal (S)-methanocarba-2′dA (5), whereas a non-rigid analogue, aristeromycin (6), is deaminated at an intermediate rate. These results are in agreement with crystallographic data from ADA-ribonucleoside complexes showing the furanose ring of the bound purine in a C3′-endo (North) conformation. The data presented here suggests that 4 and 5 are useful probes to ascertain conformational preferences by purine metabolizing enzymes.
... Marquez, V., Russ, P., Alonso, R., Siddiqui, M., Hernandez, S., George, C., Nicklaus, M., Dai... more ... Marquez, V., Russ, P., Alonso, R., Siddiqui, M., Hernandez, S., George, C., Nicklaus, M., Dai, F. and Ford, Jr., H. (1999), Synthesis of Conformationally Restricted Carbocyclic Nucleosides: The Role of the O(4′)-Atom in the Key Hydration Step of Adenosine ... Author Information. 1 ...
Resveratrol (3,5,4&am... more Resveratrol (3,5,4'-trihydroxy-trans-stilbene, 3,5,4'-THS) is a well-known natural antioxidant and cancer chemopreventive agent that has attracted much interest in the past decade. To find a more active antioxidant and investigate the antioxidative mechanism with resveratrol as the lead compound, we synthesized 3,5-dihydroxy-trans-stilbene (3,5-DHS), 4-hydroxy-trans-stilbene (4-HS) 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), 4-hydroxy-3-methoxy-trans-stilbene (3-MeO-4-HS),…
The prooxidant effect of hydroxycinnamic acids (HCAs), i.e., caffeic acid (CaA), chlorogenic acid... more The prooxidant effect of hydroxycinnamic acids (HCAs), i.e., caffeic acid (CaA), chlorogenic acid (ChA), sinapic acid (SA), ferulic acid (FA), 3-hydroxycinnamic acid (3-HCA) and 4-hydroxycinnamic acid (4-HCA) on supercoiled pBR322 plasmid DNA strand breakage and calf thymus DNA damage in the presence of Cu(II) ions has been studied. It was found that the compounds bearing ortho-dihydroxyl group (CaA and ChA) or bearing 4-hydroxy-3-methoxyl group (SA and FA) exhibited remarkably higher activity in the DNA damage than the ones bearing no such functionalities. The good correlation between the DNA damaging activity and the oxidative potential of the compounds indicates that the electron transfer between HCAs and Cu(II) plays a crucial role in the reaction. UV-Visible spectral changes demonstrated that CaA or ChA can chelate with Cu(II) as a bidentate ligand, hence facilitating intramolecular electron transfer between CaA or ChA and Cu(II). The involvement of reactive oxygen species (ROS) and Cu(I) ions in the DNA damage were affirmed by the inhibition of DNA breakage using mannitol, glutathione (GSH), catalase and bathocuproinedisulfonic acid (BCDS). These results may have important implications regarding the proposed mechanism of apoptosis induced by phenol and endogenous metal ions.
Curcumin is a naturally occurring phenolic compound isolated as a yellow pigment from turmeric (c... more Curcumin is a naturally occurring phenolic compound isolated as a yellow pigment from turmeric (curcuma longa). This compound has received much attention due to its diversity of biological and pharmacological activities. The purpose of this study was to assess the effect of curcumin on porcine coronary arteries and to investigate the mechanism of its action, if any. The isometric tension of coronary arterial rings taken from porcine hearts was measured and its response to curcumin (10(-11)-10(-5) mol/l) was studied. It was found that curcumin significantly reduced the isomeric tension of both quiescent and prostaglandin F2alpha (PGF2alpha) precontracted porcine coronary arterial rings. The relaxing effect of curcumin on coronary arteries was significantly reduced by removal of endothelium, and by the addition of N-nitro-L-arginine (L-NNA), methylene blue or propranolol, but not by indomethacin. These results suggest that curcumin-induced relaxation of isolated porcine coronary arteries might involve the action of nitric oxide (NO), cyclic guanosine monophosphate (cGMP) and adrenergic beta-receptor, but not involve the synthesis of prostaglandin.
... could react with TOH in a synergistic fashion in the native LDL, the overall inhibition time ... more ... could react with TOH in a synergistic fashion in the native LDL, the overall inhibition time would significantly longer than the sum of the intrinsic inhibition time of the native LDL and the inhibition time induced by the exogenous antioxidant (Liu et al., 2000 and Niki et al., 1984). ...
Resveratrol (3,5,4&am... more Resveratrol (3,5,4'-trihydroxy-trans-stilbene, 3,5,4'-THS) is a well-known natural antioxidant and cancer chemopreventive agent that has attracted much interest in the past decade. To find a more active antioxidant and investigate the antioxidative mechanism with resveratrol as the lead compound, we synthesized 3,5-dihydroxy-trans-stilbene (3,5-DHS), 4-hydroxy-trans-stilbene (4-HS) 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), 4-hydroxy-3-methoxy-trans-stilbene (3-MeO-4-HS),…
The prooxidant effect of hydroxycinnamic acids (HCAs), i.e., caffeic acid (CaA), chlorogenic acid... more The prooxidant effect of hydroxycinnamic acids (HCAs), i.e., caffeic acid (CaA), chlorogenic acid (ChA), sinapic acid (SA), ferulic acid (FA), 3-hydroxycinnamic acid (3-HCA) and 4-hydroxycinnamic acid (4-HCA) on supercoiled pBR322 plasmid DNA strand breakage and calf thymus DNA damage in the presence of Cu(II) ions has been studied. It was found that the compounds bearing ortho-dihydroxyl group (CaA and ChA) or bearing 4-hydroxy-3-methoxyl group (SA and FA) exhibited remarkably higher activity in the DNA damage than the ones bearing no such functionalities. The good correlation between the DNA damaging activity and the oxidative potential of the compounds indicates that the electron transfer between HCAs and Cu(II) plays a crucial role in the reaction. UV-Visible spectral changes demonstrated that CaA or ChA can chelate with Cu(II) as a bidentate ligand, hence facilitating intramolecular electron transfer between CaA or ChA and Cu(II). The involvement of reactive oxygen species (ROS) and Cu(I) ions in the DNA damage were affirmed by the inhibition of DNA breakage using mannitol, glutathione (GSH), catalase and bathocuproinedisulfonic acid (BCDS). These results may have important implications regarding the proposed mechanism of apoptosis induced by phenol and endogenous metal ions.
Curcumin is a naturally occurring phenolic compound isolated as a yellow pigment from turmeric (c... more Curcumin is a naturally occurring phenolic compound isolated as a yellow pigment from turmeric (curcuma longa). This compound has received much attention due to its diversity of biological and pharmacological activities. The purpose of this study was to assess the effect of curcumin on porcine coronary arteries and to investigate the mechanism of its action, if any. The isometric tension of coronary arterial rings taken from porcine hearts was measured and its response to curcumin (10(-11)-10(-5) mol/l) was studied. It was found that curcumin significantly reduced the isomeric tension of both quiescent and prostaglandin F2alpha (PGF2alpha) precontracted porcine coronary arterial rings. The relaxing effect of curcumin on coronary arteries was significantly reduced by removal of endothelium, and by the addition of N-nitro-L-arginine (L-NNA), methylene blue or propranolol, but not by indomethacin. These results suggest that curcumin-induced relaxation of isolated porcine coronary arteries might involve the action of nitric oxide (NO), cyclic guanosine monophosphate (cGMP) and adrenergic beta-receptor, but not involve the synthesis of prostaglandin.
... could react with TOH in a synergistic fashion in the native LDL, the overall inhibition time ... more ... could react with TOH in a synergistic fashion in the native LDL, the overall inhibition time would significantly longer than the sum of the intrinsic inhibition time of the native LDL and the inhibition time induced by the exogenous antioxidant (Liu et al., 2000 and Niki et al., 1984). ...
Adenosine deaminase (ADA) can discriminate between two distinct (North and South), conformational... more Adenosine deaminase (ADA) can discriminate between two distinct (North and South), conformationally rigid substrate conformers. (N)-methanocarba-2′dA (4) is deaminated 100 times faster than the antipodal (S)-methanocarba-2′dA (5), whereas a non-rigid analogue, aristeromycin (6), is deaminated at an intermediate rate. These results are in agreement with crystallographic data from ADA-ribonucleoside complexes showing the furanose ring of the bound purine in a C3′-endo (North) conformation. The data presented here suggests that 4 and 5 are useful probes to ascertain conformational preferences by purine metabolizing enzymes.
... Marquez, V., Russ, P., Alonso, R., Siddiqui, M., Hernandez, S., George, C., Nicklaus, M., Dai... more ... Marquez, V., Russ, P., Alonso, R., Siddiqui, M., Hernandez, S., George, C., Nicklaus, M., Dai, F. and Ford, Jr., H. (1999), Synthesis of Conformationally Restricted Carbocyclic Nucleosides: The Role of the O(4′)-Atom in the Key Hydration Step of Adenosine ... Author Information. 1 ...
Resveratrol (3,5,4&am... more Resveratrol (3,5,4'-trihydroxy-trans-stilbene, 3,5,4'-THS) is a well-known natural antioxidant and cancer chemopreventive agent that has attracted much interest in the past decade. To find a more active antioxidant and investigate the antioxidative mechanism with resveratrol as the lead compound, we synthesized 3,5-dihydroxy-trans-stilbene (3,5-DHS), 4-hydroxy-trans-stilbene (4-HS) 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), 4-hydroxy-3-methoxy-trans-stilbene (3-MeO-4-HS),…
The prooxidant effect of hydroxycinnamic acids (HCAs), i.e., caffeic acid (CaA), chlorogenic acid... more The prooxidant effect of hydroxycinnamic acids (HCAs), i.e., caffeic acid (CaA), chlorogenic acid (ChA), sinapic acid (SA), ferulic acid (FA), 3-hydroxycinnamic acid (3-HCA) and 4-hydroxycinnamic acid (4-HCA) on supercoiled pBR322 plasmid DNA strand breakage and calf thymus DNA damage in the presence of Cu(II) ions has been studied. It was found that the compounds bearing ortho-dihydroxyl group (CaA and ChA) or bearing 4-hydroxy-3-methoxyl group (SA and FA) exhibited remarkably higher activity in the DNA damage than the ones bearing no such functionalities. The good correlation between the DNA damaging activity and the oxidative potential of the compounds indicates that the electron transfer between HCAs and Cu(II) plays a crucial role in the reaction. UV-Visible spectral changes demonstrated that CaA or ChA can chelate with Cu(II) as a bidentate ligand, hence facilitating intramolecular electron transfer between CaA or ChA and Cu(II). The involvement of reactive oxygen species (ROS) and Cu(I) ions in the DNA damage were affirmed by the inhibition of DNA breakage using mannitol, glutathione (GSH), catalase and bathocuproinedisulfonic acid (BCDS). These results may have important implications regarding the proposed mechanism of apoptosis induced by phenol and endogenous metal ions.
Curcumin is a naturally occurring phenolic compound isolated as a yellow pigment from turmeric (c... more Curcumin is a naturally occurring phenolic compound isolated as a yellow pigment from turmeric (curcuma longa). This compound has received much attention due to its diversity of biological and pharmacological activities. The purpose of this study was to assess the effect of curcumin on porcine coronary arteries and to investigate the mechanism of its action, if any. The isometric tension of coronary arterial rings taken from porcine hearts was measured and its response to curcumin (10(-11)-10(-5) mol/l) was studied. It was found that curcumin significantly reduced the isomeric tension of both quiescent and prostaglandin F2alpha (PGF2alpha) precontracted porcine coronary arterial rings. The relaxing effect of curcumin on coronary arteries was significantly reduced by removal of endothelium, and by the addition of N-nitro-L-arginine (L-NNA), methylene blue or propranolol, but not by indomethacin. These results suggest that curcumin-induced relaxation of isolated porcine coronary arteries might involve the action of nitric oxide (NO), cyclic guanosine monophosphate (cGMP) and adrenergic beta-receptor, but not involve the synthesis of prostaglandin.
... could react with TOH in a synergistic fashion in the native LDL, the overall inhibition time ... more ... could react with TOH in a synergistic fashion in the native LDL, the overall inhibition time would significantly longer than the sum of the intrinsic inhibition time of the native LDL and the inhibition time induced by the exogenous antioxidant (Liu et al., 2000 and Niki et al., 1984). ...
Resveratrol (3,5,4&am... more Resveratrol (3,5,4'-trihydroxy-trans-stilbene, 3,5,4'-THS) is a well-known natural antioxidant and cancer chemopreventive agent that has attracted much interest in the past decade. To find a more active antioxidant and investigate the antioxidative mechanism with resveratrol as the lead compound, we synthesized 3,5-dihydroxy-trans-stilbene (3,5-DHS), 4-hydroxy-trans-stilbene (4-HS) 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), 4-hydroxy-3-methoxy-trans-stilbene (3-MeO-4-HS),…
The prooxidant effect of hydroxycinnamic acids (HCAs), i.e., caffeic acid (CaA), chlorogenic acid... more The prooxidant effect of hydroxycinnamic acids (HCAs), i.e., caffeic acid (CaA), chlorogenic acid (ChA), sinapic acid (SA), ferulic acid (FA), 3-hydroxycinnamic acid (3-HCA) and 4-hydroxycinnamic acid (4-HCA) on supercoiled pBR322 plasmid DNA strand breakage and calf thymus DNA damage in the presence of Cu(II) ions has been studied. It was found that the compounds bearing ortho-dihydroxyl group (CaA and ChA) or bearing 4-hydroxy-3-methoxyl group (SA and FA) exhibited remarkably higher activity in the DNA damage than the ones bearing no such functionalities. The good correlation between the DNA damaging activity and the oxidative potential of the compounds indicates that the electron transfer between HCAs and Cu(II) plays a crucial role in the reaction. UV-Visible spectral changes demonstrated that CaA or ChA can chelate with Cu(II) as a bidentate ligand, hence facilitating intramolecular electron transfer between CaA or ChA and Cu(II). The involvement of reactive oxygen species (ROS) and Cu(I) ions in the DNA damage were affirmed by the inhibition of DNA breakage using mannitol, glutathione (GSH), catalase and bathocuproinedisulfonic acid (BCDS). These results may have important implications regarding the proposed mechanism of apoptosis induced by phenol and endogenous metal ions.
Curcumin is a naturally occurring phenolic compound isolated as a yellow pigment from turmeric (c... more Curcumin is a naturally occurring phenolic compound isolated as a yellow pigment from turmeric (curcuma longa). This compound has received much attention due to its diversity of biological and pharmacological activities. The purpose of this study was to assess the effect of curcumin on porcine coronary arteries and to investigate the mechanism of its action, if any. The isometric tension of coronary arterial rings taken from porcine hearts was measured and its response to curcumin (10(-11)-10(-5) mol/l) was studied. It was found that curcumin significantly reduced the isomeric tension of both quiescent and prostaglandin F2alpha (PGF2alpha) precontracted porcine coronary arterial rings. The relaxing effect of curcumin on coronary arteries was significantly reduced by removal of endothelium, and by the addition of N-nitro-L-arginine (L-NNA), methylene blue or propranolol, but not by indomethacin. These results suggest that curcumin-induced relaxation of isolated porcine coronary arteries might involve the action of nitric oxide (NO), cyclic guanosine monophosphate (cGMP) and adrenergic beta-receptor, but not involve the synthesis of prostaglandin.
... could react with TOH in a synergistic fashion in the native LDL, the overall inhibition time ... more ... could react with TOH in a synergistic fashion in the native LDL, the overall inhibition time would significantly longer than the sum of the intrinsic inhibition time of the native LDL and the inhibition time induced by the exogenous antioxidant (Liu et al., 2000 and Niki et al., 1984). ...
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